//
//  Models.swift
//  Haru_Danim
//
//  SwiftData 데이터 모델 정의 (CLAUDE.md §10 참고)
//

import Foundation
import SwiftData
import SwiftUI

// MARK: - 추적 방식

enum TrackingType: String, CaseIterable, Identifiable {
    case time
    case count

    var id: String { rawValue }

    var label: String {
        switch self {
        case .time: return "시간 측정"
        case .count: return "횟수 기록"
        }
    }

    var symbol: String {
        switch self {
        case .time: return "timer"
        case .count: return "number"
        }
    }
}

// MARK: - 꼬리표 (Tag)

@Model
final class Tag {
    var name: String = ""
    var colorHex: String = "#2F6B4F"
    var createdAt: Date = Date()

    var actions: [Action] = []

    @Relationship(deleteRule: .nullify, inverse: \Quest.targetTag)
    var quests: [Quest] = []

    init(name: String, colorHex: String) {
        self.name = name
        self.colorHex = colorHex
        self.createdAt = .now
    }
}

extension Tag {
    var color: Color { Color(hex: colorHex) }

    var sortedActions: [Action] {
        actions.sorted { $0.sortOrder < $1.sortOrder }
    }
}

// MARK: - 행동 (Action)

@Model
final class Action {
    var name: String = ""
    var symbolName: String = "star.fill"
    var trackingTypeRaw: String = TrackingType.time.rawValue
    var sortOrder: Int = 0
    var createdAt: Date = Date()

    @Relationship(inverse: \Tag.actions)
    var tags: [Tag] = []

    @Relationship(deleteRule: .cascade, inverse: \TimeSession.action)
    var sessions: [TimeSession] = []

    @Relationship(deleteRule: .cascade, inverse: \CountEntry.action)
    var countEntries: [CountEntry] = []

    @Relationship(deleteRule: .nullify, inverse: \Quest.targetAction)
    var quests: [Quest] = []

    init(name: String, symbolName: String, trackingType: TrackingType, sortOrder: Int) {
        self.name = name
        self.symbolName = symbolName
        self.trackingTypeRaw = trackingType.rawValue
        self.sortOrder = sortOrder
        self.createdAt = .now
    }
}

extension Action {
    var trackingType: TrackingType {
        get { TrackingType(rawValue: trackingTypeRaw) ?? .time }
        set { trackingTypeRaw = newValue.rawValue }
    }

    /// 행동 버튼의 색: 지정된 꼬리표(가장 먼저 만든 것)의 색을 따른다.
    var color: Color {
        tags.sorted { $0.createdAt < $1.createdAt }.first?.color ?? AppTheme.green
    }

    var sortedTags: [Tag] {
        tags.sorted { $0.createdAt < $1.createdAt }
    }

    /// 진행 중(종료되지 않은) 세션
    var runningSession: TimeSession? {
        sessions.first { $0.endAt == nil }
    }

    var isRunning: Bool { runningSession != nil }
}

// MARK: - 시간 기록 (TimeSession)

@Model
final class TimeSession {
    var startAt: Date = Date()
    var endAt: Date?

    var action: Action?

    init(action: Action, startAt: Date, endAt: Date? = nil) {
        self.action = action
        self.startAt = startAt
        self.endAt = endAt
    }
}

extension TimeSession {
    func duration(asOf now: Date = .now) -> TimeInterval {
        max(0, (endAt ?? now).timeIntervalSince(startAt))
    }
}

// MARK: - 횟수 기록 (CountEntry)

@Model
final class CountEntry {
    var timestamp: Date = Date()
    var amount: Int = 1

    var action: Action?

    init(action: Action, timestamp: Date, amount: Int = 1) {
        self.action = action
        self.timestamp = timestamp
        self.amount = amount
    }
}

// MARK: - 목표 (Goal)

enum GoalStatus: String, CaseIterable {
    case inProgress
    case achieved
    case notAchieved

    var label: String {
        switch self {
        case .inProgress: return "진행 중"
        case .achieved: return "달성 완료"
        case .notAchieved: return "미달성 종료"
        }
    }
}

@Model
final class Goal {
    var title: String = ""
    var symbolName: String = "flag.fill"
    var colorHex: String = "#2F6B4F"
    var startDate: Date = Date()
    var endDate: Date?
    var statusRaw: String = GoalStatus.inProgress.rawValue
    var createdAt: Date = Date()

    @Relationship(deleteRule: .cascade, inverse: \Quest.goal)
    var quests: [Quest] = []

    init(title: String, symbolName: String, colorHex: String, startDate: Date, endDate: Date?) {
        self.title = title
        self.symbolName = symbolName
        self.colorHex = colorHex
        self.startDate = startDate
        self.endDate = endDate
        self.statusRaw = GoalStatus.inProgress.rawValue
        self.createdAt = .now
    }
}

extension Goal {
    var status: GoalStatus {
        get { GoalStatus(rawValue: statusRaw) ?? .inProgress }
        set { statusRaw = newValue.rawValue }
    }

    var color: Color { Color(hex: colorHex) }

    var sortedQuests: [Quest] {
        quests.sorted { $0.createdAt < $1.createdAt }
    }

    /// 종료일이 지났는지 (종료일 당일까지는 진행 중으로 취급)
    func isPastEndDate(asOf now: Date = .now, calendar: Calendar = .current) -> Bool {
        guard let endDate else { return false }
        let endOfDay = calendar.date(byAdding: .day, value: 1, to: calendar.startOfDay(for: endDate))!
        return now >= endOfDay
    }

