chore: initial commit

.editorconfig

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+root = true
+
+# All files
+[*]
+indent_style = space
+
+# Xml files
+[*.xml]
+indent_size = 2
+
+# C# files
+[*.cs]
+
+#### Core EditorConfig Options ####
+
+# Indentation and spacing
+indent_size = 2
+tab_width = 2
+
+# New line preferences
+insert_final_newline = false
+
+#### .NET Coding Conventions ####
+[*.{cs,vb}]
+
+# diagnostics
+dotnet_diagnostic.CA1707.severity = none
+dotnet_diagnostic.IDE0100.severity = none
+
+# Organize usings
+dotnet_separate_import_directive_groups = true
+dotnet_sort_system_directives_first = true
+file_header_template = unset
+
+# this. and Me. preferences
+dotnet_style_qualification_for_event = false:silent
+dotnet_style_qualification_for_field = false:silent
+dotnet_style_qualification_for_method = false:silent
+dotnet_style_qualification_for_property = false:silent
+
+# Language keywords vs BCL types preferences
+dotnet_style_predefined_type_for_locals_parameters_members = true:silent
+dotnet_style_predefined_type_for_member_access = true:silent
+
+# Parentheses preferences
+dotnet_style_parentheses_in_arithmetic_binary_operators = always_for_clarity:silent
+dotnet_style_parentheses_in_other_binary_operators = always_for_clarity:silent
+dotnet_style_parentheses_in_other_operators = never_if_unnecessary:silent
+dotnet_style_parentheses_in_relational_binary_operators = always_for_clarity:silent
+
+# Modifier preferences
+dotnet_style_require_accessibility_modifiers = omit_if_default:silent
+
+# Expression-level preferences
+dotnet_style_coalesce_expression = true:suggestion
+dotnet_style_collection_initializer = true:suggestion
+dotnet_style_explicit_tuple_names = true:suggestion
+dotnet_style_namespace_match_folder = true:suggestion
+dotnet_style_null_propagation = true:suggestion
+dotnet_style_object_initializer = true:suggestion
+dotnet_style_operator_placement_when_wrapping = beginning_of_line
+dotnet_style_prefer_auto_properties = true:suggestion
+dotnet_style_prefer_collection_expression = when_types_loosely_match:suggestion
+dotnet_style_prefer_compound_assignment = true:suggestion
+dotnet_style_prefer_conditional_expression_over_assignment = true:suggestion
+dotnet_style_prefer_conditional_expression_over_return = false:silent
+dotnet_style_prefer_foreach_explicit_cast_in_source = when_strongly_typed:suggestion
+dotnet_style_prefer_inferred_anonymous_type_member_names = true:suggestion
+dotnet_style_prefer_inferred_tuple_names = true:suggestion
+dotnet_style_prefer_is_null_check_over_reference_equality_method = true:suggestion
+dotnet_style_prefer_simplified_boolean_expressions = true:suggestion
+dotnet_style_prefer_simplified_interpolation = true:suggestion
+
+# Field preferences
+dotnet_style_readonly_field = true:warning
+
+# Parameter preferences
+dotnet_code_quality_unused_parameters = all:suggestion
+
+# Suppression preferences
+dotnet_remove_unnecessary_suppression_exclusions = none
+
+#### C# Coding Conventions ####
+[*.cs]
+
+# var preferences
+csharp_style_var_elsewhere = true:silent
+csharp_style_var_for_built_in_types = true:silent
+csharp_style_var_when_type_is_apparent = true:silent
+
+# Expression-bodied members
+csharp_style_expression_bodied_accessors = true:silent
+csharp_style_expression_bodied_constructors = false:silent
+csharp_style_expression_bodied_indexers = true:silent
+csharp_style_expression_bodied_lambdas = true:suggestion
+csharp_style_expression_bodied_local_functions = false:silent
+csharp_style_expression_bodied_methods = false:silent
+csharp_style_expression_bodied_operators = false:silent
+csharp_style_expression_bodied_properties = true:silent
+
+# Pattern matching preferences
+csharp_style_pattern_matching_over_as_with_null_check = true:suggestion
+csharp_style_pattern_matching_over_is_with_cast_check = true:suggestion
+csharp_style_prefer_extended_property_pattern = true:suggestion
+csharp_style_prefer_not_pattern = true:suggestion
+csharp_style_prefer_pattern_matching = true:silent
+csharp_style_prefer_switch_expression = true:suggestion
+
+# Null-checking preferences
+csharp_style_conditional_delegate_call = true:suggestion
+
+# Modifier preferences
+csharp_prefer_static_anonymous_function = true:suggestion
+csharp_prefer_static_local_function = true:warning
+csharp_preferred_modifier_order = public,private,protected,internal,file,const,static,extern,new,virtual,abstract,sealed,override,readonly,unsafe,required,volatile,async:suggestion
+csharp_style_prefer_readonly_struct = true:suggestion
+csharp_style_prefer_readonly_struct_member = true:suggestion
+
+# Code-block preferences
+csharp_prefer_braces = true:silent
+csharp_prefer_simple_using_statement = true:suggestion
+csharp_style_namespace_declarations = file_scoped:suggestion
+csharp_style_prefer_method_group_conversion = true:silent
+csharp_style_prefer_primary_constructors = true:suggestion
+csharp_style_prefer_top_level_statements = true:silent
+
+# Expression-level preferences
+csharp_prefer_simple_default_expression = true:suggestion
+csharp_style_deconstructed_variable_declaration = true:suggestion
+csharp_style_implicit_object_creation_when_type_is_apparent = true:suggestion
+csharp_style_inlined_variable_declaration = true:suggestion
+csharp_style_prefer_index_operator = true:suggestion
+csharp_style_prefer_local_over_anonymous_function = true:suggestion
+csharp_style_prefer_null_check_over_type_check = true:suggestion
+csharp_style_prefer_range_operator = true:suggestion
+csharp_style_prefer_tuple_swap = true:suggestion
+csharp_style_prefer_utf8_string_literals = true:suggestion
+csharp_style_throw_expression = true:suggestion
+csharp_style_unused_value_assignment_preference = discard_variable:silent
+csharp_style_unused_value_expression_statement_preference = discard_variable:silent
+dotnet_diagnostic.IDE0058.severity = none
+
+# 'using' directive preferences
+csharp_using_directive_placement = outside_namespace:silent
+
+#### C# Formatting Rules ####
+
+# New line preferences
+csharp_new_line_before_catch = true
+csharp_new_line_before_else = true
+csharp_new_line_before_finally = true
+csharp_new_line_before_members_in_anonymous_types = true
+csharp_new_line_before_members_in_object_initializers = true
+csharp_new_line_before_open_brace = all
+csharp_new_line_between_query_expression_clauses = true
+
+# Indentation preferences
+csharp_indent_block_contents = true
+csharp_indent_braces = false
+csharp_indent_case_contents = true
+csharp_indent_case_contents_when_block = true
+csharp_indent_labels = one_less_than_current
+csharp_indent_switch_labels = true
+
+# Space preferences
+csharp_space_after_cast = false
+csharp_space_after_colon_in_inheritance_clause = true
+csharp_space_after_comma = true
+csharp_space_after_dot = false
+csharp_space_after_keywords_in_control_flow_statements = true
+csharp_space_after_semicolon_in_for_statement = true
+csharp_space_around_binary_operators = before_and_after
+csharp_space_around_declaration_statements = false
+csharp_space_before_colon_in_inheritance_clause = true
+csharp_space_before_comma = false
+csharp_space_before_dot = false
+csharp_space_before_open_square_brackets = false
+csharp_space_before_semicolon_in_for_statement = false
+csharp_space_between_empty_square_brackets = false
+csharp_space_between_method_call_empty_parameter_list_parentheses = false
+csharp_space_between_method_call_name_and_opening_parenthesis = false
+csharp_space_between_method_call_parameter_list_parentheses = false
+csharp_space_between_method_declaration_empty_parameter_list_parentheses = false
+csharp_space_between_method_declaration_name_and_open_parenthesis = false
+csharp_space_between_method_declaration_parameter_list_parentheses = false
+csharp_space_between_parentheses = false
+csharp_space_between_square_brackets = false
+
+# Wrapping preferences
+csharp_preserve_single_line_blocks = true
+csharp_preserve_single_line_statements = true
+
+#### Naming styles ####
+[*.{cs,vb}]
+
+# Naming rules
+
+dotnet_naming_rule.types_and_namespaces_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.types_and_namespaces_should_be_pascalcase.symbols = types_and_namespaces
+dotnet_naming_rule.types_and_namespaces_should_be_pascalcase.style = pascalcase
+
+dotnet_naming_rule.interfaces_should_be_ipascalcase.severity = suggestion
+dotnet_naming_rule.interfaces_should_be_ipascalcase.symbols = interfaces
+dotnet_naming_rule.interfaces_should_be_ipascalcase.style = ipascalcase
+
+dotnet_naming_rule.type_parameters_should_be_tpascalcase.severity = suggestion
+dotnet_naming_rule.type_parameters_should_be_tpascalcase.symbols = type_parameters
+dotnet_naming_rule.type_parameters_should_be_tpascalcase.style = tpascalcase
+
+dotnet_naming_rule.methods_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.methods_should_be_pascalcase.symbols = methods
+dotnet_naming_rule.methods_should_be_pascalcase.style = pascalcase
+
+dotnet_naming_rule.properties_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.properties_should_be_pascalcase.symbols = properties
