import SwiftUI

public struct AIButtonStyle: ButtonStyle {
    public static let pressedScale: CGFloat = 0.97

    public enum Kind: Hashable {
        case primary
        case secondary
        case danger

        var foregroundColor: Color { foregroundColor(isEnabled: true) }

        var backgroundColor: Color { backgroundColor(isEnabled: true) }

        func foregroundColor(isEnabled: Bool) -> Color {
            switch self {
            case .primary, .danger: return .white.opacity(isEnabled ? 1 : 0.72)
            case .secondary: return isEnabled ? AITheme.ink : AITheme.muted
            }
        }

        func backgroundColor(isEnabled: Bool) -> Color {
            switch self {
            case .primary: return isEnabled ? AITheme.primary : AITheme.primary.opacity(0.35)
            case .secondary: return isEnabled ? AITheme.surface : AITheme.canvas
            case .danger: return isEnabled ? AITheme.danger : AITheme.danger.opacity(0.30)
            }
        }
    }

    public enum Size: Hashable {
        case compact
        case regular
        case large
        case toolbar
    }

    private let kind: Kind
    private let size: Size
    private let fixedWidthRequest: CGFloat?
    let fillsWidth: Bool
    @Environment(\.isEnabled) private var isEnabled

    public init(
        kind: Kind = .secondary,
        size: Size = .regular,
        fixedWidth: CGFloat? = nil,
        fillsWidth: Bool = false
    ) {
        self.kind = kind
        self.size = size
        self.fixedWidthRequest = fixedWidth
        self.fillsWidth = fillsWidth
    }

    public func makeBody(configuration: Configuration) -> some View {
        let height: CGFloat = switch size {
        case .compact: AITheme.compactButtonHeight
        case .large: AITheme.largeButtonHeight
        case .regular: AITheme.buttonHeight
        case .toolbar: AITheme.toolbarButtonHeight
        }

            configuration.label
                .labelStyle(.titleAndIcon)
                .font(.system(size: size == .toolbar ? 15 : 16, weight: .semibold))
                .lineLimit(1)
                .foregroundStyle(kind.foregroundColor(isEnabled: isEnabled))
                .frame(
                    minWidth: (!fillsWidth && fixedWidth == nil) ? minimumWidth : 0,
                    minHeight: height
                )
                .frame(maxWidth: fillsWidth ? .infinity : nil)
                .padding(.horizontal, fixedWidth == nil ? (kind == .secondary ? 12 : 14) : 0)
                .frame(width: fixedWidth)
                .background(kind.backgroundColor(isEnabled: isEnabled))
                .clipShape(RoundedRectangle(cornerRadius: AITheme.buttonRadius))
                .overlay {
                    RoundedRectangle(cornerRadius: AITheme.buttonRadius)
                        .strokeBorder(kind == .secondary || !isEnabled ? AITheme.line : .clear)
                }
                .scaleEffect(configuration.isPressed ? Self.pressedScale : 1)
                .opacity(configuration.isPressed ? 0.82 : 1)
    }

    private var minimumWidth: CGFloat {
        switch size {
        case .compact: return AITheme.compactButtonMinWidth
        case .regular: return AITheme.regularButtonMinWidth
        case .large: return 92
        case .toolbar: return AITheme.toolbarButtonMinWidth
        }
    }

    private var fixedWidth: CGFloat? {
        fixedWidthRequest ?? (size == .toolbar ? AITheme.toolbarButtonWidth : nil)
    }
}