package main

import (
	"embed"
	"mime"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"

	"log"
	"time"

	"github.com/wailsapp/wails/v3/pkg/application"
)

// Wails uses Go's `embed` package to embed the frontend files into the binary.
// Any files in the frontend/dist folder will be embedded into the binary and
// made available to the frontend.
// See https://pkg.go.dev/embed for more information.

//go:embed all:frontend/dist
var assets embed.FS

func init() {
	// Register a custom event whose associated data type is string.
	// This is not required, but the binding generator will pick up registered events
	// and provide a strongly typed JS/TS API for them.
	application.RegisterEvent[string]("time")
	
	// Force register .pdf MIME type for WebView2 default PDF reader loading
	_ = mime.AddExtensionType(".pdf", "application/pdf")
}

// main function serves as the application's entry point. It initializes the application, creates a window,
// and starts a goroutine that emits a time-based event every second. It subsequently runs the application and
// logs any error that might occur.
func main() {
	defaultHandler := application.AssetFileServerFS(assets)

	customAssetHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		path := r.URL.Path
		if strings.HasPrefix(path, "/assets/") {
			filename := strings.TrimPrefix(path, "/assets/")
			localPath := filepath.Join("assets", filename)
			if _, err := os.Stat(localPath); err == nil {
				http.ServeFile(w, r, localPath)
				return
			}
		}
		defaultHandler.ServeHTTP(w, r)
	})

	quizService := NewQuizService()

	serverHost := os.Getenv("WAILS_SERVER_HOST")
	if serverHost == "" {
		serverHost = "0.0.0.0"
	}

	serverPortStr := os.Getenv("WAILS_SERVER_PORT")
	serverPort := 8080
	if serverPortStr != "" {
		if p, err := strconv.Atoi(serverPortStr); err == nil {
			serverPort = p
		}
	}

	// Create a new Wails application by providing the necessary options.
	// Variables 'Name' and 'Description' are for application metadata.
	// 'Assets' configures the asset server with the 'FS' variable pointing to the frontend files.
	// 'Bind' is a list of Go struct instances. The frontend has access to the methods of these instances.
	// 'Mac' options tailor the application when running an macOS.
	app := application.New(application.Options{
		Name:        "Master CBT",
		Description: "Learn everything with me",
		Services: []application.Service{
			application.NewService(quizService),
		},
		Assets: application.AssetOptions{
			Handler: customAssetHandler,
		},
		Server: application.ServerOptions{
			Host: serverHost,
			Port: serverPort,
		},
		Mac: application.MacOptions{
			ApplicationShouldTerminateAfterLastWindowClosed: true,
		},
	})

	quizService.SetApp(app)

	// Create a new window with the necessary options.
	// 'Title' is the title of the window.
	// 'Mac' options tailor the window when running on macOS.
	// 'BackgroundColour' is the background colour of the window.
	// 'URL' is the URL that will be loaded into the webview.
	app.Window.NewWithOptions(application.WebviewWindowOptions{
		Title: "cbt",
		Mac: application.MacWindow{
			InvisibleTitleBarHeight: 50,
			Backdrop:                application.MacBackdropTranslucent,
			TitleBar:                application.MacTitleBarHiddenInset,
		},
		BackgroundColour: application.NewRGB(27, 38, 54),
		URL:              "/",
	})

	// Create a goroutine that emits an event containing the current time every second.
	// The frontend can listen to this event and update the UI accordingly.
	go func() {
		for {
			now := time.Now().Format(time.RFC1123)
			app.Event.Emit("time", now)
			time.Sleep(time.Second)
		}
	}()

	// Run the application. This blocks until the application has been exited.
	err := app.Run()

	// If an error occurred while running the application, log it and exit.
	if err != nil {
		log.Fatal(err)
	}
}