package handlers

import (
	"errors"
	"fmt"
	"net/http"
	"os"
	"time"

	"warpbox.dev/backend/libs/helpers"
	"warpbox.dev/backend/libs/web"
)

type downloadPageData struct {
	Box           boxView
	Files         []fileView
	ZipURL        string
	DownloadCount int
	MaxDownloads  int
	ExpiresLabel  string
}

type boxView struct {
	ID string
}

type fileView struct {
	ID          string
	Name        string
	Size        string
	ContentType string
	URL         string
}

func (a *App) DownloadPage(w http.ResponseWriter, r *http.Request) {
	box, err := a.uploadService.GetBox(r.PathValue("boxID"))
	if err != nil {
		http.NotFound(w, r)
		return
	}
	if err := a.uploadService.CanDownload(box); err != nil {
		a.renderer.Render(w, http.StatusForbidden, "download.gohtml", web.PageData{
			Title:       "Download unavailable",
			Description: "This Warpbox link is no longer available.",
			Data: downloadPageData{
				Box:          boxView{ID: box.ID},
				ExpiresLabel: err.Error(),
			},
		})
		return
	}

	files := make([]fileView, 0, len(box.Files))
	for _, file := range box.Files {
		files = append(files, fileView{
			ID:          file.ID,
			Name:        file.Name,
			Size:        helpers.FormatBytes(file.Size),
			ContentType: file.ContentType,
			URL:         fmt.Sprintf("/d/%s/f/%s", box.ID, file.ID),
		})
	}

	a.renderer.Render(w, http.StatusOK, "download.gohtml", web.PageData{
		Title:       "Download files",
		Description: "Download files shared through Warpbox.",
		Data: downloadPageData{
			Box:           boxView{ID: box.ID},
			Files:         files,
			ZipURL:        fmt.Sprintf("/d/%s/zip", box.ID),
			DownloadCount: box.DownloadCount,
			MaxDownloads:  box.MaxDownloads,
			ExpiresLabel:  box.ExpiresAt.Format("Jan 2, 2006 15:04 MST"),
		},
	})
}

func (a *App) DownloadFile(w http.ResponseWriter, r *http.Request) {
	box, err := a.uploadService.GetBox(r.PathValue("boxID"))
	if err != nil {
		http.NotFound(w, r)
		return
	}
	if err := a.uploadService.CanDownload(box); err != nil {
		http.Error(w, err.Error(), statusForDownloadError(err))
		return
	}

	file, err := a.uploadService.FindFile(box, r.PathValue("fileID"))
	if err != nil {
		http.NotFound(w, r)
		return
	}

	path := a.uploadService.FilePath(box, file)
	source, err := os.Open(path)
	if err != nil {
		http.NotFound(w, r)
		return
	}
	defer source.Close()

	stat, err := source.Stat()
	if err != nil {
		http.NotFound(w, r)
		return
	}

	w.Header().Set("Content-Type", file.ContentType)
	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%q", file.Name))
	http.ServeContent(w, r, file.Name, stat.ModTime(), source)

	if err := a.uploadService.RecordDownload(box.ID); err != nil && !errors.Is(err, os.ErrNotExist) {
		a.logger.Warn("failed to record file download", "source", "download", "code", 4002, "box_id", box.ID, "error", err.Error())
	}
}

func (a *App) DownloadZip(w http.ResponseWriter, r *http.Request) {
	box, err := a.uploadService.GetBox(r.PathValue("boxID"))
	if err != nil {
		http.NotFound(w, r)
		return
	}
	if err := a.uploadService.CanDownload(box); err != nil {
		http.Error(w, err.Error(), statusForDownloadError(err))
		return
	}

	w.Header().Set("Content-Type", "application/zip")
	w.Header().Set("Content-Disposition", fmt.Sprintf("attachment; filename=%q", "warpbox-"+box.ID+".zip"))
	w.Header().Set("Last-Modified", time.Now().UTC().Format(http.TimeFormat))

	if err := a.uploadService.WriteZip(w, box); err != nil {
		a.logger.Error("zip download failed", "source", "download", "code", 5002, "box_id", box.ID, "error", err.Error())
		return
	}
	if err := a.uploadService.RecordDownload(box.ID); err != nil && !errors.Is(err, os.ErrNotExist) {
		a.logger.Warn("failed to record zip download", "source", "download", "code", 4003, "box_id", box.ID, "error", err.Error())
	}
}