//
// ExerciseAddEditView.swift
// Workouts
//
// Created by rzen on 7/15/25 at 7:12 AM.
//
// Copyright 2025 Rouslan Zenetl. All Rights Reserved.
//

import SwiftUI
import SwiftData

struct ExerciseAddEditView: View {
    @Environment(SyncEngine.self) private var sync
    @Environment(\.dismiss) private var dismiss

    @State private var showingExercisePicker = false

    // The exercise entity provides initial values (read-only).
    let exercise: Exercise
    // The parent split is needed to rebuild and save the SplitDocument.
    let split: Split

    // Local editable state
    @State private var exerciseName: String
    @State private var originalWeight: Int
    @State private var loadType: LoadType
    @State private var minutes: Int
    @State private var seconds: Int
    @State private var weightTens: Int
    @State private var weightOnes: Int
    @State private var reps: Int
    @State private var sets: Int
    @State private var weightReminderWeeks: Int
    @State private var weightLastUpdated: Date?

    init(exercise: Exercise, split: Split) {
        self.exercise = exercise
        self.split = split

        let w = exercise.weight
        _exerciseName = State(initialValue: exercise.name)
        _originalWeight = State(initialValue: w)
        _loadType = State(initialValue: exercise.loadTypeEnum)
        _minutes = State(initialValue: exercise.durationMinutes)
        _seconds = State(initialValue: exercise.durationSeconds)
        _weightTens = State(initialValue: (w / 10) * 10)
        _weightOnes = State(initialValue: w % 10)
        _reps = State(initialValue: exercise.reps)
        _sets = State(initialValue: exercise.sets)
        _weightReminderWeeks = State(initialValue: exercise.weightReminderTimeIntervalWeeks)
        _weightLastUpdated = State(initialValue: exercise.weightLastUpdated)
    }

    var body: some View {
        NavigationStack {
            Form {
                Section(header: Text("Exercise")) {
                    if exerciseName.isEmpty {
                        Button(action: {
                            showingExercisePicker = true
                        }) {
                            HStack {
                                Text("Select Exercise")
                                Spacer()
                                Image(systemName: "chevron.right")
                                    .foregroundColor(.gray)
                            }
                        }
                    } else {
                        ListItem(title: exerciseName)
                    }
                }

                Section(header: Text("Sets/Reps")) {
                    HStack(alignment: .bottom) {
                        VStack(alignment: .center) {
                            Text("Sets")
                            Picker("", selection: $sets) {
                                ForEach(0..<20) { s in
                                    Text("\(s)").tag(s)
                                }
                            }
                            .frame(height: 100)
                            .pickerStyle(.wheel)
                        }
                        VStack(alignment: .center) {
                            Text("Reps")
                            Picker("", selection: $reps) {
                                ForEach(0..<100) { r in
                                    Text("\(r)").tag(r)
                                }
                            }
                            .frame(height: 100)
                            .pickerStyle(.wheel)
                        }
                    }
                }

                Section(
                    header: Text("Load Type"),
                    footer: Text("For bodyweight exercises choose None. For resistance or weight training select Weight. For exercises that are time oriented (like plank or meditation) select Time.")
                ) {
                    Picker("", selection: $loadType) {
                        ForEach(LoadType.allCases, id: \.self) { load in
                            Text(load.name)
                                .tag(load)
                        }
                    }
                    .pickerStyle(.segmented)
                }

                if loadType == .weight {
                    Section(header: Text("Weight")) {
                        HStack {
                            Picker("", selection: $weightTens) {
                                ForEach(0..<100) { lbs in
                                    Text("\(lbs * 10)").tag(lbs * 10)
                                }
                            }
                            .frame(height: 100)
                            .pickerStyle(.wheel)

                            Picker("", selection: $weightOnes) {
                                ForEach(0..<10) { lbs in
                                    Text("\(lbs)").tag(lbs)
                                }
                            }
                            .frame(height: 100)
                            .pickerStyle(.wheel)

                            Text("lbs")
                        }
                    }
                }

                if loadType == .duration {
                    Section(header: Text("Duration")) {
                        HStack {
                            Picker("Minutes", selection: $minutes) {
                                ForEach(0..<60) { minute in
                                    Text("\(minute) min").tag(minute)
                                }
                            }
                            .pickerStyle(.wheel)

                            Picker("Seconds", selection: $seconds) {
                                ForEach(0..<60) { second in
                                    Text("\(second) sec").tag(second)
                                }
                            }
                            .pickerStyle(.wheel)
                        }
                    }
                }

                Section(header: Text("Weight Increase")) {
                    HStack {
                        Text("Remind every \(weightReminderWeeks) weeks")
                        Spacer()
                        Stepper("", value: $weightReminderWeeks, in: 0...366)
                    }
                    if let lastUpdated = weightLastUpdated {
                        Text("Last weight change \(Date().humanTimeInterval(to: lastUpdated)) ago")
                    }
                }
            }
            .sheet(isPresented: $showingExercisePicker) {
                ExercisePickerView { exerciseNames in
                    exerciseName = exerciseNames.first ?? "Unnamed"
                }
            }
            .navigationTitle(exerciseName.isEmpty ? "New Exercise" : exerciseName)
            .toolbar {
                ToolbarItem(placement: .navigationBarLeading) {
                    Button("Cancel") {
                        dismiss()
                    }
                }

                ToolbarItem(placement: .navigationBarTrailing) {
                    Button("Save") {
                        saveExercise()
                        dismiss()
                    }
                }
            }
        }
    }

    private func saveExercise() {
        let newWeight = weightTens + weightOnes
        let updatedWeightDate: Date? = newWeight != originalWeight ? Date() : weightLastUpdated
        let durationSecs = minutes * 60 + seconds

        var doc = SplitDocument(from: split)
        if let idx = doc.exercises.firstIndex(where: { $0.id == exercise.id }) {
            doc.exercises[idx].name = exerciseName
            doc.exercises[idx].sets = sets
            doc.exercises[idx].reps = reps
            doc.exercises[idx].weight = newWeight
            doc.exercises[idx].loadType = loadType.rawValue
            doc.exercises[idx].durationSeconds = durationSecs
            doc.exercises[idx].weightLastUpdated = updatedWeightDate
            doc.exercises[idx].weightReminderWeeks = weightReminderWeeks
        }
        doc.updatedAt = Date()
        Task { await sync.save(split: doc) }
    }
}