    /// 다짐이 하나도 없는 채 종료일이 도래 → "확인 필요" 상태 (CLAUDE.md §6.4-4)
    func needsConfirmation(asOf now: Date = .now) -> Bool {
        status == .inProgress && quests.isEmpty && isPastEndDate(asOf: now)
    }

    /// 종료일이 있는 목표의 기간 경과 진행률 (0...1)
    func dateProgress(asOf now: Date = .now) -> Double? {
        guard let endDate, endDate > startDate else { return nil }
        let total = endDate.timeIntervalSince(startDate)
        let elapsed = now.timeIntervalSince(startDate)
        return min(max(elapsed / total, 0), 1)
    }
}

// MARK: - 다짐 (Quest)

enum QuestPeriod: String, CaseIterable, Identifiable {
    case daily
    case weekly
    case monthly
    case custom

    var id: String { rawValue }

    var label: String {
        switch self {
        case .daily: return "하루 단위"
        case .weekly: return "일주일 단위"
        case .monthly: return "한 달 단위"
        case .custom: return "특정 기간"
        }
    }
}

/// 하루 단위 다짐의 적용일 방식
enum QuestScheduleMode: String, CaseIterable, Identifiable {
    case everyDay
    case weekdays
    case monthDays
    case ordinalWeekday

    var id: String { rawValue }

    var label: String {
        switch self {
        case .everyDay: return "매일"
        case .weekdays: return "요일 지정"
        case .monthDays: return "날짜 지정"
        case .ordinalWeekday: return "몇째 주 요일"
        }
    }
}

enum QuestDirection: String, CaseIterable, Identifiable {
    case atLeast
    case atMost

    var id: String { rawValue }

    var label: String {
        switch self {
        case .atLeast: return "이상 달성"
        case .atMost: return "이하 유지"
        }
    }
}

@Model
final class Quest {
    var goal: Goal?

    /// 대상: 행동 또는 꼬리표 중 하나
    var targetAction: Action?
    var targetTag: Tag?

    /// 측정 기준 (행동 대상이면 그 행동의 추적 방식, 꼬리표 대상이면 생성 시 선택)
    var measureRaw: String = TrackingType.time.rawValue

    var periodRaw: String = QuestPeriod.daily.rawValue
    var scheduleModeRaw: String = QuestScheduleMode.everyDay.rawValue
    /// Calendar.weekday 값 (1=일 ... 7=토)
    var weekdays: [Int] = []
    /// 1~31
    var monthDays: [Int] = []
    /// 몇째 주 (1~5)
    var ordinalWeek: Int = 1
    /// Calendar.weekday 값
    var ordinalWeekday: Int = 2

    var customStart: Date?
    var customEnd: Date?

    /// 시간 목표(초) — measure == .time 일 때 사용
    var targetSeconds: Double = 3600
    /// 횟수 목표 — measure == .count 일 때 사용
    var targetCount: Int = 1
    var directionRaw: String = QuestDirection.atLeast.rawValue

    var createdAt: Date = Date()

    init(goal: Goal) {
        self.goal = goal
        self.createdAt = .now
    }
}

extension Quest {
    var measure: TrackingType {
        get { TrackingType(rawValue: measureRaw) ?? .time }
        set { measureRaw = newValue.rawValue }
    }

    var period: QuestPeriod {
        get { QuestPeriod(rawValue: periodRaw) ?? .daily }
        set { periodRaw = newValue.rawValue }
    }

    var scheduleMode: QuestScheduleMode {
        get { QuestScheduleMode(rawValue: scheduleModeRaw) ?? .everyDay }
        set { scheduleModeRaw = newValue.rawValue }
    }

    var direction: QuestDirection {
        get { QuestDirection(rawValue: directionRaw) ?? .atLeast }
        set { directionRaw = newValue.rawValue }
    }

    var targetName: String {
        if let targetAction { return targetAction.name }
        if let targetTag { return "#\(targetTag.name)" }
        return "대상 없음"
    }

    var targetSymbol: String {
        if let targetAction { return targetAction.symbolName }
        return "tag.fill"
    }

    var targetColor: Color {
        if let targetAction { return targetAction.color }
        if let targetTag { return targetTag.color }
        return AppTheme.green
    }

    /// 다짐이 집계 대상으로 삼는 행동들
    var targetActions: [Action] {
        if let targetAction { return [targetAction] }
        if let targetTag { return targetTag.actions.filter { $0.trackingType == measure } }
        return []
    }

    /// 목표량 (시간이면 초, 횟수면 개수)
    var targetValue: Double {
        measure == .time ? targetSeconds : Double(targetCount)
    }

    var targetValueLabel: String {
        measure == .time ? Format.durationShort(targetSeconds) : "\(targetCount)회"
    }

    /// 주기 요약 문구 (예: "매주 월·수·금")
    var scheduleLabel: String {
        switch period {
        case .daily:
            switch scheduleMode {
            case .everyDay:
                return "매일"
            case .weekdays:
                let names = weekdays.sorted().map { Format.weekdayShort($0) }
                return "매주 " + names.joined(separator: "·")
            case .monthDays:
                let names = monthDays.sorted().map { "\($0)일" }
                return "매달 " + names.joined(separator: ", ")
            case .ordinalWeekday:
                return "매달 \(ordinalWeek)째 주 \(Format.weekdayShort(ordinalWeekday))요일"
            }
        case .weekly:
            return "매주"
        case .monthly:
            return "매달"
        case .custom:
            guard let customStart, let customEnd else { return "특정 기간" }
            return "\(Format.shortDate(customStart)) ~ \(Format.shortDate(customEnd))"
        }
    }
}