package main

import (
	"fmt"
	"os"
	"sort"
)

type context struct {
	commands map[string]cliCommand
}

func (r *context) register(c cliCommand) {
	if c.name != "" {
		r.commands[c.name] = c
	}
}

func NewContext() *context {
	var exitCommand = cliCommand{
		name:        "exit",
		description: "Exit the Pokedex",
		callback:    commandExit,
	}

	var helpCommand = cliCommand{
		name:        "help",
		description: "Displays a help message",
		callback:    commandHelp,
	}

	c := &context{
		commands: map[string]cliCommand{},
	}

	c.register(exitCommand)
	c.register(helpCommand)

	return c
}

type commandFunc func(c *context) error

type cliCommand struct {
	name        string
	description string
	callback    commandFunc
}

func commandExit(c *context) error {
	fmt.Println("Closing the Pokedex... Goodbye!")
	os.Exit(0)
	return nil
}

func commandHelp(c *context) error {
	fmt.Println("Welcome to the Pokedex!")
	fmt.Println("Usage:")
	fmt.Println("")

	sortedKeys := []string{}

	for k := range c.commands {
		sortedKeys = append(sortedKeys, k)
	}

	sort.Strings(sortedKeys)

	for _, key := range sortedKeys {
		command := c.commands[key]
		fmt.Printf("%s: %s\n", command.name, command.description)
	}

	return nil
}