import SwiftUI

enum AppTheme {
    static let accent = Color(red: 0.12, green: 0.40, blue: 0.31)
    static let warmAccent = Color(red: 0.84, green: 0.71, blue: 0.48)
    static let border = Color.black.opacity(0.08)
    static let shadow = Color.black.opacity(0.05)
    static let cardFill = Color.white.opacity(0.96)
    static let mutedFill = Color(red: 0.972, green: 0.976, blue: 0.970)
}

enum AppLayout {
    static let compactHorizontalPadding: CGFloat = 16
    static let regularHorizontalPadding: CGFloat = 28
    static let compactVerticalPadding: CGFloat = 18
    static let regularVerticalPadding: CGFloat = 28
    static let compactContentWidth: CGFloat = 720
    static let regularContentWidth: CGFloat = 920
    static let cardRadius: CGFloat = 24
    static let largeCardRadius: CGFloat = 30
    static let compactSectionPadding: CGFloat = 18
    static let regularSectionPadding: CGFloat = 24
    static let compactSectionSpacing: CGFloat = 18
    static let regularSectionSpacing: CGFloat = 24
    static let compactBottomDockPadding: CGFloat = 120
    static let regularBottomPadding: CGFloat = 56

    static func horizontalPadding(for compactLayout: Bool) -> CGFloat {
        compactLayout ? compactHorizontalPadding : regularHorizontalPadding
    }

    static func verticalPadding(for compactLayout: Bool) -> CGFloat {
        compactLayout ? compactVerticalPadding : regularVerticalPadding
    }

    static func contentWidth(for compactLayout: Bool) -> CGFloat {
        compactLayout ? compactContentWidth : regularContentWidth
    }

    static func sectionPadding(for compactLayout: Bool) -> CGFloat {
        compactLayout ? compactSectionPadding : regularSectionPadding
    }

    static func sectionSpacing(for compactLayout: Bool) -> CGFloat {
        compactLayout ? compactSectionSpacing : regularSectionSpacing
    }
}

extension View {
    func appSurface(radius: CGFloat = AppLayout.cardRadius, fill: Color = AppTheme.cardFill) -> some View {
        background(
            fill,
            in: RoundedRectangle(cornerRadius: radius, style: .continuous)
        )
        .overlay(
            RoundedRectangle(cornerRadius: radius, style: .continuous)
                .stroke(AppTheme.border, lineWidth: 1)
        )
        .shadow(color: AppTheme.shadow, radius: 12, y: 3)
    }
}

struct AppBackground: View {
    var body: some View {
        LinearGradient(
            colors: [
                Color(red: 0.975, green: 0.978, blue: 0.972),
                Color.white
            ],
            startPoint: .top,
            endPoint: .bottom
        )
        .overlay(alignment: .top) {
            Rectangle()
                .fill(Color.black.opacity(0.02))
                .frame(height: 160)
                .blur(radius: 60)
                .offset(y: -90)
        }
        .ignoresSafeArea()
    }
}

struct AppScrollScreen<Content: View>: View {
    let compactLayout: Bool
    var bottomPadding: CGFloat? = nil
    let content: () -> Content

    init(
        compactLayout: Bool,
        bottomPadding: CGFloat? = nil,
        @ViewBuilder content: @escaping () -> Content
    ) {
        self.compactLayout = compactLayout
        self.bottomPadding = bottomPadding
        self.content = content
    }

    var body: some View {
        ScrollView {
            VStack(alignment: .leading, spacing: AppLayout.sectionSpacing(for: compactLayout)) {
                content()
            }
            .frame(maxWidth: AppLayout.contentWidth(for: compactLayout), alignment: .leading)
            .padding(.horizontal, AppLayout.horizontalPadding(for: compactLayout))
            .padding(.top, AppLayout.verticalPadding(for: compactLayout))
            .padding(.bottom, bottomPadding ?? AppLayout.verticalPadding(for: compactLayout))
            .frame(maxWidth: .infinity, alignment: compactLayout ? .leading : .center)
        }
        .scrollIndicators(.hidden)
    }
}