+dotnet_naming_rule.properties_should_be_pascalcase.style = pascalcase
+
+dotnet_naming_rule.events_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.events_should_be_pascalcase.symbols = events
+dotnet_naming_rule.events_should_be_pascalcase.style = pascalcase
+
+dotnet_naming_rule.local_variables_should_be_camelcase.severity = suggestion
+dotnet_naming_rule.local_variables_should_be_camelcase.symbols = local_variables
+dotnet_naming_rule.local_variables_should_be_camelcase.style = camelcase
+
+dotnet_naming_rule.local_constants_should_be_camelcase.severity = suggestion
+dotnet_naming_rule.local_constants_should_be_camelcase.symbols = local_constants
+dotnet_naming_rule.local_constants_should_be_camelcase.style = camelcase
+
+dotnet_naming_rule.parameters_should_be_camelcase.severity = suggestion
+dotnet_naming_rule.parameters_should_be_camelcase.symbols = parameters
+dotnet_naming_rule.parameters_should_be_camelcase.style = camelcase
+
+dotnet_naming_rule.public_fields_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.public_fields_should_be_pascalcase.symbols = public_fields
+dotnet_naming_rule.public_fields_should_be_pascalcase.style = pascalcase
+
+dotnet_naming_rule.private_fields_should_be__camelcase.severity = suggestion
+dotnet_naming_rule.private_fields_should_be__camelcase.symbols = private_fields
+dotnet_naming_rule.private_fields_should_be__camelcase.style = _camelcase
+
+dotnet_naming_rule.private_static_fields_should_be_s_camelcase.severity = suggestion
+dotnet_naming_rule.private_static_fields_should_be_s_camelcase.symbols = private_static_fields
+dotnet_naming_rule.private_static_fields_should_be_s_camelcase.style = s_camelcase
+
+dotnet_naming_rule.public_constant_fields_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.public_constant_fields_should_be_pascalcase.symbols = public_constant_fields
+dotnet_naming_rule.public_constant_fields_should_be_pascalcase.style = pascalcase
+
+dotnet_naming_rule.private_constant_fields_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.private_constant_fields_should_be_pascalcase.symbols = private_constant_fields
+dotnet_naming_rule.private_constant_fields_should_be_pascalcase.style = pascalcase
+
+dotnet_naming_rule.public_static_readonly_fields_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.public_static_readonly_fields_should_be_pascalcase.symbols = public_static_readonly_fields
+dotnet_naming_rule.public_static_readonly_fields_should_be_pascalcase.style = pascalcase
+
+dotnet_naming_rule.private_static_readonly_fields_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.private_static_readonly_fields_should_be_pascalcase.symbols = private_static_readonly_fields
+dotnet_naming_rule.private_static_readonly_fields_should_be_pascalcase.style = pascalcase
+
+dotnet_naming_rule.enums_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.enums_should_be_pascalcase.symbols = enums
+dotnet_naming_rule.enums_should_be_pascalcase.style = pascalcase
+
+dotnet_naming_rule.local_functions_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.local_functions_should_be_pascalcase.symbols = local_functions
+dotnet_naming_rule.local_functions_should_be_pascalcase.style = pascalcase
+
+dotnet_naming_rule.non_field_members_should_be_pascalcase.severity = suggestion
+dotnet_naming_rule.non_field_members_should_be_pascalcase.symbols = non_field_members
+dotnet_naming_rule.non_field_members_should_be_pascalcase.style = pascalcase
+
+# Symbol specifications
+
+dotnet_naming_symbols.interfaces.applicable_kinds = interface
+dotnet_naming_symbols.interfaces.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.interfaces.required_modifiers = 
+
+dotnet_naming_symbols.enums.applicable_kinds = enum
+dotnet_naming_symbols.enums.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.enums.required_modifiers = 
+
+dotnet_naming_symbols.events.applicable_kinds = event
+dotnet_naming_symbols.events.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.events.required_modifiers = 
+
+dotnet_naming_symbols.methods.applicable_kinds = method
+dotnet_naming_symbols.methods.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.methods.required_modifiers = 
+
+dotnet_naming_symbols.properties.applicable_kinds = property
+dotnet_naming_symbols.properties.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.properties.required_modifiers = 
+
+dotnet_naming_symbols.public_fields.applicable_kinds = field
+dotnet_naming_symbols.public_fields.applicable_accessibilities = public, internal
+dotnet_naming_symbols.public_fields.required_modifiers = 
+
+dotnet_naming_symbols.private_fields.applicable_kinds = field
+dotnet_naming_symbols.private_fields.applicable_accessibilities = private, protected, protected_internal, private_protected
+dotnet_naming_symbols.private_fields.required_modifiers = 
+
+dotnet_naming_symbols.private_static_fields.applicable_kinds = field
+dotnet_naming_symbols.private_static_fields.applicable_accessibilities = private, protected, protected_internal, private_protected
+dotnet_naming_symbols.private_static_fields.required_modifiers = static
+
+dotnet_naming_symbols.types_and_namespaces.applicable_kinds = namespace, class, struct, interface, enum
+dotnet_naming_symbols.types_and_namespaces.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.types_and_namespaces.required_modifiers = 
+
+dotnet_naming_symbols.non_field_members.applicable_kinds = property, event, method
+dotnet_naming_symbols.non_field_members.applicable_accessibilities = public, internal, private, protected, protected_internal, private_protected
+dotnet_naming_symbols.non_field_members.required_modifiers = 
+
+dotnet_naming_symbols.type_parameters.applicable_kinds = namespace
+dotnet_naming_symbols.type_parameters.applicable_accessibilities = *
+dotnet_naming_symbols.type_parameters.required_modifiers = 
+
+dotnet_naming_symbols.private_constant_fields.applicable_kinds = field
+dotnet_naming_symbols.private_constant_fields.applicable_accessibilities = private, protected, protected_internal, private_protected
+dotnet_naming_symbols.private_constant_fields.required_modifiers = const
+
+dotnet_naming_symbols.local_variables.applicable_kinds = local
+dotnet_naming_symbols.local_variables.applicable_accessibilities = local
+dotnet_naming_symbols.local_variables.required_modifiers = 
+
+dotnet_naming_symbols.local_constants.applicable_kinds = local
+dotnet_naming_symbols.local_constants.applicable_accessibilities = local
+dotnet_naming_symbols.local_constants.required_modifiers = const
+
+dotnet_naming_symbols.parameters.applicable_kinds = parameter
+dotnet_naming_symbols.parameters.applicable_accessibilities = *
+dotnet_naming_symbols.parameters.required_modifiers = 
+
+dotnet_naming_symbols.public_constant_fields.applicable_kinds = field
+dotnet_naming_symbols.public_constant_fields.applicable_accessibilities = public, internal
+dotnet_naming_symbols.public_constant_fields.required_modifiers = const
+
+dotnet_naming_symbols.public_static_readonly_fields.applicable_kinds = field
+dotnet_naming_symbols.public_static_readonly_fields.applicable_accessibilities = public, internal
+dotnet_naming_symbols.public_static_readonly_fields.required_modifiers = readonly, static
+
+dotnet_naming_symbols.private_static_readonly_fields.applicable_kinds = field
+dotnet_naming_symbols.private_static_readonly_fields.applicable_accessibilities = private, protected, protected_internal, private_protected
+dotnet_naming_symbols.private_static_readonly_fields.required_modifiers = readonly, static
+
+dotnet_naming_symbols.local_functions.applicable_kinds = local_function
+dotnet_naming_symbols.local_functions.applicable_accessibilities = *
+dotnet_naming_symbols.local_functions.required_modifiers = 
+
+# Naming styles
+
+dotnet_naming_style.pascalcase.required_prefix = 
+dotnet_naming_style.pascalcase.required_suffix = 
+dotnet_naming_style.pascalcase.word_separator = 
+dotnet_naming_style.pascalcase.capitalization = pascal_case
+
+dotnet_naming_style.ipascalcase.required_prefix = I
+dotnet_naming_style.ipascalcase.required_suffix = 
+dotnet_naming_style.ipascalcase.word_separator = 
+dotnet_naming_style.ipascalcase.capitalization = pascal_case
+
+dotnet_naming_style.tpascalcase.required_prefix = T
+dotnet_naming_style.tpascalcase.required_suffix = 
+dotnet_naming_style.tpascalcase.word_separator = 
+dotnet_naming_style.tpascalcase.capitalization = pascal_case
+
+dotnet_naming_style._camelcase.required_prefix = _
+dotnet_naming_style._camelcase.required_suffix = 
+dotnet_naming_style._camelcase.word_separator = 
+dotnet_naming_style._camelcase.capitalization = camel_case
+
+dotnet_naming_style.camelcase.required_prefix = 
+dotnet_naming_style.camelcase.required_suffix = 
+dotnet_naming_style.camelcase.word_separator = 
+dotnet_naming_style.camelcase.capitalization = camel_case
+
+dotnet_naming_style.s_camelcase.required_prefix = s_
+dotnet_naming_style.s_camelcase.required_suffix = 
+dotnet_naming_style.s_camelcase.word_separator = 
+dotnet_naming_style.s_camelcase.capitalization = camel_case
+

