import SwiftUI
import DSKit

/// 홈 = 풀폭 데일리 코크핏 (시안 안1). detail 전폭을 받아 1000pt 캔버스로 좌측 정렬, 내부 2칼럼.
/// 인사 → 오늘 스트립(검토 큐 + 속보 + 스탯) → 좌(빠른캡처·최근활동)/우(도메인분포·고정).
struct DashboardView: View {
    @Environment(AppModel.self) private var model

    var body: some View {
        ScrollView(.vertical) {
            VStack(alignment: .leading, spacing: 18) {
                GreetingHeader()
                if model.stats == nil && model.tree.isEmpty {
                    ProgressView().frame(maxWidth: .infinity, minHeight: 200)
                } else {
                    TodayStrip()
                    HStack(alignment: .top, spacing: 18) {
                        VStack(alignment: .leading, spacing: 18) {
                            CaptureCard()
                            ActivityTimeline()
                        }
                        .frame(maxWidth: .infinity)
                        VStack(alignment: .leading, spacing: 18) {
                            DomainDistribution()
                            PinnedItems()
                        }
                        .frame(width: 312)
                    }
                }
            }
            .frame(maxWidth: 1000, alignment: .leading)
            .padding(.horizontal, 30)
            .padding(.vertical, 26)
        }
        .frame(maxWidth: .infinity, alignment: .topLeading)
        .background(Sage.surface)
    }
}

// MARK: - Greeting

private struct GreetingHeader: View {
    @Environment(AppModel.self) private var model

    var body: some View {
        VStack(alignment: .leading, spacing: 3) {
            HStack(alignment: .firstTextBaseline, spacing: 10) {
                Text("안녕하세요, \(model.currentUser?.username ?? "사용자")")
                    .font(.system(size: 22, weight: .bold)).kerning(-0.4).foregroundStyle(Sage.ink)
                Text("오늘도 지식 쌓는 날.").font(.callout).foregroundStyle(Sage.muted)
            }
            Text(Self.today).font(.caption).foregroundStyle(Sage.muted.opacity(0.8))
        }
        .padding(.bottom, 4)
    }

    static var today: String {
        let f = DateFormatter()
        f.locale = Locale(identifier: "ko_KR")
        f.dateFormat = "y년 M월 d일 EEEE"
        return f.string(from: Date())
    }
}

// MARK: - Today strip (hero)

private struct TodayStrip: View {
    @Environment(AppModel.self) private var model

    var body: some View {
        VStack(spacing: 14) {
            HStack(alignment: .top, spacing: 0) {
                reviewQueue
                    .frame(minWidth: 150, alignment: .leading)
                Rectangle().fill(Sage.line).frame(width: 1).padding(.horizontal, 22)
                digestTeaser
                    .frame(maxWidth: .infinity, alignment: .leading)
            }
            Divider().overlay(Sage.line)
            statRow
        }
        .dashCard(padding: 20)
    }

    private var reviewQueue: some View {
        VStack(alignment: .leading, spacing: 4) {
            Text(model.reviewPendingCount.map(String.init) ?? "—")
                .font(.system(size: 38, weight: .bold)).kerning(-1.5).monospacedDigit()
                .foregroundStyle(Sage.amber)
            Text("검토 대기 문서").font(.caption).foregroundStyle(Sage.muted)
            Button { model.section = .documents } label: {
                Text("검토 시작 →").font(.caption.weight(.semibold)).foregroundStyle(Sage.brand)
            }
            .buttonStyle(.plain)
        }
    }

    @ViewBuilder private var digestTeaser: some View {
        if let t = topTopic {
            Button { model.section = .digest } label: {
                VStack(alignment: .leading, spacing: 6) {
                    HStack(spacing: 8) {
                        Chip("속보", Sage.danger)
                        Text("\(model.digest?.digestDateDisplay ?? "") 브리핑")
                            .font(.caption2).foregroundStyle(Sage.muted)
                    }
                    Text(t.label).font(.system(size: 15)).foregroundStyle(Sage.ink)
                        .lineLimit(2).fixedSize(horizontal: false, vertical: true)
                        .multilineTextAlignment(.leading)
                    Text(t.meta).font(.caption2).foregroundStyle(Sage.muted)
                }
                .frame(maxWidth: .infinity, alignment: .leading)
            }
            .buttonStyle(.plain)
        } else {
            Text("오늘 브리핑이 아직 없습니다").font(.callout).foregroundStyle(Sage.muted)
                .frame(maxWidth: .infinity, alignment: .leading)
        }
    }

    private var statRow: some View {
        HStack(spacing: 0) {
            StatCell(value: model.stats?.total ?? 0, label: "전체", color: Sage.brand)
            StatCell(value: model.stats?.counts["document"] ?? 0, label: "문서")
            StatCell(value: domainCount("Industrial_Safety"), label: "산업안전",
                     color: Sage.domainColor("Industrial_Safety"))
            StatCell(value: domainCount("Engineering"), label: "엔지니어링",
                     color: Sage.domainColor("Engineering"))
            StatCell(value: domainCount("General"), label: "자료실", color: Sage.domainColor("General"))
            StatCell(value: model.stats?.counts["memo"] ?? model.memoList.count, label: "메모")
        }
    }

