import SwiftUI
import SwiftData

/// 「健康记录」录入 sheet。
/// 主体仍是 DiaryEntry @Model;UI/文案改为面向健康记录,并加 AI 辅助区:
/// 让 Qwen3 从医生问诊角度提 3-4 个追问,用户可一键将「补充模板」追加到输入框。
/// 支持多轮——每轮把已问过的 q 传给 LLM 要求别重复;已采纳的 row 灰色 + ✓ 标记。
struct DiaryQuickSheet: View {
    @Environment(\.modelContext) private var ctx
    @Environment(\.dismiss) private var dismiss

    @State private var content: String = ""
    @State private var createdAt: Date = .now

    /// AI 辅助状态
    enum AssistPhase {
        case idle               // 从未生成
        case loading            // 正在 LLM 调用
        case ready              // 有结果显示,等待下一轮 / 采纳 / 重试
        case failed(Error)      // 最近一次失败
    }
    @State private var phase: AssistPhase = .idle
    @State private var questions: [DiaryAssistService.Question] = []
    @State private var lastRate: Double = 0
    @State private var currentRound: Int = 0
    /// 累积已覆盖的问诊维度(question.dim),回传下一轮 prompt 用于按维度去重。
    @State private var coveredDims: Set<String> = []
    @State private var suggestTask: Task<Void, Never>?
    /// sheet detent。默认 large,确保建议面板有足够展示空间。
    /// 仍保留 medium,用户可手动下拉收回为半屏(纯写文本时更轻量)。
    @State private var detent: PresentationDetent = .large
    @FocusState private var contentFocused: Bool

    private var hasContent: Bool {
        !content.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
    }
    private var hasQuestions: Bool { !questions.isEmpty }
    private var isLoading: Bool {
        if case .loading = phase { return true }
        return false
    }
    private var canRequestSuggest: Bool { hasContent && !isLoading }
    private var canSubmit: Bool { hasContent }

    var body: some View {
        VStack(spacing: 0) {
            Capsule()
                .fill(Tj.Palette.line)
                .frame(width: 40, height: 4)
                .padding(.top, 10)
                .padding(.bottom, 14)

            HStack {
                VStack(alignment: .leading, spacing: 2) {
                    Text("健康记录")
                        .font(.tjH2())
                        .foregroundStyle(Tj.Palette.text)
                    Text("记录身体状态 · 可让 AI 多轮辅助查漏补缺")
                        .font(.system(size: 11))
                        .foregroundStyle(Tj.Palette.text3)
                }
                Spacer()
                Text("本机保存")
                    .font(.system(size: 12))
                    .foregroundStyle(Tj.Palette.text3)
            }
            .padding(.horizontal, 20)
            .padding(.bottom, 14)

            ScrollViewReader { proxy in
                ScrollView(showsIndicators: false) {
                    VStack(alignment: .leading, spacing: 16) {
                        VStack(alignment: .leading, spacing: 8) {
                            sectionLabel(String(appLoc: "内容"))
                            TextField("今天身体怎么样?吃了什么药、有什么感觉?",
                                      text: $content, axis: .vertical)
                                .lineLimit(3...8)
                                .focused($contentFocused)
                                .padding(.horizontal, 14)
                                .padding(.vertical, 12)
                                .background(
                                    RoundedRectangle(cornerRadius: Tj.Radius.sm, style: .continuous)
                                        .fill(Tj.Palette.paper)
                                )
                                .overlay(
                                    RoundedRectangle(cornerRadius: Tj.Radius.sm, style: .continuous)
                                        .strokeBorder(Tj.Palette.line, lineWidth: 1)
                                )
                        }

                        assistSection

                        VStack(alignment: .leading, spacing: 8) {
                            sectionLabel(String(appLoc: "时间"))
                            DatePicker("", selection: $createdAt, in: ...Date.now)
                                .datePickerStyle(.compact)
                                .labelsHidden()
                        }
                        // 底部锚点,新一轮 question 进来后自动滚到这里
                        Color.clear.frame(height: 1).id("assist-bottom")
                    }
                    .padding(.horizontal, 20)
                    .padding(.bottom, 6)
                }
                .scrollDismissesKeyboard(.interactively)
                .onChange(of: questions.count) { old, new in
                    guard new > old else { return }
                    // 滚到新一轮的 round divider(让用户先看到「第 N 轮」的标签,
                    // 再依次看到这一轮的 questions)
                    let roundId = "round-\(questions[old].round)"
                    DispatchQueue.main.asyncAfter(deadline: .now() + 0.05) {
                        withAnimation(.easeOut(duration: 0.25)) {
                            proxy.scrollTo(roundId, anchor: .top)
                        }
                    }
                }
            }