struct AppPanel<Content: View>: View {
    let compactLayout: Bool
    let radius: CGFloat
    let content: () -> Content

    init(
        compactLayout: Bool,
        radius: CGFloat = AppLayout.cardRadius,
        @ViewBuilder content: @escaping () -> Content
    ) {
        self.compactLayout = compactLayout
        self.radius = radius
        self.content = content
    }

    var body: some View {
        VStack(alignment: .leading, spacing: 14) {
            content()
        }
        .padding(AppLayout.sectionPadding(for: compactLayout))
        .frame(maxWidth: .infinity, alignment: .leading)
        .appSurface(radius: radius)
    }
}

struct AppBadge: View {
    let title: String
    var tone: Color = AppTheme.accent

    var body: some View {
        Text(title)
            .font(.caption.weight(.semibold))
            .foregroundStyle(tone)
            .padding(.horizontal, 12)
            .padding(.vertical, 8)
            .background(tone.opacity(0.10), in: Capsule())
    }
}

struct AppSectionCard<Content: View>: View {
    let title: String
    var subtitle: String? = nil
    let compactLayout: Bool
    let content: () -> Content

    init(
        title: String,
        subtitle: String? = nil,
        compactLayout: Bool,
        @ViewBuilder content: @escaping () -> Content
    ) {
        self.title = title
        self.subtitle = subtitle
        self.compactLayout = compactLayout
        self.content = content
    }

    var body: some View {
        AppPanel(compactLayout: compactLayout) {
            AppSectionTitle(title: title, subtitle: subtitle)
            content()
        }
    }
}

struct AppSectionTitle: View {
    let title: String
    var subtitle: String? = nil

    var body: some View {
        VStack(alignment: .leading, spacing: 4) {
            Text(title)
                .font(.title3.weight(.semibold))

            if let subtitle, !subtitle.isEmpty {
                Text(subtitle)
                    .font(.subheadline)
                    .foregroundStyle(.secondary)
            }
        }
    }
}

struct AppNotice: View {
    let message: String
    var tone: Color = AppTheme.accent

    var body: some View {
        HStack(spacing: 10) {
            Image(systemName: "checkmark.circle.fill")
                .font(.footnote.weight(.bold))
                .foregroundStyle(tone)
            Text(message)
                .font(.subheadline.weight(.semibold))
        }
        .padding(.horizontal, 16)
        .padding(.vertical, 12)
        .background(tone.opacity(0.08), in: Capsule())
        .overlay(
            Capsule()
                .stroke(AppTheme.border, lineWidth: 1)
        )
    }
}

struct AppStatusTag: View {
    let title: String
    var tone: Color = AppTheme.accent

    var body: some View {
        Text(title)
            .font(.caption.weight(.semibold))
            .lineLimit(1)
            .minimumScaleFactor(0.8)
            .fixedSize(horizontal: true, vertical: false)
            .padding(.horizontal, 10)
            .padding(.vertical, 6)
            .background(tone.opacity(0.12), in: Capsule())
            .foregroundStyle(tone)
    }
}

struct AppKeyValue: View {
    let label: String
    let value: String
    var monospaced: Bool = false

    var body: some View {
        VStack(alignment: .leading, spacing: 4) {
            Text(label.uppercased())
                .font(.caption2.weight(.bold))
                .foregroundStyle(.secondary)

            Text(value)
                .font(monospaced ? .subheadline.monospaced() : .subheadline.weight(.semibold))
                .lineLimit(2)
                .minimumScaleFactor(0.8)
        }
        .frame(maxWidth: .infinity, alignment: .leading)
    }
}

struct AppMetric: View {
    let title: String
    let value: String

    var body: some View {
        VStack(alignment: .leading, spacing: 6) {
            Text(title.uppercased())
                .font(.caption.weight(.bold))
                .foregroundStyle(.secondary)

