package app

import (
	"context"
	"fmt"
	"time"

	"go.uber.org/zap"

	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/config"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/domain/collection"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/domain/file"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/domain/session"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/service/auth"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/service/httpclient"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/service/keycache"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/service/passwordstore"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/service/ratelimiter"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/service/search"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/service/securitylog"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/service/storagemanager"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/service/sync"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/service/tokenmanager"
	"codeberg.org/mapleopentech/monorepo/native/desktop/maplefile/internal/utils"
)

// Application is the main Wails application struct
type Application struct {
	ctx            context.Context
	logger         *zap.Logger
	config         config.ConfigService
	authService    *auth.Service
	tokenManager   *tokenmanager.Manager
	passwordStore  *passwordstore.Service
	keyCache       *keycache.Service
	rateLimiter    *ratelimiter.Service
	httpClient     *httpclient.Service
	syncService    sync.Service
	storageManager *storagemanager.Manager
	securityLog    *securitylog.Service
	searchService  search.SearchService
}

// ProvideApplication creates the Application for Wire
func ProvideApplication(
	logger *zap.Logger,
	configService config.ConfigService,
	authService *auth.Service,
	tokenManager *tokenmanager.Manager,
	passwordStore *passwordstore.Service,
	keyCache *keycache.Service,
	rateLimiter *ratelimiter.Service,
	httpClient *httpclient.Service,
	syncService sync.Service,
	storageManager *storagemanager.Manager,
	securityLog *securitylog.Service,
	searchService search.SearchService,
) *Application {
	return &Application{
		logger:         logger,
		config:         configService,
		authService:    authService,
		tokenManager:   tokenManager,
		passwordStore:  passwordStore,
		keyCache:       keyCache,
		rateLimiter:    rateLimiter,
		httpClient:     httpClient,
		syncService:    syncService,
		storageManager: storageManager,
		securityLog:    securityLog,
		searchService:  searchService,
	}
}

// getFileRepo returns the file repository for the current user.
// Returns nil if no user is logged in (storage not initialized).
func (a *Application) getFileRepo() file.Repository {
	return a.storageManager.GetFileRepository()
}

// mustGetFileRepo returns the file repository for the current user.
// Logs an error and returns a no-op repository if storage is not initialized.
// Use this in places where you expect the user to be logged in.
// The returned repository will never be nil - it returns a safe no-op implementation
// if the actual repository is not available.
func (a *Application) mustGetFileRepo() file.Repository {
	repo := a.storageManager.GetFileRepository()
	if repo == nil {
		a.logger.Error("File repository not available - user storage not initialized")
		return &noOpFileRepository{}
	}
	return repo
}

// getCollectionRepo returns the collection repository for the current user.
// Returns nil if no user is logged in (storage not initialized).
func (a *Application) getCollectionRepo() collection.Repository {
	return a.storageManager.GetCollectionRepository()
}

// noOpFileRepository is a safe no-op implementation of file.Repository
// that returns empty results instead of causing nil pointer dereferences.
// This is used when the actual repository is not available (user not logged in).
type noOpFileRepository struct{}

func (r *noOpFileRepository) Get(id string) (*file.File, error) {
	return nil, fmt.Errorf("storage not initialized - user must be logged in")
}

func (r *noOpFileRepository) List() ([]*file.File, error) {
	return []*file.File{}, fmt.Errorf("storage not initialized - user must be logged in")
}

func (r *noOpFileRepository) ListByCollection(collectionID string) ([]*file.File, error) {
	return []*file.File{}, fmt.Errorf("storage not initialized - user must be logged in")
}

func (r *noOpFileRepository) Create(f *file.File) error {
	return fmt.Errorf("storage not initialized - user must be logged in")
}

func (r *noOpFileRepository) Update(f *file.File) error {
	return fmt.Errorf("storage not initialized - user must be logged in")
}

func (r *noOpFileRepository) Delete(id string) error {
	return fmt.Errorf("storage not initialized - user must be logged in")
}

func (r *noOpFileRepository) ListByStatus(status file.SyncStatus) ([]*file.File, error) {
	return []*file.File{}, fmt.Errorf("storage not initialized - user must be logged in")
}

func (r *noOpFileRepository) Exists(id string) (bool, error) {
	return false, fmt.Errorf("storage not initialized - user must be logged in")
}

// Startup is called when the app starts (Wails lifecycle hook)
func (a *Application) Startup(ctx context.Context) {
	a.ctx = ctx
	a.logger.Info("MapleFile desktop application started")
	a.securityLog.LogAppLifecycle(securitylog.EventAppStart)

	// Check if there's a valid session from a previous run
	session, err := a.authService.GetCurrentSession(ctx)
	if err != nil {
		a.logger.Debug("No existing session on startup", zap.Error(err))
		return
	}

	if session == nil {
		a.logger.Info("No session found on startup")
		return
	}

	if !session.IsValid() {
		a.logger.Info("Session expired on startup, clearing",
			zap.Time("expired_at", session.ExpiresAt))
		_ = a.authService.Logout(ctx)
		return
	}

