//
// ExerciseProgressView.swift
// Workouts Watch App
//
// Copyright 2025 Rouslan Zenetl. All Rights Reserved.
//

import SwiftUI
import WatchKit

struct ExerciseProgressView: View {
    @Environment(\.dismiss) private var dismiss

    /// The shared working workout document owned by the parent. We mutate the
    /// matching log in place and ask the parent to forward each change through the
    /// bridge — driving the UI from this doc (not the cache) avoids losing rapid
    /// taps to the read-after-write race.
    @Binding var doc: WorkoutDocument
    let logID: String
    let onChange: () -> Void

    @State private var currentPage: Int = 0
    @State private var showingCancelConfirm = false

    private var log: WorkoutLogDocument? {
        doc.logs.first(where: { $0.id == logID })
    }

    private var totalSets: Int {
        max(1, log?.sets ?? 1)
    }

    private var totalPages: Int {
        // Set 1, Rest 1, Set 2, Rest 2, ..., Set N, Done
        // = N sets + (N-1) rests + 1 done = 2N
        totalSets * 2
    }

    private var firstUnfinishedSetPage: Int {
        // currentStateIndex is the number of completed sets
        let completedSets = log?.currentStateIndex ?? 0
        if completedSets >= totalSets {
            // All done, go to done page
            return totalPages - 1
        }
        // Each set is at page index * 2 (Set1=0, Set2=2, Set3=4...)
        return completedSets * 2
    }

    var body: some View {
        TabView(selection: $currentPage) {
            ForEach(0..<totalPages, id: \.self) { index in
                pageView(for: index)
                    .tag(index)
            }
        }
        .tabViewStyle(.page)
        .toolbar {
            ToolbarItem(placement: .cancellationAction) {
                Button {
                    showingCancelConfirm = true
                } label: {
                    Image(systemName: "xmark")
                }
            }
        }
        .confirmationDialog("Cancel Exercise?", isPresented: $showingCancelConfirm, titleVisibility: .visible) {
            Button("Cancel Exercise", role: .destructive) {
                dismiss()
            }
            Button("Continue", role: .cancel) { }
        }
        .onAppear {
            // Skip to first unfinished set
            currentPage = firstUnfinishedSetPage
        }
        .onChange(of: currentPage) { _, newPage in
            updateProgress(for: newPage)
        }
    }

    @ViewBuilder
    private func pageView(for index: Int) -> some View {
        let lastPageIndex = totalPages - 1

        if index == lastPageIndex {
            // Done page
            DonePageView {
                completeExercise()
                dismiss()
            }
        } else if index % 2 == 0 {
            // Set page (0, 2, 4, ...)
            let setNumber = (index / 2) + 1
            SetPageView(
                setNumber: setNumber,
                totalSets: totalSets,
                reps: log?.reps ?? 0,
                isTimeBased: LoadType(rawValue: log?.loadType ?? LoadType.weight.rawValue) == .duration,
                durationMinutes: (log?.durationSeconds ?? 0) / 60,
                durationSeconds: (log?.durationSeconds ?? 0) % 60
            )
        } else {
            // Rest page (1, 3, 5, ...)
            let restNumber = (index / 2) + 1
            RestPageView(restNumber: restNumber)
        }
    }

    private func updateProgress(for pageIndex: Int) {
        // Calculate which set we're on based on page index
        // Pages: Set1(0), Rest1(1), Set2(2), Rest2(3), Set3(4), Done(5)
        // After completing Set 1 and moving to Rest 1, progress should be 1
        let setIndex = (pageIndex + 1) / 2
        let clampedProgress = min(setIndex, totalSets)

        guard let i = doc.logs.firstIndex(where: { $0.id == logID }) else { return }
        guard clampedProgress != doc.logs[i].currentStateIndex else { return }

        doc.logs[i].currentStateIndex = clampedProgress

        if clampedProgress >= totalSets {
            doc.logs[i].status = WorkoutStatus.completed.rawValue
            doc.logs[i].completed = true
        } else if clampedProgress > 0 {
            doc.logs[i].status = WorkoutStatus.inProgress.rawValue
            doc.logs[i].completed = false
        }

        recomputeWorkoutStatus()
        doc.updatedAt = Date()
        onChange()
    }

    private func completeExercise() {
        guard let i = doc.logs.firstIndex(where: { $0.id == logID }) else { return }
        doc.logs[i].currentStateIndex = totalSets
        doc.logs[i].status = WorkoutStatus.completed.rawValue
        doc.logs[i].completed = true

