package main

import (
	"bytes"
	"fmt"
	"net/http"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"
	"time"

	"github.com/labstack/echo/v4"
	"golang.org/x/crypto/bcrypt"
)

func registerHandler(c echo.Context) error {
	return c.Render(http.StatusOK, "register.html", nil)
}

func registerPostHandler(c echo.Context) error {
	username := c.FormValue("username")
	password := c.FormValue("password")

	err := CreateUser(db, username, password)

	if err != nil {
		return c.String(http.StatusInternalServerError, "Error creating user")
	}

	return c.Redirect(http.StatusSeeOther, "/login")
}

func loginHandler(c echo.Context) error {
	return c.Render(http.StatusOK, "login.html", nil)
}

func homeHandler(c echo.Context) error {
	return c.Render(http.StatusOK, "home.html", nil)
}

func loginPostHandler(c echo.Context) error {
	username := c.FormValue("username")
	password := c.FormValue("password")

	var user User
	if err := db.Where("username = ?", username).First(&user).Error; err != nil {
		return c.String(http.StatusUnauthorized, "Invalid credentials")
	}

	if err := bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(password)); err != nil {
		return c.String(http.StatusUnauthorized, "Invalid credentials")
	}

	session, err := store.Get(c.Request(), "session")
	if err != nil {
		return c.String(http.StatusInternalServerError, "Unable to retrieve session")
	}
	session.Values["user_id"] = user.ID
	err = session.Save(c.Request(), c.Response().Writer)

	if err != nil {
		return c.String(http.StatusInternalServerError, "Unable to save session")
	}

	session, _ = store.Get(c.Request(), "session")
	_, ok := session.Values["user_id"]
	if !ok {
		return c.String(http.StatusInternalServerError, "user_id was not saved as expected")
	}

	fmt.Println("loginPostHandler: redirect to /download")
	return c.Redirect(http.StatusSeeOther, "/download")
}

func logoutHandler(c echo.Context) error {
	session, _ := store.Get(c.Request(), "session")
	delete(session.Values, "user_id")
	session.Save(c.Request(), c.Response().Writer)
	return c.Redirect(http.StatusSeeOther, "/login")
}

func downloadHandler(c echo.Context) error {
	return c.Render(http.StatusOK, "download.html", nil)
}

func downloadPostHandler(c echo.Context) error {
	url := c.FormValue("url")
	userID := c.Get("user_id").(uint)

	video := Video{URL: url, UserID: userID, Status: "pending"}
	db.Create(&video)

	go startDownload(video.ID, url)

	return c.Redirect(http.StatusSeeOther, "/videos")
}

type Meta struct {
	title string
}

func getMeta(url string) (Meta, error) {
	cmd := exec.Command("yt-dlp",
		"--simulate", "--print", "%(title)s",
		url)

	var stdout bytes.Buffer
	cmd.Stdout = &stdout
	err := cmd.Run()
	if err != nil {
		fmt.Println("getTitle error:", err, stdout.String())
		return Meta{}, err
	} else {
		return Meta{
			title: strings.TrimSpace(stdout.String()),
		}, nil
	}
}

// return the length in seconds of a video file at `path`
func getLength(path string) (float64, error) {
	cmd := exec.Command("ffprobe", "-v", "error", "-show_entries", "format=duration",
		"-of", "default=noprint_wrappers=1:nokey=1", path)

	var stdout bytes.Buffer
	cmd.Stdout = &stdout
	err := cmd.Run()
	if err != nil {
		fmt.Println("getLength cmd error:", err)
		return -1, err
	}

	result, err := strconv.ParseFloat(strings.TrimSpace(stdout.String()), 64)
	if err != nil {
		fmt.Println("getLength parse error:", err, stdout.String())
	}
	return result, nil
}

func humanLength(s float64) string {
	ss := int64(s)
	mm, ss := ss/60, ss%60
	hh, mm := mm/60, mm%60

	return fmt.Sprintf("%d:%02d:%02d", hh, mm, ss)
}

func getSize(path string) (int64, error) {
	fi, err := os.Stat(path)
	if err != nil {
		return -1, err
	}
	return fi.Size(), nil
}

func humanSize(bytes int64) string {
	const (
		KiB = 1024
		MiB = 1024 * KiB
		GiB = 1024 * MiB
	)

	if bytes >= GiB {
		return fmt.Sprintf("%.1f GiB", float64(bytes)/float64(GiB))
	} else if bytes >= MiB {
		return fmt.Sprintf("%.1f MiB", float64(bytes)/float64(MiB))
	} else if bytes >= KiB {
		return fmt.Sprintf("%.1f KiB", float64(bytes)/float64(KiB))
	}
	return fmt.Sprintf("%d bytes", bytes)
}

func startDownload(videoID uint, videoURL string) {
	db.Model(&Video{}).Where("id = ?", videoID).Update("status", "metadata")

	meta, err := getMeta(videoURL)
	if err != nil {
		db.Model(&Video{}).Where("id = ?", videoID).Update("status", "failed")
		return
	}
	fmt.Println("set video title:", meta.title)
	db.Model(&Video{}).Where("id = ?", videoID).Update("title", meta.title)