	// Valid session found - restore it
	a.logger.Info("Resuming valid session from previous run",
		zap.String("user_id", session.UserID),
		zap.String("email", utils.MaskEmail(session.Email)),
		zap.Time("expires_at", session.ExpiresAt))

	// Restore tokens to API client
	if err := a.authService.RestoreSession(ctx, session); err != nil {
		a.logger.Error("Failed to restore session", zap.Error(err))
		return
	}

	// SECURITY: Validate session with server before fully restoring
	// This prevents using stale/revoked sessions from previous runs
	if err := a.validateSessionWithServer(ctx, session); err != nil {
		a.logger.Warn("Session validation with server failed, clearing session",
			zap.String("email", utils.MaskEmail(session.Email)),
			zap.Error(err))
		_ = a.authService.Logout(ctx)
		return
	}

	a.logger.Info("Session validated with server successfully")

	// Initialize user-specific storage for the logged-in user
	if err := a.storageManager.InitializeForUser(session.Email); err != nil {
		a.logger.Error("Failed to initialize user storage", zap.Error(err))
		_ = a.authService.Logout(ctx)
		return
	}
	a.logger.Info("User storage initialized",
		zap.String("email", utils.MaskEmail(session.Email)))

	// Initialize search index for the logged-in user
	if err := a.searchService.Initialize(ctx, session.Email); err != nil {
		a.logger.Error("Failed to initialize search index", zap.Error(err))
		// Don't fail startup if search initialization fails - it's not critical
		// The app can still function without search
	} else {
		a.logger.Info("Search index initialized",
			zap.String("email", utils.MaskEmail(session.Email)))

		// Rebuild search index from local data in the background
		userEmail := session.Email // Capture email before goroutine
		go func() {
			if err := a.rebuildSearchIndexForUser(userEmail); err != nil {
				a.logger.Warn("Failed to rebuild search index on startup", zap.Error(err))
			}
		}()
	}

	// Start token manager for automatic refresh
	a.tokenManager.Start()
	a.logger.Info("Token manager started for resumed session")

	// Run background cleanup of deleted files
	go a.cleanupDeletedFiles()
}

// validateSessionWithServer validates the stored session by making a request to the server.
// This is a security measure to ensure the session hasn't been revoked server-side.
func (a *Application) validateSessionWithServer(ctx context.Context, session *session.Session) error {
	apiClient := a.authService.GetAPIClient()
	if apiClient == nil {
		return fmt.Errorf("API client not available")
	}

	// Set tokens in the API client
	apiClient.SetTokens(session.AccessToken, session.RefreshToken)

	// Make a lightweight request to validate the token
	// GetMe is a good choice as it's a simple authenticated endpoint
	_, err := apiClient.GetMe(ctx)
	if err != nil {
		return fmt.Errorf("server validation failed: %w", err)
	}

	return nil
}

// Shutdown is called when the app shuts down (Wails lifecycle hook)
func (a *Application) Shutdown(ctx context.Context) {
	a.logger.Info("MapleFile desktop application shutting down")
	a.securityLog.LogAppLifecycle(securitylog.EventAppShutdown)

	// Calculate timeout from Wails context
	timeout := 3 * time.Second
	if deadline, ok := ctx.Deadline(); ok {
		remaining := time.Until(deadline)
		if remaining > 500*time.Millisecond {
			// Leave 500ms buffer for other cleanup
			timeout = remaining - 500*time.Millisecond
		} else if remaining > 0 {
			timeout = remaining
		} else {
			timeout = 100 * time.Millisecond
		}
	}

	// Stop token manager gracefully
	stopCtx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()

	if err := a.tokenManager.Stop(stopCtx); err != nil {
		a.logger.Error("Token manager shutdown error", zap.Error(err))
	}

	// Cleanup password store (destroy RAM enclaves)
	a.logger.Info("Clearing all passwords from secure RAM")
	a.passwordStore.Cleanup()
	a.logger.Info("Password cleanup completed")

	// Cleanup key cache (destroy cached master keys)
	a.logger.Info("Clearing all cached master keys from secure memory")
	a.keyCache.Cleanup()
	a.logger.Info("Key cache cleanup completed")

	// Cleanup search index
	a.logger.Info("Closing search index")
	if err := a.searchService.Close(); err != nil {
		a.logger.Error("Search index close error", zap.Error(err))
	} else {
		a.logger.Info("Search index closed successfully")
	}

	// Cleanup user-specific storage
	a.logger.Info("Cleaning up user storage")
	a.storageManager.Cleanup()
	a.logger.Info("User storage cleanup completed")

	a.logger.Sync()
}