package valueobjects

import (
	"fmt"

	"knowfoolery/backend/shared/types"
	"knowfoolery/backend/shared/errors"
)

// UserPreferences represents a user's preferences and settings
type UserPreferences struct {
	// Game preferences
	preferredDifficulty    types.DifficultyLevel
	preferredThemes        []types.ThemeID
	enableHints           bool
	enableTimer           bool
	enableSound           bool
	enableNotifications   bool
	
	// Display preferences
	theme                 string  // "light", "dark", "auto"
	language              string  // ISO 639-1 language code
	timezone              string  // IANA timezone
	
	// Privacy preferences
	showProfile           bool
	showStatistics        bool
	showLeaderboard       bool
	allowFriendRequests   bool
	
	// Notification preferences
	emailNotifications    *EmailNotificationSettings
	pushNotifications     *PushNotificationSettings
	
	// Accessibility preferences
	accessibility         *AccessibilitySettings
	
	// Update tracking
	updatedAt             types.Timestamp
}

// EmailNotificationSettings represents email notification preferences
type EmailNotificationSettings struct {
	Enabled              bool `json:"enabled"`
	GameInvitations      bool `json:"game_invitations"`
	LeaderboardUpdates   bool `json:"leaderboard_updates"`
	WeeklyDigest         bool `json:"weekly_digest"`
	SecurityAlerts       bool `json:"security_alerts"`
	ProductUpdates       bool `json:"product_updates"`
}

// PushNotificationSettings represents push notification preferences
type PushNotificationSettings struct {
	Enabled              bool `json:"enabled"`
	GameInvitations      bool `json:"game_invitations"`
	TurnReminders        bool `json:"turn_reminders"`
	LeaderboardUpdates   bool `json:"leaderboard_updates"`
	DailyReminders       bool `json:"daily_reminders"`
}

// AccessibilitySettings represents accessibility preferences
type AccessibilitySettings struct {
	HighContrast         bool    `json:"high_contrast"`
	LargeText            bool    `json:"large_text"`
	ReducedMotion        bool    `json:"reduced_motion"`
	ScreenReaderSupport  bool    `json:"screen_reader_support"`
	KeyboardNavigation   bool    `json:"keyboard_navigation"`
	FontSize             float64 `json:"font_size"`           // 0.8 - 2.0 multiplier
}

// NewDefaultUserPreferences creates default user preferences
func NewDefaultUserPreferences() *UserPreferences {
	return &UserPreferences{
		preferredDifficulty:  types.DifficultyMedium,
		preferredThemes:      []types.ThemeID{},
		enableHints:          true,
		enableTimer:          true,
		enableSound:          true,
		enableNotifications:  true,
		theme:                "auto",
		language:             "en",
		timezone:             "UTC",
		showProfile:          true,
		showStatistics:       true,
		showLeaderboard:      true,
		allowFriendRequests:  true,
		emailNotifications:   &EmailNotificationSettings{
			Enabled:            true,
			GameInvitations:    true,
			LeaderboardUpdates: false,
			WeeklyDigest:       true,
			SecurityAlerts:     true,
			ProductUpdates:     false,
		},
		pushNotifications:    &PushNotificationSettings{
			Enabled:            true,
			GameInvitations:    true,
			TurnReminders:      true,
			LeaderboardUpdates: false,
			DailyReminders:     false,
		},
		accessibility:        &AccessibilitySettings{
			HighContrast:       false,
			LargeText:          false,
			ReducedMotion:      false,
			ScreenReaderSupport: false,
			KeyboardNavigation: false,
			FontSize:           1.0,
		},
		updatedAt:           types.NewTimestamp(),
	}
}

// NewUserPreferences creates user preferences with specified values
func NewUserPreferences(
	preferredDifficulty types.DifficultyLevel,
	preferredThemes []types.ThemeID,
	enableHints bool,
	enableTimer bool,
) (*UserPreferences, error) {
	preferences := NewDefaultUserPreferences()
	
	// Validate and set preferred difficulty
	if err := preferences.SetPreferredDifficulty(preferredDifficulty); err != nil {
		return nil, err
	}
	
