//
//  FilterView.swift
//  Feels
//
//  Created by Trey Tartt on 1/12/22.
//

import SwiftUI
import SwiftData

struct YearView: View {
    let months = [(0, "J"), (1, "F"), (2,"M"), (3,"A"), (4,"M"), (5, "J"), (6,"J"), (7,"A"), (8,"S"), (9,"O"), (10, "N"), (11,"D")]

    @State private var toggle = true

    @Query(sort: \MoodEntryModel.forDate, order: .reverse)
    private var items: [MoodEntryModel]

    @AppStorage(UserDefaultsStore.Keys.theme.rawValue, store: GroupUserDefaults.groupDefaults) private var theme: Theme = .system
    @AppStorage(UserDefaultsStore.Keys.moodTint.rawValue, store: GroupUserDefaults.groupDefaults) private var moodTint: MoodTints = .Default
    @AppStorage(UserDefaultsStore.Keys.moodImages.rawValue, store: GroupUserDefaults.groupDefaults) private var imagePack: MoodImages = .FontAwesome
    @AppStorage(UserDefaultsStore.Keys.textColor.rawValue, store: GroupUserDefaults.groupDefaults) private var textColor: Color = DefaultTextColor.textColor

    @EnvironmentObject var iapManager: IAPManager
    @StateObject public var viewModel: YearViewModel
    @StateObject private var filteredDays = DaysFilterClass.shared
    @State private var trialWarningHidden = false
    @State private var showSubscriptionStore = false

    // Heatmap-style grid: 12 columns for months
    private let heatmapColumns = Array(repeating: GridItem(.flexible(), spacing: 2), count: 12)

    var body: some View {
        ZStack {
            if self.viewModel.data.keys.isEmpty {
                EmptyHomeView(showVote: false, viewModel: nil)
                    .padding()
            } else {
                ScrollView {
                    VStack(spacing: 16) {
                        ForEach(Array(self.viewModel.data.keys.sorted(by: >)), id: \.self) { yearKey in
                            YearCard(
                                year: yearKey,
                                yearData: self.viewModel.data[yearKey]!,
                                moodTint: moodTint,
                                imagePack: imagePack,
                                textColor: textColor,
                                theme: theme,
                                filteredDays: filteredDays.currentFilters
                            )
                        }
                    }
                    .padding(.horizontal)
                    .padding(.bottom, 100)
                    .background(
                        GeometryReader { proxy in
                            let offset = proxy.frame(in: .named("scroll")).minY
                            Color.clear.preference(key: ViewOffsetKey.self, value: offset)
                        }
                    )
                }
                .disabled(iapManager.shouldShowPaywall)
            }

            if iapManager.shouldShowPaywall {
                Color.black.opacity(0.3)
                    .ignoresSafeArea()
                    .onTapGesture {
                        showSubscriptionStore = true
                    }

                VStack {
                    Spacer()
                    Button {
                        showSubscriptionStore = true
                    } label: {
                        Text(String(localized: "subscription_required_button"))
                            .font(.headline)
                            .foregroundColor(.white)
                            .frame(maxWidth: .infinity)
                            .padding()
                            .background(RoundedRectangle(cornerRadius: 10).fill(Color.pink))
                    }
                    .padding()
                }
            } else if iapManager.shouldShowTrialWarning {
                VStack {
                    Spacer()
                    if !trialWarningHidden {
                        IAPWarningView(iapManager: iapManager)
                    }
                }
            }
        }
        .sheet(isPresented: $showSubscriptionStore) {
            FeelsSubscriptionStoreView()
        }
        .onAppear(perform: {
            self.viewModel.filterEntries(startDate: Date(timeIntervalSince1970: 0), endDate: Date())
        })
        .background(
            theme.currentTheme.bg
                .edgesIgnoringSafeArea(.all)
        )
        .onPreferenceChange(ViewOffsetKey.self) { value in
            withAnimation {
                trialWarningHidden = value < 0
            }
        }
        .padding([.top])
    }
}

