//
//  StatsChartWidget.swift
//  Haru_DanimWidgets
//
//  ⑤ 행동 통계 위젯 (CLAUDE.md §8.3) — 선택한 행동들의 꺾은선 그래프
//  앱 통계 탭과 동일: 선 색 = 행동 색, 시간형은 h 단위, 횟수형은 회.
//  어수선하지 않도록 표시 행동 수를 소형 2 / 중형 4 / 대형 6개로 제한.
//  디자인은 크기와 무관하게 동일하고 그래프 영역만 확장된다.
//

import SwiftUI
import WidgetKit
import AppIntents
import Charts

// MARK: - 설정

enum StatsChartSpan: String, AppEnum {
    case week
    case monthByDay
    case monthByWeek

    static let typeDisplayRepresentation = TypeDisplayRepresentation(name: "통계 기간")
    static let caseDisplayRepresentations: [StatsChartSpan: DisplayRepresentation] = [
        .week: "일주일 (하루 단위)",
        .monthByDay: "한 달 (하루 단위, 중형 이상)",
        .monthByWeek: "한 달 (주 단위)",
    ]

    var title: String {
        switch self {
        case .week: return String(localized: "일주일 통계")
        case .monthByDay: return String(localized: "한 달 통계 (일별)")
        case .monthByWeek: return String(localized: "한 달 통계 (주별)")
        }
    }
}

struct StatsChartConfigIntent: WidgetConfigurationIntent {
    static let title: LocalizedStringResource = "통계 위젯"
    static let description = IntentDescription("그래프로 보여줄 행동들과 기간, 테마를 선택하세요. 크기에 따라 소형 2개·중형 4개·대형 6개까지 그려져요.")

    @Parameter(title: "행동")
    var actions: [ActionEntity]?

    @Parameter(title: "통계 기간", default: .week)
    var span: StatsChartSpan

    @Parameter(title: "테마", default: .matchApp)
    var theme: WidgetThemeOption
}

// MARK: - 타임라인

struct StatsPoint: Identifiable {
    let id = UUID()
    /// 하루 단위 그래프의 x축 (일별)
    let day: Date?
    /// 주 단위 그래프의 x축 ("1주차" 등)
    let weekLabel: String?
    let actionName: String
    let value: Double
}

struct StatsChartEntry: TimelineEntry {
    let date: Date
    let locked: Bool
    let theme: WidgetThemeOption
    let title: String
    let isWeekAxis: Bool
    let isTimeType: Bool
    let names: [String]
    let colorHexes: [String]
    let points: [StatsPoint]
}

struct StatsChartProvider: AppIntentTimelineProvider {
    /// 어수선함 방지: 패밀리별 최대 행동(선) 수 (소형 2 / 중형 4 / 대형 6)
    static func maxActions(_ family: WidgetFamily) -> Int {
        switch family {
        case .systemMedium: return 4
        case .systemLarge: return 6
        default: return 2
        }
    }

    @MainActor
    static func makeEntry(_ configuration: StatsChartConfigIntent, family: WidgetFamily) -> StatsChartEntry {
        IntentStore.refresh()
        guard WidgetStore.isUnlocked else {
            return StatsChartEntry(date: .now, locked: true, theme: configuration.theme, title: "",
                                   isWeekAxis: false, isTimeType: true, names: [], colorHexes: [], points: [])
        }
        // 소형은 "한 달 (하루 단위)" 제외 (CLAUDE.md §8.3) → 주 단위로 대체
        var span = configuration.span
        if family == .systemSmall && span == .monthByDay { span = .monthByWeek }

        let actions = Array(WidgetStore.selectedActions(configuration.actions,
                                                        defaultCount: Self.maxActions(family))
            .prefix(Self.maxActions(family)))
        // 동명 행동 구분 표시 이름 — 이름이 시리즈 키·범례라 같으면 한 선으로 합쳐진다 (앱 통계 탭과 동일 규칙)
        let seriesNames = Format.disambiguated(actions.map(\.name))
        let isTimeType = !actions.contains { $0.trackingType == .count }

        let math = DayMath()
        let agg = Aggregator(math: math)
        let now = Date.now
        var points: [StatsPoint] = []

        func value(_ action: Action, in range: Range<Date>) -> Double {
            switch action.trackingType {
            case .time: return agg.seconds(for: action, in: range, now: now) / 3600
            case .count: return Double(agg.count(for: action, in: range))
            }
        }

        switch span {
        case .week, .monthByDay:
            let range = span == .week ? math.weekRange(containing: now) : math.monthRange(containing: now)
            for key in math.dayKeys(in: range) {
                let dayRange = math.dayRange(forKey: key)
                for (action, seriesName) in zip(actions, seriesNames) {
                    points.append(StatsPoint(day: key, weekLabel: nil, actionName: seriesName,
                                             value: value(action, in: dayRange)))
                }
            }
        case .monthByWeek:
            let month = math.monthRange(containing: now)
            var cursor = month.lowerBound
            var index = 1
            while cursor < month.upperBound {
                let week = math.weekRange(containing: cursor)
                let clipped = max(week.lowerBound, month.lowerBound)..<min(week.upperBound, month.upperBound)
                for (action, seriesName) in zip(actions, seriesNames) {
                    // 앱 통계 탭과 같은 표기("N주차") + String(localized:)로 en/ja 지역화
                    points.append(StatsPoint(day: nil, weekLabel: String(localized: "\(index)주차"),
                                             actionName: seriesName,
                                             value: value(action, in: clipped)))
                }
                cursor = week.upperBound
                index += 1
            }
        }

        return StatsChartEntry(
            date: now,
            locked: false,
            theme: configuration.theme,
            title: span.title,
            isWeekAxis: span == .monthByWeek,
            isTimeType: isTimeType,
            names: seriesNames,
            colorHexes: actions.map { $0.tags.sorted { $0.createdAt < $1.createdAt }.first?.colorHex ?? "#2F6B4F" },
            points: points
        )
    }

