import LChatCore
import SwiftUI
import WebKit

// 🤖 A space-wide app's full-pane surface on iOS (docs/native-apps.md phase
// 4): the webview seeded with the SPACE thread + its key, wearing the app's
// identity — bootEmbed's space flag routes it through the web's own
// openSpaceApp path (the space thread has no chat surface). Pushed from the
// chat list's space band.
struct SpaceAppScreen: View {
    let store: ThreadStore
    let app: String

    var body: some View {
        Group {
            if let thread = store.spaceApps.surfaceThread(
                app: app, title: store.registry.title(app), glyph: store.registry.glyph(app)) {
                SpaceAppSurface(instance: store.instance, thread: thread,
                                myUserId: store.myUserId,
                                instanceKeyB64: store.instanceKey(), app: app)
            } else {
                ContentUnavailableView("This app isn't ready yet",
                                       systemImage: "square.grid.2x2",
                                       description: Text("Try again in a moment."))
            }
        }
        .navigationTitle(store.registry.title(app))
        .navigationBarTitleDisplayMode(.inline)
    }
}

// The webview plus its bridge-observing chrome: the inline app-update offer
// (AppUpdateBar) above the pane, so a space app that changed while on screen
// asks before reloading like every other app surface.
private struct SpaceAppSurface: View {
    @ObservedObject private var bridge: WebBridge
    let instance: SavedInstance
    let thread: ChatThread
    let myUserId: String
    let instanceKeyB64: String?
    let app: String

    @MainActor
    init(instance: SavedInstance, thread: ChatThread, myUserId: String,
         instanceKeyB64: String?, app: String) {
        self.instance = instance
        self.thread = thread
        self.myUserId = myUserId
        self.instanceKeyB64 = instanceKeyB64
        self.app = app
        bridge = FeedWebCache.shared.bridge(for: instance, thread: thread,
                                            myUserId: myUserId,
                                            instanceKeyB64: instanceKeyB64,
                                            app: app, space: true)
    }

    var body: some View {
        VStack(spacing: 0) {
            AppUpdateBar(bridge: bridge)
            SpaceAppWebView(instance: instance, thread: thread, myUserId: myUserId,
                            instanceKeyB64: instanceKeyB64, app: app)
                .ignoresSafeArea(edges: .bottom)
        }
    }
}

private struct SpaceAppWebView: UIViewRepresentable {
    let instance: SavedInstance
    let thread: ChatThread
    let myUserId: String
    let instanceKeyB64: String?
    let app: String

    func makeUIView(context: Context) -> WKWebView {
        FeedWebCache.shared.webView(for: instance, thread: thread, myUserId: myUserId,
                                    instanceKeyB64: instanceKeyB64, app: app, space: true)
    }

    func updateUIView(_ web: WKWebView, context: Context) {}
}

// 🤖 The chat list's SPACE BAND: one chip per space-wide install with an
// openable surface — the iOS shape of the web sidebar's space rows (the
// UIKit-backed thread list can't grow SwiftUI rows, so the band rides a
// safe-area inset: in the layout, never floating over rows someone is
// reading). Its own view so it observes SpaceAppsStore and AppRegistry
// directly.
struct SpaceBand: View {
    @ObservedObject var spaceApps: SpaceAppsStore
    @ObservedObject var registry: AppRegistry
    let onOpen: (String) -> Void

    private var apps: [AppManifest] {
        registry.knownSpace(spaceApps.installs)
            .compactMap { registry.manifest($0.id) }
            .filter { $0.surface ?? true }
    }

    var body: some View {
        if !apps.isEmpty {
            ScrollView(.horizontal, showsIndicators: false) {
                HStack(spacing: 8) {
                    ForEach(apps) { app in
                        Button { onOpen(app.name) } label: {
                            HStack(spacing: 6) {
                                Text(app.glyph).font(.system(size: 15))
                                Text(app.title)
                                    .font(.subheadline.weight(.medium))
                                    .lineLimit(1)
                            }
                            .padding(.horizontal, 12)
                            .padding(.vertical, 7)
                            .floatingGlass(in: Capsule())
                            .contentShape(Capsule())
                        }
                        .buttonStyle(.plain)
                        .accessibilityLabel("\(app.title), space app")
                        .accessibilityHint("Opens the app shared with everyone in this space")
                    }
                }
                .padding(.horizontal, 14)
                .padding(.vertical, 8)
            }
        }
    }
}