.gitignore

@@ -0,0 +1,488 @@
+## Ignore Visual Studio temporary files, build results, and
+## files generated by popular Visual Studio add-ons.
+##
+## Get latest from `dotnet new gitignore`
+
+# appsettings
+appsettings*.json
+!appsettings.Example.json
+
+# dotenv files
+.env
+
+# User-specific files
+*.rsuser
+*.suo
+*.user
+*.userosscache
+*.sln.docstates
+
+# User-specific files (MonoDevelop/Xamarin Studio)
+*.userprefs
+
+# Mono auto generated files
+mono_crash.*
+
+# Build results
+[Dd]ebug/
+[Dd]ebugPublic/
+[Rr]elease/
+[Rr]eleases/
+x64/
+x86/
+[Ww][Ii][Nn]32/
+[Aa][Rr][Mm]/
+[Aa][Rr][Mm]64/
+bld/
+[Bb]in/
+[Oo]bj/
+[Ll]og/
+[Ll]ogs/
+
+# Visual Studio 2015/2017 cache/options directory
+.vs/
+# Uncomment if you have tasks that create the project's static files in wwwroot
+#wwwroot/
+
+# Visual Studio 2017 auto generated files
+Generated\ Files/
+
+# MSTest test Results
+[Tt]est[Rr]esult*/
+[Bb]uild[Ll]og.*
+
+# NUnit
+*.VisualState.xml
+TestResult.xml
+nunit-*.xml
+
+# Build Results of an ATL Project
+[Dd]ebugPS/
+[Rr]eleasePS/
+dlldata.c
+
+# Benchmark Results
+BenchmarkDotNet.Artifacts/
+
+# .NET
+project.lock.json
+project.fragment.lock.json
+artifacts/
+
+# Tye
+.tye/
+
+# ASP.NET Scaffolding
+ScaffoldingReadMe.txt
+
+# StyleCop
+StyleCopReport.xml
+
+# Files built by Visual Studio
+*_i.c
+*_p.c
+*_h.h
+*.ilk
+*.meta
+*.obj
+*.iobj
+*.pch
+*.pdb
+*.ipdb
+*.pgc
+*.pgd
+*.rsp
+*.sbr
+*.tlb
+*.tli
+*.tlh
+*.tmp
+*.tmp_proj
+*_wpftmp.csproj
+*.log
+*.tlog
+*.vspscc
+*.vssscc
+.builds
+*.pidb
+*.svclog
+*.scc
+
+# Chutzpah Test files
+_Chutzpah*
+
+# Visual C++ cache files
+ipch/
+*.aps
+*.ncb
+*.opendb
+*.opensdf
+*.sdf
+*.cachefile
+*.VC.db
+*.VC.VC.opendb
+
+# Visual Studio profiler
+*.psess
+*.vsp
+*.vspx
+*.sap
+
+# Visual Studio Trace Files
+*.e2e
+
+# TFS 2012 Local Workspace
+$tf/
+
+# Guidance Automation Toolkit
+*.gpState
+
+# ReSharper is a .NET coding add-in
+_ReSharper*/
+*.[Rr]e[Ss]harper
+*.DotSettings.user
+
+# TeamCity is a build add-in
+_TeamCity*
+
+# DotCover is a Code Coverage Tool
+*.dotCover
+
+# AxoCover is a Code Coverage Tool
+.axoCover/*
+!.axoCover/settings.json
+
+# Coverlet is a free, cross platform Code Coverage Tool
+coverage*.json
+coverage*.xml
+coverage*.info
+
+# Visual Studio code coverage results
+*.coverage
+*.coveragexml
+
+# NCrunch
+_NCrunch_*
+.*crunch*.local.xml
+nCrunchTemp_*
+
+# MightyMoose
+*.mm.*
+AutoTest.Net/
+
+# Web workbench (sass)
+.sass-cache/
+
+# Installshield output folder
+[Ee]xpress/
+
+# DocProject is a documentation generator add-in
+DocProject/buildhelp/
+DocProject/Help/*.HxT
+DocProject/Help/*.HxC
+DocProject/Help/*.hhc
+DocProject/Help/*.hhk
+DocProject/Help/*.hhp
+DocProject/Help/Html2
+DocProject/Help/html
+
+# Click-Once directory
+publish/
+
+# Publish Web Output
+*.[Pp]ublish.xml
+*.azurePubxml
+# Note: Comment the next line if you want to checkin your web deploy settings,
+# but database connection strings (with potential passwords) will be unencrypted
+*.pubxml
+*.publishproj
+
+# Microsoft Azure Web App publish settings. Comment the next line if you want to
+# checkin your Azure Web App publish settings, but sensitive information contained
+# in these scripts will be unencrypted
+PublishScripts/
+
+# NuGet Packages
+*.nupkg
+# NuGet Symbol Packages
+*.snupkg
+# The packages folder can be ignored because of Package Restore
+**/[Pp]ackages/*
+# except build/, which is used as an MSBuild target.
+!**/[Pp]ackages/build/
+# Uncomment if necessary however generally it will be regenerated when needed
+#!**/[Pp]ackages/repositories.config
+# NuGet v3's project.json files produces more ignorable files
+*.nuget.props
+*.nuget.targets
+
+# Microsoft Azure Build Output
+csx/
+*.build.csdef
+
+# Microsoft Azure Emulator
+ecf/
+rcf/
+
+# Windows Store app package directories and files
+AppPackages/
+BundleArtifacts/
+Package.StoreAssociation.xml
+_pkginfo.txt
+*.appx
+*.appxbundle
+*.appxupload
+
+# Visual Studio cache files
+# files ending in .cache can be ignored
+*.[Cc]ache
+# but keep track of directories ending in .cache
+!?*.[Cc]ache/
+
+# Others
+ClientBin/
+~$*
+*~
+*.dbmdl
+*.dbproj.schemaview
+*.jfm
+*.pfx
+*.publishsettings
+orleans.codegen.cs
+
+# Including strong name files can present a security risk
+# (https://github.com/github/gitignore/pull/2483#issue-259490424)
+#*.snk
+
+# Since there are multiple workflows, uncomment next line to ignore bower_components
+# (https://github.com/github/gitignore/pull/1529#issuecomment-104372622)
+#bower_components/
+
+# RIA/Silverlight projects
+Generated_Code/
+
+# Backup & report files from converting an old project file
+# to a newer Visual Studio version. Backup files are not needed,
+# because we have git ;-)