    /// 갤러리·잠금 등에서 실데이터 없이도 그래프 모양이 보이도록 하는 샘플
    private static let samplePoints: [StatsPoint] = {
        let cal = Calendar.current
        let today = cal.startOfDay(for: .now)
        let names = [String(localized: "독서"), String(localized: "달리기")]
        let curves: [[Double]] = [[0.5, 1.2, 0.8, 1.5, 0.6, 1.8, 1.0], [0.3, 0.5, 0.7, 0.4, 0.9, 0.6, 0.8]]
        var points: [StatsPoint] = []
        for offset in 0..<7 {
            let day = cal.date(byAdding: .day, value: offset - 6, to: today)!
            for (index, name) in names.enumerated() {
                points.append(StatsPoint(day: day, weekLabel: nil, actionName: name, value: curves[index][offset]))
            }
        }
        return points
    }()

    func placeholder(in context: Context) -> StatsChartEntry {
        StatsChartEntry(
            date: .now, locked: false, theme: .matchApp, title: String(localized: "일주일 통계"),
            isWeekAxis: false, isTimeType: true,
            names: [String(localized: "독서"), String(localized: "달리기")],
            colorHexes: ["#2F6B4F", "#9D5B4A"], points: Self.samplePoints
        )
    }

    @MainActor
    func snapshot(for configuration: StatsChartConfigIntent, in context: Context) async -> StatsChartEntry {
        Self.makeEntry(configuration, family: context.family)
    }

    @MainActor
    func timeline(for configuration: StatsChartConfigIntent, in context: Context) async -> Timeline<StatsChartEntry> {
        // 값 변경은 인텐트 실행/앱 사용 시 reloadAllTimelines가 즉시 반영하므로
        // 여기서는 날짜 경계 안전망만 둔다 (측정 중 오늘 막대는 다음 갱신에 반영)
        let first = Self.makeEntry(configuration, family: context.family)
        return WidgetRefresh.timeline(first: first, live: false) { _ in first }
    }
}

// MARK: - 뷰

struct StatsChartWidgetView: View {
    @Environment(\.widgetFamily) private var envFamily
    /// 앱 내 DEBUG 미리보기에서 패밀리를 강제할 때 사용
    var previewFamily: WidgetFamily? = nil
    private var family: WidgetFamily { previewFamily ?? envFamily }
    let entry: StatsChartEntry

    var body: some View {
        Group {
            if entry.locked {
                WidgetLockedView()
            } else if entry.points.isEmpty {
                WidgetEmptyView(symbolName: "chart.xyaxis.line", message: "앱에서 행동을 만들고 기록하면\n그래프가 표시돼요")
            } else {
                VStack(alignment: .leading, spacing: 4) {
                    Text(entry.title)
                        .font(.caption2.weight(.semibold))
                        .foregroundStyle(.secondary)
                    chart
                }
            }
        }
        .padding(13)
        .widgetAppTheme(entry.theme)
    }

    private var colors: [Color] {
        entry.colorHexes.map { Color(hex: $0) }
    }

    @ViewBuilder
    private var chart: some View {
        Chart(entry.points) { point in
            if let day = point.day {
                LineMark(
                    x: .value("날짜", day, unit: .day),
                    y: .value(entry.isTimeType ? String(localized: "시간") : String(localized: "값"), point.value)
                )
                .foregroundStyle(by: .value("행동", point.actionName))
                .interpolationMethod(.monotone)
            } else if let weekLabel = point.weekLabel {
                LineMark(
                    x: .value("주차", weekLabel),
                    y: .value(entry.isTimeType ? String(localized: "시간") : String(localized: "값"), point.value)
                )
                .foregroundStyle(by: .value("행동", point.actionName))
                .interpolationMethod(.monotone)
            }
        }
        .chartForegroundStyleScale(domain: entry.names, range: colors)
        .chartLegend(family == .systemSmall ? .hidden : .visible)
        .chartYAxisLabel(family == .systemSmall ? "" : (entry.isTimeType ? String(localized: "시간(h)") : String(localized: "횟수")))
        .chartXAxis {
            if entry.isWeekAxis {
                AxisMarks { _ in
                    AxisGridLine()
                    AxisValueLabel()
                }
            } else if dayCount > 7 {
                // 한 달(일별) 등 포인트가 많으면 라벨이 서로 겹치므로 눈금만 표시
                AxisMarks(values: .stride(by: .day)) { _ in
                    AxisGridLine()
                    AxisTick()
                }
            } else {
                AxisMarks(values: .stride(by: .day, count: family == .systemSmall ? 2 : 1)) { value in
                    AxisGridLine()
                    AxisValueLabel(format: .dateTime.day(), centered: false)
                }
            }
        }
    }

    /// X축에 표시될 날짜 개수 (라벨 겹침 판단용)
    private var dayCount: Int {
        Set(entry.points.compactMap(\.day)).count
    }
}

// MARK: - 위젯 정의

struct StatsChartWidget: Widget {
    var body: some WidgetConfiguration {
        AppIntentConfiguration(
            kind: "HaruStatsChartWidget",
            intent: StatsChartConfigIntent.self,
            provider: StatsChartProvider()
        ) { entry in
            StatsChartWidgetView(entry: entry)
        }
        .configurationDisplayName("행동 통계")
        .description("선택한 행동들의 통계 꺾은선 그래프를 확인해요. (프리미엄)")
        .supportedFamilies([.systemSmall, .systemMedium, .systemLarge])
        .contentMarginsDisabled()
    }
}