            Text(value)
                .font(.title3.weight(.bold))
        }
        .frame(maxWidth: .infinity, alignment: .leading)
    }
}

struct AppTextSurface: View {
    let text: String
    var monospaced: Bool = false

    var body: some View {
        content
            .frame(maxWidth: .infinity, alignment: .leading)
            .padding(16)
            .background(AppTheme.mutedFill, in: RoundedRectangle(cornerRadius: 20, style: .continuous))
            .overlay(
                RoundedRectangle(cornerRadius: 20, style: .continuous)
                    .stroke(AppTheme.border, lineWidth: 1)
            )
    }

    @ViewBuilder
    private var content: some View {
        #if os(watchOS)
        Text(text)
            .font(monospaced ? .body.monospaced() : .body)
        #else
        Text(text)
            .font(monospaced ? .body.monospaced() : .body)
            .textSelection(.enabled)
        #endif
    }
}

struct AppTextEditorField: View {
    @Binding var text: String
    var minHeight: CGFloat = 120
    var monospaced: Bool = true

    var body: some View {
        editor
            .frame(minHeight: minHeight)
            .background(AppTheme.mutedFill, in: RoundedRectangle(cornerRadius: 20, style: .continuous))
            .overlay(
                RoundedRectangle(cornerRadius: 20, style: .continuous)
                    .stroke(AppTheme.border, lineWidth: 1)
            )
    }

    @ViewBuilder
    private var editor: some View {
        #if os(watchOS)
        Text(text)
            .font(monospaced ? .body.monospaced() : .body)
            .frame(maxWidth: .infinity, alignment: .leading)
            .padding(14)
        #else
        TextEditor(text: $text)
            .font(monospaced ? .body.monospaced() : .body)
            .scrollContentBackground(.hidden)
            .autocorrectionDisabled()
            .padding(14)
        #endif
    }
}

struct AppActionRow: View {
    let title: String
    var subtitle: String? = nil
    let systemImage: String
    var tone: Color = AppTheme.accent

    var body: some View {
        HStack(alignment: .top, spacing: 12) {
            Image(systemName: systemImage)
                .font(.subheadline.weight(.semibold))
                .foregroundStyle(tone)
                .frame(width: 28, height: 28)

            VStack(alignment: .leading, spacing: 4) {
                Text(title)
                    .font(.headline)

                if let subtitle, !subtitle.isEmpty {
                    Text(subtitle)
                        .font(.subheadline)
                        .foregroundStyle(.secondary)
                        .multilineTextAlignment(.leading)
                }
            }

            Spacer(minLength: 0)

            Image(systemName: "arrow.right")
                .font(.footnote.weight(.bold))
                .foregroundStyle(.secondary)
        }
        .frame(maxWidth: .infinity, alignment: .leading)
    }
}

struct AppActionTile: View {
    let title: String
    let systemImage: String
    var tone: Color = AppTheme.accent
    var isBusy: Bool = false

    var body: some View {
        VStack(alignment: .leading, spacing: 14) {
            HStack(alignment: .center) {
                ZStack {
                    Circle()
                        .fill(tone.opacity(0.10))
                        .frame(width: 38, height: 38)

                    if isBusy {
                        ProgressView()
                            .tint(tone)
                    } else {
                        Image(systemName: systemImage)
                            .font(.headline.weight(.semibold))
                            .foregroundStyle(tone)
                    }
                }

                Spacer(minLength: 0)

                Image(systemName: "arrow.up.right")
                    .font(.caption.weight(.bold))
                    .foregroundStyle(.secondary)
            }

            Text(title)
                .font(.headline)
                .multilineTextAlignment(.leading)
                .lineLimit(2)
                .frame(maxWidth: .infinity, alignment: .leading)
        }
        .padding(16)
        .frame(maxWidth: .infinity, minHeight: 92, alignment: .topLeading)
        .appSurface(radius: 22)
    }
}