#if canImport(SwiftUI)
import SwiftUI

/// A complete recipient inbox, using organization branding returned by the recipient API.
@available(iOS 15.0, macOS 12.0, *)
public struct InboxView: View {
    private let client: InboxClient
    private let onAction: (InboxMessage, InboxAction?) -> Void
    @State private var snapshot: InboxSnapshot?
    @State private var branding: InboxBranding?
    @State private var error: String?
    @State private var busy: Set<String> = []
    @State private var generation=0
    @State private var recipientClient: ObjectIdentifier?
    @Environment(\.scenePhase) private var scenePhase
    public init(client: InboxClient, onAction: @escaping (InboxMessage, InboxAction?) -> Void = {_,_ in}) { self.client=client; self.onAction=onAction }
    private var visibleBranding: InboxBranding? { recipientClient == ObjectIdentifier(client) ? branding : nil }
    private var brand: Color { color(visibleBranding?.brandColor) ?? Color.accentColor }
    public var body: some View {
        let currentSnapshot = recipientClient == ObjectIdentifier(client) ? snapshot : nil
        VStack(alignment:.leading,spacing:0) {
            HStack(spacing:12) {
                if let branding=visibleBranding, let url=client.logoURL(branding) { AsyncImage(url:url) { image in image.resizable().scaledToFit() } placeholder: { Color.clear }.frame(width:36,height:36).accessibilityHidden(true) }
                VStack(alignment:.leading) { Text(visibleBranding?.displayName ?? "Notifications").font(.title2.bold()); if let snapshot=currentSnapshot { Text("\(snapshot.unreadCount) unread").font(.subheadline).foregroundStyle(.secondary) } }
                Spacer()
                Button { generation += 1 } label: { Image(systemName:"arrow.clockwise") }.accessibilityLabel("Refresh notifications")
            }.padding().overlay(alignment:.bottom) { Rectangle().fill(brand).frame(height:2) }
            if let error,recipientClient == ObjectIdentifier(client) { HStack { Text(error).font(.callout); Spacer(); Button("Retry") {generation += 1} }.padding().accessibilityElement(children:.contain) }
            if let snapshot=currentSnapshot {
                if snapshot.messages.isEmpty { VStack(spacing:8) { Image(systemName:"bell").font(.largeTitle).foregroundStyle(brand); Text("No notifications yet").font(.headline); Text("Your notifications will appear here.").foregroundStyle(.secondary) }.frame(maxWidth:.infinity,maxHeight:.infinity).padding() }
                else { List(snapshot.messages) { message in
                    VStack(alignment:.leading,spacing:8) {
                        HStack { if message.readAt == nil { Circle().fill(brand).frame(width:8,height:8).accessibilityLabel("Unread") }; Text(message.title).font(.headline); Spacer() }
                        Text(message.body).font(.body)
                        Text(message.createdAt).font(.caption).foregroundStyle(.secondary)
                        HStack {
                            if message.readAt == nil { Button("Mark read") { mutate(message,archive:false) } }
                            Button("Archive") { mutate(message,archive:true) }
                            if let url=InboxClient.safeActionURL(message.url) { Link("Open",destination:url).simultaneousGesture(TapGesture().onEnded { onAction(message,nil) }) }
                        }.buttonStyle(.borderless).disabled(busy.contains(message.id))
                        ForEach(message.actions ?? [],id:\.id) { action in
                            if let url=InboxClient.safeActionURL(action.url) { Link(action.label,destination:url).simultaneousGesture(TapGesture().onEnded {onAction(message,action)}) }
                            else if action.url == nil { Button(action.label) {onAction(message,action)}.buttonStyle(.borderless) }
                        }
                    }.padding(.vertical,8)
                }.listStyle(.plain) }
            } else if error == nil || recipientClient != ObjectIdentifier(client) { ProgressView("Loading notifications").frame(maxWidth:.infinity,maxHeight:.infinity) }
        }.tint(.primary).task(id:"\(ObjectIdentifier(client)):\(generation)") { await load() }
        .onChange(of:scenePhase) { _ in generation += 1 }
    }
    @MainActor private func load() async {
        guard scenePhase == .active else {return}
        let identity=ObjectIdentifier(client)
        if recipientClient != identity {snapshot=nil;branding=nil;busy=[];recipientClient=identity}
        error=nil
        do { let settings=try await client.preferences();let first=try await client.messages();try Task.checkCancellation();guard recipientClient==identity else{return};branding=settings.branding;snapshot=first; for try await value in client.updates() { try Task.checkCancellation();guard recipientClient==identity else{return};snapshot=value } }
        catch { if !Task.isCancelled && recipientClient==identity { self.error=error.localizedDescription } }
    }
    private func mutate(_ message: InboxMessage, archive: Bool) {
        let identity=ObjectIdentifier(client)
        busy.insert(message.id)
        Task { @MainActor in
            defer {if recipientClient==identity {busy.remove(message.id)}}
            do { if archive { _=try await client.archive(message.id) } else { _=try await client.markRead(message.id) }; let value=try await client.messages();if recipientClient==identity {snapshot=value} }
            catch {if recipientClient==identity {self.error=error.localizedDescription}}
        }
    }
    private func color(_ text: String?) -> Color? {
        guard let text,text.range(of:"^#[a-fA-F0-9]{6}$",options:.regularExpression) != nil, let hex=UInt32(text.dropFirst(),radix:16) else {return nil}
        return Color(red:Double((hex>>16)&255)/255,green:Double((hex>>8)&255)/255,blue:Double(hex&255)/255)
    }
}
#endif