//
//  MainDashboardView.swift
//  HaruDanim
//
//  The main dashboard: shows currently running time sessions and a grid of
//  Actions the user can tap to start/stop tracking or add a count.
//

import SwiftUI
import SwiftData

struct MainDashboardView: View {
    @Environment(\.modelContext) private var context
    @Query(sort: \Action.createdAt, order: .forward) private var actions: [Action]

    @State private var viewModel = TrackingViewModel()

    private let columns = [
        GridItem(.flexible(), spacing: 12),
        GridItem(.flexible(), spacing: 12)
    ]

    var body: some View {
        NavigationStack {
            ScrollView {
                VStack(alignment: .leading, spacing: 24) {
                    activeSection
                    actionsSection
                }
                .padding()
            }
            .navigationTitle("메인")
            .onAppear { viewModel.refreshActiveSessions(context: context) }
        }
    }

    // MARK: - Currently tracking

    @ViewBuilder
    private var activeSection: some View {
        if !viewModel.activeSessions.isEmpty {
            VStack(alignment: .leading, spacing: 12) {
                Text("현재 진행 중")
                    .font(.headline)

                ForEach(viewModel.activeSessions) { session in
                    ActiveSessionRow(session: session) {
                        viewModel.stopSession(session, context: context)
                    }
                }
            }
        }
    }

    // MARK: - Actions grid

    @ViewBuilder
    private var actionsSection: some View {
        if actions.isEmpty {
            Text("등록된 행동이 없습니다.")
                .foregroundStyle(.secondary)
                .frame(maxWidth: .infinity, alignment: .center)
                .padding(.top, 40)
        } else {
            LazyVGrid(columns: columns, spacing: 12) {
                ForEach(actions) { action in
                    ActionTile(
                        action: action,
                        isTracking: viewModel.isTracking(action)
                    ) {
                        tapped(action)
                    }
                }
            }
        }
    }

    private func tapped(_ action: Action) {
        switch action.type {
        case .time:
            viewModel.toggleTimeTracking(for: action, context: context)
        case .count:
            viewModel.incrementCount(for: action, context: context)
        }
    }
}

// MARK: - Active session row

private struct ActiveSessionRow: View {
    let session: TimeSession
    let onStop: () -> Void

    var body: some View {
        HStack(spacing: 12) {
            Image(systemName: session.action?.iconName ?? "circle")
                .font(.title3)
                .foregroundStyle(Color.brandPrimary)

            VStack(alignment: .leading, spacing: 2) {
                Text(session.action?.name ?? "행동")
                    .font(.subheadline.weight(.semibold))
                TimelineView(.periodic(from: session.startTime, by: 1)) { _ in
                    Text(elapsedString)
                        .font(.caption.monospacedDigit())
                        .foregroundStyle(.secondary)
                }
            }

            Spacer()

            Button(action: onStop) {
                Image(systemName: "stop.fill")
                    .font(.title3)
                    .foregroundStyle(.white)
                    .frame(width: 40, height: 40)
                    .background(Color.brandPrimary, in: Circle())
            }
            .buttonStyle(.plain)
        }
        .padding(12)
        .background(Color.brandPrimary.opacity(0.12), in: RoundedRectangle(cornerRadius: 14))
    }

    private var elapsedString: String {
        let seconds = Int(Date.now.timeIntervalSince(session.startTime))
        let h = seconds / 3600
        let m = (seconds % 3600) / 60
        let s = seconds % 60
        return String(format: "%02d:%02d:%02d", h, m, s)
    }
}

// MARK: - Action tile

private struct ActionTile: View {
    let action: Action
    let isTracking: Bool
    let onTap: () -> Void

    private var tileColor: Color {
        Color(hex: action.tags.first?.colorHex ?? "#2F6B4F")
    }

    var body: some View {
        Button(action: onTap) {
            VStack(spacing: 10) {
                Image(systemName: action.iconName)
                    .font(.system(size: 30))
                Text(action.name)
                    .font(.subheadline.weight(.semibold))
                    .lineLimit(1)
                if action.type == .time && isTracking {
                    Text("진행 중")
                        .font(.caption2.weight(.bold))
                }
            }
            .foregroundStyle(.white)
            .frame(maxWidth: .infinity)
            .frame(height: 120)
            .background(tileColor, in: RoundedRectangle(cornerRadius: 18))
            .overlay {
                if isTracking {
                    RoundedRectangle(cornerRadius: 18)
                        .strokeBorder(.white, lineWidth: 3)
                }
            }
        }
        .buttonStyle(.plain)
    }
}

// MARK: - Color helpers

extension Color {
    /// App primary green (adapts light/dark via asset-free literal fallback).
    static let brandPrimary = Color(hex: "#2F6B4F")

    /// Builds a `Color` from a `#RRGGBB` (or `RRGGBB`) hex string.
    init(hex: String) {
        let cleaned = hex.trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
        var value: UInt64 = 0
        Scanner(string: cleaned).scanHexInt64(&value)

        let r, g, b, a: Double
        switch cleaned.count {
        case 6:
            r = Double((value & 0xFF0000) >> 16) / 255
            g = Double((value & 0x00FF00) >> 8) / 255
            b = Double(value & 0x0000FF) / 255
            a = 1
        case 8:
            r = Double((value & 0xFF000000) >> 24) / 255
            g = Double((value & 0x00FF0000) >> 16) / 255
            b = Double((value & 0x0000FF00) >> 8) / 255
            a = Double(value & 0x000000FF) / 255
        default:
            r = 0.18; g = 0.42; b = 0.31; a = 1 // fallback to primary green
        }
        self.init(.sRGB, red: r, green: g, blue: b, opacity: a)
    }
}

#Preview {
    MainDashboardView()
        .modelContainer(for: [Action.self, Tag.self, TimeSession.self, CountEntry.self], inMemory: true)
}