package universal

import (
	"io"
	"net/http"
	"path/filepath"
	"strings"

	"github.com/debridmediamanager/zurg/internal/config"
	intTor "github.com/debridmediamanager/zurg/internal/torrent"
	zurghttp "github.com/debridmediamanager/zurg/pkg/http"
	"github.com/debridmediamanager/zurg/pkg/logutil"
	"github.com/debridmediamanager/zurg/pkg/realdebrid"
)

type Downloader struct {
	client *zurghttp.HTTPClient
}

func NewDownloader(client *zurghttp.HTTPClient) *Downloader {
	return &Downloader{
		client: client,
	}
}

// DownloadFile handles a GET request for files in torrents
func (dl *Downloader) DownloadFile(directory, torrentName, fileName string, resp http.ResponseWriter, req *http.Request, torMgr *intTor.TorrentManager, cfg config.ConfigInterface, log *logutil.Logger) {
	torrents, ok := torMgr.DirectoryMap.Get(directory)
	if !ok {
		log.Warnf("Cannot find directory %s", directory)
		http.Error(resp, "File not found", http.StatusNotFound)
		return
	}

	torrent, ok := torrents.Get(torrentName)
	if !ok {
		log.Warnf("Cannot find torrent %sfrom path %s", torrentName, req.URL.Path)
		http.Error(resp, "File not found", http.StatusNotFound)
		return
	}

	file, ok := torrent.SelectedFiles.Get(fileName)
	if !ok || file.IsDeleted {
		log.Warnf("Cannot find file %s from path %s", fileName, req.URL.Path)
		http.Error(resp, "File not found", http.StatusNotFound)
		return
	}

	// log.Debugf("Opening file %s from torrent %s (%s)", fileName, torMgr.GetKey(torrent), file.Link)
	if file.IsBroken {
		http.Error(resp, "File is not available", http.StatusInternalServerError)
		return
	}

	unrestrict := torMgr.UnrestrictUntilOk(file.Link)
	if unrestrict == nil {
		file.IsBroken = true
		if cfg.EnableRepair() {
			log.Warnf("File %s cannot be unrestricted (link=%s) (repairing...)", fileName, file.Link)
			torMgr.TriggerRepair(torrent)
		} else {
			log.Warnf("Repair is disabled, skipping repair for unavailable file %s (link=%s)", fileName, file.Link)
		}
		http.Error(resp, "File is not available", http.StatusInternalServerError)
		return
	} else {
		if unrestrict.Filesize != file.Bytes {
			// this is possible if there's only 1 streamable file in the torrent
			// and then suddenly it's a rar file
			actualExt := strings.ToLower(filepath.Ext(unrestrict.Filename))
			expectedExt := strings.ToLower(filepath.Ext(fileName))
			if actualExt != expectedExt && unrestrict.Streamable != 1 {
				log.Warnf("File was changed and is not streamable: %s and %s (link=%s)", fileName, unrestrict.Filename, unrestrict.Link)
			} else {
				log.Warnf("File mismatch: %s and %s", fileName, unrestrict.Filename)
			}
		}
		if cfg.ShouldServeFromRclone() {
			if cfg.ShouldVerifyDownloadLink() {
				if !dl.client.CanFetchFirstByte(unrestrict.Download) {
					log.Warnf("File %s is not available", fileName)
					http.Error(resp, "File is not available", http.StatusInternalServerError)
					return
				}
			}
			redirect(resp, req, unrestrict.Download, cfg)
		} else {
			dl.streamFileToResponse(torrent, file, unrestrict, resp, req, torMgr, cfg, log)
		}
		return
	}
}