            HStack(spacing: 12) {
                Button("取消") { dismiss() }
                    .buttonStyle(TjGhostButton(height: 44, fontSize: 15, horizontalPadding: 18))
                Button("保存") { submit() }
                    .buttonStyle(TjPrimaryButton(height: 44, fontSize: 15, horizontalPadding: 18))
                    .disabled(!canSubmit)
                    .opacity(canSubmit ? 1 : 0.4)
            }
            .padding(.horizontal, 20)
            .padding(.vertical, 14)
        }
        .background(
            Tj.Palette.sand
                .clipShape(RoundedRectangle(cornerRadius: Tj.Radius.xl, style: .continuous))
                .ignoresSafeArea(edges: .bottom)
        )
        .presentationDetents([.medium, .large], selection: $detent)
        .presentationDragIndicator(.hidden)
        .presentationBackground(Tj.Palette.sand)
        .presentationCornerRadius(Tj.Radius.xl)
        .onDisappear { suggestTask?.cancel() }
    }

    // MARK: - AI 辅助区

    @ViewBuilder
    private var assistSection: some View {
        VStack(alignment: .leading, spacing: 10) {
            // section header
            HStack(spacing: 6) {
                Image(systemName: "sparkles")
                    .font(.system(size: 11, weight: .semibold))
                    .foregroundStyle(Tj.Palette.brick)
                sectionLabel(String(appLoc: "AI 辅助 · 医生角度查漏补缺"))
                Spacer()
                if hasQuestions {
                    Text("\(questions.count) 个建议")
                        .font(.system(size: 10, design: .monospaced))
                        .foregroundStyle(Tj.Palette.text3)
                }
                if lastRate > 0 {
                    Text(String(format: "%.1f tok/s", lastRate))
                        .font(.system(size: 10, design: .monospaced))
                        .foregroundStyle(Tj.Palette.leaf)
                }
            }

            // 累积的 questions 列表(多轮,带轮次分隔)
            if hasQuestions {
                VStack(spacing: 8) {
                    ForEach(Array(questions.enumerated()), id: \.element.id) { idx, q in
                        if idx == 0 || questions[idx - 1].round != q.round {
                            roundDivider(round: q.round,
                                         count: questions.filter { $0.round == q.round }.count)
                                .id("round-\(q.round)")
                        }
                        questionRow(index: roundLocalIndex(at: idx), question: q)
                    }
                }
            }

            // 底部主操作按钮(状态机驱动)
            phaseFooter
        }
    }

    @ViewBuilder
    private var phaseFooter: some View {
        switch phase {
        case .idle:
            assistPrimaryButton(
                icon: "sparkles",
                label: canRequestSuggest
                    ? String(appLoc: "让 AI 帮我想想还能记什么")
                    : String(appLoc: "先写几个字,AI 来帮忙补充"),
                enabled: canRequestSuggest,
                action: requestSuggestions
            )

        case .loading:
            HStack(spacing: 10) {
                ProgressView().controlSize(.small)
                Text("AI 思考中…  本地推理,通常 5-10 秒")
                    .font(.system(size: 13))
                    .foregroundStyle(Tj.Palette.text2)
                Spacer()
                Button("取消") { cancelSuggestions() }
                    .font(.system(size: 12, weight: .semibold))
                    .foregroundStyle(Tj.Palette.text3)
            }
            .padding(.vertical, 11)
            .padding(.horizontal, 12)
            .background(
                RoundedRectangle(cornerRadius: Tj.Radius.sm, style: .continuous)
                    .fill(Tj.Palette.paper)
            )
            .overlay(
                RoundedRectangle(cornerRadius: Tj.Radius.sm, style: .continuous)
                    .strokeBorder(Tj.Palette.lineSoft, lineWidth: 1)
            )

        case .ready:
            assistPrimaryButton(
                icon: "arrow.clockwise",
                label: canRequestSuggest
                    ? String(appLoc: "再问一轮 · 让 AI 从新角度追问")
                    : String(appLoc: "更新一下原文,再让 AI 继续追问"),
                enabled: canRequestSuggest,
                action: requestSuggestions
            )

        case .failed(let err):
            VStack(alignment: .leading, spacing: 8) {
                HStack(spacing: 6) {
                    Image(systemName: "exclamationmark.triangle.fill")
                        .foregroundStyle(Tj.Palette.brick)
                    Text(err.localizedDescription)
                        .font(.system(size: 12))
                        .foregroundStyle(Tj.Palette.text)
                    Spacer()
                }
                Button { requestSuggestions() } label: {
                    Text("重试")
                        .font(.system(size: 12, weight: .semibold))
                        .foregroundStyle(Tj.Palette.ink)
                }
                .buttonStyle(.plain)
            }
            .padding(10)
            .frame(maxWidth: .infinity, alignment: .leading)
            .background(
                RoundedRectangle(cornerRadius: Tj.Radius.sm, style: .continuous)
                    .fill(Tj.Palette.brickSoft.opacity(0.5))
            )
        }
    }