    private func domainCount(_ name: String) -> Int {
        model.tree.first { $0.name == name }?.count ?? 0
    }

    private var topTopic: (label: String, meta: String)? {
        guard let digest = model.digest else { return nil }
        var best: (TopicResponse, String)?
        for c in digest.countries {
            for t in c.topics where best == nil || (t.importanceScore ?? 0) > (best!.0.importanceScore ?? 0) {
                best = (t, c.country)
            }
        }
        guard let (t, country) = best else { return nil }
        let arts = t.articleCount ?? t.articles.count
        var meta = "관련 기사 \(arts)건"
        if let imp = t.importanceScore { meta += " · 중요도 \(String(format: "%.0f", imp))" }
        if !country.isEmpty { meta += " · \(country)" }
        return (t.topicLabel, meta)
    }
}

// MARK: - Left column

private struct CaptureCard: View {
    @Environment(AppModel.self) private var model

    var body: some View {
        @Bindable var m = model
        VStack(alignment: .leading, spacing: 12) {
            SectionLabel("빠른 캡처")
            HStack(spacing: 8) {
                TextField("메모 한 줄 남기기…", text: $m.captureText)
                    .textFieldStyle(.plain)
                    .padding(.horizontal, 14).frame(height: 38)
                    .background(Sage.surface, in: RoundedRectangle(cornerRadius: 8))
                    .overlay(RoundedRectangle(cornerRadius: 8).stroke(Sage.line))
                    .onSubmit { Task { await model.saveMemo() } }
                Button { Task { await model.saveMemo() } } label: {
                    Text("저장").font(.callout.weight(.semibold)).foregroundStyle(.white)
                        .padding(.horizontal, 18).frame(height: 38)
                        .background(Sage.brand, in: RoundedRectangle(cornerRadius: 8))
                }
                .buttonStyle(.plain)
                .disabled(model.captureText.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty)
            }
            Button {
                guard let url = FilePanels.pickFileToUpload() else { return }
                Task { await model.uploadPicked(url) }
            } label: {
                Text("＋ 파일 업로드").font(.caption.weight(.semibold)).foregroundStyle(Sage.brand)
                    .padding(.horizontal, 10).padding(.vertical, 5)
                    .background(Sage.brand.opacity(0.12), in: Capsule())
            }
            .buttonStyle(.plain)
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .dashCard()
    }
}

private struct ActivityTimeline: View {
    @Environment(AppModel.self) private var model

    private var recent: [DocumentResponse] {
        model.documentList
            .sorted { ($0.updatedAt ?? .distantPast) > ($1.updatedAt ?? .distantPast) }
            .prefix(5).map { $0 }
    }

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            HStack(alignment: .firstTextBaseline) {
                SectionLabel("최근 활동")
                Spacer()
                Button { model.section = .documents } label: {
                    Text("전체 보기 →").font(.caption.weight(.semibold)).foregroundStyle(Sage.brand)
                }
                .buttonStyle(.plain)
            }
            if recent.isEmpty {
                Text("최근 활동이 없습니다").font(.caption).foregroundStyle(Sage.muted)
            } else {
                VStack(spacing: 0) {
                    ForEach(Array(recent.enumerated()), id: \.element.id) { idx, doc in
                        ActivityRow(doc: doc, isLast: idx == recent.count - 1)
                        if idx != recent.count - 1 { Divider().overlay(Sage.line) }
                    }
                }
            }
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .dashCard()
    }
}

private struct ActivityRow: View {
    @Environment(AppModel.self) private var model
    let doc: DocumentResponse
    let isLast: Bool

    var body: some View {
        HStack(alignment: .top, spacing: 12) {
            Text(Self.relative(doc.updatedAt))
                .font(.caption2).foregroundStyle(Sage.muted)
                .frame(width: 54, alignment: .trailing)
            VStack(spacing: 0) {
                Circle().fill(Sage.domainColor(doc.aiDomain)).frame(width: 8, height: 8).padding(.top, 4)
                if !isLast { Rectangle().fill(Sage.line).frame(width: 1).frame(maxHeight: .infinity) }
            }
            .frame(width: 14)
            VStack(alignment: .leading, spacing: 3) {
                Text("\(localizedDomain(doc.aiDomain)) · \(doc.displayFormat.uppercased())")
                    .font(.caption2.weight(.bold)).foregroundStyle(Sage.domainColor(doc.aiDomain))
                Text(doc.title ?? doc.downloadLabel).font(.callout).foregroundStyle(Sage.ink).lineLimit(2)
            }
            .frame(maxWidth: .infinity, alignment: .leading)
            .padding(.bottom, isLast ? 0 : 10)
        }
        .contentShape(Rectangle())
        .onTapGesture { model.section = .documents; Task { await model.openDocument(doc.id) } }
    }

    static func relative(_ date: Date?) -> String {
        guard let date else { return "" }
        let f = RelativeDateTimeFormatter()
        f.locale = Locale(identifier: "ko_KR")
        f.unitsStyle = .short
        return f.localizedString(for: date, relativeTo: Date())
    }
}