+_UpgradeReport_Files/
+Backup*/
+UpgradeLog*.XML
+UpgradeLog*.htm
+ServiceFabricBackup/
+*.rptproj.bak
+
+# SQL Server files
+*.mdf
+*.ldf
+*.ndf
+
+# Business Intelligence projects
+*.rdl.data
+*.bim.layout
+*.bim_*.settings
+*.rptproj.rsuser
+*- [Bb]ackup.rdl
+*- [Bb]ackup ([0-9]).rdl
+*- [Bb]ackup ([0-9][0-9]).rdl
+
+# Microsoft Fakes
+FakesAssemblies/
+
+# GhostDoc plugin setting file
+*.GhostDoc.xml
+
+# Node.js Tools for Visual Studio
+.ntvs_analysis.dat
+node_modules/
+
+# Visual Studio 6 build log
+*.plg
+
+# Visual Studio 6 workspace options file
+*.opt
+
+# Visual Studio 6 auto-generated workspace file (contains which files were open etc.)
+*.vbw
+
+# Visual Studio 6 auto-generated project file (contains which files were open etc.)
+*.vbp
+
+# Visual Studio 6 workspace and project file (working project files containing files to include in project)
+*.dsw
+*.dsp
+
+# Visual Studio 6 technical files
+*.ncb
+*.aps
+
+# Visual Studio LightSwitch build output
+**/*.HTMLClient/GeneratedArtifacts
+**/*.DesktopClient/GeneratedArtifacts
+**/*.DesktopClient/ModelManifest.xml
+**/*.Server/GeneratedArtifacts
+**/*.Server/ModelManifest.xml
+_Pvt_Extensions
+
+# Paket dependency manager
+.paket/paket.exe
+paket-files/
+
+# FAKE - F# Make
+.fake/
+
+# CodeRush personal settings
+.cr/personal
+
+# Python Tools for Visual Studio (PTVS)
+__pycache__/
+*.pyc
+
+# Cake - Uncomment if you are using it
+# tools/**
+# !tools/packages.config
+
+# Tabs Studio
+*.tss
+
+# Telerik's JustMock configuration file
+*.jmconfig
+
+# BizTalk build output
+*.btp.cs
+*.btm.cs
+*.odx.cs
+*.xsd.cs
+
+# OpenCover UI analysis results
+OpenCover/
+
+# Azure Stream Analytics local run output
+ASALocalRun/
+
+# MSBuild Binary and Structured Log
+*.binlog
+
+# NVidia Nsight GPU debugger configuration file
+*.nvuser
+
+# MFractors (Xamarin productivity tool) working folder
+.mfractor/
+
+# Local History for Visual Studio
+.localhistory/
+
+# Visual Studio History (VSHistory) files
+.vshistory/
+
+# BeatPulse healthcheck temp database
+healthchecksdb
+
+# Backup folder for Package Reference Convert tool in Visual Studio 2017
+MigrationBackup/
+
+# Ionide (cross platform F# VS Code tools) working folder
+.ionide/
+
+# Fody - auto-generated XML schema
+FodyWeavers.xsd
+
+# VS Code files for those working on multiple tools
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+*.code-workspace
+
+# Local History for Visual Studio Code
+.history/
+
+# Windows Installer files from build outputs
+*.cab
+*.msi
+*.msix
+*.msm
+*.msp
+
+# JetBrains Rider
+*.sln.iml
+.idea/
+
+##
+## Visual studio for Mac
+##
+
+
+# globs
+Makefile.in
+*.userprefs
+*.usertasks
+config.make
+config.status
+aclocal.m4
+install-sh
+autom4te.cache/
+*.tar.gz
+tarballs/
+test-results/
+
+# Mac bundle stuff
+*.dmg
+*.app
+
+# content below from: https://github.com/github/gitignore/blob/main/Global/macOS.gitignore
+# General
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Icon must end with two \r
+Icon
+
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+# content below from: https://github.com/github/gitignore/blob/main/Global/Windows.gitignore
+# Windows thumbnail cache files
+Thumbs.db
+ehthumbs.db
+ehthumbs_vista.db
+
+# Dump file
+*.stackdump
+
+# Folder config file
+[Dd]esktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msix
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+
+# Vim temporary swap files
+*.swp

README.md

@@ -0,0 +1,6 @@
+# AltGen
+
+⚠️  **This project is still in development.** ⚠️
+
+An LLM-powered alternative text generation tool for images.
+

src/AltGen.API.Tests/AltGen.API.Tests.csproj

@@ -0,0 +1,40 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <IsPackable>false</IsPackable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="coverlet.collector" Version="6.0.2" />
+    <PackageReference Include="FluentAssertions" Version="7.1.0" />
+    <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="9.0.1" />
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
+    <PackageReference Include="RichardSzalay.MockHttp" Version="7.0.0" />
+    <PackageReference Include="xunit" Version="2.9.2" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="2.8.2" />
+  </ItemGroup>
+
+  <!--TODO: Add test coverage-->
+
+  <ItemGroup>
+    <Using Include="Xunit" />
+    <Using Include="FluentAssertions" />
+  </ItemGroup>
+  
+  <ItemGroup>
+    <ProjectReference Include="..\AltGen.API\AltGen.API.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <Content Include="Files\**\*">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </Content>
+    <Content Include="appsettings.Test.json">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
+
+</Project>