// MARK: - Year Card Component
struct YearCard: View {
    let year: Int
    let yearData: [Int: [DayChartView]]
    let moodTint: MoodTints
    let imagePack: MoodImages
    let textColor: Color
    let theme: Theme
    let filteredDays: [Int]

    @State private var showStats = true

    private let months = ["J", "F", "M", "A", "M", "J", "J", "A", "S", "O", "N", "D"]
    private let heatmapColumns = Array(repeating: GridItem(.flexible(), spacing: 2), count: 12)

    private var yearEntries: [MoodEntryModel] {
        let firstOfYear = Calendar.current.date(from: DateComponents(year: year, month: 1, day: 1))!
        let lastOfYear = Calendar.current.date(from: DateComponents(year: year + 1, month: 1, day: 1))!
        return DataController.shared.getData(startDate: firstOfYear, endDate: lastOfYear, includedDays: filteredDays)
    }

    private var metrics: [MoodMetrics] {
        return Random.createTotalPerc(fromEntries: yearEntries)
    }

    private var totalEntries: Int {
        yearEntries.filter { ![Mood.missing, Mood.placeholder].contains($0.mood) }.count
    }

    var body: some View {
        VStack(spacing: 0) {
            // Year Header
            Button(action: { withAnimation(.easeInOut(duration: 0.2)) { showStats.toggle() } }) {
                HStack {
                    Text(String(year))
                        .font(.title2.bold())
                        .foregroundColor(textColor)

                    Spacer()

                    Text("\(totalEntries) days")
                        .font(.subheadline)
                        .foregroundColor(textColor.opacity(0.6))

                    Image(systemName: showStats ? "chevron.up" : "chevron.down")
                        .font(.caption.weight(.semibold))
                        .foregroundColor(textColor.opacity(0.5))
                        .padding(.leading, 4)
                }
                .padding(.horizontal, 16)
                .padding(.vertical, 12)
            }
            .buttonStyle(.plain)

            // Stats Section (collapsible)
            if showStats {
                HStack(spacing: 16) {
                    // Donut Chart
                    MoodDonutChart(metrics: metrics, moodTint: moodTint)
                        .frame(width: 100, height: 100)

                    // Bar Chart
                    VStack(spacing: 6) {
                        ForEach(metrics.filter { $0.total > 0 }) { metric in
                            HStack(spacing: 8) {
                                imagePack.icon(forMood: metric.mood)
                                    .resizable()
                                    .aspectRatio(contentMode: .fit)
                                    .frame(width: 16, height: 16)
                                    .foregroundColor(moodTint.color(forMood: metric.mood))

                                GeometryReader { geo in
                                    ZStack(alignment: .leading) {
                                        RoundedRectangle(cornerRadius: 3)
                                            .fill(Color.gray.opacity(0.15))
                                        RoundedRectangle(cornerRadius: 3)
                                            .fill(moodTint.color(forMood: metric.mood))
                                            .frame(width: max(4, geo.size.width * CGFloat(metric.percent / 100)))
                                    }
                                }
                                .frame(height: 8)

                                Text("\(Int(metric.percent))%")
                                    .font(.caption2.weight(.medium))
                                    .foregroundColor(textColor.opacity(0.7))
                                    .frame(width: 32, alignment: .trailing)
                            }
                        }
                    }
                    .frame(maxWidth: .infinity)
                }
                .padding(.horizontal, 16)
                .padding(.bottom, 12)
                .transition(.opacity.combined(with: .move(edge: .top)))
            }

            Divider()
                .padding(.horizontal, 16)

            // Month Labels
            HStack(spacing: 2) {
                ForEach(months, id: \.self) { month in
                    Text(month)
                        .font(.system(size: 9, weight: .medium))
                        .foregroundColor(textColor.opacity(0.5))
                        .frame(maxWidth: .infinity)
                }
            }
            .padding(.horizontal, 16)
            .padding(.top, 10)
            .padding(.bottom, 4)

