import AppKit
import SstCore
import SstData
import SstUI
import SstWhisper
import SwiftUI

struct SettingsView: View {
    private enum Tab: CaseIterable {
        case hotkey, model, privacy

        var title: String {
            switch self {
            case .hotkey: Strings.tabHotkey
            case .model: Strings.tabModel
            case .privacy: Strings.tabPrivacy
            }
        }
    }

    @State private var tab: Tab = .hotkey

    var body: some View {
        ZStack {
            BrushedBackground()
            VStack(alignment: .leading, spacing: Layout.panelGap) {
                HStack(spacing: Space.s3) {
                    ForEach(Tab.allCases, id: \.self) { candidate in
                        Button(candidate.title) { tab = candidate }
                            .buttonStyle(KeyButtonStyle(latched: tab == candidate))
                    }
                }
                Group {
                    switch tab {
                    case .hotkey: HotkeySettingsView()
                    case .model: ModelSettingsView()
                    case .privacy: PrivacySettingsView()
                    }
                }
                .padding(Layout.panelPadding)
                .frame(maxWidth: .infinity, alignment: .topLeading)
                .background(PanelBackground())
            }
            .padding(Layout.panelPadding)
        }
        .frame(width: Layout.settingsWidth)
        .fixedSize(horizontal: false, vertical: true)
    }
}

// MARK: hotkey

extension HotkeyBinding {
    /// The matching flag in an AppKit event, used while capturing a new key.
    fileprivate var eventFlag: NSEvent.ModifierFlags {
        switch id {
        case "fn": .function
        case "rightOption": .option
        case "rightCommand": .command
        default: .control
        }
    }
}

@MainActor
private final class HotkeyCapture: ObservableObject {
    @Published var isCapturing = false
    @Published var message: String?
    private var monitor: Any?

    func start(onCapture: @escaping (HotkeyBinding) -> Void) {
        stop()
        isCapturing = true
        message = Strings.capturing
        monitor = NSEvent.addLocalMonitorForEvents(matching: [.flagsChanged, .keyDown]) { [weak self] event in
            guard let self else { return event }
            if event.type == .keyDown {
                if event.keyCode == 53 { self.stop() }   // Escape cancels
                return nil
            }
            guard let binding = HotkeyBinding.binding(keyCode: Int(event.keyCode)) else {
                self.message = Strings.hotkeyRejected
                return nil
            }
            if event.modifierFlags.contains(binding.eventFlag) {
                self.stop()
                onCapture(binding)
            }
            return nil
        }
    }

    func stop() {
        if let monitor { NSEvent.removeMonitor(monitor) }
        monitor = nil
        isCapturing = false
        message = nil
    }
}

private struct HotkeySettingsView: View {
    @EnvironmentObject private var settings: AppSettings
    @StateObject private var capture = HotkeyCapture()

    private var current: HotkeyBinding { HotkeyBinding.binding(id: settings.hotkeyID) ?? .fn }

    var body: some View {
        VStack(alignment: .leading, spacing: Layout.panelGap) {
            SilkLabel(Strings.tabHotkey, style: Typography.heading)
            HStack(spacing: Layout.panelGap) {
                Text(current.displayName)
                    .textStyle(Typography.heading)
                    .foregroundStyle(Palette.inkPrimary)
                    .padding(.horizontal, Space.s4)
                    .frame(minHeight: Size.controlHeight)
                    .background(WellBackground())
                Button(Strings.captureHotkey) {
                    capture.start { settings.hotkeyID = $0.id }
                }
                .buttonStyle(KeyButtonStyle(latched: capture.isCapturing))
            }
            if let message = capture.message {
                Text(message).textStyle(Typography.meta).foregroundStyle(Palette.inkSecondary)
            }
            SeamDivider()
            Text(HotkeyBinding.allowed.map(\.displayName).joined(separator: " · "))
                .textStyle(Typography.meta)
                .foregroundStyle(Palette.inkSecondary)
            if current == .fn {
                Text(Strings.globeHint).textStyle(Typography.meta).foregroundStyle(Palette.inkSecondary)
            }
        }
        .onDisappear { capture.stop() }
    }
}

// MARK: model

private struct ModelSettingsView: View {
    @EnvironmentObject private var model: AppModel

    var body: some View {
        VStack(alignment: .leading, spacing: Layout.panelGap) {
            SilkLabel(Strings.tabModel, style: Typography.heading)
            ForEach(ModelCatalog.all) { option in
                row(option)
                SeamDivider()
            }
            HStack {
                Text(model.storage.base.path)
                    .textStyle(Typography.code)
                    .foregroundStyle(Palette.inkSecondary)
                    .lineLimit(1)
                    .truncationMode(.middle)
                Spacer()
                Button(Strings.showInFinder) {
                    NSWorkspace.shared.activateFileViewerSelecting([model.storage.base])
                }
                .buttonStyle(KeyButtonStyle())
            }
        }
        .onAppear { model.refreshInstalled() }
    }

    private func row(_ option: ModelOption) -> some View {
        let isActive = model.activeVariant == option.id
        let installed = model.installedVariants.contains(option.id)
        let progress: Double? = {
            if case .downloading(option.id, let fraction) = model.modelStatus { return fraction }
            return nil
        }()
        return HStack(alignment: .center, spacing: Layout.panelGap) {
            LampView(isOn: isActive, tint: .amber)
            VStack(alignment: .leading, spacing: Space.s1) {
                Text(option.title).textStyle(Typography.body).foregroundStyle(Palette.inkPrimary)
                Text("\(option.detail) · \(option.approxSizeMB) MB")
                    .textStyle(Typography.meta)
                    .foregroundStyle(Palette.inkSecondary)
                if let progress {
                    LEDBarView(fraction: progress)
                } else if case .loading(option.id) = model.modelStatus {
                    SilkLabel(Strings.modelLoading(option.title), style: Typography.labelSmall)
                }
            }
            Spacer()
            if installed && !isActive {
                Button(Strings.useModel) { model.activateModel(option.id) }.buttonStyle(KeyButtonStyle())
                    .disabled(model.loadingVariant != nil)
                Button(Strings.remove) { model.deleteModel(option.id) }.buttonStyle(KeyButtonStyle())
                    .disabled(model.loadingVariant != nil)
            } else if !installed {
                Button(Strings.download) { model.activateModel(option.id) }.buttonStyle(KeyButtonStyle())
                    .disabled(model.loadingVariant != nil)
            }
        }
    }
}

// MARK: privacy

private struct PrivacySettingsView: View {
    @EnvironmentObject private var model: AppModel
    @EnvironmentObject private var settings: AppSettings
    @State private var confirming = false

    var body: some View {
        VStack(alignment: .leading, spacing: Layout.panelGap) {
            SilkLabel(Strings.tabPrivacy, style: Typography.heading)
            Toggle(isOn: $settings.keepHistory) {
                Text(Strings.keepHistory).textStyle(Typography.body).foregroundStyle(Palette.inkPrimary)
            }
            .toggleStyle(RockerToggleStyle())
            SeamDivider()
            Button(Strings.clearHistory) { confirming = true }
                .buttonStyle(KeyButtonStyle())
        }
        .confirmationDialog(Strings.clearHistoryConfirm, isPresented: $confirming) {
            Button(Strings.erase, role: .destructive) { model.clearHistory() }
            Button(Strings.cancel, role: .cancel) {}
        } message: {
            Text(Strings.clearHistoryDetail)
        }
    }
}