import SwiftUI
import UIKit

// MARK: - Colors

struct AppColors {
    private init() {}
    // Brandbook 2026 (Pedi Foods)
    // Primary now follows the "FOODS" dark green tone from the logo.
    static let primary = Color(.sRGB, red: 52/255.0, green: 93/255.0, blue: 84/255.0, opacity: 1.0)
    // Secondary keeps the vivid lime from the symbol/logo body.
    static let secondary = Color(.sRGB, red: 213/255.0, green: 216/255.0, blue: 65/255.0, opacity: 1.0)
    static let tertiary = Color(.sRGB, red: 167/255.0, green: 191/255.0, blue: 66/255.0, opacity: 1.0)

    static let brandDark = Color(.sRGB, red: 31/255.0, green: 45/255.0, blue: 64/255.0, opacity: 1.0)
    static let brandSoft = Color(.sRGB, red: 242/255.0, green: 245/255.0, blue: 227/255.0, opacity: 1.0)

    static let backgroundLight = Color(.sRGB, red: 243/255.0, green: 245/255.0, blue: 247/255.0, opacity: 1.0)
    static let backgroundDark = Color(.sRGB, red: 31/255.0, green: 45/255.0, blue: 64/255.0, opacity: 1.0)
    static let surface = Color.white
    static let textPrimary = Color.black
    static let textInverse = Color.white
    static let textMuted = Color(.sRGB, red: 102/255.0, green: 112/255.0, blue: 133/255.0, opacity: 1.0)
}

struct AppDarkColors {
    private init() {}
    static let background = Color(.sRGB, red: 31/255.0, green: 45/255.0, blue: 64/255.0, opacity: 1.0)
    static let surface = Color.white.opacity(0.08)
    static let textPrimary = Color.white
    static let textSecondary = Color(.sRGB, red: 208/255.0, green: 213/255.0, blue: 221/255.0, opacity: 1.0)
    static let primary = AppColors.primary
    static let secondary = AppColors.secondary
    static let tertiary = AppColors.tertiary
}

// MARK: - Typography

struct AppTypography {
    private init() {}
    // Brandbook typography: Nexa (fallback: system font)
    static let fontFamily = "Nexa-Regular"

    static let heading1 = resolvedFont(size: 28, fallbackWeight: .bold)
    static let heading25 = resolvedFont(size: 25, fallbackWeight: .bold)
    static let heading2 = resolvedFont(size: 20, fallbackWeight: .semibold)
    static let heading3 = resolvedFont(size: 16, fallbackWeight: .semibold)
    static let body = resolvedFont(size: 16, fallbackWeight: .regular)
    static let button = resolvedFont(size: 14, fallbackWeight: .semibold)
    static let caption = resolvedFont(size: 10, fallbackWeight: .regular)
    static let overline = resolvedFont(size: 11, fallbackWeight: .regular)

    static let bodyLineHeight: CGFloat = 1.6
    static let buttonLetterSpacing: CGFloat = 0.08
    static let captionLetterSpacing: CGFloat = 0.12

    private static func resolvedFont(size: CGFloat, fallbackWeight: Font.Weight) -> Font {
        if isBrandFontAvailable {
            return Font.custom(fontFamily, size: size)
        }
        return .system(size: size, weight: fallbackWeight, design: .default)
    }

    private static var isBrandFontAvailable: Bool {
        UIFont(name: fontFamily, size: 16) != nil
    }
}

// MARK: - Layout

struct AppLayout {
    private init() {}
    static let radiusMD: CGFloat = 12
    static let radiusLG: CGFloat = 16
    static let radiusXL: CGFloat = 24
    static let radiusFull: CGFloat = 9999

    static let spacing: [CGFloat] = [4, 8, 12, 16, 24, 32]
}

// MARK: - Shadow

struct ShadowSpec {
    let color: Color
    let radius: CGFloat
    let y: CGFloat
}

struct AppShadow {
    private init() {}
    static let soft = ShadowSpec(color: Color.black.opacity(0.08), radius: 20, y: 6)
    static let glow = ShadowSpec(color: AppColors.tertiary.opacity(0.2), radius: 24, y: 8)
}

// MARK: - Helpers

extension Color {
    init(hex: String, alpha: Double = 1.0) {
        let cleaned = hex.trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
        var int: UInt64 = 0
        if let val = UInt64(cleaned, radix: 16) {
            int = val
        }

        let r, g, b: UInt64
        switch cleaned.count {
        case 6: // RRGGBB
            r = (int >> 16) & 0xFF
            g = (int >> 8) & 0xFF
            b = int & 0xFF
        case 3: // RGB
            r = ((int >> 8) & 0xF) * 17
            g = ((int >> 4) & 0xF) * 17
            b = (int & 0xF) * 17
        default:
            r = 0; g = 0; b = 0
        }

        self.init(.sRGB,
                  red: Double(r) / 255,
                  green: Double(g) / 255,
                  blue: Double(b) / 255,
                  opacity: alpha)
    }
}