markdown-hub/internal/api/handlers.go

package api

import (
	"encoding/json"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"sync"
	"time"

	"github.com/google/uuid"

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

const maxBodySize = 10 * 1024 * 1024 // 10MB

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()
	limited := io.LimitReader(r.Body, maxBodySize)
	return json.NewDecoder(limited).Decode(v)
}

// Simple rate limiter for login
var loginAttempts = struct {
	sync.Mutex
	m map[string][]time.Time
}{m: make(map[string][]time.Time)}

func isRateLimited(ip string) bool {
	loginAttempts.Lock()
	defer loginAttempts.Unlock()
	now := time.Now()
	cutoff := now.Add(-5 * time.Minute)
	// Clean old entries
	valid := loginAttempts.m[ip][:0]
	for _, t := range loginAttempts.m[ip] {
		if t.After(cutoff) {
			valid = append(valid, t)
		}
	}
	loginAttempts.m[ip] = valid
	return len(valid) >= 10 // max 10 attempts per 5 minutes
}

func recordLoginAttempt(ip string) {
	loginAttempts.Lock()
	defer loginAttempts.Unlock()
	loginAttempts.m[ip] = append(loginAttempts.m[ip], time.Now())
}

func validatePassword(pw string) string {
	if len(pw) < 8 {
		return "password must be at least 8 characters"
	}
	return ""
}

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

func (s *Server) handleLogin(w http.ResponseWriter, r *http.Request) {
	ip := r.RemoteAddr
	if isRateLimited(ip) {
		writeJSON(w, 429, map[string]string{"error": "too many attempts, try again later"})
		return
	}

	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)

	localAuthOK := err == nil && auth.CheckPassword(hash, req.Password)

	// Try LDAP if local auth failed
	if !localAuthOK {
		ldapCfg := auth.LDAPConfigFromEnv()
		if ldapCfg != nil {
			email, displayName, ldapErr := auth.LDAPAuth(ldapCfg, req.Email, req.Password)
			if ldapErr == nil {
				// LDAP success — find or create local user
				err2 := s.db.QueryRow(
					"SELECT id, password_hash, is_admin, totp_secret FROM users WHERE email = ?", email,
				).Scan(&id, &hash, &isAdmin, &totpSecret)
				if err2 != nil {
					// Auto-create user from LDAP
					id = uuid.New().String()
					username := displayName
					if username == "" {
						username = req.Email
					}
					s.db.Exec(
						"INSERT INTO users (id, username, email, password_hash, is_admin) VALUES (?, ?, ?, ?, 0)",
						id, username, email, "ldap",
					)
					files.EnsureUserDir(s.dataDir, id)
					totpSecret = nil
				}
				localAuthOK = true
			}
		}
	}

	if !localAuthOK {
		recordLoginAttempt(ip)
		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,
		Secure:   r.Header.Get("X-Forwarded-Proto") == "https",
		SameSite: http.SameSiteLaxMode,
		Expires:  time.Now().Add(72 * time.Hour),
	})

	writeJSON(w, 200, map[string]interface{}{
		"token":   token,
		"userId":  id,
		"isAdmin": isAdmin,
	})
	s.audit(id, "login", req.Email)
}

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
	}
	if msg := validatePassword(req.NewPassword); msg != "" {
		writeJSON(w, 400, map[string]string{"error": msg})
		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)
	s.audit(userID, "change_password", "")
	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
	}
	if msg := validatePassword(req.Password); msg != "" {
		writeJSON(w, 400, map[string]string{"error": msg})
		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"`
		OwnerID string `json:"owner_id"`
	}
	if err := decodeBody(r, &req); err != nil || req.Path == "" {
		writeJSON(w, 400, map[string]string{"error": "path required"})
		return
	}

	userID := getUserID(r)
	readFrom := userID

	// If owner_id specified, check permissions (shared file access)
	if req.OwnerID != "" && req.OwnerID != userID {
		var level string
		err := s.db.QueryRow(`
			SELECT p.level FROM permissions p
			JOIN files f ON f.id = p.file_id
			WHERE f.owner_id = ? AND f.path = ? AND p.user_id = ?`,
			req.OwnerID, req.Path, userID).Scan(&level)
		if err != nil {
			writeJSON(w, 403, map[string]string{"error": "access denied"})
			return
		}
		readFrom = req.OwnerID
	}

	content, err := files.ReadFile(s.dataDir, readFrom, req.Path)
	if err != nil {
		writeJSON(w, 404, map[string]string{"error": "file not found"})
		return
	}
	created := files.GetCreatedTime(s.dataDir, readFrom, 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
	}
	if len(req.Content) > maxBodySize {
		writeJSON(w, 413, map[string]string{"error": "file too large (max 10MB)"})
		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) handleRenameFile(w http.ResponseWriter, r *http.Request) {
	var req struct {
		Path    string `json:"path"`
		NewName string `json:"new_name"`
	}
	if err := decodeBody(r, &req); err != nil || req.Path == "" || req.NewName == "" {
		writeJSON(w, 400, map[string]string{"error": "path and new_name required"})
		return
	}

	userID := getUserID(r)
	dir := filepath.Dir(req.Path)
	newPath := filepath.Join(dir, req.NewName)
	if err := files.MoveFile(s.dataDir, userID, req.Path, newPath); err != nil {
		writeJSON(w, 500, map[string]string{"error": "rename failed"})
		return
	}
	s.audit(userID, "rename", req.Path+" -> "+newPath)
	writeJSON(w, 200, map[string]string{"status": "renamed", "new_path": newPath})
}

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) handleUploadImage(w http.ResponseWriter, r *http.Request) {
	r.Body = http.MaxBytesReader(w, r.Body, 10*1024*1024)
	if err := r.ParseMultipartForm(10 << 20); err != nil {
		writeJSON(w, 413, map[string]string{"error": "file too large (max 10MB)"})
		return
	}
	file, header, err := r.FormFile("image")
	if err != nil {
		writeJSON(w, 400, map[string]string{"error": "image field required"})
		return
	}
	defer file.Close()

	userID := getUserID(r)
	assetsDir := filepath.Join(files.UserDir(s.dataDir, userID), ".assets")
	os.MkdirAll(assetsDir, 0755)

	filename := header.Filename
	dest := filepath.Join(assetsDir, filename)
	out, err := os.Create(dest)
	if err != nil {
		writeJSON(w, 500, map[string]string{"error": "save failed"})
		return
	}
	defer out.Close()
	io.Copy(out, file)

	url := "/api/files/image/" + filename
	writeJSON(w, 200, map[string]string{"url": url, "filename": filename})
}

func (s *Server) handleServeImage(w http.ResponseWriter, r *http.Request) {
	userID := getUserID(r)
	filename := filepath.Base(r.URL.Path)
	if filename == "" || filename == "." {
		http.Error(w, "not found", 404)
		return
	}
	p := filepath.Join(files.UserDir(s.dataDir, userID), ".assets", filename)
	http.ServeFile(w, r, p)
}

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"})
}