package app

import (
	"bufio"
	"fmt"
	"io"
	"log"
	"os"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"

	"github.com/go-errors/errors"

	"github.com/jesseduffield/generics/slices"
	"github.com/jesseduffield/lazygit/pkg/commands"
	"github.com/jesseduffield/lazygit/pkg/commands/git_config"
	"github.com/jesseduffield/lazygit/pkg/commands/oscommands"
	"github.com/jesseduffield/lazygit/pkg/common"
	"github.com/jesseduffield/lazygit/pkg/config"
	"github.com/jesseduffield/lazygit/pkg/constants"
	"github.com/jesseduffield/lazygit/pkg/env"
	"github.com/jesseduffield/lazygit/pkg/gui"
	"github.com/jesseduffield/lazygit/pkg/i18n"
	"github.com/jesseduffield/lazygit/pkg/updates"
)

// App is the struct that's instantiated from within main.go and it manages
// bootstrapping and running the application.
type App struct {
	*common.Common
	closers   []io.Closer
	Config    config.AppConfigurer
	OSCommand *oscommands.OSCommand
	Gui       *gui.Gui
	Updater   *updates.Updater // may only need this on the Gui
}

func Run(config config.AppConfigurer, common *common.Common, filterPath string) {
	app, err := NewApp(config, common)

	if err == nil {
		err = app.Run(filterPath)
	}

	if err != nil {
		if errorMessage, known := knownError(common.Tr, err); known {
			log.Fatal(errorMessage)
		}
		newErr := errors.Wrap(err, 0)
		stackTrace := newErr.ErrorStack()
		app.Log.Error(stackTrace)

		log.Fatalf("%s: %s\n\n%s", common.Tr.ErrorOccurred, constants.Links.Issues, stackTrace)
	}
}

func NewCommon(config config.AppConfigurer) (*common.Common, error) {
	userConfig := config.GetUserConfig()

	var err error
	log := newLogger(config)
	tr, err := i18n.NewTranslationSetFromConfig(log, userConfig.Gui.Language)
	if err != nil {
		return nil, err
	}

	return &common.Common{
		Log:        log,
		Tr:         tr,
		UserConfig: userConfig,
		Debug:      config.GetDebug(),
	}, nil
}

// NewApp bootstrap a new application
func NewApp(config config.AppConfigurer, common *common.Common) (*App, error) {
	app := &App{
		closers: []io.Closer{},
		Config:  config,
		Common:  common,
	}

	app.OSCommand = oscommands.NewOSCommand(common, config, oscommands.GetPlatform(), oscommands.NewNullGuiIO(app.Log))

	var err error
	app.Updater, err = updates.NewUpdater(common, config, app.OSCommand)
	if err != nil {
		return app, err
	}

	dirName, err := os.Getwd()
	if err != nil {
		return app, err
	}

	showRecentRepos, err := app.setupRepo()
	if err != nil {
		return app, err
	}

	gitConfig := git_config.NewStdCachedGitConfig(app.Log)

	app.Gui, err = gui.NewGui(common, config, gitConfig, app.Updater, showRecentRepos, dirName)
	if err != nil {
		return app, err
	}
	return app, nil
}

func (app *App) validateGitVersion() error {
	output, err := app.OSCommand.Cmd.New("git --version").RunWithOutput()
	// if we get an error anywhere here we'll show the same status
	minVersionError := errors.New(app.Tr.MinGitVersionError)
	if err != nil {
		return minVersionError
	}

	if isGitVersionValid(output) {
		return nil
	}

	return minVersionError
}

func isGitVersionValid(versionStr string) bool {
	// output should be something like: 'git version 2.23.0 (blah)'
	re := regexp.MustCompile(`[^\d]+([\d\.]+)`)
	matches := re.FindStringSubmatch(versionStr)

	if len(matches) == 0 {
		return false
	}

	gitVersion := matches[1]
	majorVersion, err := strconv.Atoi(gitVersion[0:1])
	if err != nil {
		return false
	}
	if majorVersion < 2 {
		return false
	}

	return true
}

func (app *App) setupRepo() (bool, error) {
	if err := app.validateGitVersion(); err != nil {
		return false, err
	}

	if env.GetGitDirEnv() != "" {
		// we've been given the git dir directly. We'll verify this dir when initializing our Git object
		return false, nil
	}

	// if we are not in a git repo, we ask if we want to `git init`
	if err := commands.VerifyInGitRepo(app.OSCommand); err != nil {
		cwd, err := os.Getwd()
		if err != nil {
			return false, err
		}
		info, _ := os.Stat(filepath.Join(cwd, ".git"))
		if info != nil && info.IsDir() {
			return false, err // Current directory appears to be a git repository.
		}

		shouldInitRepo := true
		notARepository := app.UserConfig.NotARepository
		if notARepository == "prompt" {
			// Offer to initialize a new repository in current directory.
			fmt.Print(app.Tr.CreateRepo)
			response, _ := bufio.NewReader(os.Stdin).ReadString('\n')
			if strings.Trim(response, " \n") != "y" {
				shouldInitRepo = false
			}
		} else if notARepository == "skip" {
			shouldInitRepo = false
		}

		if !shouldInitRepo {
			// check if we have a recent repo we can open
			recentRepos := app.Config.GetAppState().RecentRepos
			if len(recentRepos) > 0 {
				var err error
				// try opening each repo in turn, in case any have been deleted
				for _, repoDir := range recentRepos {
					if err = os.Chdir(repoDir); err == nil {
						return true, nil
					}
				}
				return false, err
			}

			os.Exit(1)
		}
		if err := app.OSCommand.Cmd.New("git init").Run(); err != nil {
			return false, err
		}
	}

	return false, nil
}

func (app *App) Run(filterPath string) error {
	err := app.Gui.RunAndHandleError(filterPath)
	return err
}

// Close closes any resources
func (app *App) Close() error {
	return slices.TryForEach(app.closers, func(closer io.Closer) error {
		return closer.Close()
	})
}