	// Set preferred themes
	if err := preferences.SetPreferredThemes(preferredThemes); err != nil {
		return nil, err
	}
	
	preferences.enableHints = enableHints
	preferences.enableTimer = enableTimer
	
	return preferences, nil
}

// Getters

// PreferredDifficulty returns the preferred difficulty level
func (p *UserPreferences) PreferredDifficulty() types.DifficultyLevel {
	return p.preferredDifficulty
}

// PreferredThemes returns the preferred themes
func (p *UserPreferences) PreferredThemes() []types.ThemeID {
	return append([]types.ThemeID(nil), p.preferredThemes...) // Return copy
}

// EnableHints returns true if hints are enabled
func (p *UserPreferences) EnableHints() bool {
	return p.enableHints
}

// EnableTimer returns true if timer is enabled
func (p *UserPreferences) EnableTimer() bool {
	return p.enableTimer
}

// EnableSound returns true if sound is enabled
func (p *UserPreferences) EnableSound() bool {
	return p.enableSound
}

// EnableNotifications returns true if notifications are enabled
func (p *UserPreferences) EnableNotifications() bool {
	return p.enableNotifications
}

// Theme returns the display theme
func (p *UserPreferences) Theme() string {
	return p.theme
}

// Language returns the language code
func (p *UserPreferences) Language() string {
	return p.language
}

// Timezone returns the timezone
func (p *UserPreferences) Timezone() string {
	return p.timezone
}

// ShowProfile returns true if profile should be shown
func (p *UserPreferences) ShowProfile() bool {
	return p.showProfile
}

// ShowStatistics returns true if statistics should be shown
func (p *UserPreferences) ShowStatistics() bool {
	return p.showStatistics
}

// ShowLeaderboard returns true if leaderboard should be shown
func (p *UserPreferences) ShowLeaderboard() bool {
	return p.showLeaderboard
}

// AllowFriendRequests returns true if friend requests are allowed
func (p *UserPreferences) AllowFriendRequests() bool {
	return p.allowFriendRequests
}

// EmailNotifications returns email notification settings
func (p *UserPreferences) EmailNotifications() *EmailNotificationSettings {
	if p.emailNotifications == nil {
		return nil
	}
	// Return copy
	return &EmailNotificationSettings{
		Enabled:            p.emailNotifications.Enabled,
		GameInvitations:    p.emailNotifications.GameInvitations,
		LeaderboardUpdates: p.emailNotifications.LeaderboardUpdates,
		WeeklyDigest:       p.emailNotifications.WeeklyDigest,
		SecurityAlerts:     p.emailNotifications.SecurityAlerts,
		ProductUpdates:     p.emailNotifications.ProductUpdates,
	}
}

// PushNotifications returns push notification settings
func (p *UserPreferences) PushNotifications() *PushNotificationSettings {
	if p.pushNotifications == nil {
		return nil
	}
	// Return copy
	return &PushNotificationSettings{
		Enabled:            p.pushNotifications.Enabled,
		GameInvitations:    p.pushNotifications.GameInvitations,
		TurnReminders:      p.pushNotifications.TurnReminders,
		LeaderboardUpdates: p.pushNotifications.LeaderboardUpdates,
		DailyReminders:     p.pushNotifications.DailyReminders,
	}
}

// Accessibility returns accessibility settings
func (p *UserPreferences) Accessibility() *AccessibilitySettings {
	if p.accessibility == nil {
		return nil
	}
	// Return copy
	return &AccessibilitySettings{
		HighContrast:       p.accessibility.HighContrast,
		LargeText:          p.accessibility.LargeText,
		ReducedMotion:      p.accessibility.ReducedMotion,
		ScreenReaderSupport: p.accessibility.ScreenReaderSupport,
		KeyboardNavigation: p.accessibility.KeyboardNavigation,
		FontSize:           p.accessibility.FontSize,
	}
}

// UpdatedAt returns the last update timestamp
func (p *UserPreferences) UpdatedAt() types.Timestamp {
	return p.updatedAt
}