            // Heatmap Grid
            YearHeatmapGrid(
                yearData: yearData,
                moodTint: moodTint,
                filteredDays: filteredDays
            )
            .padding(.horizontal, 16)
            .padding(.bottom, 16)
        }
        .background(
            RoundedRectangle(cornerRadius: 16)
                .fill(theme.currentTheme.secondaryBGColor)
        )
    }
}

// MARK: - Year Heatmap Grid
struct YearHeatmapGrid: View {
    let yearData: [Int: [DayChartView]]
    let moodTint: MoodTints
    let filteredDays: [Int]

    private let heatmapColumns = Array(repeating: GridItem(.flexible(), spacing: 2), count: 12)

    var body: some View {
        LazyVGrid(columns: heatmapColumns, spacing: 2) {
            ForEach(Array(yearData.keys.sorted(by: <)), id: \.self) { monthKey in
                if let monthData = yearData[monthKey] {
                    MonthColumn(
                        monthData: monthData,
                        moodTint: moodTint,
                        filteredDays: filteredDays
                    )
                }
            }
        }
    }
}

// MARK: - Month Column (Vertical stack of days)
struct MonthColumn: View {
    let monthData: [DayChartView]
    let moodTint: MoodTints
    let filteredDays: [Int]

    var body: some View {
        VStack(spacing: 2) {
            ForEach(monthData, id: \.self) { dayView in
                YearHeatmapCell(
                    color: dayView.color,
                    weekDay: dayView.weekDay,
                    isFiltered: filteredDays.contains(dayView.weekDay)
                )
            }
        }
    }
}

// MARK: - Year Heatmap Cell
struct YearHeatmapCell: View {
    let color: Color
    let weekDay: Int
    let isFiltered: Bool

    var body: some View {
        RoundedRectangle(cornerRadius: 2)
            .fill(cellColor)
            .aspectRatio(1, contentMode: .fit)
    }

    private var cellColor: Color {
        if !isFiltered {
            return Color.gray.opacity(0.1)
        } else if color == Mood.placeholder.color || color == Mood.missing.color {
            return Color.gray.opacity(0.2)
        } else {
            return color
        }
    }
}

// MARK: - Donut Chart
struct MoodDonutChart: View {
    let metrics: [MoodMetrics]
    let moodTint: MoodTints

    private var filteredMetrics: [MoodMetrics] {
        metrics.filter { $0.total > 0 }
    }

    private var total: Int {
        metrics.reduce(0) { $0 + $1.total }
    }

    var body: some View {
        GeometryReader { geo in
            let size = min(geo.size.width, geo.size.height)
            let lineWidth = size * 0.2

            ZStack {
                // Background ring
                Circle()
                    .stroke(Color.gray.opacity(0.15), lineWidth: lineWidth)

                // Mood segments
                ForEach(Array(filteredMetrics.enumerated()), id: \.element.id) { index, metric in
                    Circle()
                        .trim(from: startAngle(for: index), to: endAngle(for: index))
                        .stroke(moodTint.color(forMood: metric.mood), style: StrokeStyle(lineWidth: lineWidth, lineCap: .butt))
                        .rotationEffect(.degrees(-90))
                }

                // Center text
                VStack(spacing: 0) {
                    Text("\(total)")
                        .font(.system(size: size * 0.22, weight: .bold, design: .rounded))
                    Text("days")
                        .font(.system(size: size * 0.12, weight: .medium))
                        .foregroundColor(.secondary)
                }
            }
            .frame(width: size, height: size)
        }
    }

    private func startAngle(for index: Int) -> CGFloat {
        let precedingTotal = filteredMetrics.prefix(index).reduce(0) { $0 + $1.total }
        return CGFloat(precedingTotal) / CGFloat(max(1, total))
    }

    private func endAngle(for index: Int) -> CGFloat {
        let includingCurrent = filteredMetrics.prefix(index + 1).reduce(0) { $0 + $1.total }
        return CGFloat(includingCurrent) / CGFloat(max(1, total))
    }
}

struct YearView_Previews: PreviewProvider {
    static var previews: some View {
        Group {
            YearView(viewModel: YearViewModel())

            YearView(viewModel: YearViewModel())
                .preferredColorScheme(.dark)
        }
    }
}