ShadowsocksX-NG/ShadowsocksX-NG2/App/ServerPluginSection.swift

import SwiftUI

/// 服务器详情的插件区（issue #38/D10，地图 #52 票 #55）：受管选择器——
/// 「无」+ 受管列表；集外引用（Legacy 导入/订阅带入）追加显式「本版本未
/// 提供」项使当前状态可见并原样保留。选中受管项才显示参数输入与可用性警告。
struct ServerPluginSection: View {
  @Binding var selection: PluginSelection
  @Binding var optionsText: String
  let plugin: PluginSectionState?
  let isEditable: Bool
  /// 参数字段的行内校验错误（issue #81，如字节超限）。
  let optionsError: ServerFormFieldError?
  let optionsFocus: FocusState<ServerFormField?>.Binding

  var body: some View {
    VStack(alignment: .leading, spacing: 6) {
      picker
      detail
    }
  }

  @ViewBuilder
  private var picker: some View {
    if let plugin {
      Picker("插件", selection: $selection) {
        Text("无").tag(PluginSelection.none)
        ForEach(plugin.managed, id: \.program) { info in
          Text(info.program).tag(PluginSelection.managed(program: info.program))
        }
        if case .unknown(let program) = plugin.selection {
          Text("\(program)（本版本未提供）").tag(PluginSelection.unknown(program: program))
        }
      }
      .labelsHidden()
      .accessibilityLabel("插件")
      .disabled(!isEditable)
    } else {
      Text("不可用").foregroundStyle(.secondary)
    }
  }

  @ViewBuilder
  private var detail: some View {
    if let plugin {
      switch selection {
      case .none:
        EmptyView()
      case .managed(let program):
        managedDetails(program: program, plugin: plugin)
      case .unknown(let program):
        unknownNotice(program: program, plugin: plugin)
      }
    }
  }

  /// 选中受管项：参数输入与可用性警告。
  @ViewBuilder
  private func managedDetails(program: String, plugin: PluginSectionState) -> some View {
    if plugin.managed.contains(where: { $0.program == program }) {
      VStack(alignment: .leading, spacing: 8) {
        if !plugin.provided {
          Label(
            "受管插件可执行文件缺失：激活会被点名拒绝；请重新安装本 app。",
            systemImage: "exclamationmark.triangle.fill"
          )
          .font(.footnote)
          .foregroundStyle(.orange)
        }
        Text("插件参数")
          .font(.callout.weight(.medium))
          .foregroundStyle(.secondary)
        TextField(
          "插件参数",
          text: $optionsText,
          prompt: Text("选择插件后填写参数（如 mode=websocket;host=…）")
        )
        .textFieldStyle(.roundedBorder)
        .focused(optionsFocus, equals: .pluginOptions)
        .disabled(!isEditable)
        if let optionsError {
          Text(optionsErrorText(optionsError))
            .font(.footnote)
            .foregroundStyle(.red)
        }
      }
    }
  }

  /// 集外引用：原样保留并明确指出当前 app 无法提供该插件。
  @ViewBuilder
  private func unknownNotice(program: String, plugin: PluginSectionState) -> some View {
    VStack(alignment: .leading, spacing: 8) {
      Label(
        "本版本未提供「\(program)」：引用原样保留，激活包含该服务器会被点名拒绝；可改选「无」或受管插件。",
        systemImage: "exclamationmark.triangle.fill"
      )
      .font(.footnote)
      .foregroundStyle(.orange)
      if plugin.optionsPresent {
        Text("插件参数已配置（存于钥匙串，原样保留）。")
          .font(.footnote)
          .foregroundStyle(.secondary)
      }
    }
  }

  /// 参数错误文案：只呈现原因与上限，不回显参数内容。
  private func optionsErrorText(_ error: ServerFormFieldError) -> LocalizedStringKey {
    switch error {
    case .tooManyBytes(let limit): return "插件参数最多 \(limit) 个字节"
    case .missingName, .tooManyCharacters, .invalidPort: return ""
    }
  }
}