// DownloadLink handles a GET request for downloads
func (dl *Downloader) DownloadLink(fileName, link string, resp http.ResponseWriter, req *http.Request, torMgr *intTor.TorrentManager, cfg config.ConfigInterface, log *logutil.Logger) {
	// log.Debugf("Opening file %s (%s)", fileName, link)
	unrestrict := torMgr.UnrestrictUntilOk(link)
	if unrestrict == nil {
		log.Warnf("File %s cannot be unrestricted (link=%s)", fileName, link)
		http.Error(resp, "File is not available", http.StatusInternalServerError)
		return
	} else {
		lFilename := strings.ToLower(fileName)
		unrestrictFilename := strings.ToLower(strings.TrimPrefix(unrestrict.Filename, "/"))
		if strings.Contains(lFilename, unrestrictFilename) {
			// this is possible if there's only 1 streamable file in the torrent
			// and then suddenly it's a rar file
			actualExt := filepath.Ext(unrestrictFilename)
			expectedExt := filepath.Ext(lFilename)
			if actualExt != expectedExt && unrestrict.Streamable != 1 {
				log.Warnf("File was changed and is not streamable: %s and %s (link=%s)", fileName, unrestrict.Filename, unrestrict.Link)
			} else {
				log.Warnf("Filename mismatch: %s and %s", fileName, unrestrict.Filename)
			}
		}
		if cfg.ShouldServeFromRclone() {
			if cfg.ShouldVerifyDownloadLink() {
				if !dl.client.CanFetchFirstByte(unrestrict.Download) {
					log.Warnf("File %s is not available", fileName)
					http.Error(resp, "File is not available", http.StatusInternalServerError)
					return
				}
			}
			redirect(resp, req, unrestrict.Download, cfg)
		} else {
			dl.streamFileToResponse(nil, nil, unrestrict, resp, req, torMgr, cfg, log)
		}
		return
	}
}

func (dl *Downloader) streamFileToResponse(torrent *intTor.Torrent, file *intTor.File, unrestrict *realdebrid.Download, resp http.ResponseWriter, req *http.Request, torMgr *intTor.TorrentManager, cfg config.ConfigInterface, log *logutil.Logger) {
	// Create a new request for the file download.
	dlReq, err := http.NewRequest(http.MethodGet, unrestrict.Download, nil)
	if err != nil {
		if file != nil {
			log.Errorf("Error creating new request for file %s: %v", file.Path, err)
		}
		http.Error(resp, "File is not available", http.StatusInternalServerError)
		return
	}

	// copy range header if it exists
	// rangeLog := ""
	if req.Header.Get("Range") != "" {
		dlReq.Header.Add("Range", req.Header.Get("Range"))
		// rangeLog = " (range: " + req.Header.Get("Range") + ")"
	}

	// if torrent != nil {
	// 	log.Debugf("Downloading unrestricted link %s from torrent %s (%s)%s", unrestrict.Download, torMgr.GetKey(torrent), unrestrict.Link, rangeLog)
	// } else {
	// 	log.Debugf("Downloading unrestricted link %s (%s)%s", unrestrict.Download, unrestrict.Link, rangeLog)
	// }

	download, err := dl.client.Do(dlReq)
	if err != nil {
		if file != nil && unrestrict.Streamable == 1 {
			file.IsBroken = true
			if cfg.EnableRepair() && torrent != nil {
				log.Warnf("Cannot download file %s: %v (repairing...)", unrestrict.Download, err)
				torMgr.TriggerRepair(torrent)
			} else {
				log.Warnf("Repair is disabled, skipping repair for unavailable file %s (link=%s)", file.Path, file.Link)
			}
		} else {
			log.Warnf("Cannot download file %s: %v", unrestrict.Download, err)
		}
		http.Error(resp, "File is not available", http.StatusInternalServerError)
		return
	}
	defer download.Body.Close()

	if download.StatusCode/100 != 2 {
		if file != nil && unrestrict.Streamable == 1 {
			file.IsBroken = true
			if cfg.EnableRepair() && torrent != nil {
				log.Warnf("Received a %s status code for file %s (repairing...)", download.Status, file.Path)
				torMgr.TriggerRepair(torrent)
			} else {
				log.Warnf("Repair is disabled, skipping repair for unavailable file %s (link=%s)", file.Path, file.Link)
			}
		} else {
			log.Warnf("Received a %s status code for file %s", download.Status, unrestrict.Download)
		}
		http.Error(resp, "File is not available", http.StatusInternalServerError)
		return
	}

	for k, vv := range download.Header {
		for _, v := range vv {
			resp.Header().Add(k, v)
		}
	}

	// log.Debugf("Serving file %s%s", unrestrict.Download, rangeLog)

	buf := make([]byte, cfg.GetNetworkBufferSize())
	io.CopyBuffer(resp, download.Body, buf)
}

func redirect(resp http.ResponseWriter, req *http.Request, url string, cfg config.ConfigInterface) {
	http.Redirect(resp, req, url, http.StatusFound)
}