import { Dimensions, PixelRatio, Platform } from 'react-native';

// Base dimensions (design reference - typically iPhone 14/15 or similar)
const BASE_WIDTH = 390;
const BASE_HEIGHT = 844;

const { width: SCREEN_WIDTH, height: SCREEN_HEIGHT } = Dimensions.get('window');

/**
 * Scale a value based on screen width (horizontal scaling)
 * Use for: horizontal padding, margins, widths, font sizes
 */
export function scale(size: number): number {
    const scaleFactor = SCREEN_WIDTH / BASE_WIDTH;
    const newSize = size * scaleFactor;

    if (Platform.OS === 'web') {
        // On web, respect user zoom settings by using rem-like scaling
        return size;
    }

    return Math.round(PixelRatio.roundToNearestPixel(newSize));
}

/**
 * Scale a value based on screen height (vertical scaling)
 * Use for: vertical padding, margins, heights
 */
export function verticalScale(size: number): number {
    const scaleFactor = SCREEN_HEIGHT / BASE_HEIGHT;
    const newSize = size * scaleFactor;

    if (Platform.OS === 'web') {
        return size;
    }

    return Math.round(PixelRatio.roundToNearestPixel(newSize));
}

/**
 * Moderate scaling - scales less aggressively (recommended for most use cases)
 * Use for: font sizes, icon sizes, border radius
 * @param factor - how much to scale (0 = no scaling, 1 = full scaling, default 0.5)
 */
export function moderateScale(size: number, factor: number = 0.5): number {
    const scaleFactor = SCREEN_WIDTH / BASE_WIDTH;
    const newSize = size + (scaleFactor - 1) * size * factor;

    if (Platform.OS === 'web') {
        return size;
    }

    return Math.round(PixelRatio.roundToNearestPixel(newSize));
}

/**
 * Get responsive value based on screen size breakpoints
 * Use for: completely different layouts at different sizes
 */
export function responsive<T>(options: {
    small?: T;    // < 375px (iPhone SE, small phones)
    medium?: T;   // 375-428px (most phones)
    large?: T;    // > 428px (tablets, large phones, web)
    default: T;
}): T {
    if (SCREEN_WIDTH < 375) {
        return options.small ?? options.default;
    }
    if (SCREEN_WIDTH <= 428) {
        return options.medium ?? options.default;
    }
    return options.large ?? options.default;
}

/**
 * Check if device is a tablet or large screen
 */
export function isTablet(): boolean {
    const aspectRatio = SCREEN_HEIGHT / SCREEN_WIDTH;
    return (
        (Platform.OS !== 'web' && SCREEN_WIDTH >= 768) ||
        (Platform.OS === 'web' && SCREEN_WIDTH >= 1024) ||
        aspectRatio < 1.6
    );
}

/**
 * Get screen dimensions (updates on rotation/resize)
 */
export function getScreenDimensions() {
    const { width, height } = Dimensions.get('window');
    return { width, height };
}

// Font scaling with accessibility support
export function scaledFontSize(size: number): number {
    const scaled = moderateScale(size, 0.3);
    // Respect system font scaling but cap it to prevent extreme sizes
    const maxScale = 1.3;
    const fontScale = Math.min(PixelRatio.getFontScale(), maxScale);
    return Math.round(scaled * fontScale);
}