// MARK: - Right column

private struct DomainDistribution: View {
    @Environment(AppModel.self) private var model

    private var domains: [DomainTreeNode] { model.tree.sorted { $0.count > $1.count } }
    private var domainTotal: Int { domains.reduce(0) { $0 + $1.count } }
    private var sum: Int { max(1, domainTotal) }   // 0-나눗셈 가드 (막대 폭 분모 전용)

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            SectionLabel("도메인 분포")
            // 헤드라인 합계 = 막대/범례와 동일 분모(도메인 트리 합) — 사용자가 범례를 더해 같은 값에 도달.
            HStack(alignment: .firstTextBaseline, spacing: 3) {
                Text("분류").font(.caption).foregroundStyle(Sage.muted)
                Text("\(domainTotal)").font(.system(size: 18, weight: .semibold))
                    .monospacedDigit().foregroundStyle(Sage.ink)
                Text("건").font(.caption).foregroundStyle(Sage.muted)
            }
            GeometryReader { geo in
                HStack(spacing: 2) {
                    ForEach(domains) { d in
                        Rectangle().fill(Sage.domainColor(d.name))
                            .frame(width: max(2, geo.size.width * CGFloat(d.count) / CGFloat(sum)))
                    }
                }
            }
            .frame(height: 8)
            .clipShape(RoundedRectangle(cornerRadius: 4))
            VStack(spacing: 7) {
                ForEach(domains) { d in
                    Button {
                        model.section = .documents
                        Task { await model.loadDocuments(domain: d.path) }
                    } label: {
                        HStack(spacing: 8) {
                            RoundedRectangle(cornerRadius: 2).fill(Sage.domainColor(d.name)).frame(width: 10, height: 10)
                            Text(localizedDomain(d.name)).font(.caption).foregroundStyle(Sage.ink)
                                .lineLimit(1).frame(maxWidth: .infinity, alignment: .leading)
                            Text("\(d.count)").font(.caption.monospacedDigit()).foregroundStyle(Sage.muted)
                        }
                    }
                    .buttonStyle(.plain)
                }
            }
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .dashCard()
    }
}

private struct PinnedItems: View {
    @Environment(AppModel.self) private var model

    private var docs: [DocumentResponse] { model.documentList.filter { $0.pinned == true } }
    private var memos: [MemoResponse] { model.memoList.filter { $0.isPinned } }

    var body: some View {
        VStack(alignment: .leading, spacing: 12) {
            HStack {
                SectionLabel("고정 항목")
                Spacer()
                Button { model.section = .documents } label: {
                    Text("관리 →").font(.caption.weight(.semibold)).foregroundStyle(Sage.brand)
                }
                .buttonStyle(.plain)
            }
            if docs.isEmpty && memos.isEmpty {
                Text("고정된 항목이 없습니다").font(.caption).foregroundStyle(Sage.muted)
            } else {
                VStack(spacing: 8) {
                    ForEach(docs) { d in
                        PinRow(kind: "문서", kindColor: Sage.domainColor("Engineering"),
                               title: d.title ?? d.downloadLabel, date: d.updatedAtRaw) {
                            model.section = .documents; Task { await model.openDocument(d.id) }
                        }
                    }
                    ForEach(memos) { m in
                        PinRow(kind: "메모", kindColor: Sage.brand,
                               title: m.title ?? (m.content ?? "메모"), date: m.updatedAtRaw ?? "") {
                            model.section = .memos; Task { await model.openMemo(m.id) }
                        }
                    }
                }
            }
        }
        .frame(maxWidth: .infinity, alignment: .leading)
        .dashCard()
    }
}

private struct PinRow: View {
    let kind: String
    let kindColor: Color
    let title: String
    let date: String
    let action: () -> Void

    var body: some View {
        Button(action: action) {
            HStack(alignment: .top, spacing: 10) {
                Chip(kind, kindColor)
                Text(title).font(.caption).foregroundStyle(Sage.ink).lineLimit(2)
                    .frame(maxWidth: .infinity, alignment: .leading)
                Text(date.prefix(10)).font(.caption2.monospacedDigit()).foregroundStyle(Sage.muted)
            }
            .padding(10)
            .background(Sage.surface, in: RoundedRectangle(cornerRadius: 8))
        }
        .buttonStyle(.plain)
    }
}

#if DEBUG
#Preview("Dashboard") {
    @Previewable @State var model = AppModel.preview
    DashboardView()
        .environment(model)
        .frame(width: 1100, height: 760)
        .task { await model.bootstrap() }
}
#endif