LevelSelectionView.swift

//
//  LevelSelectionView.swift
//  InstantEnglish
//
//  Created on 2024/12/08.
//

import SwiftUI

enum CourseType: String, CaseIterable {
    case stepUp = "ステップアップ"
    case test = "テスト用"
}

struct LevelSelectionView: View {
    @ObservedObject var questionManager: QuestionManager
    @Binding var isPresented: Bool
    @State private var showLevelAssessment = false
    @State private var selectedCourseType: CourseType = .stepUp
    @State private var selectedStepUpCourse: (from: CEFRLevel, to: CEFRLevel)? = nil
    
    let stepUpCourses: [StepUpCourse] = [
        StepUpCourse(
            fromLevel: .a1,
            toLevel: .a2,
            name: "A1 → A2 ステップアップ",
            description: "基礎から日常会話へステップアップ",
            questionCount: 5,
            estimatedTime: 10
        ),
        StepUpCourse(
            fromLevel: .a2,
            toLevel: .b1,
            name: "A2 → B1 ステップアップ",
            description: "日常会話から中級へステップアップ",
            questionCount: 5,
            estimatedTime: 12
        ),
        StepUpCourse(
            fromLevel: .b1,
            toLevel: .b2,
            name: "B1 → B2 ステップアップ",
            description: "中級から上級中級へステップアップ",
            questionCount: 5,
            estimatedTime: 15
        ),
        StepUpCourse(
            fromLevel: .b2,
            toLevel: .c1,
            name: "B2 → C1 ステップアップ",
            description: "上級中級から上級へステップアップ",
            questionCount: 5,
            estimatedTime: 18
        ),
        StepUpCourse(
            fromLevel: .c1,
            toLevel: .c2,
            name: "C1 → C2 ステップアップ",
            description: "上級から最上級へステップアップ",
            questionCount: 5,
            estimatedTime: 20
        )
    ]
    
    let courses: [Course] = [
        Course(
            level: .a1,
            name: "A1 基礎コース",
            description: "基本的な日常表現と簡単な文を学びます",
            questionCount: 8,
            estimatedTime: 15
        ),
        Course(
            level: .a2,
            name: "A2 日常会話コース",
            description: "日常的な場面でよく使われる表現を学びます",
            questionCount: 8,
            estimatedTime: 20
        ),
        Course(
            level: .b1,
            name: "B1 中級コース",
            description: "仕事、学校、娯楽などで使われる標準的な表現を学びます",
            questionCount: 8,
            estimatedTime: 25
        ),
        Course(
            level: .b2,
            name: "B2 上級中級コース",
            description: "複雑な文章の要点を理解し、流暢に表現する方法を学びます",
            questionCount: 8,
            estimatedTime: 30
        ),
        Course(
            level: .c1,
            name: "C1 上級コース",
            description: "様々な分野の長文を理解し、流暢に表現する方法を学びます",
            questionCount: 8,
            estimatedTime: 35
        ),
        Course(
            level: .c2,
            name: "C2 最上級コース",
            description: "ほぼすべての内容を容易に理解し、流暢かつ正確に表現する方法を学びます",
            questionCount: 8,
            estimatedTime: 40
        )
    ]
    
    var body: some View {
        ZStack {
            // 背景
            Color(.systemGroupedBackground)
                .ignoresSafeArea()
            
            ScrollView {
                VStack(spacing: 20) {
                    // ヘッダー
                    VStack(spacing: 16) {
                        Text("CEFRレベルを選択")
                            .font(.title)
                            .fontWeight(.bold)
                        
                        Text("あなたのレベルに合わせたコースを選んでください")
                            .font(.subheadline)
                            .foregroundColor(.secondary)
                            .multilineTextAlignment(.center)
                        
                        // レベル測定テストボタン
                        Button(action: {
                            showLevelAssessment = true
                        }) {
                            HStack {
                                Image(systemName: "chart.bar.fill")
                                Text("レベル測定テストを受ける")
                                    .fontWeight(.semibold)
                            }
                            .frame(maxWidth: .infinity)
                            .padding()
                            .background(
                                LinearGradient(
                                    gradient: Gradient(colors: [Color.blue, Color.purple]),
                                    startPoint: .leading,
                                    endPoint: .trailing
                                )
                            )
                            .foregroundColor(.white)
                            .cornerRadius(12)
                        }
                        .padding(.horizontal)
                        
                        // コースタイプ選択セグメント
                        Picker("コースタイプ", selection: $selectedCourseType) {
                            ForEach(CourseType.allCases, id: \.self) { type in
                                Text(type.rawValue).tag(type)
                            }
                        }
                        .pickerStyle(SegmentedPickerStyle())
                        .padding(.horizontal)
                    }
                    .padding(.top, 20)
                    .padding(.horizontal)
                    
