//
//  StatsChartWidget.swift
//  Haru_DanimWidgets
//
//  통계 위젯 (CLAUDE.md §8.3) — 선택한 행동들의 꺾은선 그래프
//  앱 통계 탭과 동일: 선 색 = 행동 색, 시간형은 h 단위, 횟수형은 회
//

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 "일주일 통계"
        case .monthByDay: return "한 달 통계 (일별)"
        case .monthByWeek: return "한 달 통계 (주별)"
        }
    }
}

struct StatsChartConfigIntent: WidgetConfigurationIntent {
    static let title: LocalizedStringResource = "통계 위젯"
    static let description = IntentDescription("그래프로 보여줄 행동과 기간을 선택하세요.")

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

    @Parameter(title: "행동 1")
    var action1: ActionEntity?

    @Parameter(title: "행동 2")
    var action2: ActionEntity?

    @Parameter(title: "행동 3")
    var action3: ActionEntity?
}

// 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 title: String
    let isWeekAxis: Bool
    let isTimeType: Bool
    let names: [String]
    let colorHexes: [String]
    let points: [StatsPoint]
}

struct StatsChartProvider: AppIntentTimelineProvider {
    @MainActor
    static func makeEntry(_ configuration: StatsChartConfigIntent, family: WidgetFamily) -> StatsChartEntry {
        guard WidgetStore.isUnlocked else {
            return StatsChartEntry(date: .now, locked: true, 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 chosen = [configuration.action1, configuration.action2, configuration.action3]
            .compactMap { $0 }
            .compactMap { WidgetStore.action($0.id) }
        let actions = chosen.isEmpty ? WidgetStore.defaultActions(3) : chosen
        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 in actions {
                    points.append(StatsPoint(day: key, weekLabel: nil, actionName: action.name,
                                             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 in actions {
                    points.append(StatsPoint(day: nil, weekLabel: "\(index)주", actionName: action.name,
                                             value: value(action, in: clipped)))
                }
                cursor = week.upperBound
                index += 1
            }
        }

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

    func placeholder(in context: Context) -> StatsChartEntry {
        StatsChartEntry(date: .now, locked: false, title: "일주일 통계", isWeekAxis: false,
                        isTimeType: true, names: [], colorHexes: [], points: [])
    }

    @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> {
        Timeline(entries: [Self.makeEntry(configuration, family: context.family)],
                 policy: .after(.now.addingTimeInterval(30 * 60)))
    }
}

// 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 {
                Text("앱에서 행동을 만들고 기록하면 그래프가 표시돼요.")
                    .font(.caption2)
                    .foregroundStyle(.secondary)
                    .multilineTextAlignment(.center)
            } else {
                VStack(alignment: .leading, spacing: 4) {
                    Text(entry.title)
                        .font(.caption2.weight(.semibold))
                        .foregroundStyle(.secondary)
                    chart
                }
            }
        }
        .containerBackground(AppTheme.background, for: .widget)
    }

    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 ? "시간" : "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 ? "시간" : "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 ? "시간(h)" : "횟수"))
        .chartXAxis {
            if entry.isWeekAxis {
                AxisMarks { _ in
                    AxisGridLine()
                    AxisValueLabel()
                }
            } else {
                AxisMarks(values: .stride(by: .day, count: family == .systemSmall ? 2 : 1)) { value in
                    AxisGridLine()
                    AxisValueLabel(format: .dateTime.day(), centered: false)
                }
            }
        }
    }
}

// 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])
    }
}