package api

import (
	"encoding/json"
	"net/http"
	"time"

	"github.com/google/uuid"

	"markdownhub/internal/auth"
	"markdownhub/internal/files"
	"markdownhub/internal/git"
)

func writeJSON(w http.ResponseWriter, status int, v interface{}) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	json.NewEncoder(w).Encode(v)
}

func decodeBody(r *http.Request, v interface{}) error {
	defer r.Body.Close()
	return json.NewDecoder(r.Body).Decode(v)
}

// ─── Auth ────────────────────────────────────────────────────────────────────

func (s *Server) handleLogin(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Email    string `json:"email"`
		Password string `json:"password"`
		TOTPCode string `json:"totp_code"`
	}
	if err := decodeBody(r, &req); err != nil {
		writeJSON(w, 400, map[string]string{"error": "invalid request"})
		return
	}

	var id, hash string
	var isAdmin bool
	var totpSecret *string
	err := s.db.QueryRow(
		"SELECT id, password_hash, is_admin, totp_secret FROM users WHERE email = ?", req.Email,
	).Scan(&id, &hash, &isAdmin, &totpSecret)
	if err != nil || !auth.CheckPassword(hash, req.Password) {
		writeJSON(w, 401, map[string]string{"error": "invalid credentials"})
		return
	}

	// Check TOTP if enabled
	if totpSecret != nil && *totpSecret != "" {
		if req.TOTPCode == "" {
			writeJSON(w, 401, map[string]string{"error": "totp_required"})
			return
		}
		if !auth.ValidateTOTP(*totpSecret, req.TOTPCode) {
			writeJSON(w, 401, map[string]string{"error": "invalid TOTP code"})
			return
		}
	}

	token, err := auth.CreateToken(id, isAdmin, s.secret)
	if err != nil {
		writeJSON(w, 500, map[string]string{"error": "token creation failed"})
		return
	}

	http.SetCookie(w, &http.Cookie{
		Name:     "authToken",
		Value:    token,
		Path:     "/",
		HttpOnly: true,
		SameSite: http.SameSiteLaxMode,
		Expires:  time.Now().Add(72 * time.Hour),
	})

	writeJSON(w, 200, map[string]interface{}{
		"token":   token,
		"userId":  id,
		"isAdmin": isAdmin,
	})
}

func (s *Server) handleLogout(w http.ResponseWriter, r *http.Request) {
	http.SetCookie(w, &http.Cookie{
		Name:     "authToken",
		Value:    "",
		Path:     "/",
		HttpOnly: true,
		MaxAge:   -1,
	})
	writeJSON(w, 200, map[string]string{"status": "ok"})
}

func (s *Server) handleChangePassword(w http.ResponseWriter, r *http.Request) {
	var req struct {
		CurrentPassword string `json:"current_password"`
		NewPassword     string `json:"new_password"`
	}
	if err := decodeBody(r, &req); err != nil || req.CurrentPassword == "" || req.NewPassword == "" {
		writeJSON(w, 400, map[string]string{"error": "current_password and new_password required"})
		return
	}

	userID := getUserID(r)
	var hash string
	s.db.QueryRow("SELECT password_hash FROM users WHERE id = ?", userID).Scan(&hash)
	if !auth.CheckPassword(hash, req.CurrentPassword) {
		writeJSON(w, 401, map[string]string{"error": "current password is incorrect"})
		return
	}

	newHash, err := auth.HashPassword(req.NewPassword)
	if err != nil {
		writeJSON(w, 500, map[string]string{"error": "failed to hash password"})
		return
	}

	s.db.Exec("UPDATE users SET password_hash = ?, updated_at = datetime('now') WHERE id = ?", newHash, userID)
	writeJSON(w, 200, map[string]string{"status": "password changed"})
}

// ─── Users ───────────────────────────────────────────────────────────────────

func (s *Server) handleCreateUser(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Username string `json:"username"`
		Email    string `json:"email"`
		Password string `json:"password"`
		IsAdmin  bool   `json:"isAdmin"`
	}
	if err := decodeBody(r, &req); err != nil || req.Email == "" || req.Password == "" || req.Username == "" {
		writeJSON(w, 400, map[string]string{"error": "username, email, and password required"})
		return
	}

	hash, err := auth.HashPassword(req.Password)
	if err != nil {
		writeJSON(w, 500, map[string]string{"error": "failed to hash password"})
		return
	}

	id := uuid.New().String()
	_, err = s.db.Exec(
		"INSERT INTO users (id, username, email, password_hash, is_admin) VALUES (?, ?, ?, ?, ?)",
		id, req.Username, req.Email, hash, req.IsAdmin,
	)
	if err != nil {
		writeJSON(w, 409, map[string]string{"error": "user already exists"})
		return
	}

	// Create user's file directory
	files.EnsureUserDir(s.dataDir, id)

	writeJSON(w, 201, map[string]interface{}{"id": id, "username": req.Username, "email": req.Email})
}

func (s *Server) handleListUsers(w http.ResponseWriter, r *http.Request) {
	rows, err := s.db.Query("SELECT id, username, email, is_admin, created_at FROM users")
	if err != nil {
		writeJSON(w, 500, map[string]string{"error": "query failed"})
		return
	}
	defer rows.Close()

	var users []map[string]interface{}
	for rows.Next() {
		var id, username, email, createdAt string
		var isAdmin bool
		rows.Scan(&id, &username, &email, &isAdmin, &createdAt)
		users = append(users, map[string]interface{}{
			"id": id, "username": username, "email": email,
			"isAdmin": isAdmin, "createdAt": createdAt,
		})
	}
	if users == nil {
		users = []map[string]interface{}{}
	}
	writeJSON(w, 200, users)
}