                    // 選択されたコースタイプに応じて表示を切り替え
                    if selectedCourseType == .stepUp {
                        // ステップアップコースセクション
                        VStack(alignment: .leading, spacing: 12) {
                            HStack {
                                Image(systemName: "arrow.up.circle.fill")
                                    .foregroundColor(.orange)
                                Text("ステップアップコース")
                                    .font(.headline)
                                    .fontWeight(.semibold)
                            }
                            .padding(.horizontal)
                            
                            LazyVStack(spacing: 12) {
                            ForEach(stepUpCourses) { stepUpCourse in
                                StepUpCourseCardView(
                                    stepUpCourse: stepUpCourse,
                                    onSelect: {
                                        selectedStepUpCourse = (stepUpCourse.fromLevel, stepUpCourse.toLevel)
                                    }
                                )
                            }
                            }
                            .padding(.horizontal)
                        }
                        .padding(.top, 8)
                        .padding(.bottom, 20)
                    } else {
                        // テスト用コースセクション
                        VStack(alignment: .leading, spacing: 12) {
                            HStack {
                                Image(systemName: "book.fill")
                                    .foregroundColor(.blue)
                                Text("テスト用コース")
                                    .font(.headline)
                                    .fontWeight(.semibold)
                            }
                            .padding(.horizontal)
                            
                            LazyVStack(spacing: 16) {
                                ForEach(courses) { course in
                                    CourseCardView(
                                        course: course,
                                        onSelect: {
                                            // コース選択時にリセット処理を実行
                                            questionManager.resetQuiz()
                                            questionManager.loadQuestionsForLevel(course.level)
                                            DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
                                                isPresented = false
                                            }
                                        }
                                    )
                                }
                            }
                            .padding(.horizontal)
                        }
                        .padding(.top, 8)
                        .padding(.bottom, 20)
                    }
                }
            }
        }
        .navigationTitle("コース選択")
        .navigationBarTitleDisplayMode(.large)
        .toolbar {
            ToolbarItem(placement: .navigationBarLeading) {
                Button(action: {
                    isPresented = false
                }) {
                    HStack(spacing: 4) {
                        Image(systemName: "chevron.left")
                        Text("ホーム")
                    }
                    .font(.subheadline)
                    .foregroundColor(.blue)
                }
            }
        }
        .fullScreenCover(isPresented: $showLevelAssessment) {
            LevelAssessmentView(
                questionManager: questionManager,
                isPresented: $showLevelAssessment
            )
        }
        .sheet(item: Binding(
            get: { 
                guard let course = selectedStepUpCourse else { return nil }
                return StepUpCourseSelection(from: course.from, to: course.to)
            },
            set: { (course: StepUpCourseSelection?) in
                if let course = course {
                    selectedStepUpCourse = (course.from, course.to)
                } else {
                    selectedStepUpCourse = nil
                }
            }
        )) { course in
            NavigationView {
                LessonSelectionView(
                    questionManager: questionManager,
                    isPresented: Binding(
                        get: { selectedStepUpCourse != nil },
                        set: { if !$0 { selectedStepUpCourse = nil } }
                    ),
                    fromLevel: course.from,
                    toLevel: course.to
                )
            }
        }
    }
}

struct CourseCardView: View {
    let course: Course
    let onSelect: () -> Void
    
    var body: some View {
        Button(action: onSelect) {
            HStack(spacing: 16) {
                // レベルアイコン
                ZStack {
                    Circle()
                        .fill(
                            LinearGradient(
                                gradient: Gradient(colors: [
                                    colorForLevel(course.level),
                                    colorForLevel(course.level).opacity(0.7)
                                ]),
                                startPoint: .topLeading,
                                endPoint: .bottomTrailing
                            )
                        )
                        .frame(width: 70, height: 70)
                        .shadow(color: colorForLevel(course.level).opacity(0.3), radius: 8, x: 0, y: 4)
                    
                    Text(course.level.rawValue)
                        .font(.title)
                        .fontWeight(.bold)
                        .foregroundColor(.white)
                }
                
                // コース情報
                VStack(alignment: .leading, spacing: 8) {
                    Text(course.name)
                        .font(.headline)
                        .fontWeight(.bold)
                        .foregroundColor(.primary)
                    
                    Text(course.description)
                        .font(.subheadline)
                        .foregroundColor(.secondary)
                        .lineLimit(2)
                    
                    HStack(spacing: 16) {
                        HStack(spacing: 4) {
                            Image(systemName: "questionmark.circle.fill")
                                .font(.caption)
                                .foregroundColor(.blue)
                            Text("\(course.questionCount)問")
                                .font(.caption)
                                .fontWeight(.semibold)
                                .foregroundColor(.primary)
                        }
                        
                        HStack(spacing: 4) {
                            Image(systemName: "clock.fill")
                                .font(.caption)
                                .foregroundColor(.orange)
                            Text("約\(course.estimatedTime)分")
                                .font(.caption)
                                .fontWeight(.semibold)
                                .foregroundColor(.primary)
                        }
                    }
                }
                
                Spacer()
                