    private func assistPrimaryButton(icon: String,
                                     label: String,
                                     enabled: Bool,
                                     action: @escaping () -> Void) -> some View {
        Button(action: action) {
            HStack(spacing: 8) {
                Image(systemName: icon)
                Text(label)
            }
            .font(.system(size: 13, weight: .semibold))
            .foregroundStyle(enabled ? Tj.Palette.ink : Tj.Palette.text3)
            .frame(maxWidth: .infinity)
            .padding(.vertical, 11)
            .background(
                RoundedRectangle(cornerRadius: Tj.Radius.sm, style: .continuous)
                    .strokeBorder(
                        enabled ? Tj.Palette.ink : Tj.Palette.line,
                        style: StrokeStyle(lineWidth: 1, dash: enabled ? [] : [3, 3])
                    )
            )
        }
        .buttonStyle(.plain)
        .disabled(!enabled)
    }

    /// 给定整张 questions list 里 idx 位置的 question,返回它在自己 round 内的序号(1-based)。
    private func roundLocalIndex(at idx: Int) -> Int {
        let target = questions[idx].round
        var count = 0
        for i in 0...idx where questions[i].round == target {
            count += 1
        }
        return count
    }

    /// 第 N 轮的分隔条 —— 让用户清楚下一轮 LLM 看到的是更新过的最新文本。
    private func roundDivider(round: Int, count: Int) -> some View {
        HStack(spacing: 8) {
            HStack(spacing: 6) {
                Image(systemName: round == 1 ? "1.circle.fill" : "arrow.triangle.2.circlepath")
                    .font(.system(size: 11, weight: .semibold))
                    .foregroundStyle(Tj.Palette.brick)
                Text(round == 1
                     ? String(appLoc: "第 1 轮 · \(count) 条")
                     : String(appLoc: "第 \(round) 轮 · 基于你刚才更新的文本 · \(count) 条"))
                    .font(.system(size: 11, weight: .semibold))
                    .tracking(0.3)
                    .foregroundStyle(Tj.Palette.text2)
            }
            Rectangle()
                .fill(Tj.Palette.line)
                .frame(height: 1)
                .mask(
                    HStack(spacing: 3) {
                        ForEach(0..<60, id: \.self) { _ in
                            Rectangle().frame(width: 3, height: 1)
                        }
                    }
                )
        }
        .padding(.top, round == 1 ? 0 : 6)
    }

    private func questionRow(index: Int, question: DiaryAssistService.Question) -> some View {
        let adopted = question.adopted
        return VStack(alignment: .leading, spacing: 6) {
            HStack(alignment: .top, spacing: 8) {
                Text("\(index).")
                    .font(.system(size: 13, weight: .semibold, design: .monospaced))
                    .foregroundStyle(adopted ? Tj.Palette.text3 : Tj.Palette.brick)
                Text(question.q)
                    .font(.system(size: 13, weight: .medium))
                    .foregroundStyle(adopted ? Tj.Palette.text3 : Tj.Palette.text)
                    .strikethrough(adopted, color: Tj.Palette.text3)
                    .fixedSize(horizontal: false, vertical: true)
                Spacer(minLength: 4)

                if adopted {
                    HStack(spacing: 4) {
                        Image(systemName: "checkmark")
                            .font(.system(size: 10, weight: .bold))
                        Text("已采纳")
                            .font(.system(size: 11, weight: .semibold))
                    }
                    .foregroundStyle(Tj.Palette.leaf)
                    .padding(.horizontal, 8)
                    .padding(.vertical, 5)
                    .background(Capsule().fill(Tj.Palette.leafSoft))
                } else {
                    Button { adopt(question) } label: {
                        HStack(spacing: 4) {
                            Image(systemName: "plus.circle.fill")
                                .font(.system(size: 12))
                            Text("采纳")
                                .font(.system(size: 12, weight: .semibold))
                        }
                        .foregroundStyle(Tj.Palette.paper)
                        .padding(.horizontal, 10)
                        .padding(.vertical, 5)
                        .background(Capsule().fill(Tj.Palette.ink))
                    }
                    .buttonStyle(.plain)
                }
            }
            if !question.fill.isEmpty && !adopted {
                HStack(alignment: .top, spacing: 4) {
                    Text("将追加:")
                        .font(.system(size: 11))
                        .foregroundStyle(Tj.Palette.text3)
                    Text(question.fill)
                        .font(.system(size: 11))
                        .foregroundStyle(Tj.Palette.text2)
                        .fixedSize(horizontal: false, vertical: true)
                }
                .padding(.leading, 22)
            }
        }
        .padding(10)
        .frame(maxWidth: .infinity, alignment: .leading)
        .background(
            RoundedRectangle(cornerRadius: Tj.Radius.sm, style: .continuous)
                .fill(adopted ? Tj.Palette.sand2 : Tj.Palette.paper)
        )
        .overlay(
            RoundedRectangle(cornerRadius: Tj.Radius.sm, style: .continuous)
                .strokeBorder(Tj.Palette.lineSoft, lineWidth: 1)
        )
    }

