import SwiftUI

/// The Calls server setting, as one Form section: in Calls → Settings…
/// on a Mac and in the home screen's settings sheet on iPhone.
///
/// The field is a draft until Use this server; changing the server while
/// signed in asks first, because it signs out.
@MainActor public struct ServerSettingsSection: View {
  @ObservedObject private var model: CallsModel
  @State private var draft: String
  @State private var problem = ""
  @State private var confirming: String?

  public init(model: CallsModel) {
    self.model = model
    _draft = State(initialValue: model.server)
  }

  private var changed: Bool {
    guard case .success(let origin) = CallsServer.validate(draft) else { return true }
    return origin != model.server
  }

  public var body: some View {
    Section {
      TextField("Server address", text: $draft, prompt: Text(CallsServer.defaultOrigin))
        .accessibilityIdentifier("serverAddress")
        #if os(iOS)
          .keyboardType(.URL).textInputAutocapitalization(.never).autocorrectionDisabled()
        #endif
        .onSubmit(apply)
        .onChange(of: draft) { problem = "" }
      if !problem.isEmpty {
        Label(problem, systemImage: "exclamationmark.circle.fill")
          .foregroundStyle(.red).fixedSize(horizontal: false, vertical: true)
          .accessibilityLabel("Error: \(problem)")
      }
      HStack {
        Button("Use this server", action: apply)
          .disabled(!changed || model.joining).accessibilityIdentifier("useServer")
        Spacer()
        Button("Reset to \(CallsServer.host(of: CallsServer.defaultOrigin))") {
          draft = CallsServer.defaultOrigin
          apply()
        }
        .disabled(model.server == CallsServer.defaultOrigin || model.joining)
      }
      #if os(iOS)
        .buttonStyle(.borderless)
      #endif
    } header: {
      Text("Calls server")
    } footer: {
      Text(
        model.joining
          ? "Leave the current meeting to change the server."
          : "Sign in goes to this server. If you run your own Calls, enter its address here. Links to meetings on other servers still open, just for that meeting."
      )
    }
    .confirmationDialog(
      "Change server and sign out?", isPresented: Binding(
        get: { confirming != nil }, set: { if !$0 { confirming = nil } }),
      titleVisibility: .visible
    ) {
      Button("Change and sign out", role: .destructive) {
        if let origin = confirming { model.changeServer(to: origin) }
        confirming = nil
      }
      Button("Cancel", role: .cancel) {
        confirming = nil
        draft = model.server
      }
    } message: {
      Text(
        "You’re signed in to \(model.host). Changing the server signs you out there; you can sign in to \(CallsServer.host(of: confirming ?? "")) next."
      )
    }
    .onChange(of: model.server) { draft = model.server }
  }

  private func apply() {
    switch CallsServer.validate(draft) {
    case .failure(let failure):
      problem = failure.message
    case .success(let origin):
      draft = origin
      guard origin != model.server else { return }
      if model.changingServerSignsOut {
        confirming = origin
      } else {
        model.changeServer(to: origin)
      }
    }
  }
}

/// iPhone's settings: there is no Settings scene, so the home screen's
/// gear opens this.
@MainActor public struct ServerSettingsSheet: View {
  @ObservedObject private var model: CallsModel
  private let done: () -> Void
  @AppStorage(CallLayoutStyle.key) private var callLayout = CallLayoutStyle.defaultStyle

  public init(model: CallsModel, done: @escaping () -> Void) {
    self.model = model
    self.done = done
  }

  public var body: some View {
    NavigationStack {
      Form {
        Section {
          Picker("Call layout", selection: $callLayout) {
            ForEach(CallLayoutStyle.allCases) { style in
              Text(style.title).tag(style)
            }
          }
          .accessibilityIdentifier("callLayout")
        } header: {
          Text("During a call")
        } footer: {
          Text(
            callLayout == .fullWindow
              ? "The call fills the screen. Tap it to show the controls."
              : "The call sits above a row of controls that are always showing."
          )
        }
        ServerSettingsSection(model: model)
        QualityReportsSection()
      }
        .formStyle(.grouped)
        .navigationTitle("Settings")
        #if os(iOS)
          .navigationBarTitleDisplayMode(.inline)
        #endif
        .toolbar {
          ToolbarItem(placement: .confirmationAction) { Button("Done", action: done) }
        }
    }
    .tint(CallsAppearance.accent)
  }
}

/// The automatic quality reports (spec §15.26): said, and a switch. Off,
/// no automatic reports go; "Report a problem" still works, because that
/// one is sent by the person on purpose.
@MainActor public struct QualityReportsSection: View {
  @AppStorage(QualityReporting.enabledKey) private var send = true

  public init() {}

  public var body: some View {
    Section {
      Toggle("Send anonymous quality reports", isOn: $send)
        .accessibilityIdentifier("qualityReports")
    } header: {
      Text("Call quality")
    } footer: {
      Text(
        QualityReporting.disclosure
          + " They hold connection numbers only — no names, no audio or video, nothing you type.")
    }
  }
}