                // 矢印アイコン
                Image(systemName: "chevron.right")
                    .font(.headline)
                    .foregroundColor(colorForLevel(course.level))
            }
            .padding(16)
            .background(
                RoundedRectangle(cornerRadius: 20)
                    .fill(Color(.systemBackground))
                    .shadow(color: Color.black.opacity(0.08), radius: 8, x: 0, y: 4)
            )
            .overlay(
                RoundedRectangle(cornerRadius: 20)
                    .stroke(
                        LinearGradient(
                            gradient: Gradient(colors: [
                                colorForLevel(course.level).opacity(0.3),
                                colorForLevel(course.level).opacity(0.1)
                            ]),
                            startPoint: .topLeading,
                            endPoint: .bottomTrailing
                        ),
                        lineWidth: 2
                    )
            )
        }
        .buttonStyle(PlainButtonStyle())
    }
    
    private func colorForLevel(_ level: CEFRLevel) -> Color {
        switch level {
        case .a1: return .green
        case .a2: return .mint
        case .b1: return .blue
        case .b2: return .cyan
        case .c1: return .purple
        case .c2: return .indigo
        }
    }
}

struct StepUpCourseCardView: View {
    let stepUpCourse: StepUpCourse
    let onSelect: () -> Void
    
    var body: some View {
        Button(action: onSelect) {
            HStack(spacing: 16) {
                // レベルアイコン（矢印付き）
                ZStack {
                    Circle()
                        .fill(
                            LinearGradient(
                                gradient: Gradient(colors: [
                                    colorForLevel(stepUpCourse.fromLevel),
                                    colorForLevel(stepUpCourse.toLevel)
                                ]),
                                startPoint: .topLeading,
                                endPoint: .bottomTrailing
                            )
                        )
                        .frame(width: 70, height: 70)
                        .shadow(color: colorForLevel(stepUpCourse.toLevel).opacity(0.3), radius: 8, x: 0, y: 4)
                    
                    VStack(spacing: 3) {
                        Text(stepUpCourse.fromLevel.rawValue)
                            .font(.caption)
                            .fontWeight(.bold)
                            .foregroundColor(.white)
                        
                        Image(systemName: "arrow.down")
                            .font(.caption2)
                            .foregroundColor(.white)
                        
                        Text(stepUpCourse.toLevel.rawValue)
                            .font(.caption)
                            .fontWeight(.bold)
                            .foregroundColor(.white)
                    }
                }
                
                // コース情報
                VStack(alignment: .leading, spacing: 8) {
                    HStack(spacing: 6) {
                        Image(systemName: "arrow.up.circle.fill")
                            .font(.caption)
                            .foregroundColor(.orange)
                        Text(stepUpCourse.displayName)
                            .font(.headline)
                            .fontWeight(.bold)
                            .foregroundColor(.primary)
                    }
                    
                    Text(stepUpCourse.description)
                        .font(.subheadline)
                        .foregroundColor(.secondary)
                        .lineLimit(2)
                    
                    HStack(spacing: 16) {
                        HStack(spacing: 4) {
                            Image(systemName: "questionmark.circle.fill")
                                .font(.caption)
                                .foregroundColor(.blue)
                            Text("\(stepUpCourse.questionCount)問")
                                .font(.caption)
                                .fontWeight(.semibold)
                                .foregroundColor(.primary)
                        }
                        
                        HStack(spacing: 4) {
                            Image(systemName: "clock.fill")
                                .font(.caption)
                                .foregroundColor(.orange)
                            Text("約\(stepUpCourse.estimatedTime)分")
                                .font(.caption)
                                .fontWeight(.semibold)
                                .foregroundColor(.primary)
                        }
                    }
                }
                
                Spacer()
                
                // 矢印アイコン
                Image(systemName: "chevron.right")
                    .font(.headline)
                    .foregroundColor(colorForLevel(stepUpCourse.toLevel))
            }
            .padding(16)
            .background(
                RoundedRectangle(cornerRadius: 20)
                    .fill(Color(.systemBackground))
                    .shadow(color: Color.black.opacity(0.08), radius: 8, x: 0, y: 4)
            )
            .overlay(
                RoundedRectangle(cornerRadius: 20)
                    .stroke(
                        LinearGradient(
                            gradient: Gradient(colors: [
                                colorForLevel(stepUpCourse.fromLevel).opacity(0.4),
                                colorForLevel(stepUpCourse.toLevel).opacity(0.4)
                            ]),
                            startPoint: .leading,
                            endPoint: .trailing
                        ),
                        lineWidth: 2
                    )
            )
        }
        .buttonStyle(PlainButtonStyle())
    }
    
    private func colorForLevel(_ level: CEFRLevel) -> Color {
        switch level {
        case .a1: return .green
        case .a2: return .mint
        case .b1: return .blue
        case .b2: return .cyan
        case .c1: return .purple
        case .c2: return .indigo
        }
    }
}

struct StepUpCourseSelection: Identifiable {
    let id = UUID()
    let from: CEFRLevel
    let to: CEFRLevel
}

#Preview {
    LevelSelectionView(
        questionManager: QuestionManager(),
        isPresented: .constant(true)
    )
}