package universal

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

	"github.com/debridmediamanager.com/zurg/internal/config"
	"github.com/debridmediamanager.com/zurg/internal/dav"
	intHttp "github.com/debridmediamanager.com/zurg/internal/http"
	intTor "github.com/debridmediamanager.com/zurg/internal/torrent"
	zurghttp "github.com/debridmediamanager.com/zurg/pkg/http"
	"go.uber.org/zap"
)

type GetFile struct {
	client *zurghttp.HTTPClient
}

func NewGetFile(client *zurghttp.HTTPClient) *GetFile {
	return &GetFile{client: client}
}

// HandleGetRequest handles a GET request universally for both WebDAV and HTTP
func (gf *GetFile) HandleGetRequest(w http.ResponseWriter, r *http.Request, t *intTor.TorrentManager, c config.ConfigInterface, log *zap.SugaredLogger) {
	requestPath := path.Clean(r.URL.Path)
	isDav := true
	if strings.Contains(requestPath, "/http") {
		requestPath = strings.Replace(requestPath, "/http", "/", 1)
		isDav = false
	}
	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) <= 3 {
		if isDav {
			dav.HandlePropfindRequest(w, r, t, log)
		} else {
			intHttp.HandleDirectoryListing(w, r, t, log)
		}
		return
	}

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

	torrents, ok := t.DirectoryMap.Get(baseDirectory)
	if !ok {
		log.Warnf("Cannot find directory %s", baseDirectory)
		http.Error(w, "File not found", http.StatusNotFound)
		return
	}
	torrent, ok := torrents.Get(accessKey)
	if !ok {
		log.Warnf("Cannot find torrent %s in the directory %s", accessKey, baseDirectory)
		http.Error(w, "File not found", http.StatusNotFound)
		return
	}

	file, ok := torrent.SelectedFiles.Get(filename)
	if !ok {
		log.Warnf("Cannot find file from path %s", requestPath)
		http.Error(w, "File not found", http.StatusNotFound)
		return
	}

	if !strings.HasPrefix(file.Link, "http") {
		// This is a dead file, serve an alternate file
		log.Warnf("File %s is not available", filename)
		http.Error(w, "File is not available", http.StatusNotFound)
		return
	}
	link := file.Link

	if download, exists := t.DownloadCache.Get(link); exists {
		if c.ShouldServeFromRclone() && t.Api.CanFetchFirstByte(download.Download) {
			redirect(w, r, download.Download, c)
		} else {
			err := gf.streamCachedLinkToResponse(download.Download, w, r, t, c, log)
			if err == nil {
				return
			}
		}
	}

	resp := t.UnrestrictUntilOk(link)
	if resp == nil {
		// log.Warnf("File %s is no longer available, link %s", filepath.Base(file.Path), link)
		file.Link = "repair"
		if c.EnableRepair() {
			// log.Debugf("File %s is marked for repair", filepath.Base(file.Path))
			t.SetChecksum("") // force a recheck
		}
		http.Error(w, "File is not available", http.StatusNotFound)
		return
	} else {
		if resp.Filename != filename {
			// this is possible if there's only 1 streamable file in the torrent
			// and then suddenly it's a rar file
			actualExt := filepath.Ext(resp.Filename)
			expectedExt := filepath.Ext(filename)
			if actualExt != expectedExt && resp.Streamable != 1 {
				log.Warnf("File was changed and is not streamable: %s and %s", filename, resp.Filename)
				http.Error(w, "File is not available", http.StatusNotFound)
				return
			} else {
				log.Warnf("Filename mismatch: %s and %s", filename, resp.Filename)
			}
		}
		t.DownloadCache.Set(link, resp)
		if c.ShouldServeFromRclone() {
			redirect(w, r, resp.Download, c)
		} else {
			gf.streamFileToResponse(file, resp.Download, w, r, t, c, log)
		}
		return
	}
}

func (gf *GetFile) streamCachedLinkToResponse(url string, w http.ResponseWriter, r *http.Request, torMgr *intTor.TorrentManager, cfg config.ConfigInterface, log *zap.SugaredLogger) error {
	// Create a new request for the file download.
	req, err := http.NewRequest(http.MethodGet, url, nil)
	if err != nil {
		return fmt.Errorf("file is not available")
	}

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

	resp, err := gf.client.Do(req)
	if err != nil {
		return fmt.Errorf("file is not available")
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusPartialContent {
		return fmt.Errorf("file is not available")
	}

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

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

func (gf *GetFile) streamFileToResponse(file *intTor.File, url string, w http.ResponseWriter, r *http.Request, torMgr *intTor.TorrentManager, cfg config.ConfigInterface, log *zap.SugaredLogger) {
	// Create a new request for the file download.
	req, err := http.NewRequest(http.MethodGet, url, nil)
	if err != nil {
		if file != nil {
			log.Errorf("Error creating new request for file %s: %v", file.Path, err)
		}
		http.Error(w, "File is not available", http.StatusNotFound)
		return
	}

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

	resp, err := gf.client.Do(req)
	if err != nil {
		if file != nil {
			log.Warnf("Cannot download file %s: %v", file.Path, err)
			file.Link = "repair"
			if cfg.EnableRepair() {
				// log.Debugf("File %s is marked for repair", filepath.Base(file.Path))
				torMgr.SetChecksum("") // force a recheck
			}
		}
		http.Error(w, "File is not available", http.StatusNotFound)
		return
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusPartialContent {
		if file != nil {
			log.Warnf("Received a %s status code for file %s", resp.Status, file.Path)
			file.Link = "repair"
			if cfg.EnableRepair() {
				// log.Debugf("File %s is marked for repair", filepath.Base(file.Path))
				torMgr.SetChecksum("") // force a recheck
			}
		}
		http.Error(w, "File is not available", http.StatusNotFound)
		return
	}

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

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

func redirect(w http.ResponseWriter, r *http.Request, url string, c config.ConfigInterface) {
	prefHost := c.GetRandomPreferredHost()
	if prefHost != "" {
		url = replaceHostInURL(url, prefHost)
	}
	http.Redirect(w, r, url, http.StatusFound)
}

func replaceHostInURL(inputURL string, newHost string) string {
	u, err := url.Parse(inputURL)
	if err != nil {
		return ""
	}
	u.Host = newHost
	return u.String()
}