import AppKit
import IPodSyncKit
import SwiftUI
import UniformTypeIdentifiers

struct ExportView: View {
    @State private var model = ExportModel()
    @State private var isChoosingFiles = false
    @State private var isChoosingDestination = false

    var body: some View {
        Form {
            Section {
                Text(
                    "Prepares contacts and calendars for a click-wheel iPod, which reads "
                    + "dropped .vcf and .ics files but rejects the timezone, alarm and "
                    + "embedded-image data a normal export contains."
                )
                .font(.callout)
                .foregroundStyle(.secondary)
                .fixedSize(horizontal: false, vertical: true)
            }

            contactsSection
            calendarsSection
            filesSection
            destinationSection
            resultsSection
        }
        .formStyle(.grouped)
        .frame(minWidth: 520, idealWidth: 580, minHeight: 560)
        .safeAreaInset(edge: .bottom) { footer }
        .task { await model.refreshAccessOnAppear() }
        .fileImporter(
            isPresented: $isChoosingFiles,
            allowedContentTypes: Self.importableTypes,
            allowsMultipleSelection: true
        ) { result in
            if case .success(let urls) = result { model.addInputFiles(urls) }
        }
        .fileImporter(
            isPresented: $isChoosingDestination,
            allowedContentTypes: [.folder]
        ) { result in
            if case .success(let url) = result { model.destination = url }
        }
        .alert(
            "Something went wrong",
            isPresented: Binding(
                get: { model.errorMessage != nil },
                set: { if !$0 { model.errorMessage = nil } }
            )
        ) {
            Button("OK") { model.errorMessage = nil }
        } message: {
            Text(model.errorMessage ?? "")
        }
    }

    private static var importableTypes: [UTType] {
        [.vCard, UTType(filenameExtension: "ics") ?? .calendarEvent]
    }

    // MARK: - Sections

    private var contactsSection: some View {
        Section("Contacts") {
            Toggle("Export contacts", isOn: $model.includeContacts)

            if model.includeContacts {
                if model.contactsGranted {
                    Label("Access granted — one .vcf per contact", systemImage: "checkmark.circle")
                        .foregroundStyle(.secondary)
                        .font(.callout)
                } else {
                    HStack {
                        Text("Contacts access is needed to read your address book.")
                            .font(.callout)
                            .foregroundStyle(.secondary)
                        Spacer()
                        Button("Grant Access…") {
                            Task { await model.requestContactsAccess() }
                        }
                    }
                }
            }
        }
    }

    private var calendarsSection: some View {
        Section("Calendars") {
            Toggle("Export calendars", isOn: $model.includeCalendars)

            if model.includeCalendars {
                if model.calendarsGranted {
                    DatePicker("From", selection: $model.rangeStart, displayedComponents: .date)
                    DatePicker("To", selection: $model.rangeEnd, displayedComponents: .date)

                    if model.calendars.isEmpty {
                        Text("No calendars found.")
                            .font(.callout)
                            .foregroundStyle(.secondary)
                    } else {
                        ForEach(model.calendars) { calendar in
                            Toggle(isOn: Binding(
                                get: { model.isSelected(calendar) },
                                set: { model.setSelected(calendar, $0) }
                            )) {
                                VStack(alignment: .leading, spacing: 1) {
                                    Text(calendar.title)
                                    if !calendar.accountName.isEmpty {
                                        Text(calendar.accountName)
                                            .font(.caption)
                                            .foregroundStyle(.secondary)
                                    }
                                }
                            }
                        }
                    }

                    Text("Repeating events are written out one occurrence at a time, so the "
                         + "iPod never has to interpret a recurrence rule.")
                        .font(.caption)
                        .foregroundStyle(.secondary)
                        .fixedSize(horizontal: false, vertical: true)
                } else {
                    HStack {
                        Text("Calendar access is needed to read your events.")
                            .font(.callout)
                            .foregroundStyle(.secondary)
                        Spacer()
                        Button("Grant Access…") {
                            Task { await model.requestCalendarAccess() }
                        }
                    }
                }
            }
        }
    }

    private var filesSection: some View {
        Section("Existing files") {
            Toggle("Sanitize .vcf / .ics files I already have", isOn: $model.includeFiles)

            if model.includeFiles {
                HStack {
                    Text(model.inputFiles.isEmpty
                         ? "No files chosen."
                         : "\(model.inputFiles.count) file(s) chosen.")
                        .font(.callout)
                        .foregroundStyle(.secondary)
                    Spacer()
                    if !model.inputFiles.isEmpty {
                        Button("Clear") { model.inputFiles.removeAll() }
                    }
                    Button("Choose Files…") { isChoosingFiles = true }
                }

                ForEach(model.inputFiles, id: \.self) { url in
                    Text(url.lastPathComponent)
                        .font(.callout)
                        .foregroundStyle(.secondary)
                }
            }
        }
    }

    private var destinationSection: some View {
        Section("Output folder") {
            HStack {
                Text(model.destination?.path(percentEncoded: false) ?? "Not chosen.")
                    .font(.callout)
                    .foregroundStyle(model.destination == nil ? .secondary : .primary)
                    .lineLimit(2)
                    .truncationMode(.middle)
                Spacer()
                Button("Choose…") { isChoosingDestination = true }
            }

            Text("Files are written into Contacts and Calendars subfolders, matching the "
                 + "folders on the iPod, so you can drag them straight across in Finder.")
                .font(.caption)
                .foregroundStyle(.secondary)
                .fixedSize(horizontal: false, vertical: true)
        }
    }

    @ViewBuilder
    private var resultsSection: some View {
        if model.phase == .finished {
            Section("Result") {
                Text(model.summary)

                ForEach(Array(model.warnings.enumerated()), id: \.offset) { _, warning in
                    Label(warning, systemImage: "exclamationmark.triangle")
                        .font(.callout)
                        .foregroundStyle(.secondary)
                        .fixedSize(horizontal: false, vertical: true)
                }

                if let first = model.writtenFiles.first {
                    Button("Reveal in Finder") {
                        NSWorkspace.shared.activateFileViewerSelecting([first.path])
                    }
                }
            }
        }
    }

    private var footer: some View {
        HStack {
            if case .working(let message) = model.phase {
                ProgressView().controlSize(.small)
                Text(message).font(.callout).foregroundStyle(.secondary)
            }
            Spacer()
            Button("Export") {
                Task { await model.export() }
            }
            .keyboardShortcut(.defaultAction)
            .disabled(!model.canExport)
        }
        .padding(.horizontal)
        .padding(.vertical, 10)
        .background(.bar)
    }
}