import SwiftUI
import SwiftData

struct ArchiveListView: View {
    @Query(sort: \Indicator.capturedAt, order: .reverse)
    private var indicators: [Indicator]

    @Query(sort: \Report.reportDate, order: .reverse)
    private var reports: [Report]

    @Query(sort: \DiaryEntry.createdAt, order: .reverse)
    private var diaries: [DiaryEntry]

    @Query(sort: \Symptom.startedAt, order: .reverse)
    private var symptoms: [Symptom]

    @State private var filter: TimelineKind? = nil

    @MainActor
    private var allEntries: [TimelineEntry] {
        let mapped =
            indicators.map(TimelineEntry.from(indicator:)) +
            reports.map(TimelineEntry.from(report:)) +
            diaries.map(TimelineEntry.from(diary:)) +
            symptoms.map(TimelineEntry.from(symptom:))
        let filtered = filter.map { kind in mapped.filter { $0.kind == kind } } ?? mapped
        return filtered.sorted { $0.date > $1.date }
    }

    private var grouped: [(section: DateSection, items: [TimelineEntry])] {
        TimelineGrouping.group(allEntries)
    }

    private var totalCount: Int { allEntries.count }

    var body: some View {
        VStack(alignment: .leading, spacing: 0) {
            header
                .padding(.horizontal, 20)
                .padding(.top, 8)
                .padding(.bottom, 14)

            filterChips
                .padding(.bottom, 14)

            if allEntries.isEmpty {
                emptyState
            } else {
                ScrollView(showsIndicators: false) {
                    LazyVStack(alignment: .leading, spacing: 18, pinnedViews: [.sectionHeaders]) {
                        ForEach(grouped, id: \.section) { group in
                            Section {
                                VStack(spacing: 10) {
                                    ForEach(group.items) { entry in
                                        TimelineRow(entry: entry)
                                    }
                                }
                                .padding(.horizontal, 20)
                            } header: {
                                sectionHeader(group.section, count: group.items.count)
                            }
                        }
                    }
                    .padding(.bottom, 24)
                }
            }
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .topLeading)
        .background(Tj.Palette.sand.ignoresSafeArea())
    }

    private var header: some View {
        HStack(alignment: .lastTextBaseline) {
            Text("记录")
                .font(.tjTitle(26))
                .foregroundStyle(Tj.Palette.text)
            Text(totalCount == 0 ? "" : "\(totalCount) 条")
                .font(.system(size: 12))
                .foregroundStyle(Tj.Palette.text3)
            Spacer()
        }
    }

    private var filterChips: some View {
        ScrollView(.horizontal, showsIndicators: false) {
            HStack(spacing: 8) {
                chip(label: "全部", selected: filter == nil) { filter = nil }
                ForEach(TimelineKind.allCases) { kind in
                    chip(label: kind.label, selected: filter == kind) {
                        filter = filter == kind ? nil : kind
                    }
                }
            }
            .padding(.horizontal, 20)
        }
    }

    private func chip(label: String, selected: Bool, action: @escaping () -> Void) -> some View {
        Button(action: action) {
            Text(label)
                .font(.system(size: 13, weight: selected ? .semibold : .regular))
                .foregroundStyle(selected ? Tj.Palette.paper : Tj.Palette.text)
                .padding(.horizontal, 14)
                .padding(.vertical, 8)
                .background(
                    Capsule().fill(selected ? Tj.Palette.ink : Tj.Palette.paper)
                )
                .overlay(
                    Capsule().strokeBorder(Tj.Palette.line, lineWidth: selected ? 0 : 1)
                )
        }
        .buttonStyle(.plain)
    }

    private func sectionHeader(_ section: DateSection, count: Int) -> some View {
        HStack {
            Text(section.label)
                .font(.system(size: 12, weight: .semibold))
                .tracking(0.5)
                .foregroundStyle(Tj.Palette.text2)
            Rectangle()
                .fill(Tj.Palette.lineSoft)
                .frame(height: 1)
            Text("\(count)")
                .font(.system(size: 11, design: .monospaced))
                .foregroundStyle(Tj.Palette.text3)
        }
        .padding(.horizontal, 20)
        .padding(.vertical, 8)
        .background(Tj.Palette.sand)
    }

    private var emptyState: some View {
        VStack(spacing: 14) {
            Spacer()
            TjPlaceholder(label: "还没有任何记录\n点底部 + 号开始")
                .frame(width: 240, height: 140)
            Text(filter == nil ? "记录会按时间归类显示" : "这个类别下没有记录")
                .font(.system(size: 13))
                .foregroundStyle(Tj.Palette.text3)
            Spacer()
        }
        .frame(maxWidth: .infinity)
    }
}

#Preview {
    ArchiveListView()
        .modelContainer(for: [
            Indicator.self, Report.self, DiaryEntry.self, Symptom.self, Asset.self
        ], inMemory: true)
}