    // MARK: - Actions

    private func sectionLabel(_ text: String) -> some View {
        Text(text)
            .font(.system(size: 12, weight: .semibold))
            .tracking(0.3)
            .foregroundStyle(Tj.Palette.text2)
    }

    /// 触发一轮 AI 辅助。把已覆盖的问诊维度(coveredDims)传给 LLM,
    /// 要求本轮避开这些维度,从结构上压住跨轮换皮重复。
    private func requestSuggestions() {
        suggestTask?.cancel()
        let snapshotContent = content.trimmingCharacters(in: .whitespacesAndNewlines)
        let covered = Array(coveredDims)
        // 1. 主动收起键盘 —— 否则建议面板被键盘吃掉一半
        contentFocused = false
        // 2. 确保 sheet 在 large(用户可能下拉到 medium 又触发 AI)
        if detent != .large {
            withAnimation(.snappy(duration: 0.25)) {
                detent = .large
            }
        }
        phase = .loading
        suggestTask = Task { @MainActor in
            do {
                let result = try await DiaryAssistService.shared.suggest(
                    content: snapshotContent,
                    coveredDimensions: covered
                )
                if Task.isCancelled { return }
                // 客户端字面兜底(防 LLM 不听话);跨轮去重主要靠 prompt 的维度排除。
                let existing = Set(questions.map { Self.normalize($0.q) })
                let nextRound = currentRound + 1
                let fresh = result.questions
                    .filter { !existing.contains(Self.normalize($0.q)) }
                    .map { q -> DiaryAssistService.Question in
                        var stamped = q
                        stamped.round = nextRound
                        return stamped
                    }
                withAnimation(.snappy(duration: 0.2)) {
                    questions.append(contentsOf: fresh)
                    for q in fresh where !q.dim.isEmpty { coveredDims.insert(q.dim) }
                    lastRate = result.decodeRate
                    currentRound = nextRound
                    phase = .ready
                }
            } catch is CancellationError {
                if !Task.isCancelled {
                    phase = hasQuestions ? .ready : .idle
                }
            } catch {
                if !Task.isCancelled {
                    phase = .failed(error)
                }
            }
        }
    }

    /// 简单归一化:去空白 + 折叠成统一形式,用于客户端去重比对。
    private static func normalize(_ s: String) -> String {
        s.trimmingCharacters(in: .whitespacesAndNewlines)
         .replacingOccurrences(of: " ", with: "")
         .replacingOccurrences(of: "?", with: "?")
    }

    private func cancelSuggestions() {
        suggestTask?.cancel()
        phase = hasQuestions ? .ready : .idle
    }

    /// 把 question.fill 追加到 textfield 末尾,并把该 question 标记为 adopted。
    /// 已采纳的 q 不会从列表里消失;其维度已在生成时计入 coveredDims,下一轮 prompt 会避开。
    private func adopt(_ question: DiaryAssistService.Question) {
        if let idx = questions.firstIndex(where: { $0.id == question.id }) {
            withAnimation(.snappy(duration: 0.18)) {
                questions[idx].adopted = true
            }
        }
        let toAppend = question.fill.isEmpty ? question.q : question.fill
        let trimmed = content.trimmingCharacters(in: .whitespacesAndNewlines)
        if trimmed.isEmpty {
            content = toAppend
        } else if content.hasSuffix("\n") {
            content += toAppend
        } else {
            content += "\n" + toAppend
        }
    }

    private func submit() {
        guard canSubmit else { return }
        let entry = DiaryEntry(
            content: content.trimmingCharacters(in: .whitespacesAndNewlines),
            createdAt: createdAt
        )
        ctx.insert(entry)
        try? ctx.save()
        dismiss()
    }
}

#Preview {
    DiaryQuickSheet()
}