src/AltGen.API.Tests/EndToEnd/EndToEndTest.cs

@@ -0,0 +1,7 @@
+namespace AltGen.API.Tests.EndToEnd;
+
+public class EndToEndTest(AppFactory factory, TestConfiguration config) : IClassFixture<AppFactory>, IClassFixture<TestConfiguration>
+{
+  protected HttpClient Client { get; } = factory.CreateClient();
+  protected TestConfiguration Config { get; } = config;
+}

src/AltGen.API.Tests/EndToEnd/GenerateEndpointTests.cs

@@ -0,0 +1,31 @@
+
+
+namespace AltGen.API.Tests.EndToEnd;
+
+public class GenerateEndpointTests(
+  AppFactory factory,
+  TestConfiguration config
+) : EndToEndTest(factory, config)
+{
+  [Fact]
+  public async Task GenerateEndpoint_WhenCalled_ItShouldReturnOk()
+  {
+    var fileName = "library.jpg";
+    var file = await TestFileManager.GetFileAsync(fileName);
+    var byteContent = new ByteArrayContent(file);
+    byteContent.Headers.ContentType = new MediaTypeHeaderValue("image/jpg");
+
+    var content = new MultipartFormDataContent()
+    {
+      { new StringContent("Gemini"), "Provider" },
+      { new StringContent(Config.GeminiApiKey), "ProviderKey" },
+      { byteContent, "File", fileName }
+    };
+
+    var response = await Client.PostAsync("/generate", content);
+    var altText = await response.Content.ReadFromJsonAsync<GenerateResponse>();
+
+    response.Should().HaveStatusCode(HttpStatusCode.OK);
+    altText!.AltText.Should().NotBeNullOrWhiteSpace();
+  }
+}

src/AltGen.API.Tests/EndToEnd/PromptEvaluation.cs

@@ -0,0 +1,49 @@
+namespace AltGen.API.Tests.EndToEnd;
+
+public class PromptEvaluations(
+  AppFactory factory,
+  TestConfiguration config
+) : EndToEndTest(factory, config)
+{
+  // TODO: Use LLM-assisted prompt evaluation instead of
+  // doing partial string matching. Better suited due to
+  // subjective nature of the task.
+  [Theory]
+  [ClassData(typeof(TestData))]
+  public async Task Generate_WhenCalled_ItShouldRespondWithAltTextContainingKeyWords(string imageName, string[] keyWords)
+  {
+    var file = await TestFileManager.GetFileAsync(imageName);
+    var byteContent = new ByteArrayContent(file);
+    byteContent.Headers.ContentType = new MediaTypeHeaderValue("image/jpg");
+
+    var content = new MultipartFormDataContent()
+    {
+      { new StringContent("Gemini"), "Provider" },
+      { new StringContent(Config.GeminiApiKey), "ProviderKey" },
+      { byteContent, "File", imageName }
+    };
+
+    var response = await Client.PostAsync("/generate", content);
+    var altText = await response.Content.ReadFromJsonAsync<GenerateResponse>();
+
+    response.Should().HaveStatusCode(HttpStatusCode.OK);
+    altText!.AltText.ToLowerInvariant().Should().ContainAll(keyWords);
+  }
+
+  class TestData : IEnumerable<object[]>
+  {
+    public IEnumerator<object[]> GetEnumerator()
+    {
+      yield return new object[] { "library.jpg", new[] { "book", } };
+      yield return new object[] { "ascii_art.jpg", new[] { "test", "100", "success", } };
+      yield return new object[] { "living_room.jpg", new[] { "blue", "dog", } };
+      yield return new object[] { "podcast.jpg", new[] { "podcast", "scott", "mark", } };
+      yield return new object[] { "youtube_comment.jpg", new[] { "feedback", } };
+    }
+
+    IEnumerator IEnumerable.GetEnumerator()
+    {
+      return GetEnumerator();
+    }
+  }
+}

src/AltGen.API.Tests/Fixtures/AppFactory.cs

@@ -0,0 +1,11 @@
+using Microsoft.Extensions.Logging;
+
+namespace AltGen.API.Tests.Fixtures;
+
+public class AppFactory : WebApplicationFactory<Program>
+{
+  protected override void ConfigureWebHost(IWebHostBuilder builder)
+  {
+    builder.ConfigureLogging(static l => l.ClearProviders());
+  }
+}

src/AltGen.API.Tests/Fixtures/TestConfiguration.cs

@@ -0,0 +1,27 @@
+using Microsoft.Extensions.Configuration;
+
+namespace AltGen.API.Tests.Fixtures;
+
+public class TestConfiguration
+{
+  static IConfiguration Config { get; } = new ConfigurationBuilder()
+    .AddJsonFile("appsettings.Test.json")
+    .AddEnvironmentVariables()
+    .Build();
+
+#pragma warning disable CA1822
+  public string GeminiApiKey => GetGeminiApiKey();
+#pragma warning restore CA1822
+
+  static string GetGeminiApiKey()
+  {
+    var apiKey = Config.GetSection("Gemini").GetValue<string>("ApiKey");
+
+    if (string.IsNullOrWhiteSpace(apiKey))
+    {
+      throw new InvalidOperationException("Gemini__ApiKey is required");
+    }
+
+    return apiKey;
+  }
+}

