import ByreAPI
import SwiftUI
import UserNotifications

typealias NotificationPrefs = Components.Schemas.NotificationPrefs

@MainActor
private let kinds: [(key: WritableKeyPath<NotificationPrefs, Bool>, label: String)] = [
    (\.questions, "Questions"),
    (\.ready, "Ready to merge"),
    (\.discard, "Suggests discard"),
    (\.mergeProblems, "Merge problems"),
    (\.workflows, "Workflow finished"),
    (\.errors, "Session errors"),
    (\.rateLimits, "Rate limits"),
    (\.reports, "Turn summaries"),
]

struct SettingsView: View {
    @Environment(Store.self) private var store

    var body: some View {
        ScrollView {
            VStack(alignment: .leading, spacing: 0) {
                heading("Window color")
                Text("Windows for this server have a border in this color, on every device you use.")
                    .foregroundStyle(Palette.muted)
                    .fixedSize(horizontal: false, vertical: true)
                ServerColorPicker()
                heading("Font size")
                Text("The size of body text and of code, on every device you use. Other text grows and shrinks with them.")
                    .foregroundStyle(Palette.muted)
                    .fixedSize(horizontal: false, vertical: true)
                FontSizeStepper(label: "Text", size: FontSize.shared.body) { n in
                    FontSize.shared.set(body: n, code: FontSize.shared.code)
                }
                FontSizeStepper(label: "Code", size: FontSize.shared.code) { n in
                    FontSize.shared.set(body: FontSize.shared.body, code: n)
                }
                heading("Notifications")
                DeviceNotifications()
                PrefsBox()
                heading("Default model")
                Text("New tasks you start from byre run on this model.")
                    .foregroundStyle(Palette.muted)
                    .fixedSize(horizontal: false, vertical: true)
                ModelMenu(current: store.defaultModel, help: "Model for new tasks") { m in
                    try await store.api.client.updateDefaultModel(body: .json(.init(model: m))).ok.body.json
                }
                heading("Saved commands")
                Text("Each is a button in the Terminal tab of every task on this server. It opens a new shell in the task's worktree and runs the command there.")
                    .foregroundStyle(Palette.muted)
                    .fixedSize(horizontal: false, vertical: true)
                SavedCommands()
                heading("iCloud sync")
                SyncState()
                #if os(macOS)
                heading("This Mac's permissions")
                Text("The macOS privacy grants byre's app needs for agents to see and control this Mac. Checking asks macOS for any that are missing.")
                    .foregroundStyle(Palette.muted)
                    .fixedSize(horizontal: false, vertical: true)
                PermissionsCheck(run: checkLocalPermissions)
                #endif
            }
            .padding(.horizontal, 16)
            .padding(.top, 8)
            .padding(.bottom, 16)
            .frame(maxWidth: .infinity, alignment: .leading)
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .background(Palette.bg)
    }

    private func heading(_ text: String) -> some View {
        Text(text)
            .font(Fonts.font(13, weight: 700))
            .padding(.top, 16)
            .padding(.bottom, 6)
    }
}

private struct ServerColorPicker: View {
    @Environment(Store.self) private var store

    var body: some View {
        let origin = store.api.origin.absoluteString
        let current = Servers.shared.record(origin)?.color
        HStack(spacing: 4) {
            ForEach(taskPalette.indices, id: \.self) { i in
                Button {
                    Servers.shared.setColor(origin, i)
                } label: {
                    Circle()
                        .fill(taskPalette[i])
                        .frame(width: 18, height: 18)
                        .padding(3)
                        .overlay(Circle().stroke(i == current ? Palette.text : .clear, lineWidth: 1.5))
                        .contentShape(Circle())
                }
                .buttonStyle(.plain)
            }
        }
        .padding(.top, 8)
    }
}

private struct FontSizeStepper: View {
    let label: String
    let size: Int
    let set: (Int) -> Void

    var body: some View {
        HStack(spacing: 8) {
            Text(label)
                .frame(width: 48, alignment: .leading)
            Button("−") {
                set(size - 1)
            }
            .buttonStyle(WebButtonStyle())
            .disabled(size <= FontSize.range.lowerBound)
            Text("\(size) pt")
                .monospacedDigit()
            Button("+") {
                set(size + 1)
            }
            .buttonStyle(WebButtonStyle())
            .disabled(size >= FontSize.range.upperBound)
        }
        .padding(.top, 8)
    }
}