        recomputeWorkoutStatus()
        doc.updatedAt = Date()
        onChange()
    }

    private func recomputeWorkoutStatus() {
        let statuses = doc.logs.map { WorkoutStatus(rawValue: $0.status) ?? .notStarted }
        let allCompleted = !statuses.isEmpty && statuses.allSatisfy { $0 == .completed }
        let anyInProgress = statuses.contains { $0 == .inProgress }
        let allNotStarted = statuses.allSatisfy { $0 == .notStarted }

        if allCompleted {
            doc.status = WorkoutStatus.completed.rawValue
            doc.end = Date()
        } else if anyInProgress || !allNotStarted {
            doc.status = WorkoutStatus.inProgress.rawValue
            doc.end = nil
        } else {
            doc.status = WorkoutStatus.notStarted.rawValue
            doc.end = nil
        }
    }
}

// MARK: - Set Page View

struct SetPageView: View {
    let setNumber: Int
    let totalSets: Int
    let reps: Int
    let isTimeBased: Bool
    let durationMinutes: Int
    let durationSeconds: Int

    var body: some View {
        VStack(spacing: 8) {
            Text("Set \(setNumber) of \(totalSets)")
                .font(.headline)
                .foregroundColor(.secondary)

            Text("\(setNumber)")
                .font(.system(size: 72, weight: .bold, design: .rounded))
                .foregroundColor(.green)

            if isTimeBased {
                Text(formattedDuration)
                    .font(.title3)
                    .foregroundColor(.secondary)
            } else {
                Text("\(reps) reps")
                    .font(.title3)
                    .foregroundColor(.secondary)
            }
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .onAppear {
            WKInterfaceDevice.current().play(.start)
        }
    }

    private var formattedDuration: String {
        if durationMinutes > 0 && durationSeconds > 0 {
            return "\(durationMinutes)m \(durationSeconds)s"
        } else if durationMinutes > 0 {
            return "\(durationMinutes) min"
        } else {
            return "\(durationSeconds) sec"
        }
    }
}

// MARK: - Rest Page View

struct RestPageView: View {
    let restNumber: Int

    @State private var elapsedSeconds: Int = 0

    private let ticker = Timer.publish(every: 1.0, on: .main, in: .common).autoconnect()

    var body: some View {
        VStack(spacing: 8) {
            Text("Rest")
                .font(.headline)
                .foregroundColor(.secondary)

            Text(formattedTime)
                .font(.system(size: 56, weight: .bold, design: .monospaced))
                .foregroundColor(.orange)

            Text("Swipe to continue")
                .font(.caption2)
                .foregroundColor(.secondary)
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .onAppear {
            elapsedSeconds = 0
            WKInterfaceDevice.current().play(.start)
        }
        .onReceive(ticker) { _ in
            elapsedSeconds += 1
            checkHapticPing()
        }
    }

    private var formattedTime: String {
        let minutes = elapsedSeconds / 60
        let seconds = elapsedSeconds % 60
        return String(format: "%d:%02d", minutes, seconds)
    }

    private func checkHapticPing() {
        // Haptic ping every 10 seconds with pattern:
        // 10s: single, 20s: double, 30s: triple, 40s: single, 50s: double, etc.
        guard elapsedSeconds > 0 && elapsedSeconds % 10 == 0 else { return }

        let cyclePosition = (elapsedSeconds / 10) % 3
        let pingCount: Int
        switch cyclePosition {
        case 1: pingCount = 1  // 10s, 40s, 70s...
        case 2: pingCount = 2  // 20s, 50s, 80s...
        case 0: pingCount = 3  // 30s, 60s, 90s...
        default: pingCount = 1
        }

        playHapticPings(count: pingCount)
    }

    private func playHapticPings(count: Int) {
        for i in 0..<count {
            DispatchQueue.main.asyncAfter(deadline: .now() + Double(i) * 0.2) {
                WKInterfaceDevice.current().play(.click)
            }
        }
    }
}

// MARK: - Done Page View

struct DonePageView: View {
    let onDone: () -> Void

    var body: some View {
        VStack(spacing: 16) {
            Image(systemName: "checkmark.circle.fill")
                .font(.system(size: 60))
                .foregroundColor(.green)

            Text("Done!")
                .font(.title2)
                .fontWeight(.bold)

            Text("Tap to finish")
                .font(.caption)
                .foregroundColor(.secondary)
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .contentShape(Rectangle())
        .onTapGesture {
            WKInterfaceDevice.current().play(.success)
            onDone()
        }
        .onAppear {
            WKInterfaceDevice.current().play(.success)
        }
    }
}