package main

import (
	"encoding/json"
	"fmt"
	"os"
	"strings"

	"gopkg.in/yaml.v3"
)

type Command struct {
	Name        string
	Description string
	Action      CommandAction
	Arguments   []string
	IsVarargs   bool
}

type CommandAction func([]string, []string) (string, error)

var commands = []Command{
	{
		Name:        "install",
		Description: "Install one or more mod archives into modman",
		Arguments:   []string{"game name", "archive path"},
		IsVarargs:   true,

		Action: func(requiredArguments []string, providedArguments []string) (string, error) {
			if len(providedArguments) < len(requiredArguments) {
				return "", fmt.Errorf("expected %s folowed by at least one %ss",
					requiredArguments[0], requiredArguments[1])
			}

			var archivePaths = providedArguments[1:]

			if game, openGameError := LoadGame(providedArguments[0]); openGameError == nil {
				if installError := game.InstallMods(archivePaths); installError != nil {
					return "", installError
				}
			}

			if len(archivePaths) > 1 {
				return "mods installed", nil
			}

			return "mod installed", nil
		},
	},

	{
		Name:        "register",
		Description: "Registers the data directory path of game for management under the given name",
		Arguments:   []string{"data path", "game name"},
		IsVarargs:   false,

		Action: func(requiredArguments []string, providedArguments []string) (string, error) {
			if len(providedArguments) < len(requiredArguments) {
				return "", fmt.Errorf("expected %s folowed by at least one %ss",
					requiredArguments[0], requiredArguments[1])
			}

			var dataPath = providedArguments[0]
			var gameName = providedArguments[1]

			if registerGameError := RegisterGame(gameName, dataPath); registerGameError != nil {
				return "", registerGameError
			}

			return fmt.Sprintf("Registered %s at %s", gameName, dataPath), nil
		},
	},

	{
		Name:        "remove",
		Description: "Remove one or more mods from modman",
		Arguments:   []string{"game name", "mod name"},
		IsVarargs:   true,

		Action: func(requiredArguments []string, providedArguments []string) (string, error) {
			if len(providedArguments) < len(requiredArguments) {
				return "", fmt.Errorf("expected %s followed by one or more %ss",
					requiredArguments[0], requiredArguments[1])
			}

			var modNames = providedArguments[1:]

			if game, openGameError := LoadGame(providedArguments[0]); openGameError == nil {
				for _, name := range modNames {
					if removeError := game.RemoveMod(name); removeError != nil {
						return "", removeError
					}
				}
			} else {
				return "", openGameError
			}

			if len(modNames) > 1 {
				return "removed mods", nil
			}

			return "removed mod", nil
		},
	},

	{
		Name:        "rename",
		Description: "Rename a mod within modman",
		Arguments:   []string{"game name", "mod name", "new name"},
		IsVarargs:   false,

		Action: func(requiredArguments []string, providedArguments []string) (string, error) {
			if len(providedArguments) != len(requiredArguments) {
				return "", fmt.Errorf("expected %s followed by %s and %s",
					requiredArguments[0], requiredArguments[1], requiredArguments[2])
			}

			if game, openGameError := LoadGame(providedArguments[0]); openGameError == nil {
				if renameError := game.RenameMod(providedArguments[1], providedArguments[2]); renameError != nil {
					return "", renameError
				}
			} else {
				return "", openGameError
			}

			return "renamed", nil
		},
	},

	{
		Name:        "manifest",
		Description: "Retrieve a manifest of all installed mods",
		Arguments:   []string{"game name", "format"},
		IsVarargs:   false,

		Action: func(requiredArguments []string, providedArguments []string) (string, error) {
			if len(providedArguments) != len(requiredArguments) {
				return "", fmt.Errorf("expected %s followed by %s",
					requiredArguments[0], requiredArguments[1])
			}

			var manifestBuilder = strings.Builder{}

			if game, openGameError := LoadGame(providedArguments[0]); openGameError == nil {
				var format = providedArguments[1]

				if formatter, exists := formatters[format]; exists {
					if formatError := formatter(&manifestBuilder, game.Mods); formatError != nil {
						return "", formatError
					}
				} else {
					return "", fmt.Errorf("unsupported format: `%s`", format)
				}
			} else {
				return "", openGameError
			}

			return manifestBuilder.String(), nil
		},
	},

	{
		Name:        "deploy",
		Description: "Deploy all specified mods in order of listing",
		Arguments:   []string{"game name", "mod name"},
		IsVarargs:   true,

		Action: func(requiredArguments []string, providedArguments []string) (string, error) {
			if len(providedArguments) < len(requiredArguments) {
				return "", fmt.Errorf("expected %s followed by one or more %ss",
					requiredArguments[0], requiredArguments[1])
			}

			if game, openGameError := LoadGame(providedArguments[0]); openGameError == nil {
				if deployError := game.Deploy(providedArguments[1:]); deployError != nil {
					return "", deployError
				}
			} else {
				return "", openGameError
			}

			return "deployed", nil
		},
	},

	{
		Name:        "clean",
		Description: "Clean all deployed mods",
		Arguments:   []string{"game name"},
		IsVarargs:   false,

		Action: func(requiredArguments []string, arguments []string) (string, error) {
			if len(arguments) != len(requiredArguments) {
				return "", fmt.Errorf("expected %s", requiredArguments[0])
			}

			if game, openGameError := LoadGame(arguments[0]); openGameError == nil {
				if cleanError := game.Clean(); cleanError != nil {
					return "", cleanError
				}
			} else {
				return "", openGameError
			}

			return "cleaned", nil
		},
	},
}

var formatters = map[string]func(*strings.Builder, any) error{
	"json": func(builder *strings.Builder, data any) error {
		var encoder = json.NewEncoder(builder)

		if encodeError := encoder.Encode(data); encodeError != nil {
			return encodeError
		}

		return nil
	},

	"yaml": func(builder *strings.Builder, data any) error {
		var encoder = yaml.NewEncoder(builder)

		encoder.SetIndent(2)

		if encodeError := encoder.Encode(data); encodeError != nil {
			return encodeError
		}

		return nil
	},
}

func main() {
	var argCount = len(os.Args)

	if argCount == 1 {
		fmt.Println("Modman v0.1")
		fmt.Println("Enter one of the following commands following modman:")

		for i := range commands {
			var command = commands[i]

			fmt.Print("\t", command.Name)

			for j := range command.Arguments {
				fmt.Print(" [", command.Arguments[j], "]")
			}

			if command.IsVarargs {
				fmt.Println("...")
			} else {
				fmt.Println()
			}
		}

		return
	}

	var commandName = os.Args[1]

	for i := range commands {
		var command = commands[i]

		if command.Name == commandName {
			var response, actionError = command.Action(command.Arguments, os.Args[2:])

			if actionError != nil {
				fmt.Fprintln(os.Stderr, actionError.Error())
				os.Exit(1)
			}

			if len(response) != 0 {
				fmt.Println(response)
			}

			return
		}
	}

	fmt.Fprintf(os.Stderr, "unknown command: `%s`\n", commandName)
}