import SwiftUI
import AVFoundation
import OnyxDesign
import FaceProvider
import LockProvider

/// Sperrbildschirm und Gesichtsvergleich.
///
/// **Die Einschränkung steht oben und nicht unten.** Wer diese Seite öffnet,
/// soll zuerst lesen, was das hier ist und was nicht — nicht erst, nachdem er
/// sein Gesicht angelernt hat.
struct LockSettingsView: View {

    @Bindable var model: AppModel
    let controller: LockController

    @State private var enrollment = FaceEnrollment()
    @State private var isEnrolling = false
    @State private var cameraDenied = false

    var body: some View {
        SettingsPage {
            OnyxFormCard(String(localized: "lock.section.what"),
                         hint: String(localized: "lock.disclaimer.settings")) {
                EmptyView()
            }

            OnyxFormCard(String(localized: "lock.section.screen")) {
                OnyxFormRow(String(localized: "lock.enabled"),
                            hint: String(localized: "lock.enabled.hint")) {
                    Toggle("", isOn: $model.lockScreenEnabled).labelsHidden()
                }
                OnyxFormRow(String(localized: "lock.now")) {
                    Button(String(localized: "lock.now.action")) { controller.lock() }
                }
            }

            OnyxFormCard(String(localized: "lock.section.face")) {
                OnyxFormRow(String(localized: "lock.face.enabled"),
                            hint: String(localized: "lock.face.hint")) {
                    Toggle("", isOn: $model.faceUnlockEnabled).labelsHidden()
                        .disabled(!controller.isEnrolled)
                }

                OnyxFormRow(String(localized: "lock.face.enrolled"),
                            hint: controller.isEnrolled
                                ? nil : String(localized: "lock.face.notEnrolled")) {
                    HStack(spacing: Onyx.Space.lg) {
                        Button(controller.isEnrolled
                               ? String(localized: "lock.face.again")
                               : String(localized: "lock.face.enroll")) {
                            Task { await beginEnrollment() }
                        }
                        if controller.isEnrolled {
                            Button(String(localized: "lock.face.forget"), role: .destructive) {
                                enrollment.reset()
                                model.faceUnlockEnabled = false
                            }
                        }
                    }
                }

                if cameraDenied {
                    OnyxFormRow(String(localized: "lock.face.denied")) {
                        Button(String(localized: "lock.face.openSettings")) {
                            NSWorkspace.shared.open(URL(string:
                                "x-apple.systempreferences:com.apple.preference.security?Privacy_Camera")!)
                        }
                    }
                }
            }
        }
        .sheet(isPresented: $isEnrolling) {
            EnrollmentSheet(enrollment: enrollment) { isEnrolling = false }
        }
    }

    private func beginEnrollment() async {
        guard await FaceCapture.requestAccess() else {
            cameraDenied = true
            return
        }
        cameraDenied = false
        enrollment.reset()
        isEnrolling = true
        enrollment.start()
    }
}

/// Das Anlernen: Vorschau, Anweisung, Auslöser.
private struct EnrollmentSheet: View {
    let enrollment: FaceEnrollment
    let onClose: () -> Void

    var body: some View {
        VStack(spacing: Onyx.Space.xl) {
            if let failure = enrollment.failure {
                Text(failure).foregroundStyle(Onyx.Color.critical)
            } else if enrollment.isFinished {
                VStack(spacing: Onyx.Space.md) {
                    Image(systemName: "checkmark.circle.fill")
                        .font(.system(size: Onyx.Symbol.hero))
                        .foregroundStyle(Onyx.Color.positive)
                    Text("lock.enroll.done")
                }
            } else {
                CameraPreview(session: enrollment.session)
                    .frame(width: 320, height: 240)
                    .clipShape(RoundedRectangle(cornerRadius: Onyx.Radius.card,
                                                style: .continuous))

                Text(enrollment.pose.localizedName, bundle: .main)
                    .font(Onyx.Font.headline)

                Text(enrollment.seesFace ? "lock.enroll.ready" : "lock.enroll.noFace")
                    .font(Onyx.Font.footnote)
                    .foregroundStyle(enrollment.seesFace
                                     ? Onyx.Color.positive : Onyx.Color.textTertiary)

                Button(String(localized: "lock.enroll.capture")) {
                    enrollment.captureCurrentPose()
                }
                .disabled(!enrollment.seesFace)
            }

            Button(enrollment.isFinished
                   ? String(localized: "lock.enroll.close")
                   : String(localized: "lock.enroll.cancel")) {
                enrollment.stop()
                onClose()
            }
        }
        .padding(Onyx.Space.xxl)
        .frame(width: 420)
    }
}