//
// ExerciseView.swift
// Workouts
//
// Created by rzen on 7/18/25 at 5:44 PM.
//
// Copyright 2025 Rouslan Zenetl. All Rights Reserved.
//

import SwiftUI
import CoreData
import Charts

struct ExerciseView: View {
    @Environment(\.managedObjectContext) private var viewContext
    @Environment(\.dismiss) private var dismiss

    @ObservedObject var workoutLog: WorkoutLog

    @State private var progress: Int = 0
    @State private var showingPlanEdit = false
    @State private var showingNotesEdit = false

    let notStartedColor = Color.white
    let completedColor = Color.green

    var body: some View {
        Form {
            // MARK: - Progress Section
            Section(header: Text("Progress")) {
                LazyVGrid(columns: Array(repeating: GridItem(.flexible()), count: Int(workoutLog.sets)), spacing: 4) {
                    ForEach(1...max(1, Int(workoutLog.sets)), id: \.self) { index in
                        ZStack {
                            let completed = index <= progress
                            let color = completed ? completedColor : notStartedColor
                            RoundedRectangle(cornerRadius: 8)
                                .fill(
                                    LinearGradient(
                                        gradient: Gradient(colors: [color, color.darker(by: 0.2)]),
                                        startPoint: .topLeading,
                                        endPoint: .bottomTrailing
                                    )
                                )
                                .aspectRatio(0.618, contentMode: .fit)
                                .shadow(radius: 2)
                            Text("\(index)")
                                .font(.title)
                                .fontWeight(.bold)
                                .foregroundColor(.primary)
                                .colorInvert()
                        }
                        .onTapGesture {
                            let totalSets = Int(workoutLog.sets)
                            let isLastTile = index == totalSets
                            let wasAlreadyAtThisProgress = progress == index

                            withAnimation(.easeInOut(duration: 0.2)) {
                                if wasAlreadyAtThisProgress {
                                    progress = 0
                                } else {
                                    progress = index
                                }
                            }

                            updateLogStatus()

                            // If tapping the last tile to complete, go back to list
                            if isLastTile && !wasAlreadyAtThisProgress {
                                dismiss()
                            }
                        }
                    }
                }
            }

            // MARK: - Plan Section (Read-only with Edit button)
            Section {
                PlanTilesView(workoutLog: workoutLog)
            } header: {
                HStack {
                    Text("Plan")
                    Spacer()
                    Button("Edit") {
                        showingPlanEdit = true
                    }
                    .font(.subheadline)
                    .textCase(.none)
                }
            }

            // MARK: - Notes Section (Read-only with Edit button)
            Section {
                if let notes = workoutLog.notes, !notes.isEmpty {
                    Text(notes)
                        .foregroundColor(.primary)
                } else {
                    Text("No notes")
                        .foregroundColor(.secondary)
                        .italic()
                }
            } header: {
                HStack {
                    Text("Notes")
                    Spacer()
                    Button("Edit") {
                        showingNotesEdit = true
                    }
                    .font(.subheadline)
                    .textCase(.none)
                }
            }

            // MARK: - Progress Tracking Chart
            Section(header: Text("Progress Tracking")) {
                WeightProgressionChartView(exerciseName: workoutLog.exerciseName)
            }
        }
        .navigationTitle(workoutLog.exerciseName)
        .sheet(isPresented: $showingPlanEdit) {
            PlanEditView(workoutLog: workoutLog)
        }
        .sheet(isPresented: $showingNotesEdit) {
            NotesEditView(workoutLog: workoutLog)
        }
        .onAppear {
            progress = Int(workoutLog.currentStateIndex)
        }
    }

    private func updateLogStatus() {
        workoutLog.currentStateIndex = Int32(progress)
        if progress >= Int(workoutLog.sets) {
            workoutLog.status = .completed
            workoutLog.completed = true
        } else if progress > 0 {
            workoutLog.status = .inProgress
            workoutLog.completed = false
        } else {
            workoutLog.status = .notStarted
            workoutLog.completed = false
        }
        updateWorkoutStatus()
        saveChanges()
    }

    private func updateWorkoutStatus() {
        guard let workout = workoutLog.workout else { return }
        let logs = workout.logsArray
        let allCompleted = logs.allSatisfy { $0.status == .completed }
        let anyInProgress = logs.contains { $0.status == .inProgress }
        let allNotStarted = logs.allSatisfy { $0.status == .notStarted }

        if allCompleted {
            workout.status = .completed
            workout.end = Date()
        } else if anyInProgress || !allNotStarted {
            workout.status = .inProgress
        } else {
            workout.status = .notStarted
        }
    }

    private func saveChanges() {
        try? viewContext.save()
    }
}

// MARK: - Plan Tiles View

struct PlanTilesView: View {
    @ObservedObject var workoutLog: WorkoutLog

    var body: some View {
        if workoutLog.loadTypeEnum == .duration {
            // Duration layout: Sets | Duration
            HStack(spacing: 0) {
                PlanTile(label: "Sets", value: "\(workoutLog.sets)")
                PlanTile(label: "Duration", value: formattedDuration)
            }
        } else {
            // Weight layout: Sets | Reps | Weight
            HStack(spacing: 0) {
                PlanTile(label: "Sets", value: "\(workoutLog.sets)")
                PlanTile(label: "Reps", value: "\(workoutLog.reps)")
                PlanTile(label: "Weight", value: "\(workoutLog.weight) lbs")
            }
        }
    }

    private var formattedDuration: String {
        let mins = workoutLog.durationMinutes
        let secs = workoutLog.durationSeconds
        if mins > 0 && secs > 0 {
            return "\(mins)m \(secs)s"
        } else if mins > 0 {
            return "\(mins) min"
        } else if secs > 0 {
            return "\(secs) sec"
        } else {
            return "0 sec"
        }
    }
}

struct PlanTile: View {
    let label: String
    let value: String

    var body: some View {
        VStack(spacing: 4) {
            Text(label)
                .font(.caption)
                .foregroundColor(.secondary)
            Text(value)
                .font(.title2)
                .fontWeight(.semibold)
                .foregroundColor(.primary)
        }
        .frame(maxWidth: .infinity)
        .padding(.vertical, 12)
        .background(Color(.systemGray6))
        .cornerRadius(8)
    }
}