import SwiftUI

struct InstanceFormView: View {
    @Environment(\.dismiss) private var dismiss
    @ObservedObject var model: FleetViewModel
    @State private var name = ""
    @State private var originText = ""
    @State private var tagsText = ""
    @State private var password = ""
    @State private var validationMessage: String?

    private var canSave: Bool {
        !name.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
            && !originText.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
    }

    var body: some View {
        NavigationStack {
            ZStack {
                AITheme.canvas.ignoresSafeArea()
                ScrollView {
                    VStack(spacing: 12) {
                        AICard {
                            VStack(alignment: .leading, spacing: 14) {
                                field("名称", text: $name, placeholder: "Home Node")
                                field("地址", text: $originText, placeholder: "http://192.168.1.10:3000")
                                field("标签", text: $tagsText, placeholder: "home, primary")
                                field("实例密码", text: $password, placeholder: "可选，保存在本机沙盒", secure: true)
                            }
                        }
                        if let validationMessage {
                            AIStatusBanner(validationMessage, tint: AITheme.danger, systemImage: "exclamationmark.triangle")
                        }
                    }
                    .padding(16)
                }
            }
            .navigationTitle("添加实例")
            .aiBottomActionBar {
                HStack(spacing: 10) {
                    Button("取消") { dismiss() }
                        .buttonStyle(
                            AIButtonStyle(
                                kind: .secondary,
                                size: .regular,
                                fixedWidth: AITheme.footerSecondaryButtonWidth
                            )
                        )

                    Button("保存实例") { save() }
                        .buttonStyle(AIButtonStyle(kind: .primary, size: .regular, fillsWidth: true))
                        .disabled(!canSave)
                }
            }
        }
    }

    private func field(
        _ title: String,
        text: Binding<String>,
        placeholder: String,
        secure: Bool = false
    ) -> some View {
        VStack(alignment: .leading, spacing: 6) {
            Text(title)
                .font(.subheadline.weight(.semibold))
                .foregroundStyle(AITheme.ink)
            if secure {
                SecureField(placeholder, text: text)
                    .textFieldStyle(AIFieldStyle())
                    .textContentType(.password)
            } else {
                TextField(placeholder, text: text)
                    .textFieldStyle(AIFieldStyle())
                    #if os(iOS)
                    .keyboardType(title == "地址" ? .URL : .default)
                    .textInputAutocapitalization(title == "地址" || title == "标签" ? .never : nil)
                    #endif
                    .autocorrectionDisabled(title == "地址" || title == "标签")
            }
        }
    }

    private func save() {
        let normalizedName = name.trimmingCharacters(in: .whitespacesAndNewlines)
        guard let origin = URL(string: originText.trimmingCharacters(in: .whitespacesAndNewlines)),
              origin.scheme == "http" || origin.scheme == "https",
              origin.host != nil
        else {
            validationMessage = "请输入有效的 HTTP 或 HTTPS 根地址。"
            return
        }
        let tags = tagsText
            .split(separator: ",")
            .map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }
            .filter { !$0.isEmpty }
        let input = InstanceInput(
            name: normalizedName,
            origin: origin,
            tags: tags,
            password: password.isEmpty ? nil : password
        )
        Task {
            do {
                try await model.add(input)
                dismiss()
            } catch {
                validationMessage = "保存失败，请检查地址是否重复。"
            }
        }
    }
}