src/AltGen.API.Tests/Integration/GenerateEndpointTests.cs

@@ -0,0 +1,211 @@
+namespace AltGen.API.Tests.Integration;
+
+public class GenerateEndpointTests : IntegrationTest
+{
+  const string TestImageName = "library.jpg";
+
+  public GenerateEndpointTests(AppFactory factory) : base(factory)
+  {
+    MockGeminiServiceHandler.Clear();
+  }
+
+  [Theory]
+  [ClassData(typeof(InvalidRequestTestData))]
+  public async Task GenerateEndpoint_WhenCalledWithoutInvalidParameters_ItShouldReturnAProblemDetailWithStatusCode400(MultipartFormDataContent content, Dictionary<string, string[]> errors)
+  {
+    var response = await Client.PostAsync("/generate", content);
+    var problem = await response.Content.ReadFromJsonAsync<ValidationProblemDetails>();
+
+    response.Should().HaveStatusCode(HttpStatusCode.BadRequest);
+    problem!.Errors.Should().BeEquivalentTo(errors);
+  }
+
+  [Theory]
+  [ClassData(typeof(ValidRequestTestData))]
+  public async Task GenerateEndpoint_WhenCalledWithRequiredParameters_ItShouldReturnOkWithAltText(MultipartFormDataContent content)
+  {
+    MockGeminiServiceHandler
+      .When(HttpMethod.Post, "https://generativelanguage.googleapis.com/v1beta/models/gemini-1.5-flash:generateContent/?key=ProviderKey")
+      .Respond(
+        "application/json",
+        /*lang=json,strict*/
+        @"{
+            ""candidates"": [
+              {
+                ""content"": {
+                  ""parts"": [
+                    { ""text"": ""A long, perspective view of a classic library interior showcases richly colored wooden bookshelves filled with antique books, creating an atmosphere of history and scholarship.\n""
+                    }
+                  ],
+                  ""role"": ""model""
+                },
+                ""finishReason"": ""STOP"",
+                ""avgLogprobs"": -0.3317602475484212
+              }
+            ],
+            ""usageMetadata"": {
+              ""promptTokenCount"": 405,
+              ""candidatesTokenCount"": 30,
+              ""totalTokenCount"": 435,
+              ""promptTokensDetails"": [
+                  {
+                    ""modality"": ""TEXT"",
+                    ""tokenCount"": 147
+                  },
+                  {
+                    ""modality"": ""IMAGE"",
+                    ""tokenCount"": 258
+                  }
+                ],
+              ""candidatesTokensDetails"": [
+                {
+                  ""modality"": ""TEXT"",
+                  ""tokenCount"": 30
+                }
+              ]
+            },
+            ""modelVersion"": ""gemini-1.5-flash""
+          }"
+      );
+
+    var response = await Client.PostAsync("/generate", content);
+    var altText = await response.Content.ReadFromJsonAsync<GenerateResponse>();
+
+    response.Should().HaveStatusCode(HttpStatusCode.OK);
+    altText!.AltText.Should().NotBeNullOrWhiteSpace();
+  }
+
+  class ValidRequestTestData : IEnumerable<object[]>
+  {
+    public IEnumerator<object[]> GetEnumerator()
+    {
+      var testImage = TestFileManager.GetFile(TestImageName);
+      var byteContent = new ByteArrayContent(testImage);
+      byteContent.Headers.ContentType = new MediaTypeHeaderValue("image/jpg");
+
+      yield return new object[]
+      {
+        new MultipartFormDataContent()
+        {
+          { new StringContent("Gemini"), "Provider" },
+          { new StringContent("ProviderKey"), "ProviderKey" },
+          { byteContent, "File", TestImageName }
+        }
+      };
+
+      yield return new object[]
+      {
+        new MultipartFormDataContent()
+        {
+          { new StringContent("Gemini"), "Provider" },
+          { new StringContent("ProviderKey"), "ProviderKey" },
+          { byteContent, "File", TestImageName }
+        }
+      };
+    }
+
+    IEnumerator IEnumerable.GetEnumerator()
+    {
+      return GetEnumerator();
+    }
+  }
+
+  class InvalidRequestTestData : IEnumerable<object[]>
+  {
+    public IEnumerator<object[]> GetEnumerator()
+    {
+      yield return new object[]
+      {
+        new MultipartFormDataContent()
+        {
+          { new StringContent(string.Empty), "Provider" },
+          { new StringContent(string.Empty), "ProviderKey" },
+          { new ByteArrayContent([]), "File", "file.jpeg" }
+        },
+        new Dictionary<string, string[]>
+        {
+          { "Provider", ["The Provider field is required."] },
+          { "ProviderKey", ["The ProviderKey field is required."] },
+          { "File", ["The File has no content."] }
+        },
+      };
+
+      yield return new object[]
+      {
+        new MultipartFormDataContent()
+        {
+          { new StringContent("Gemini"), "Provider" },
+          { new StringContent(string.Empty), "ProviderKey" },
+          { new ByteArrayContent([]), "File", "file.jpeg" }
+        },
+        new Dictionary<string, string[]>
+        {
+          { "ProviderKey", ["The ProviderKey field is required."] },
+          { "File", ["The File has no content."] }
+        },
+      };
+
+      yield return new object[]
+      {
+        new MultipartFormDataContent()
+        {
+          { new StringContent(string.Empty), "Provider" },
+          { new StringContent("ProviderKey"), "ProviderKey" },
+          { new ByteArrayContent([]), "File", "file.jpeg" }
+        },
+        new Dictionary<string, string[]>
+        {
+          { "Provider", ["The Provider field is required."] },
+          { "File", ["The File has no content."] }
+        },
+      };
+
+      yield return new object[]
+      {
+        new MultipartFormDataContent()
+        {
+          { new StringContent("Gemini"), "Provider" },
+          { new StringContent("ProviderKey"), "ProviderKey" },
+          { new ByteArrayContent([]), "File", "file.jpeg" }
+        },
+        new Dictionary<string, string[]>
+        {
+          { "File", ["The File has no content."] }
+        },
+      };
+
+      yield return new object[]
+      {
+        new MultipartFormDataContent()
+        {
+          { new StringContent("MadeUp"), "Provider" },
+          { new StringContent("ProviderKey"), "ProviderKey" },
+          { new ByteArrayContent(Encoding.UTF8.GetBytes("Hello, World!")), "File", "file.jpeg" }
+        },
+        new Dictionary<string, string[]>()
+        {
+          { "Provider", ["The Provider field is invalid."] }
+        },
+      };
+
+      yield return new object[]
+      {
+        new MultipartFormDataContent()
+        {
+          { new StringContent("Gemini"), "Provider" },
+          { new StringContent("ProviderKey"), "ProviderKey" },
+          { new ByteArrayContent(Encoding.UTF8.GetBytes("Hello, World!")), "File", "file.txt" }
+        },
+        new Dictionary<string, string[]>()
+        {
+          { "File", ["The File must be a valid image file."] }
+        },
+      };
+    }
+
+    IEnumerator IEnumerable.GetEnumerator()
+    {
+      return GetEnumerator();
+    }
+  }
+}

src/AltGen.API.Tests/Integration/IntegrationTest.cs

@@ -0,0 +1,20 @@
+namespace AltGen.API.Tests.Integration;
+
+public class IntegrationTest : IClassFixture<AppFactory>
+{
+  protected MockHttpMessageHandler MockGeminiServiceHandler { get; } = new();
+  protected WebApplicationFactory<Program> Factory { get; }
+  protected HttpClient Client { get; }
+
+  public IntegrationTest(AppFactory factory)
+  {
+    Factory = factory.WithWebHostBuilder(
+      builder => builder.ConfigureTestServices(
+        services => services.AddHttpClient<IGeminiService, GeminiService>()
+          .ConfigurePrimaryHttpMessageHandler(() => MockGeminiServiceHandler)
+      )
+    );
+
+    Client = Factory.CreateClient();
+  }
+}

src/AltGen.API.Tests/Usings.cs

@@ -0,0 +1,18 @@
+global using System.Collections;
+global using System.Net;
+global using System.Net.Http.Headers;
+global using System.Net.Http.Json;
+global using System.Text;
+
+global using AltGen.API.Generate;
+global using AltGen.API.Generate.Providers.Gemini;
+global using AltGen.API.Tests.Fixtures;
+global using AltGen.API.Tests.Utils;
+
+global using Microsoft.AspNetCore.Hosting;
+global using Microsoft.AspNetCore.Mvc;
+global using Microsoft.AspNetCore.Mvc.Testing;
+global using Microsoft.AspNetCore.TestHost;
+global using Microsoft.Extensions.DependencyInjection;
+
+global using RichardSzalay.MockHttp;

src/AltGen.API.Tests/Utils/TestFileManager.cs

@@ -0,0 +1,18 @@
+namespace AltGen.API.Tests.Utils;
+
+public static class TestFileManager
+{
+  public static byte[] GetFile(string testFileName)
+  {
+    var filePath = Path.Combine(AppContext.BaseDirectory, "Files", testFileName);
+    var file = File.ReadAllBytes(filePath);
+    return file;
+  }
+
+  public static Task<byte[]> GetFileAsync(string testFileName)
+  {
+    var filePath = Path.Combine(AppContext.BaseDirectory, "Files", testFileName);
+    var file = File.ReadAllBytesAsync(filePath);
+    return file;
+  }
+}

src/AltGen.API.Tests/appsettings.Example.json

@@ -0,0 +1,5 @@
+{
+  "Gemini": {
+    "ApiKey": "ApiKey"
+  }
+}

src/AltGen.API/AltGen.API.csproj

@@ -0,0 +1,20 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net9.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="9.0.1" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <InternalsVisibleTo Include="$(AssemblyName).Tests" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <EmbeddedResource Include="Resources\**\*" />
+  </ItemGroup>
+</Project>

src/AltGen.API/AltGen.API.http

@@ -0,0 +1,6 @@
+@AltGen.API_HostAddress = http://localhost:5005
+
+GET {{AltGen.API_HostAddress}}/weatherforecast/
+Accept: application/json
+
+###

