package handler

import (
	"archive/zip"
	"fmt"
	"html/template"
	"io"
	"log"
	"net/http"
	"strings"
	"time"

	"golang.org/x/crypto/bcrypt"

	"github.com/jeffemmett/upload-service/internal/store"
)

var batchTmpl *template.Template
var batchPasswordTmpl *template.Template

// batchPasswordHash returns the password hash if any file in the batch is password-protected.
func batchPasswordHash(files []*store.FileRecord) *string {
	for _, f := range files {
		if f.PasswordHash != nil {
			return f.PasswordHash
		}
	}
	return nil
}

// checkBatchAuth returns true if the batch auth cookie is present and valid.
func checkBatchAuth(r *http.Request, batchID string) bool {
	cookie, err := r.Cookie("auth_b_" + batchID)
	return err == nil && cookie.Value == "granted"
}

func (h *Handler) Batch(w http.ResponseWriter, r *http.Request) {
	batchID := r.PathValue("slug")
	if batchID == "" {
		http.NotFound(w, r)
		return
	}

	files, err := h.store.GetBatch(batchID)
	if err != nil {
		log.Printf("db get batch error: %v", err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}
	if len(files) == 0 {
		http.NotFound(w, r)
		return
	}

	// Check batch-level password
	if hash := batchPasswordHash(files); hash != nil {
		if !checkBatchAuth(r, batchID) {
			http.Redirect(w, r, "/"+batchID+"/auth", http.StatusSeeOther)
			return
		}
	}

	type fileData struct {
		ID          string
		Filename    string
		Size        int64
		ContentType string
		UploadedAt  string
		ThumbType   string
		PreviewURL  string
		ViewURL     string
		DownloadURL string
	}

	var items []fileData
	var totalSize int64
	for _, f := range files {
		if f.ExpiresAt != nil && f.ExpiresAt.Before(time.Now().UTC()) {
			continue
		}

		thumbType := ""
		previewURL := ""
		if strings.HasPrefix(f.ContentType, "image/") {
			thumbType = "image"
		} else if strings.HasPrefix(f.ContentType, "video/") {
			thumbType = "video"
		} else if strings.HasPrefix(f.ContentType, "audio/") {
			thumbType = "audio"
		} else if f.ContentType == "application/pdf" {
			thumbType = "pdf"
		}
		if thumbType != "" {
			if url, err := h.r2.PresignGet(r.Context(), f.R2Key, f.Filename, true); err == nil {
				previewURL = url
			}
		}

		totalSize += f.SizeBytes
		items = append(items, fileData{
			ID:          f.ID,
			Filename:    f.Filename,
			Size:        f.SizeBytes,
			ContentType: f.ContentType,
			UploadedAt:  f.UploadedAt.Format("Jan 2, 2006 at 3:04 PM"),
			ThumbType:   thumbType,
			PreviewURL:  previewURL,
			ViewURL:     "/f/" + f.ID + "/view",
			DownloadURL: "/f/" + f.ID + "/dl",
		})
	}

	if len(items) == 0 {
		http.NotFound(w, r)
		return
	}

	data := map[string]any{
		"BatchID":   batchID,
		"Files":     items,
		"Count":     len(items),
		"TotalSize": totalSize,
	}

	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	w.Header().Set("Cache-Control", "no-cache, must-revalidate")
	batchTmpl.Execute(w, data)
}

// BatchDownload streams all batch files as a zip archive.
func (h *Handler) BatchDownload(w http.ResponseWriter, r *http.Request) {
	batchID := r.PathValue("slug")
	if batchID == "" {
		http.NotFound(w, r)
		return
	}

	files, err := h.store.GetBatch(batchID)
	if err != nil {
		log.Printf("db get batch error: %v", err)
		http.Error(w, "internal error", http.StatusInternalServerError)
		return
	}
	if len(files) == 0 {
		http.NotFound(w, r)
		return
	}

	// Check batch-level password
	if hash := batchPasswordHash(files); hash != nil {
		if !checkBatchAuth(r, batchID) {
			http.Redirect(w, r, "/"+batchID+"/auth", http.StatusSeeOther)
			return
		}
	}

	w.Header().Set("Content-Type", "application/zip")
	w.Header().Set("Content-Disposition", fmt.Sprintf(`attachment; filename="%s.zip"`, batchID))

	zw := zip.NewWriter(w)
	defer zw.Close()

	for _, f := range files {
		if f.ExpiresAt != nil && f.ExpiresAt.Before(time.Now().UTC()) {
			continue
		}

		dlURL, err := h.r2.PresignGet(r.Context(), f.R2Key, f.Filename, false)
		if err != nil {
			log.Printf("batch zip presign error for %s: %v", f.ID, err)
			continue
		}

		resp, err := http.Get(dlURL)
		if err != nil {
			log.Printf("batch zip fetch error for %s: %v", f.ID, err)
			continue
		}

		fw, err := zw.Create(f.Filename)
		if err != nil {
			resp.Body.Close()
			log.Printf("batch zip create entry error: %v", err)
			continue
		}

		io.Copy(fw, resp.Body)
		resp.Body.Close()
	}
}

// BatchAuthPage shows the password form for a batch.
func (h *Handler) BatchAuthPage(w http.ResponseWriter, r *http.Request) {
	batchID := r.PathValue("slug")
	if batchID == "" {
		http.NotFound(w, r)
		return
	}

	files, err := h.store.GetBatch(batchID)
	if err != nil || len(files) == 0 {
		http.NotFound(w, r)
		return
	}

	if batchPasswordHash(files) == nil {
		http.Redirect(w, r, "/"+batchID, http.StatusSeeOther)
		return
	}

	data := map[string]any{
		"BatchID": batchID,
		"Count":   len(files),
		"Error":   r.URL.Query().Get("error"),
	}
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	batchPasswordTmpl.Execute(w, data)
}

// BatchAuthSubmit validates the password and sets a batch cookie.
func (h *Handler) BatchAuthSubmit(w http.ResponseWriter, r *http.Request) {
	batchID := r.PathValue("slug")
	if batchID == "" {
		http.NotFound(w, r)
		return
	}

	if err := r.ParseForm(); err != nil {
		http.Error(w, "bad request", http.StatusBadRequest)
		return
	}

	password := r.FormValue("password")
	if password == "" {
		http.Redirect(w, r, "/"+batchID+"/auth?error=password+required", http.StatusSeeOther)
		return
	}

	files, err := h.store.GetBatch(batchID)
	if err != nil || len(files) == 0 {
		http.NotFound(w, r)
		return
	}

	hash := batchPasswordHash(files)
	if hash == nil {
		http.Redirect(w, r, "/"+batchID, http.StatusSeeOther)
		return
	}

	if err := bcrypt.CompareHashAndPassword([]byte(*hash), []byte(password)); err != nil {
		http.Redirect(w, r, "/"+batchID+"/auth?error=wrong+password", http.StatusSeeOther)
		return
	}

	// Set batch auth cookie (10 min, covers /b/ and /f/ paths)
	http.SetCookie(w, &http.Cookie{
		Name:     "auth_b_" + batchID,
		Value:    "granted",
		Path:     "/",
		MaxAge:   600,
		HttpOnly: true,
		SameSite: http.SameSiteLaxMode,
		Secure:   true,
		Expires:  time.Now().Add(10 * time.Minute),
	})

	http.Redirect(w, r, "/"+batchID, http.StatusSeeOther)
}