package main

import (
	"bufio"
	"bytes"
	"errors"
	"slices"
	"strings"
	"testing"
)

func TestCleanInput(t *testing.T) {
	t.Parallel()

	cases := []struct {
		name     string
		input    string
		expected []string
	}{
		{
			name:     "it should split words at whitepspace",
			input:    "stevan  reece freeborn",
			expected: []string{"stevan", "reece", "freeborn"},
		},
		{
			name:     "it should trim leading and or training whitespace",
			input:    " hello world  ",
			expected: []string{"hello", "world"},
		},
		{
			name:     "it should normalize words to lowercase",
			input:    "got to catch them ALL",
			expected: []string{"got", "to", "catch", "them", "all"},
		},
	}

	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			t.Parallel()

			result := cleanInput(c.input)

			if slices.Equal(result, c.expected) {
				return
			}

			t.Errorf("received %v but expected %v", result, c.expected)
		})
	}
}

type erroringInputScanner struct {
	timesCalled int
}

func (m *erroringInputScanner) Err() error {
	if m.timesCalled == 0 {
		m.timesCalled += 1
		return errors.New("oh no!")
	}

	return nil
}

func (m *erroringInputScanner) Text() string {
	return ""
}

func (m *erroringInputScanner) Scan() bool {
	return true
}

func TestRunRepl(t *testing.T) {
	t.Parallel()

	cases := []struct {
		name       string
		input      string
		expected   string
		getScanner func(*strings.Reader) inputScanner
		sanitizer  func(string) []string
	}{
		{
			name:     "it should print custom prompt",
			input:    "",
			expected: "Pokedex > ",
			getScanner: func(r *strings.Reader) inputScanner {
				return bufio.NewScanner(r)
			},
			sanitizer: cleanInput,
		},
		{
			name:     "it should print appropriate error message when scan fails",
			input:    "",
			expected: "Pokedex > Sorry I didn't get that.",
			getScanner: func(r *strings.Reader) inputScanner {
				return &erroringInputScanner{}
			},
			sanitizer: cleanInput,
		},
		{
			name:     "it should print appropriate error message when sanitizer returns no words",
			input:    "Hi! my command is hello\n",
			expected: "Pokedex > Sorry I couldn't understand that.",
			getScanner: func(r *strings.Reader) inputScanner {
				return bufio.NewScanner(r)
			},
			sanitizer: func(s string) []string {
				return []string{}
			},
		},
		{
			name:     "it should print expected message for unknown command",
			input:    "STFU please\n",
			expected: "Unknown command",
			getScanner: func(r *strings.Reader) inputScanner {
				return bufio.NewScanner(r)
			},
			sanitizer: cleanInput,
		},
		// TODO: Need to refactor after considering os.exit call
		// {
		// 	name:     "it should execute command if found",
		// 	input:    "EXIT\n",
		// 	expected: "Closing the Pokedex... Goodbye!\n",
		// 	getScanner: func(r *strings.Reader) inputScanner {
		// 		return bufio.NewScanner(r)
		// 	},
		// 	sanitizer: cleanInput,
		// },
	}

	for _, c := range cases {
		t.Run(c.name, func(t *testing.T) {
			t.Parallel()

			in := strings.NewReader(c.input)
			out := new(bytes.Buffer)

			runREPL(c.getScanner(in), out, c.sanitizer)

			result := out.String()

			if strings.Contains(result, c.expected) {
				return
			}

			t.Errorf("expected %q to contain %q", result, c.expected)
		})
	}
}