private struct SyncState: View {
    var body: some View {
        TimelineView(.periodic(from: .now, by: 30)) { _ in
            if let sync = Servers.shared.sync {
                if sync.ok {
                    Text("This \(deviceKind) shares its servers, window colors, font sizes, drafts and task visits through iCloud. Last synced \(ago(sync.at)).")
                        .fixedSize(horizontal: false, vertical: true)
                } else {
                    Text("iCloud sync is failing on this \(deviceKind), so changes made here aren't reaching your other devices. Failed \(ago(sync.at)): \(sync.error ?? "")")
                        .foregroundStyle(Palette.danger)
                        .textSelection(.enabled)
                        .fixedSize(horizontal: false, vertical: true)
                }
            } else {
                Text("No iCloud sync has finished since byre started.").foregroundStyle(Palette.muted)
            }
        }
    }
}

private struct DeviceNotifications: View {
    @ViewState private var status: UNAuthorizationStatus?
    @ViewState private var asking = false

    var body: some View {
        Group {
            switch status {
            case .none:
                EmptyView()
            case .denied:
                Text(touchOnly ? "Notifications are blocked for byre in Settings." : "Notifications are blocked for byre in System Settings.").foregroundStyle(Palette.muted)
            case .authorized, .provisional:
                Text(touchOnly ? "This iPhone shows notifications while byre is open." : "This Mac shows notifications while byre is running.")
            default:
                VStack(alignment: .leading, spacing: 8) {
                    Text("This \(deviceKind) doesn't show notifications from byre.")
                    Button("Turn on for this \(deviceKind)") {
                        asking = true
                        Task {
                            _ = try? await UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound])
                            await read()
                            asking = false
                        }
                    }
                    .buttonStyle(WebButtonStyle())
                    .disabled(asking)
                }
            }
        }
        .padding(.bottom, 8)
        .task {
            await read()
        }
        .onReceive(NotificationCenter.default.publisher(for: appBecameActive)) { _ in
            Task {
                await read()
            }
        }
    }

    private func read() async {
        status = await UNUserNotificationCenter.current().notificationSettings().authorizationStatus
    }
}

private struct PrefsBox: View {
    @Environment(Store.self) private var store
    @Environment(Overlays.self) private var overlays

    var body: some View {
        if let me = store.me {
            VStack(alignment: .leading, spacing: 4) {
                Text("Notify me about")
                    .foregroundStyle(Palette.muted)
                    .padding(.horizontal, 4)
                    .background(Palette.bg)
                    .offset(y: -18)
                    .padding(.bottom, -18)
                ForEach(kinds, id: \.label) { kind in
                    Toggle(kind.label, isOn: Binding(get: { me.notificationPrefs[keyPath: kind.key] }, set: { on in
                        var prefs = me.notificationPrefs
                        prefs[keyPath: kind.key] = on
                        Task {
                            do {
                                store.me = try await store.api.client.updateNotificationPrefs(body: .json(prefs)).ok.body.json
                            } catch {
                                overlays.showAlert(errorText(error))
                            }
                        }
                    }))
                    .toggleStyle(.checkbox)
                    .tint(Palette.accent)
                }
            }
            .padding(.horizontal, 12)
            .padding(.top, 8)
            .padding(.bottom, 10)
            .frame(maxWidth: .infinity, alignment: .leading)
            .background(RoundedRectangle(cornerRadius: 8).stroke(Palette.border))
            .padding(.top, 16)
        }
    }
}

private struct SavedCommands: View {
    @Environment(Store.self) private var store
    @Environment(Overlays.self) private var overlays
    @ViewState private var list: [SavedCommand] = []
    @ViewState private var editing: String?
    @ViewState private var name = ""
    @ViewState private var command = ""
    @ViewState private var off: (() -> Void)?