// ─── Files ───────────────────────────────────────────────────────────────────

func (s *Server) handleListFiles(w http.ResponseWriter, r *http.Request) {
	userID := getUserID(r)
	tree, err := files.ListTree(s.dataDir, userID)
	if err != nil {
		writeJSON(w, 500, map[string]string{"error": "failed to list files"})
		return
	}
	if tree == nil {
		tree = []files.FileInfo{}
	}
	writeJSON(w, 200, tree)
}

func (s *Server) handleReadFile(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Path string `json:"path"`
	}
	if err := decodeBody(r, &req); err != nil || req.Path == "" {
		writeJSON(w, 400, map[string]string{"error": "path required"})
		return
	}

	userID := getUserID(r)
	content, err := files.ReadFile(s.dataDir, userID, req.Path)
	if err != nil {
		writeJSON(w, 404, map[string]string{"error": "file not found"})
		return
	}
	created := files.GetCreatedTime(s.dataDir, userID, req.Path)
	writeJSON(w, 200, map[string]interface{}{"path": req.Path, "content": content, "created": created})
}

func (s *Server) handleWriteFile(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Path    string `json:"path"`
		Content string `json:"content"`
	}
	if err := decodeBody(r, &req); err != nil || req.Path == "" {
		writeJSON(w, 400, map[string]string{"error": "path required"})
		return
	}

	userID := getUserID(r)
	if err := files.WriteFile(s.dataDir, userID, req.Path, req.Content); err != nil {
		writeJSON(w, 500, map[string]string{"error": "write failed"})
		return
	}

	// Auto-commit on save
	go func() {
		git.InitRepo(s.dataDir, userID)
		git.AutoCommit(s.dataDir, userID, req.Path)
	}()

	writeJSON(w, 200, map[string]string{"status": "ok", "path": req.Path})
}

func (s *Server) handleCreateFile(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Path    string `json:"path"`
		Content string `json:"content"`
	}
	if err := decodeBody(r, &req); err != nil || req.Path == "" {
		writeJSON(w, 400, map[string]string{"error": "path required"})
		return
	}

	userID := getUserID(r)
	if err := files.WriteFile(s.dataDir, userID, req.Path, req.Content); err != nil {
		writeJSON(w, 500, map[string]string{"error": "create failed"})
		return
	}
	writeJSON(w, 201, map[string]string{"status": "created", "path": req.Path})
}

func (s *Server) handleCreateFolder(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Path string `json:"path"`
	}
	if err := decodeBody(r, &req); err != nil || req.Path == "" {
		writeJSON(w, 400, map[string]string{"error": "path required"})
		return
	}

	userID := getUserID(r)
	if err := files.CreateFolder(s.dataDir, userID, req.Path); err != nil {
		writeJSON(w, 500, map[string]string{"error": "create folder failed"})
		return
	}
	writeJSON(w, 201, map[string]string{"status": "created", "path": req.Path})
}

func (s *Server) handleDeleteFile(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Path string `json:"path"`
	}
	if err := decodeBody(r, &req); err != nil || req.Path == "" {
		writeJSON(w, 400, map[string]string{"error": "path required"})
		return
	}

	userID := getUserID(r)
	if err := files.DeleteFile(s.dataDir, userID, req.Path); err != nil {
		writeJSON(w, 404, map[string]string{"error": "file not found"})
		return
	}
	writeJSON(w, 200, map[string]string{"status": "deleted"})
}

func (s *Server) handleMoveFile(w http.ResponseWriter, r *http.Request) {
	var req struct {
		From string `json:"from"`
		To   string `json:"to"`
	}
	if err := decodeBody(r, &req); err != nil || req.From == "" || req.To == "" {
		writeJSON(w, 400, map[string]string{"error": "from and to required"})
		return
	}

	userID := getUserID(r)
	if err := files.MoveFile(s.dataDir, userID, req.From, req.To); err != nil {
		writeJSON(w, 500, map[string]string{"error": "move failed"})
		return
	}
	writeJSON(w, 200, map[string]string{"status": "moved"})
}

func (s *Server) handleSharedFiles(w http.ResponseWriter, r *http.Request) {
	// TODO: query permissions table for files shared with this user
	// For now return empty list
	writeJSON(w, 200, []files.FileInfo{})
}

func (s *Server) handleListTrash(w http.ResponseWriter, r *http.Request) {
	userID := getUserID(r)
	items, err := files.ListTrash(s.dataDir, userID)
	if err != nil {
		writeJSON(w, 500, map[string]string{"error": "failed to list trash"})
		return
	}
	if items == nil {
		items = []files.FileInfo{}
	}
	writeJSON(w, 200, items)
}

func (s *Server) handleRestoreTrash(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Name string `json:"name"`
	}
	if err := decodeBody(r, &req); err != nil || req.Name == "" {
		writeJSON(w, 400, map[string]string{"error": "name required"})
		return
	}
	userID := getUserID(r)
	if err := files.RestoreFromTrash(s.dataDir, userID, req.Name); err != nil {
		writeJSON(w, 500, map[string]string{"error": "restore failed"})
		return
	}
	writeJSON(w, 200, map[string]string{"status": "restored"})
}

func (s *Server) handleEmptyTrash(w http.ResponseWriter, r *http.Request) {
	userID := getUserID(r)
	if err := files.EmptyTrash(s.dataDir, userID); err != nil {
		writeJSON(w, 500, map[string]string{"error": "empty trash failed"})
		return
	}
	writeJSON(w, 200, map[string]string{"status": "emptied"})
}