#if DEBUG
import SwiftUI
import UIKit
import UniformTypeIdentifiers

/// DEBUG 自检:加载 LLM 并跑一段 prompt,流式显示 token + 速率。
/// 同时显示沙盒 Application Support 路径,方便把模型拷进去。
struct DebugAIRunner: View {
    @State private var output: String = ""
    @State private var status: String = "未开始"
    @State private var rate: Double = 0
    @State private var running = false
    @State private var modelReady: Bool = false
    @State private var importingModel = false
    @State private var importError: String?

    private var appSupportPath: String {
        (try? FileManager.default.url(
            for: .applicationSupportDirectory,
            in: .userDomainMask,
            appropriateFor: nil,
            create: false
        ).path) ?? "(无法获取)"
    }

    private var modelExpectedPath: String {
        appSupportPath + "/Models/Qwen3-1.7B-4bit"
    }

    var body: some View {
        VStack(alignment: .leading, spacing: 14) {
            Text("DEBUG · AI 自检")
                .font(.system(size: 15, weight: .semibold))
                .foregroundStyle(Tj.Palette.text)

            // 沙盒路径与模型状态卡
            VStack(alignment: .leading, spacing: 8) {
                Text("模型预期路径")
                    .font(.system(size: 11, weight: .medium))
                    .foregroundStyle(Tj.Palette.text3)
                Text(modelExpectedPath)
                    .font(.system(size: 10, design: .monospaced))
                    .foregroundStyle(Tj.Palette.text2)
                    .textSelection(.enabled)
                    .lineLimit(3)
                HStack(spacing: 8) {
                    Button("复制路径") {
                        UIPasteboard.general.string = modelExpectedPath
                    }
                    .font(.system(size: 11))
                    .buttonStyle(.borderless)

                    Button(importingModel ? "导入中..." : "导入模型") {
                        importingModel = true
                    }
                    .font(.system(size: 11))
                    .buttonStyle(.borderless)
                    .disabled(importingModel)

                    Spacer()

                    Text(modelReady ? "✓ 模型就绪" : "⚠ 模型未就绪")
                        .font(.system(size: 11, weight: .medium))
                        .foregroundStyle(modelReady ? Tj.Palette.leaf : Tj.Palette.brick)
                }
                if let importError {
                    Text(importError)
                        .font(.system(size: 10))
                        .foregroundStyle(Tj.Palette.brick)
                        .lineLimit(3)
                }
            }
            .padding(10)
            .background(
                RoundedRectangle(cornerRadius: 6)
                    .fill(Color.black.opacity(0.03))
            )

            // 推理状态
            HStack {
                Text("状态:\(status)")
                Spacer()
                Text(String(format: "%.1f tok/s", rate))
                    .foregroundStyle(Tj.Palette.text3)
                    .monospaced()
            }
            .font(.system(size: 12))

            Button(running ? "推理中..." : "跑一段 prompt") {
                Task { await run() }
            }
            .buttonStyle(TjPrimaryButton())
            .disabled(running)

            ScrollView {
                Text(output.isEmpty ? "(暂无输出)" : output)
                    .font(.system(.footnote, design: .monospaced))
                    .frame(maxWidth: .infinity, alignment: .leading)
                    .padding(10)
            }
            .frame(maxHeight: 240)
            .background(
                RoundedRectangle(cornerRadius: 6)
                    .fill(Color.black.opacity(0.04))
            )
        }
        .padding(16)
        .background(
            RoundedRectangle(cornerRadius: Tj.Radius.md)
                .fill(Color.yellow.opacity(0.08))
        )
        .padding(.horizontal, 16)
        .onAppear { refreshModelStatus() }
        .fileImporter(
            isPresented: $importingModel,
            allowedContentTypes: [.folder],
            allowsMultipleSelection: false
        ) { result in
            importModelFolder(from: result)
        }
    }

    private func refreshModelStatus() {
        modelReady = ModelStore.shared.isReady(.llm)
    }

    private func importModelFolder(from result: Result<[URL], Error>) {
        defer {
            refreshModelStatus()
            importingModel = false
        }

        do {
            guard let pickedURL = try result.get().first else {
                importError = "未选择模型文件夹"
                return
            }

            let securityScoped = pickedURL.startAccessingSecurityScopedResource()
            defer {
                if securityScoped {
                    pickedURL.stopAccessingSecurityScopedResource()
                }
            }

            let sourceURL = resolvedModelSourceURL(from: pickedURL)
            guard FileManager.default.fileExists(
                atPath: sourceURL.appendingPathComponent(ModelKind.llm.sentinelFilename).path
            ) else {
                importError = "请选择包含 config.json 的 Qwen3-1.7B-4bit 文件夹"
                return
            }

            let targetURL = ModelStore.shared.localURL(for: .llm)
            let parentURL = targetURL.deletingLastPathComponent()
            try FileManager.default.createDirectory(at: parentURL, withIntermediateDirectories: true)
            if FileManager.default.fileExists(atPath: targetURL.path) {
                try FileManager.default.removeItem(at: targetURL)
            }
            try FileManager.default.copyItem(at: sourceURL, to: targetURL)
            importError = nil
        } catch {
            importError = "导入失败:\(error.localizedDescription)"
        }
    }

    private func resolvedModelSourceURL(from pickedURL: URL) -> URL {
        let nestedURL = pickedURL.appendingPathComponent(ModelKind.llm.rawValue, isDirectory: true)
        if FileManager.default.fileExists(
            atPath: nestedURL.appendingPathComponent(ModelKind.llm.sentinelFilename).path
        ) {
            return nestedURL
        }
        return pickedURL
    }

    @MainActor
    private func run() async {
        running = true
        output = ""
        rate = 0
        status = "加载模型..."
        do {
            try await AIRuntime.shared.prepare()
            status = "推理中..."

            let prompt = "用中文一句话介绍肝功能里 ALT 这个指标。"
            for try await chunk in await AIRuntime.shared.generate(
                prompt: prompt,
                maxTokens: 200
            ) {
                output += chunk.text
                rate = chunk.decodeRate
            }
            status = "完成 ✓"
        } catch {
            status = "失败:\(error.localizedDescription)"
        }
        running = false
        refreshModelStatus()
    }
}

#Preview("DebugAIRunner") {
    ScrollView {
        DebugAIRunner()
            .padding(.vertical, 24)
    }
    .background(Tj.Palette.sand.ignoresSafeArea())
}
#endif