    var body: some View {
        VStack(alignment: .leading, spacing: 0) {
            ForEach(list, id: \.id) { c in
                if editing == c.id {
                    form(c.id)
                } else {
                    HStack(alignment: .firstTextBaseline, spacing: 12) {
                        VStack(alignment: .leading, spacing: 2) {
                            Text(c.name)
                            Text(c.command)
                                .font(Fonts.font(12, mono: true))
                                .foregroundStyle(Palette.muted)
                                .textSelection(.enabled)
                                .fixedSize(horizontal: false, vertical: true)
                        }
                        .frame(maxWidth: .infinity, alignment: .leading)
                        Button("Edit") {
                            editing = c.id
                            name = c.name
                            command = c.command
                        }
                        .buttonStyle(SmallLinkButtonStyle())
                        Button("Delete") {
                            delete(c)
                        }
                        .buttonStyle(SmallLinkButtonStyle(color: Palette.danger))
                    }
                    .padding(.vertical, 6)
                    .overlay(alignment: .top) {
                        Rectangle().fill(Palette.border).frame(height: 1)
                    }
                }
            }
            if editing == nil {
                form(nil)
            }
        }
        .padding(.top, 8)
        .onAppear {
            off = store.events.add { ev in
                if ev.kind == "command.saved" || ev.kind == "command.deleted" {
                    load()
                }
            }
            load()
        }
        .onDisappear {
            off?()
            off = nil
        }
    }

    private func form(_ id: String?) -> some View {
        let valid = !name.trimmingCharacters(in: .whitespaces).isEmpty && !command.trimmingCharacters(in: .whitespaces).isEmpty
        return HStack(spacing: 6) {
            TextField("Name", text: $name)
                .modifier(FieldStyle())
                .frame(width: touchOnly ? 100 : 180)
                .onSubmit {
                    save(id, valid)
                }
            TextField("Command", text: $command)
                .font(Fonts.font(13, mono: true))
                .modifier(FieldStyle())
                .onSubmit {
                    save(id, valid)
                }
            Button(id == nil ? "Add" : "Save") {
                save(id, valid)
            }
            .buttonStyle(WebButtonStyle())
            .disabled(!valid)
            if id != nil {
                Button("Cancel") {
                    editing = nil
                    name = ""
                    command = ""
                }
                .buttonStyle(WebButtonStyle())
            }
        }
        .padding(.vertical, 6)
    }

    private func load() {
        Task {
            do {
                list = try await store.api.client.listSavedCommands().ok.body.json
            } catch {
                overlays.showAlert(errorText(error))
            }
        }
    }

    private func save(_ id: String?, _ valid: Bool) {
        if !valid {
            return
        }
        let body = Components.Schemas.SavedCommandSave(name: name, command: command)
        Task {
            do {
                if let id {
                    _ = try await store.api.client.updateSavedCommand(path: .init(commandId: id), body: .json(body)).ok.body.json
                } else {
                    _ = try await store.api.client.createSavedCommand(body: .json(body)).created.body.json
                }
                editing = nil
                name = ""
                command = ""
            } catch {
                overlays.showAlert(errorText(error))
            }
        }
    }

    private func delete(_ c: SavedCommand) {
        Task {
            do {
                _ = try await store.api.client.deleteSavedCommand(path: .init(commandId: c.id)).noContent
            } catch {
                overlays.showAlert(errorText(error))
            }
        }
    }
}

private struct ModelMenu: View {
    let current: String
    let help: String
    let pick: (String) async throws -> User
    @Environment(Store.self) private var store
    @Environment(Overlays.self) private var overlays

    var body: some View {
        Menu {
            ForEach(models, id: \.self) { m in
                Button(m) {
                    Task {
                        do {
                            store.me = try await pick(m)
                        } catch {
                            overlays.showAlert(errorText(error))
                        }
                    }
                }
            }
        } label: {
            HStack(spacing: 8) {
                Text(current)
                Image(systemName: "chevron.up.chevron.down")
                    .font(Fonts.font(9, weight: 600))
            }
            .foregroundStyle(Palette.text)
            .modifier(FieldStyle())
            .contentShape(Rectangle())
        }
        .menuStyle(.button)
        .buttonStyle(.plain)
        .menuIndicator(.hidden)
        .fixedSize()
        .help(help)
        .padding(.top, 8)
    }
}