package dl

import (
	"bufio"
	"fmt"
	"io"
	"log"
	"net/http"
	"net/url"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"
	"sync"

	"git.meatbag.se/varl/subsyt/internal/config"
)

type Download struct {
	Url      string
	OutDir   string
	Name     string
	DryRun   bool
	Metadata bool
}

func UpgradeYtDlp(cmd string) error {
	resolved, err := resolveYtDlpPath(cmd)
	if err != nil {
		return err
	}

	if strings.Contains(resolved, filepath.Join("pipx", "venvs")) {
		return runLoggedCommand("pipx", exec.Command("pipx", "upgrade-all"))
	}

	return runLoggedCommand("yt-dlp", exec.Command(resolved, "--update"))
}

func resolveYtDlpPath(cmd string) (string, error) {
	if cmd == "" {
		cmd = "yt-dlp"
	}

	if filepath.IsAbs(cmd) {
		return evalPath(cmd)
	}

	if strings.Contains(cmd, string(os.PathSeparator)) {
		abs, err := filepath.Abs(cmd)
		if err != nil {
			return "", fmt.Errorf("resolve yt-dlp path: %w", err)
		}
		return evalPath(abs)
	}

	located, err := exec.LookPath(cmd)
	if err != nil {
		return "", fmt.Errorf("locate yt-dlp: %w", err)
	}

	return evalPath(located)
}

func evalPath(path string) (string, error) {
	resolved, err := filepath.EvalSymlinks(path)
	if err != nil {
		return "", fmt.Errorf("resolve yt-dlp symlink: %w", err)
	}
	return resolved, nil
}

func runLoggedCommand(tag string, cmd *exec.Cmd) error {
	stdout, err := cmd.StdoutPipe()
	if err != nil {
		return fmt.Errorf("%s stdout: %w", tag, err)
	}

	stderr, err := cmd.StderrPipe()
	if err != nil {
		return fmt.Errorf("%s stderr: %w", tag, err)
	}

	log.Printf("[%s] running %s %v\n", tag, cmd.Path, cmd.Args[1:])

	var wg sync.WaitGroup
	wg.Add(2)

	go func() {
		defer wg.Done()
		scanner := bufio.NewScanner(stdout)
		for scanner.Scan() {
			log.Printf("[%s] %s\n", tag, scanner.Text())
		}
		if err := scanner.Err(); err != nil {
			log.Printf("[%s] stdout error: %v\n", tag, err)
		}
	}()

	go func() {
		defer wg.Done()
		scanner := bufio.NewScanner(stderr)
		for scanner.Scan() {
			log.Printf("[%s] %s\n", tag, scanner.Text())
		}
		if err := scanner.Err(); err != nil {
			log.Printf("[%s] stderr error: %v\n", tag, err)
		}
	}()

	if err := cmd.Start(); err != nil {
		return fmt.Errorf("%s start: %w", tag, err)
	}

	wg.Wait()

	if err := cmd.Wait(); err != nil {
		return fmt.Errorf("%s failed: %w", tag, err)
	}

	return nil
}

func Youtube(d Download, p config.Provider) {
	if p.Bgutil_server != "" && p.Po_token != "" {
		log.Fatal("please only provide bgutil_server OR po_token, not both")
	}

	vUrl, err := url.Parse(d.Url)
	if err != nil {
		panic(err)
	}

	args := []string{
		"--no-progress",
		"--paths", d.OutDir,
		"--restrict-filenames",
		"--write-thumbnail",
		"--write-info-json",
		"--convert-thumbnails", "jpg",
	}

	if p.Verbose == true {
		args = append(args, "--verbose")
	}

	if d.DryRun == true {
		log.Println("/!\\ DRY RUN ENABLED /!\\")
		args = append(args, "--simulate")
	} else {
		args = append(args, "--no-simulate")
	}

	// NOTE: we want to download the metadata for a channel, without
	// downloading every video in the channel. This uses
	// --playlist-items to download the video indices 0 to 0 with a step
	// of 1 ... this results in zero videos being downloaded.

	if d.Metadata == true {
		log.Println("Downloading channel metadata")
		mArgs := []string{
			"--skip-download",
			"--no-overwrites",
			"--playlist-items", "0:0:1",
		}
		args = append(args, mArgs...)
	} else {
		log.Println("Downloading video")
		archive := filepath.Join(d.OutDir, "archive.txt")
		throttle := strconv.Itoa(p.Throttle)

		dArgs := []string{
			"--no-playlist",
			"--sleep-interval", throttle,
			"--sleep-subtitles", throttle,
			"--sleep-requests", throttle,
			"--max-sleep-interval", "90",
			"--embed-metadata",
			"--write-subs",
			"--no-write-automatic-subs",
			"--sub-langs", "en",
			"--prefer-free-formats",
			"--download-archive", archive,
			"--break-on-existing",
			"--match-filters", "!is_live & duration>?60",
		}
		args = append(args, dArgs...)

		if p.Format != "" {
			args = append(args, "--format", p.Format)
		}

		if p.Format_sort != "" {
			args = append(args, "--format-sort", p.Format_sort)
		}
	}

	if p.Cookies_file != "" {
		args = append(args, "--cookies", p.Cookies_file)
	} else {
		args = append(args, "--no-cookies")
	}

	if p.Bgutil_server != "" {
		args = append(args, "--extractor-args", fmt.Sprintf("youtubepot-bgutilhttp:base_url=%s", p.Bgutil_server))
	}

	// NOTE: every unqiue extractor's args needs to be combined into one string
	var youtubeArgs []string
	if p.Po_token != "" {
		youtubeArgs = append(youtubeArgs, fmt.Sprintf("po_token=web.gvs+%s", p.Po_token))
	}
	if p.Player_client != "" {
		youtubeArgs = append(youtubeArgs, fmt.Sprintf("player_client=%s", p.Player_client))
	}

	if len(youtubeArgs) > 0 {
		args = append(args, "--extractor-args", fmt.Sprintf("youtube:%s", strings.Join(youtubeArgs, ";")))
	}

	if p.Output_path_template != "" {
		args = append(args, "--output", p.Output_path_template)
	} else {
		args = append(args, "--output", "s%(upload_date>%Y)s/%(channel)s.s%(upload_date>%Y)Se%(upload_date>%m%d)S.%(title)s.%(id)s.%(ext)s")
	}

	args = append(args, vUrl.String())

	cmd := exec.Command(p.Cmd, args...)

	stdout, err := cmd.StdoutPipe()
	if err != nil {
		log.Fatal(err)
	}

	stderr, err := cmd.StderrPipe()
	if err != nil {
		log.Fatal(err)
	}

	log.Printf("[%s] running yt-dlp with args: %v\n", d.OutDir, args)

	var wg sync.WaitGroup
	wg.Add(2)

	go func() {
		defer wg.Done()
		scanner := bufio.NewScanner(stdout)
		for scanner.Scan() {
			log.Printf("[%s] %s\n", d.OutDir, scanner.Text())
		}
	}()

	go func() {
		defer wg.Done()
		scanner := bufio.NewScanner(stderr)
		for scanner.Scan() {
			log.Printf("[%s] %s\n", d.OutDir, scanner.Text())
		}
	}()

	err = cmd.Start()
	if err != nil {
		log.Fatal(err)
	}

	wg.Wait()
	err = cmd.Wait()

	if err != nil {
		log.Printf("Error: %s\n", err)
	}
}

func Fetch(d Download) {
	// Create output directory if it doesn't exist
	if err := os.MkdirAll(d.OutDir, 0755); err != nil {
	}

	outputPath := filepath.Join(d.OutDir, d.Name)

	out, err := os.Create(outputPath)
	if err != nil {
		log.Printf("failed to create '%s'\n", outputPath)
		return
	}
	defer out.Close()

	resp, err := http.Get(d.Url)
	if err != nil {
		log.Printf("failed to download '%s'\n", d.Url)
		return
	}
	defer resp.Body.Close()

	_, err = io.Copy(out, resp.Body)
	if err != nil {
		log.Printf("failed to write file")
	}
}

func RssDownloader(url string) ([]byte, error) {
	resp, err := http.Get(url)
	if err != nil {
		return nil, fmt.Errorf("failed to fetch RSS feed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("failed to fetch RSS feed: %s", resp.Status)
	}

	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read RSS data: %w", err)
	}

	return data, nil
}