// Business methods

// SetPreferredDifficulty sets the preferred difficulty level
func (p *UserPreferences) SetPreferredDifficulty(difficulty types.DifficultyLevel) error {
	// Validate difficulty level
	validDifficulties := []types.DifficultyLevel{
		types.DifficultyEasy,
		types.DifficultyMedium,
		types.DifficultyHard,
		types.DifficultyExpert,
		types.DifficultyImpossible,
	}
	
	isValid := false
	for _, valid := range validDifficulties {
		if difficulty == valid {
			isValid = true
			break
		}
	}
	
	if !isValid {
		return errors.ErrValidationFailed("preferred_difficulty", "invalid difficulty level")
	}
	
	p.preferredDifficulty = difficulty
	p.markUpdated()
	
	return nil
}

// SetPreferredThemes sets the preferred themes
func (p *UserPreferences) SetPreferredThemes(themes []types.ThemeID) error {
	if len(themes) > types.MaxPreferredThemes {
		return errors.ErrValidationFailed("preferred_themes", 
			fmt.Sprintf("too many preferred themes (max %d)", types.MaxPreferredThemes))
	}
	
	// Validate theme IDs
	for i, themeID := range themes {
		if themeID.IsEmpty() {
			return errors.ErrValidationFailed("preferred_themes", 
				fmt.Sprintf("theme ID at index %d is empty", i))
		}
	}
	
	// Remove duplicates
	uniqueThemes := make([]types.ThemeID, 0, len(themes))
	themeSet := make(map[types.ThemeID]bool)
	
	for _, themeID := range themes {
		if !themeSet[themeID] {
			uniqueThemes = append(uniqueThemes, themeID)
			themeSet[themeID] = true
		}
	}
	
	p.preferredThemes = uniqueThemes
	p.markUpdated()
	
	return nil
}

// AddPreferredTheme adds a theme to preferred themes
func (p *UserPreferences) AddPreferredTheme(themeID types.ThemeID) error {
	if themeID.IsEmpty() {
		return errors.ErrValidationFailed("theme_id", "theme ID cannot be empty")
	}
	
	// Check if already in preferred themes
	for _, existing := range p.preferredThemes {
		if existing == themeID {
			return nil // Already exists
		}
	}
	
	if len(p.preferredThemes) >= types.MaxPreferredThemes {
		return errors.ErrValidationFailed("preferred_themes", 
			fmt.Sprintf("too many preferred themes (max %d)", types.MaxPreferredThemes))
	}
	
	p.preferredThemes = append(p.preferredThemes, themeID)
	p.markUpdated()
	
	return nil
}

// RemovePreferredTheme removes a theme from preferred themes
func (p *UserPreferences) RemovePreferredTheme(themeID types.ThemeID) error {
	for i, existing := range p.preferredThemes {
		if existing == themeID {
			p.preferredThemes = append(p.preferredThemes[:i], p.preferredThemes[i+1:]...)
			p.markUpdated()
			return nil
		}
	}
	
	return errors.ErrNotFound("preferred_theme", string(themeID))
}

// SetGamePreferences sets game-related preferences
func (p *UserPreferences) SetGamePreferences(
	enableHints bool,
	enableTimer bool,
	enableSound bool,
	enableNotifications bool,
) {
	p.enableHints = enableHints
	p.enableTimer = enableTimer
	p.enableSound = enableSound
	p.enableNotifications = enableNotifications
	p.markUpdated()
}

// SetDisplayPreferences sets display-related preferences
func (p *UserPreferences) SetDisplayPreferences(
	theme string,
	language string,
	timezone string,
) error {
	if err := p.SetTheme(theme); err != nil {
		return err
	}
	
	if err := p.SetLanguage(language); err != nil {
		return err
	}
	
	if err := p.SetTimezone(timezone); err != nil {
		return err
	}
	
	return nil
}

// SetTheme sets the display theme
func (p *UserPreferences) SetTheme(theme string) error {
	validThemes := []string{"light", "dark", "auto"}
	
	isValid := false
	for _, valid := range validThemes {
		if theme == valid {
			isValid = true
			break
		}
	}
	
	if !isValid {
		return errors.ErrValidationFailed("theme", "theme must be 'light', 'dark', or 'auto'")
	}
	
	p.theme = theme
	p.markUpdated()
	
	return nil
}

// SetLanguage sets the language
func (p *UserPreferences) SetLanguage(language string) error {
	if len(language) != 2 {
		return errors.ErrValidationFailed("language", "language must be a 2-character ISO 639-1 code")
	}
	