src/AltGen.API/Common/AltGenException.cs

@@ -0,0 +1,5 @@
+namespace AltGen.API.Common;
+
+class AltGenException(string message) : Exception(message)
+{
+}

src/AltGen.API/Common/ValidationResultsExtensions.cs

@@ -0,0 +1,14 @@
+namespace AltGen.API.Common;
+
+static class ValidationResultsExtensions
+{
+  public static Dictionary<string, string[]> ToErrors(this IEnumerable<ValidationResult> results)
+  {
+    // group by the first member name and select the error message
+    return results.GroupBy(static r => r.MemberNames.First())
+      .ToDictionary(
+        static r => r.Key,
+        static r => r.Select(static e => e.ErrorMessage!).ToArray()
+      );
+  }
+}

src/AltGen.API/Generate/GenerateEndpoint.cs

@@ -0,0 +1,27 @@
+namespace AltGen.API.Generate;
+
+static class GenerateEndpoint
+{
+  public static async Task<IResult> HandleAsync([AsParameters] GenerateRequest request, [FromServices] IAltTextProviderFactory factory)
+  {
+    var validationResults = request.Validate(new ValidationContext(request));
+
+    if (validationResults.Any())
+    {
+      return Results.ValidationProblem(validationResults.ToErrors());
+    }
+
+    var provider = factory.Create(request.Provider);
+
+    var imageStream = new MemoryStream();
+    await request.File.CopyToAsync(imageStream);
+
+    var altText = await provider.GenerateAltTextAsync(
+      request.ProviderKey,
+      request.File.ContentType,
+      imageStream
+    );
+
+    return Results.Ok(new GenerateResponse(altText));
+  }
+}

src/AltGen.API/Generate/GenerateRequest.cs

@@ -0,0 +1,47 @@
+namespace AltGen.API.Generate;
+
+record GenerateRequest(
+  [FromForm]
+  string Provider,
+  [FromForm]
+  string ProviderKey,
+  IFormFile File
+) : IValidatableObject
+{
+  public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
+  {
+    if (string.IsNullOrWhiteSpace(Provider))
+    {
+      yield return new ValidationResult($"The {nameof(Provider)} field is required.", [nameof(Provider)]);
+    }
+
+    if (string.IsNullOrWhiteSpace(Provider) is false && LLMProvider.IsValid(Provider) is false)
+    {
+      yield return new ValidationResult($"The {nameof(Provider)} field is invalid.", [nameof(Provider)]);
+    }
+
+    if (string.IsNullOrWhiteSpace(ProviderKey))
+    {
+      yield return new ValidationResult($"The {nameof(ProviderKey)} field is required.", [nameof(ProviderKey)]);
+    }
+
+    // TODO: Probably need to consider upper bound for file size
+    // this also needs to take into account provider-specific limits
+    if (File.Length is 0)
+    {
+      yield return new ValidationResult($"The {nameof(File)} has no content.", [nameof(File)]);
+    }
+
+    if (File.Length > 0)
+    {
+      var extension = Path.GetExtension(File.FileName);
+
+      // TODO: prob needs to be specific to the provider
+      // different LLMs support different image formats
+      if (extension is not ".jpeg" and not ".jpg" and not ".png")
+      {
+        yield return new ValidationResult($"The {nameof(File)} must be a valid image file.", [nameof(File)]);
+      }
+    }
+  }
+}

src/AltGen.API/Generate/GenerateResponse.cs

@@ -0,0 +1,3 @@
+namespace AltGen.API.Generate;
+
+record GenerateResponse(string AltText);

src/AltGen.API/Generate/Providers/AltTextProviderFactory.cs

@@ -0,0 +1,15 @@
+namespace AltGen.API.Generate.Providers;
+
+class AltTextProviderFactory(IServiceProvider serviceProvider) : IAltTextProviderFactory
+{
+  readonly IServiceProvider _serviceProvider = serviceProvider;
+
+  public IAltTextProvider Create(string provider)
+  {
+    return provider switch
+    {
+      LLMProvider.Gemini => _serviceProvider.GetRequiredKeyedService<IAltTextProvider>(LLMProvider.Gemini),
+      _ => throw new NotSupportedException($"The provider '{provider}' is not supported.")
+    };
+  }
+}

src/AltGen.API/Generate/Providers/Gemini/Candidate.cs

@@ -0,0 +1,3 @@
+namespace AltGen.API.Generate.Providers.Gemini;
+
+record Candidate(Content Content);

src/AltGen.API/Generate/Providers/Gemini/Content.cs

@@ -0,0 +1,3 @@
+namespace AltGen.API.Generate.Providers.Gemini;
+
+record Content(Part[] Parts, string Role);

src/AltGen.API/Generate/Providers/Gemini/GeminiAltTextProvider.cs

@@ -0,0 +1,11 @@
+namespace AltGen.API.Generate.Providers.Gemini;
+
+class GeminiAltTextProvider(IGeminiService geminiService) : IAltTextProvider
+{
+  readonly IGeminiService _geminiService = geminiService;
+
+  public Task<string> GenerateAltTextAsync(string providerKey, string mimeType, MemoryStream image)
+  {
+    return _geminiService.GenerateContentAsync(providerKey, mimeType, image);
+  }
+}

src/AltGen.API/Generate/Providers/Gemini/GeminiRequest.cs

@@ -0,0 +1,6 @@
+namespace AltGen.API.Generate.Providers.Gemini;
+
+record GeminiRequest(
+  Content SystemInstruction,
+  Content[] Contents
+);

src/AltGen.API/Generate/Providers/Gemini/GeminiResponse.cs

@@ -0,0 +1,3 @@
+namespace AltGen.API.Generate.Providers.Gemini;
+
+record GeminiResponse(Candidate[] Candidates);

src/AltGen.API/Generate/Providers/Gemini/GeminiRole.cs

@@ -0,0 +1,8 @@
+namespace AltGen.API.Generate.Providers.Gemini;
+
+static class GeminiRole
+{
+  public const string System = "system";
+  public const string User = "user";
+  public const string Model = "model";
+}

