import { Alert, Platform } from 'react-native';

// Track active alerts to prevent stacking
const activeAlerts = new Set<string>();

export interface AlertButton {
    text?: string;
    onPress?: () => void;
    style?: 'default' | 'cancel' | 'destructive';
}

export interface ShowAlertOptions {
    title: string;
    message?: string;
    buttons?: AlertButton[];
    cancelable?: boolean;
    onDismiss?: () => void;
    alertId?: string;
}

/**
 * Cross-platform alert that works on web, iOS, and Android
 * On web, uses window.confirm() for confirmation dialogs and window.alert() for simple alerts
 * On native platforms, uses React Native's Alert.alert()
 */
export const showAlert = (options: ShowAlertOptions) => {
    const {
        title,
        message,
        buttons,
        cancelable,
        onDismiss,
        alertId,
    } = options;

    // Generate unique ID for this alert
    const id = alertId || `${title}-${message || ''}`;

    // Prevent stacking
    if (activeAlerts.has(id)) {
        return;
    }

    activeAlerts.add(id);

    if (Platform.OS === 'web') {
        // Web implementation
        handleWebAlert(id, title, message, buttons, onDismiss);
    } else {
        // Native implementation
        handleNativeAlert(id, title, message, buttons, cancelable, onDismiss);
    }
};

/**
 * Handle alerts on web using window.confirm/alert
 */
const handleWebAlert = (
    id: string,
    title: string,
    message?: string,
    buttons?: AlertButton[],
    onDismiss?: () => void
) => {
    const fullMessage = message ? `${title}\n\n${message}` : title;

    // Use setTimeout to ensure the alert runs after current execution
    setTimeout(() => {
        try {
            if (!buttons || buttons.length === 0) {
                // Simple alert with OK button
                window.alert(fullMessage);
                activeAlerts.delete(id);
                onDismiss?.();
            } else if (buttons.length === 1) {
                // Single button - use alert
                window.alert(fullMessage);
                activeAlerts.delete(id);
                buttons[0].onPress?.();
                onDismiss?.();
            } else if (buttons.length === 2) {
                // Two buttons - use confirm
                // Find cancel and confirm buttons
                const cancelButton = buttons.find(b => b.style === 'cancel');
                const confirmButton = buttons.find(b => b.style !== 'cancel') || buttons[1];

                const result = window.confirm(fullMessage);
                activeAlerts.delete(id);

                if (result) {
                    // User clicked OK - trigger the non-cancel button
                    confirmButton?.onPress?.();
                } else {
                    // User clicked Cancel
                    cancelButton?.onPress?.();
                }
                onDismiss?.();
            } else {
                // More than 2 buttons - use confirm for first two, warn about limitation
                console.warn('Web alerts only support up to 2 buttons. Additional buttons will be ignored.');
                const cancelButton = buttons.find(b => b.style === 'cancel');
                const confirmButton = buttons.find(b => b.style === 'destructive') ||
                    buttons.find(b => b.style !== 'cancel') ||
                    buttons[0];

                const result = window.confirm(fullMessage);
                activeAlerts.delete(id);

                if (result) {
                    confirmButton?.onPress?.();
                } else {
                    cancelButton?.onPress?.();
                }
                onDismiss?.();
            }
        } catch (error) {
            activeAlerts.delete(id);
            console.error('Error showing web alert:', error);
        }
    }, 0);
};

/**
 * Handle alerts on native platforms using React Native Alert
 */
const handleNativeAlert = (
    id: string,
    title: string,
    message?: string,
    buttons?: AlertButton[],
    cancelable?: boolean,
    onDismiss?: () => void
) => {
    // Wrap button callbacks to clear the alert ID
    const wrappedButtons = buttons?.map(button => ({
        ...button,
        onPress: () => {
            activeAlerts.delete(id);
            button.onPress?.();
        },
    }));

    // Wrap onDismiss to clear the alert ID
    const wrappedOptions = {
        cancelable,
        onDismiss: () => {
            activeAlerts.delete(id);
            onDismiss?.();
        },
    };

    Alert.alert(title, message, wrappedButtons, wrappedOptions);
};

/**
 * Simple alert with just an OK button
 * Works on all platforms
 */
export const alertOk = (title: string, message?: string, onOk?: () => void) => {
    showAlert({
        title,
        message,
        buttons: [{ text: 'OK', onPress: onOk }],
    });
};

/**
 * Confirmation dialog with Cancel and Confirm buttons
 * Works on all platforms
 */
export const alertConfirm = (
    title: string,
    message: string,
    onConfirm: () => void,
    onCancel?: () => void,
    confirmText: string = 'Confirm',
    cancelText: string = 'Cancel',
    destructive: boolean = false
) => {
    showAlert({
        title,
        message,
        buttons: [
            { text: cancelText, style: 'cancel', onPress: onCancel },
            { text: confirmText, style: destructive ? 'destructive' : 'default', onPress: onConfirm },
        ],
    });
};

/**
 * Clear a specific alert from the active set (useful for manual cleanup)
 */
export const clearAlert = (alertId: string) => {
    activeAlerts.delete(alertId);
};

/**
 * Clear all active alerts (useful for cleanup on unmount)
 */
export const clearAllAlerts = () => {
    activeAlerts.clear();
};