	// Could validate against known language codes
	p.language = language
	p.markUpdated()
	
	return nil
}

// SetTimezone sets the timezone
func (p *UserPreferences) SetTimezone(timezone string) error {
	// Basic validation - could be more comprehensive
	if timezone == "" {
		timezone = "UTC"
	}
	
	p.timezone = timezone
	p.markUpdated()
	
	return nil
}

// SetPrivacyPreferences sets privacy-related preferences
func (p *UserPreferences) SetPrivacyPreferences(
	showProfile bool,
	showStatistics bool,
	showLeaderboard bool,
	allowFriendRequests bool,
) {
	p.showProfile = showProfile
	p.showStatistics = showStatistics
	p.showLeaderboard = showLeaderboard
	p.allowFriendRequests = allowFriendRequests
	p.markUpdated()
}

// UpdateEmailNotifications updates email notification settings
func (p *UserPreferences) UpdateEmailNotifications(settings *EmailNotificationSettings) error {
	if settings == nil {
		return errors.ErrValidationFailed("email_notifications", "email notification settings cannot be nil")
	}
	
	p.emailNotifications = &EmailNotificationSettings{
		Enabled:            settings.Enabled,
		GameInvitations:    settings.GameInvitations,
		LeaderboardUpdates: settings.LeaderboardUpdates,
		WeeklyDigest:       settings.WeeklyDigest,
		SecurityAlerts:     settings.SecurityAlerts,
		ProductUpdates:     settings.ProductUpdates,
	}
	p.markUpdated()
	
	return nil
}

// UpdatePushNotifications updates push notification settings
func (p *UserPreferences) UpdatePushNotifications(settings *PushNotificationSettings) error {
	if settings == nil {
		return errors.ErrValidationFailed("push_notifications", "push notification settings cannot be nil")
	}
	
	p.pushNotifications = &PushNotificationSettings{
		Enabled:            settings.Enabled,
		GameInvitations:    settings.GameInvitations,
		TurnReminders:      settings.TurnReminders,
		LeaderboardUpdates: settings.LeaderboardUpdates,
		DailyReminders:     settings.DailyReminders,
	}
	p.markUpdated()
	
	return nil
}

// UpdateAccessibility updates accessibility settings
func (p *UserPreferences) UpdateAccessibility(settings *AccessibilitySettings) error {
	if settings == nil {
		return errors.ErrValidationFailed("accessibility", "accessibility settings cannot be nil")
	}
	
	// Validate font size
	if settings.FontSize < 0.5 || settings.FontSize > 3.0 {
		return errors.ErrValidationFailed("font_size", "font size must be between 0.5 and 3.0")
	}
	
	p.accessibility = &AccessibilitySettings{
		HighContrast:       settings.HighContrast,
		LargeText:          settings.LargeText,
		ReducedMotion:      settings.ReducedMotion,
		ScreenReaderSupport: settings.ScreenReaderSupport,
		KeyboardNavigation: settings.KeyboardNavigation,
		FontSize:           settings.FontSize,
	}
	p.markUpdated()
	
	return nil
}

// Query methods

// HasPreferredTheme checks if a theme is in preferred themes
func (p *UserPreferences) HasPreferredTheme(themeID types.ThemeID) bool {
	for _, preferred := range p.preferredThemes {
		if preferred == themeID {
			return true
		}
	}
	return false
}

// IsAccessibilityEnabled returns true if any accessibility features are enabled
func (p *UserPreferences) IsAccessibilityEnabled() bool {
	if p.accessibility == nil {
		return false
	}
	
	return p.accessibility.HighContrast ||
		   p.accessibility.LargeText ||
		   p.accessibility.ReducedMotion ||
		   p.accessibility.ScreenReaderSupport ||
		   p.accessibility.KeyboardNavigation ||
		   p.accessibility.FontSize != 1.0
}

// AreEmailNotificationsEnabled returns true if email notifications are globally enabled
func (p *UserPreferences) AreEmailNotificationsEnabled() bool {
	return p.emailNotifications != nil && p.emailNotifications.Enabled
}

// ArePushNotificationsEnabled returns true if push notifications are globally enabled
func (p *UserPreferences) ArePushNotificationsEnabled() bool {
	return p.pushNotifications != nil && p.pushNotifications.Enabled
}

// Validation

// Validate performs comprehensive validation
func (p *UserPreferences) Validate() *types.ValidationResult {
	result := types.NewValidationResult()
	
	// Validate preferred difficulty
	validDifficulties := []types.DifficultyLevel{
		types.DifficultyEasy,
		types.DifficultyMedium,
		types.DifficultyHard,
		types.DifficultyExpert,
		types.DifficultyImpossible,
	}
	
	isValidDifficulty := false
	for _, valid := range validDifficulties {
		if p.preferredDifficulty == valid {
			isValidDifficulty = true
			break
		}
	}
	
	if !isValidDifficulty {
		result.AddError("invalid preferred difficulty")
	}
	
	// Validate preferred themes count
	if len(p.preferredThemes) > types.MaxPreferredThemes {
		result.AddErrorf("too many preferred themes (max %d)", types.MaxPreferredThemes)
	}
	
	// Validate theme IDs
	for i, themeID := range p.preferredThemes {
		if themeID.IsEmpty() {
			result.AddErrorf("preferred theme at index %d is empty", i)
		}
	}
	
	// Validate theme
	validThemes := []string{"light", "dark", "auto"}
	isValidTheme := false
	for _, valid := range validThemes {
		if p.theme == valid {
			isValidTheme = true
			break
		}
	}
	
	if !isValidTheme {
		result.AddError("invalid theme")
	}
	
	// Validate language
	if len(p.language) != 2 {
		result.AddError("invalid language code")
	}
	
	// Validate accessibility settings
	if p.accessibility != nil {
		if p.accessibility.FontSize < 0.5 || p.accessibility.FontSize > 3.0 {
			result.AddError("font size must be between 0.5 and 3.0")
		}
	}
	
	return result
}

// Helper methods

// markUpdated updates the timestamp
func (p *UserPreferences) markUpdated() {
	p.updatedAt = types.NewTimestamp()
}

// ToSnapshot creates a read-only snapshot
func (p *UserPreferences) ToSnapshot() *UserPreferencesSnapshot {
	return &UserPreferencesSnapshot{
		PreferredDifficulty: p.preferredDifficulty,
		PreferredThemes:     append([]types.ThemeID(nil), p.preferredThemes...),
		EnableHints:         p.enableHints,
		EnableTimer:         p.enableTimer,
		EnableSound:         p.enableSound,
		EnableNotifications: p.enableNotifications,
		Theme:               p.theme,
		Language:            p.language,
		Timezone:            p.timezone,
		ShowProfile:         p.showProfile,
		ShowStatistics:      p.showStatistics,
		ShowLeaderboard:     p.showLeaderboard,
		AllowFriendRequests: p.allowFriendRequests,
		EmailNotifications:  p.EmailNotifications(),
		PushNotifications:   p.PushNotifications(),
		Accessibility:       p.Accessibility(),
		UpdatedAt:           p.updatedAt,
	}
}

// UserPreferencesSnapshot represents a read-only view of user preferences
type UserPreferencesSnapshot struct {
	PreferredDifficulty types.DifficultyLevel         `json:"preferred_difficulty"`
	PreferredThemes     []types.ThemeID               `json:"preferred_themes"`
	EnableHints         bool                          `json:"enable_hints"`
	EnableTimer         bool                          `json:"enable_timer"`
	EnableSound         bool                          `json:"enable_sound"`
	EnableNotifications bool                          `json:"enable_notifications"`
	Theme               string                        `json:"theme"`
	Language            string                        `json:"language"`
	Timezone            string                        `json:"timezone"`
	ShowProfile         bool                          `json:"show_profile"`
	ShowStatistics      bool                          `json:"show_statistics"`
	ShowLeaderboard     bool                          `json:"show_leaderboard"`
	AllowFriendRequests bool                          `json:"allow_friend_requests"`
	EmailNotifications  *EmailNotificationSettings    `json:"email_notifications"`
	PushNotifications   *PushNotificationSettings     `json:"push_notifications"`
	Accessibility       *AccessibilitySettings        `json:"accessibility"`
	UpdatedAt           types.Timestamp               `json:"updated_at"`
}

// HasPreferredTheme checks if a theme is preferred in the snapshot
func (ps *UserPreferencesSnapshot) HasPreferredTheme(themeID types.ThemeID) bool {
	for _, preferred := range ps.PreferredThemes {
		if preferred == themeID {
			return true
		}
	}
	return false
}