	db.Model(&Video{}).Where("id = ?", videoID).Update("status", "downloading")
	videoFilename := fmt.Sprintf("%d-%s.mp4", videoID, meta.title)
	videoFilepath := filepath.Join(getDownloadDir(), "video", videoFilename)
	cmd := exec.Command("yt-dlp",
		"-f", "bestvideo[height<=720]+bestaudio/best[height<=720]",
		"--recode-video", "mp4",
		"-o", videoFilepath,
		videoURL)
	err = cmd.Run()
	if err != nil {
		db.Model(&Video{}).Where("id = ?", videoID).Update("status", "failed")
		return
	}

	db.Model(&Video{}).Where("id = ?", videoID).Update("status", "audio")
	audioFilename := fmt.Sprintf("%d-%s.mp3", videoID, meta.title)
	audioFilepath := filepath.Join(getDownloadDir(), "audio", audioFilename)
	audioDir := filepath.Dir(audioFilepath)
	fmt.Println("Create", audioDir)
	err = os.MkdirAll(audioDir, 0700)
	if err != nil {
		fmt.Println("Error: couldn't create", audioDir)
		db.Model(&Video{}).Where("id = ?", videoID).Update("status", "failed")
		return
	}
	ffmpeg := "ffmpeg"
	ffmpegArgs := []string{"-i", videoFilepath, "-vn", "-acodec",
		"mp3", "-b:a", "160k", audioFilepath}
	fmt.Println(ffmpeg, ffmpegArgs)
	cmd = exec.Command(ffmpeg, ffmpegArgs...)
	err = cmd.Run()
	if err != nil {
		fmt.Println("Error: convert to audio file", videoFilepath, "->", audioFilepath)
		db.Model(&Video{}).Where("id = ?", videoID).Update("status", "failed")
		return
	}

	// FIXME: ensure expected files exist
	db.Model(&Video{}).Where("id = ?", videoID).Updates(map[string]interface{}{
		"video_filename": videoFilename,
		"audio_filename": audioFilename,
		"status":         "completed",
	})

	length, err := getLength(videoFilepath)
	if err == nil {
		db.Model(&Video{}).Where("id = ?", videoID).Update("length", humanLength(length))
	}

	videoSize, err := getSize(videoFilepath)
	if err == nil {
		db.Model(&Video{}).Where("id = ?", videoID).Update("video_size", humanSize(videoSize))
	}

	audioSize, err := getSize(audioFilepath)
	if err == nil {
		db.Model(&Video{}).Where("id = ?", videoID).Update("audio_size", humanSize(audioSize))
	}

}

func videosHandler(c echo.Context) error {
	userID := c.Get("user_id").(uint)
	var videos []Video
	db.Where("user_id = ?", userID).Find(&videos)
	return c.Render(http.StatusOK, "videos.html", map[string]interface{}{"videos": videos})
}

func videoHandler(c echo.Context) error {
	id, _ := strconv.Atoi(c.Param("id"))
	var video Video
	if err := db.First(&video, id).Error; err != nil {
		return c.Redirect(http.StatusSeeOther, "/videos")
	}

	downloadDir := getDownloadDir()

	tempURL, err := CreateTempURL(filepath.Join(downloadDir, "video", video.VideoFilename))
	if err != nil {
		return err
	}

	return c.Render(http.StatusOK, "video.html",
		map[string]interface{}{
			"video":       video,
			"downloadDir": downloadDir,
			"tempURL":     fmt.Sprintf("/temp/%s", tempURL.Token),
		})
}

func videoCancelHandler(c echo.Context) error {
	id, _ := strconv.Atoi(c.Param("id"))
	var video Video
	if err := db.First(&video, id).Error; err != nil {
		return c.Redirect(http.StatusSeeOther, "/videos")
	}

	// Cancel the download (this is a simplified version, you might need to implement a more robust cancellation mechanism)
	video.Status = "cancelled"
	db.Save(&video)

	return c.Redirect(http.StatusSeeOther, "/videos")
}

func videoRestartHandler(c echo.Context) error {
	id, _ := strconv.Atoi(c.Param("id"))
	var video Video
	if err := db.First(&video, id).Error; err != nil {
		return c.Redirect(http.StatusSeeOther, "/videos")
	}

	video.Status = "pending"
	db.Save(&video)
	go startDownload(uint(id), video.URL)

	return c.Redirect(http.StatusSeeOther, "/videos")
}

func videoDeleteHandler(c echo.Context) error {
	id, _ := strconv.Atoi(c.Param("id"))
	var video Video
	if err := db.First(&video, id).Error; err != nil {
		return c.Redirect(http.StatusSeeOther, "/videos")
	}

	// Delete the file
	if video.VideoFilename != "" {
		os.Remove(filepath.Join(getDownloadDir(), "video", video.VideoFilename))
	}
	if video.AudioFilename != "" {
		os.Remove(filepath.Join(getDownloadDir(), "audio", video.AudioFilename))
	}

	// Delete from database
	db.Delete(&video)

	return c.Redirect(http.StatusSeeOther, "/videos")
}

func tempHandler(c echo.Context) error {
	token := c.Param("token")

	var tempURL TempURL
	if err := db.Where("token = ? AND expires_at > ?", token, time.Now()).First(&tempURL).Error; err != nil {
		return c.JSON(http.StatusNotFound, map[string]string{"error": "Invalid or expired token"})
	}

	return c.File(tempURL.FilePath)
}