import SwiftUI

struct SendMessageFormView: View {
  @Environment(\.dismiss) private var dismiss
  @ObservedObject var model: MessagesViewModel
  @State private var phoneNumber = ""
  @State private var content = ""
  @State private var validationMessage: String?
  @State private var isSending = false

  private var trimmedPhoneNumber: String {
    phoneNumber.trimmingCharacters(in: .whitespacesAndNewlines)
  }

  private var trimmedContent: String {
    content.trimmingCharacters(in: .whitespacesAndNewlines)
  }

  private var canSend: Bool {
    !model.instances.isEmpty && !trimmedPhoneNumber.isEmpty && !trimmedContent.isEmpty
  }

  var body: some View {
    NavigationStack {
      ScrollView {
        VStack(spacing: 12) {
          AICard {
            VStack(alignment: .leading, spacing: 14) {
              VStack(alignment: .leading, spacing: 6) {
                AIFieldLabel("实例")
                Picker(
                  "实例",
                  selection: Binding(
                    get: { model.selectedInstanceID ?? model.instances.first?.id },
                    set: { model.selectedInstanceID = $0 }
                  )
                ) {
                  if model.instances.isEmpty {
                    Text("暂无实例").tag(Optional<UUID>.none)
                  }
                  ForEach(model.instances) { instance in
                    Text(instance.name).tag(Optional(instance.id))
                  }
                }
                .pickerStyle(.menu)
                .aiSelectSurface()
              }

              VStack(alignment: .leading, spacing: 6) {
                AIFieldLabel("收件号码")
                TextField("收件号码", text: $phoneNumber)
                  .textFieldStyle(AIFieldStyle())
                  .accessibilityLabel("收件号码")
                  .submitLabel(.next)
                  #if os(iOS)
                    .keyboardType(.phonePad)
                  #endif
              }

              VStack(alignment: .leading, spacing: 6) {
                AIFieldLabel("消息内容")
                TextField("消息内容", text: $content, axis: .vertical)
                  .textFieldStyle(AIFieldStyle())
                  .accessibilityLabel("消息内容")
                  .submitLabel(.send)
                  .onSubmit {
                    if canSend { send() }
                  }
                  .lineLimit(4...8)
              }
            }
          }
          if let validationMessage {
            AIStatusBanner(
              validationMessage, tint: AITheme.danger, systemImage: "exclamationmark.triangle")
          }
        }
        .padding(16)
        .padding(.bottom, 8)
      }
      .aiBottomActionBar {
        AIActionRow {
          Button("取消") { dismiss() }
            .buttonStyle(AIButtonStyle(kind: .secondary, size: .regular, fillsWidth: true))

          Button {
            send()
          } label: {
            HStack(spacing: 8) {
              if isSending {
                ProgressView()
                  .controlSize(.small)
              }
              Text(isSending ? "发送中" : "发送")
            }
          }
          .buttonStyle(AIButtonStyle(kind: .primary, size: .regular, fillsWidth: true))
          .disabled(!canSend || isSending)
        }
      }
      .background(AITheme.canvas.ignoresSafeArea())
      .navigationTitle("发送消息")
      #if os(iOS)
        .scrollDismissesKeyboard(.interactively)
      #endif
    }
  }
  private func send() {
    guard !isSending else { return }
    isSending = true
    Task {
      do {
        try await model.send(phoneNumber: trimmedPhoneNumber, content: trimmedContent)
        phoneNumber = ""
        content = ""
        validationMessage = nil
        dismiss()
      } catch {
        validationMessage = "发送失败，请检查号码、内容和实例登录状态。"
      }
      isSending = false
    }
  }
}