src/AltGen.API/Generate/Providers/Gemini/GeminiService.cs

@@ -0,0 +1,79 @@
+namespace AltGen.API.Generate.Providers.Gemini;
+
+class GeminiService(HttpClient httpClient) : IGeminiService
+{
+  const string BaseUri = "https://generativelanguage.googleapis.com/v1beta/models";
+  const string Method = "generateContent";
+  const string ModelId = "gemini-1.5-flash";
+  const string ApiKeyQueryKey = "key";
+
+  // TODO: Use Lazy<T> to load the prompt resource
+  string _prompt = "";
+  string Prompt
+  {
+    get
+    {
+      if (string.IsNullOrWhiteSpace(_prompt))
+      {
+        var resource = Assembly.GetExecutingAssembly()
+          .GetManifestResourceStream("AltGen.API.Resources.prompt.txt") ?? throw new AltGenException("Failed to load the prompt resource.");
+        using var reader = new StreamReader(resource);
+        _prompt = reader.ReadToEnd();
+      }
+
+      return _prompt;
+    }
+  }
+
+  static readonly JsonSerializerOptions Options = new()
+  {
+    PropertyNameCaseInsensitive = true,
+    PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
+    Converters = { new PartConverter() }
+  };
+  readonly HttpClient _httpClient = httpClient;
+
+  public async Task<string> GenerateContentAsync(string providerKey, string mimeType, MemoryStream image)
+  {
+    var requestUri = GetRequestUri(providerKey);
+    var imageBase64 = ConvertToBase64(image);
+
+    var request = new GeminiRequest(
+      new Content([new TextPart(Prompt)], GeminiRole.System),
+      [new Content(
+        [
+          new TextPart(""),
+          new InlineDataPart(new InlineData(mimeType, imageBase64))
+        ],
+        GeminiRole.User
+      )]
+    );
+
+    var response = await _httpClient.PostAsJsonAsync(requestUri, request, Options);
+    var content = await response.Content.ReadAsStringAsync();
+
+    if (response.IsSuccessStatusCode is false)
+    {
+      throw new AltGenException("Failed to generate alt text.");
+    }
+
+    var geminiResponse = JsonSerializer.Deserialize<GeminiResponse>(content, Options) ?? throw new AltGenException("Failed to deserialize the Gemini response.");
+    var firstCandidate = geminiResponse.Candidates.FirstOrDefault() ?? throw new AltGenException("No candidates found in the Gemini response.");
+    var altText = firstCandidate.Content.Parts
+      .OfType<TextPart>()
+      .Aggregate(new StringBuilder(), static (sb, part) => sb.Append(part.Text))
+      .ToString();
+
+    return altText;
+  }
+
+  static string GetRequestUri(string providerKey)
+  {
+    return $"{BaseUri}/{ModelId}:{Method}/?{ApiKeyQueryKey}={providerKey}";
+  }
+
+  static string ConvertToBase64(MemoryStream image)
+  {
+    return Convert.ToBase64String(image.ToArray());
+  }
+}

src/AltGen.API/Generate/Providers/Gemini/IGeminiService.cs

@@ -0,0 +1,6 @@
+namespace AltGen.API.Generate.Providers.Gemini;
+
+interface IGeminiService
+{
+  Task<string> GenerateContentAsync(string providerKey, string mimeType, MemoryStream image);
+}

src/AltGen.API/Generate/Providers/Gemini/Part.cs

@@ -0,0 +1,9 @@
+namespace AltGen.API.Generate.Providers.Gemini;
+
+record Part();
+
+record TextPart(string Text) : Part;
+
+record InlineDataPart(InlineData InlineData) : Part;
+
+record InlineData(string MimeType, string Data);

src/AltGen.API/Generate/Providers/Gemini/PartConverter.cs

@@ -0,0 +1,27 @@
+namespace AltGen.API.Generate.Providers.Gemini;
+
+class PartConverter : JsonConverter<Part>
+{
+  public override Part? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+  {
+    using var doc = JsonDocument.ParseValue(ref reader);
+    var root = doc.RootElement;
+
+    if (root.TryGetProperty("text", out var text))
+    {
+      return JsonSerializer.Deserialize<TextPart>(root.GetRawText(), options);
+    }
+
+    if (root.TryGetProperty("inlineData", out var inlineData))
+    {
+      return JsonSerializer.Deserialize<InlineDataPart>(root.GetRawText(), options);
+    }
+
+    throw new JsonException("Invalid part type.");
+  }
+
+  public override void Write(Utf8JsonWriter writer, Part value, JsonSerializerOptions options)
+  {
+    JsonSerializer.Serialize(writer, value, value.GetType(), options);
+  }
+}

src/AltGen.API/Generate/Providers/IAltTextProvider.cs

@@ -0,0 +1,6 @@
+namespace AltGen.API.Generate.Providers;
+
+interface IAltTextProvider
+{
+  Task<string> GenerateAltTextAsync(string providerKey, string mimeType, MemoryStream image);
+}

src/AltGen.API/Generate/Providers/IAltTextProviderFactory.cs

@@ -0,0 +1,6 @@
+namespace AltGen.API.Generate.Providers;
+
+interface IAltTextProviderFactory
+{
+  IAltTextProvider Create(string provider);
+}

src/AltGen.API/Generate/Providers/LLMProvider.cs

@@ -0,0 +1,11 @@
+namespace AltGen.API.Generate.Providers;
+
+static class LLMProvider
+{
+  public const string Gemini = "Gemini";
+
+  public static bool IsValid(string provider)
+  {
+    return provider is Gemini;
+  }
+}

src/AltGen.API/Program.cs

@@ -0,0 +1,26 @@
+var builder = WebApplication.CreateBuilder(args);
+
+builder.Services.AddProblemDetails();
+builder.Services.AddOpenApi();
+
+builder.Services.AddHttpClient<IGeminiService, GeminiService>();
+builder.Services.AddSingleton<IAltTextProviderFactory, AltTextProviderFactory>();
+builder.Services.AddKeyedSingleton<IAltTextProvider, GeminiAltTextProvider>(LLMProvider.Gemini);
+
+var app = builder.Build();
+
+if (app.Environment.IsDevelopment())
+{
+  app.MapOpenApi();
+}
+
+app.UseHttpsRedirection();
+
+app.UseStatusCodePages();
+
+app.MapPost("/generate", GenerateEndpoint.HandleAsync).DisableAntiforgery();
+
+app.Run();
+
+[ExcludeFromCodeCoverage]
+public partial class Program { }

src/AltGen.API/Properties/launchSettings.json

@@ -0,0 +1,23 @@
+{
+  "$schema": "https://json.schemastore.org/launchsettings.json",
+  "profiles": {
+    "https": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": false,
+      "applicationUrl": "https://localhost:7297;http://localhost:5005",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+    "http": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": false,
+      "applicationUrl": "http://localhost:5005",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      }
+    },
+  }
+}

src/AltGen.API/Resources/prompt.txt

@@ -0,0 +1,17 @@
+Generate descriptive alt text that captures the essential visual information of the image. Follow these guidelines:
+
+1. Be concise, but comprehensive (1-2 sentences)
+2. Describe the most important visual elements
+3. Convey the image's purpose or key message
+4. Use objective language
+5. Avoid redundant phrases
+
+Priority details to include:
+- Main subject(s)
+- Action or context
+- Color or distinctive visual characteristics
+- Emotional tone or artistic intent
+
+Exclude unnecessary details like background minutiae or decorative elements unless they are crucial to understanding the image.
+
+Please DO NOT respond with anything over than the alt text.

src/AltGen.API/Usings.cs

@@ -0,0 +1,13 @@
+global using System.ComponentModel.DataAnnotations;
+global using System.Diagnostics.CodeAnalysis;
+global using System.Reflection;
+global using System.Text;
+global using System.Text.Json;
+global using System.Text.Json.Serialization;
+
+global using AltGen.API.Common;
+global using AltGen.API.Generate;
+global using AltGen.API.Generate.Providers;
+global using AltGen.API.Generate.Providers.Gemini;
+
+global using Microsoft.AspNetCore.Mvc;

src/AltGen.sln

@@ -0,0 +1,28 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.0.31903.59
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "AltGen.API", "AltGen.API\AltGen.API.csproj", "{2865924B-D42C-4126-856F-AD0B762710FB}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "AltGen.API.Tests", "AltGen.API.Tests\AltGen.API.Tests.csproj", "{FC95942B-3579-4F83-A447-A96D8EEF8E45}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{2865924B-D42C-4126-856F-AD0B762710FB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{2865924B-D42C-4126-856F-AD0B762710FB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{2865924B-D42C-4126-856F-AD0B762710FB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{2865924B-D42C-4126-856F-AD0B762710FB}.Release|Any CPU.Build.0 = Release|Any CPU
+		{FC95942B-3579-4F83-A447-A96D8EEF8E45}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{FC95942B-3579-4F83-A447-A96D8EEF8E45}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{FC95942B-3579-4F83-A447-A96D8EEF8E45}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{FC95942B-3579-4F83-A447-A96D8EEF8E45}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal