package http

import (
	"fmt"
	"log"
	"net/http"
	"path"
	"path/filepath"
	"strings"

	"github.com/debridmediamanager.com/zurg/internal/config"
	"github.com/debridmediamanager.com/zurg/internal/torrent"
	"github.com/debridmediamanager.com/zurg/pkg/davextra"
	"github.com/debridmediamanager.com/zurg/pkg/realdebrid"
	"github.com/hashicorp/golang-lru/v2/expirable"
)

func HandleGetRequest(w http.ResponseWriter, r *http.Request, t *torrent.TorrentManager, c config.ConfigInterface, cache *expirable.LRU[string, string]) {
	requestPath := path.Clean(r.URL.Path)
	requestPath = strings.Replace(requestPath, "/http", "/", 1)
	if requestPath == "/favicon.ico" {
		return
	}
	segments := strings.Split(requestPath, "/")
	// If there are less than 3 segments, return an error or adjust as needed
	if len(segments) < 4 {
		HandleDirectoryListing(w, r, t, c, cache)
		return
	}
	if data, exists := cache.Get(requestPath); exists {
		http.Redirect(w, r, data, http.StatusFound)
		return
	}

	baseDirectory := segments[len(segments)-3]
	torrentName := segments[len(segments)-2]
	filename := segments[len(segments)-1]

	torrents := findAllTorrentsWithName(t, baseDirectory, torrentName)
	if torrents == nil {
		log.Println("Cannot find torrent", torrentName)
		http.Error(w, "Cannot find file", http.StatusNotFound)
		return
	}

	filenameV2, linkFragment := davextra.ExtractLinkFragment(filename)
	torrent, file := getFile(torrents, filenameV2, linkFragment)
	if file == nil {
		log.Println("Cannot find file", filename)
		http.Error(w, "Cannot find file", http.StatusNotFound)
		return
	}
	if file.Link == "" {
		log.Println("Link not found", filename)
		http.Error(w, "Cannot find file", http.StatusNotFound)
		return
	}
	link := file.Link

	unrestrictFn := func() (*realdebrid.UnrestrictResponse, error) {
		return realdebrid.UnrestrictLink(c.GetToken(), link)
	}
	resp := realdebrid.RetryUntilOk(unrestrictFn)
	if resp == nil {
		// TODO: Readd the file
		// when unrestricting fails, it means the file is not available anymore, but still in their database
		// if it's the only file, tough luck
		// if it's the only file, try to readd it
		// delete the old one, add a new one
		log.Println("Cannot unrestrict link", link, filenameV2)
		t.MarkFileAsDeleted(torrent, file)
		http.Error(w, "Cannot find file", http.StatusNotFound)
		return
	}
	if resp.Filename != filenameV2 {
		// TODO: Redo the logic to handle mismatch
		// [SRS] Pokemon S22E01-35 1080p WEBRip AAC 2.0 x264 CC.rar
		// Pokemon.S22E24.The.Secret.Princess.DUBBED.1080p.WEBRip.AAC.2.0.x264-SRS.mkv
		// Action: schedule a "cleanup" job for the parent torrent
		// If the file extension changed, that means it's a different file
		log.Println("Filename mismatch", resp.Filename, filenameV2)
	}
	cache.Add(requestPath, resp.Download)
	http.Redirect(w, r, resp.Download, http.StatusFound)
}

// getFile finds a link by a fragment, it might be wrong
func getFile(torrents []torrent.Torrent, filename, fragment string) (*torrent.Torrent, *torrent.File) {
	for t := range torrents {
		for f, file := range torrents[t].SelectedFiles {
			fname := filepath.Base(file.Path)
			if filename == fname && strings.HasPrefix(file.Link, fmt.Sprintf("https://real-debrid.com/d/%s", fragment)) {
				return &torrents[t], &torrents[t].SelectedFiles[f]
			}
		}
	}
	return nil, nil
}

func findAllTorrentsWithName(t *torrent.TorrentManager, directory, torrentName string) []torrent.Torrent {
	matchingTorrents := make([]torrent.Torrent, 0, 10)
	torrents := t.GetByDirectory(directory)
	for i := range torrents {
		if torrents[i].Name == torrentName || strings.HasPrefix(torrents[i].Name, torrentName) {
			matchingTorrents = append(matchingTorrents, torrents[i])
		}
	}
	return matchingTorrents
}

func HandleDirectoryListing(w http.ResponseWriter, r *http.Request, t *torrent.TorrentManager, c config.ConfigInterface, cache *expirable.LRU[string, string]) {
	requestPath := path.Clean(r.URL.Path)

	if data, exists := cache.Get(requestPath); exists {
		w.Header().Set("Content-Type", "text/html; charset=\"utf-8\"")
		w.WriteHeader(http.StatusOK)
		fmt.Fprint(w, data)
		return
	}

	var output *string
	var err error

	filteredSegments := removeEmptyStrings(strings.Split(requestPath, "/"))
	switch {
	case len(filteredSegments) == 1:
		output, err = handleRoot(w, r, c)
	case len(filteredSegments) == 2:
		output, err = handleListOfTorrents(requestPath, w, r, t, c)
	case len(filteredSegments) == 3:
		output, err = handleSingleTorrent(requestPath, w, r, t)
	case len(filteredSegments) > 3:
		HandleGetRequest(w, r, t, c, cache)
	default:
		writeHTTPError(w, "Not Found", http.StatusNotFound)
		return
	}

	if err != nil {
		log.Printf("Error processing request: %v\n", err)
		writeHTTPError(w, "Server error", http.StatusInternalServerError)
		return
	}

	if output != nil {
		cache.Add(requestPath, *output)

		w.Header().Set("Content-Type", "text/html; charset=\"utf-8\"")
		w.WriteHeader(http.StatusOK)
		fmt.Fprint(w, *output)
	}
}

func handleRoot(w http.ResponseWriter, r *http.Request, c config.ConfigInterface) (*string, error) {
	htmlDoc := "<ul>"

	for _, directory := range c.GetDirectories() {
		htmlDoc += fmt.Sprintf("<li><a href=\"/http/%s/\">%s</a></li>", directory, directory)
	}

	return &htmlDoc, nil
}

func handleListOfTorrents(requestPath string, w http.ResponseWriter, r *http.Request, t *torrent.TorrentManager, c config.ConfigInterface) (*string, error) {
	basePath := path.Base(requestPath)

	for _, directory := range c.GetDirectories() {
		if basePath == directory {
			torrents := t.GetByDirectory(basePath)
			resp, err := createMultiTorrentResponse(requestPath, torrents)
			if err != nil {
				return nil, fmt.Errorf("cannot read directory (%s): %w", basePath, err)
			}
			return &resp, nil
		}
	}

	return nil, fmt.Errorf("cannot find directory when generating list: %s", requestPath)
}

func handleSingleTorrent(requestPath string, w http.ResponseWriter, r *http.Request, t *torrent.TorrentManager) (*string, error) {
	fullDir := path.Dir(requestPath)
	directory := path.Base(fullDir)
	torrentName := path.Base(requestPath)

	sameNameTorrents := findAllTorrentsWithName(t, directory, torrentName)
	if len(sameNameTorrents) == 0 {
		return nil, fmt.Errorf("cannot find directory when generating single torrent: %s", requestPath)
	}

	resp, err := createSingleTorrentResponse(requestPath, sameNameTorrents)
	if err != nil {
		return nil, fmt.Errorf("cannot read directory (%s): %w", requestPath, err)
	}
	return &resp, nil
}

func writeHTTPError(w http.ResponseWriter, errorMessage string, statusCode int) {
	log.Println(errorMessage)
	http.Error(w, errorMessage, statusCode)
}

func removeEmptyStrings(slice []string) []string {
	var result []string
	for _, s := range slice {
		if s != "" {
			result = append(result, s)
		}
	}
	return result
}