mycode/myApp/Haru_Danim/IOS/Core/QuestProgress.swift

//
//  QuestProgress.swift
//  Haru_Danim
//
//  다짐 진행률 계산 (CLAUDE.md §3.3, §6.4)
//

import Foundation

/// 하루/주간/월간 표시 구간
enum StatSpan: String, CaseIterable, Identifiable {
    case day, week, month

    var id: String { rawValue }

    var label: String {
        switch self {
        case .day: return "하루"
        case .week: return "주간"
        case .month: return "월간"
        }
    }
}

struct QuestProgressResult {
    let value: Double
    let target: Double
    let direction: QuestDirection

    /// 게이지 표시용 비율 (0...1).
    /// '이하 유지'는 기준을 넘지 않는 동안 100%(달성 유지), 초과하는 순간 0%(실패)로 취급.
    var ratio: Double {
        switch direction {
        case .atLeast:
            guard target > 0 else { return 0 }
            return min(value / target, 1)
        case .atMost:
            return value <= target ? 1 : 0
        }
    }

    /// 퍼센트 문구 표시용 값. '이상 달성'은 100%를 넘을 수 있고, '이하 유지'는 100% 또는 0%.
    var displayRatio: Double {
        switch direction {
        case .atLeast:
            return target > 0 ? value / target : 0
        case .atMost:
            return value <= target ? 1 : 0
        }
    }

    /// 현재 시점 기준 달성 여부
    var isAchieved: Bool {
        switch direction {
        case .atLeast: return value >= target
        case .atMost: return value <= target
        }
    }
}

struct QuestProgress {
    let quest: Quest
    let math: DayMath

    init(quest: Quest, math: DayMath = DayMath()) {
        self.quest = quest
        self.math = math
    }

    // MARK: 적용일 판정

    /// 하루 단위 다짐에서 해당 논리적 하루가 적용일인지
    func isActiveDay(_ dayKey: Date) -> Bool {
        guard quest.period == .daily else { return true }
        let cal = math.calendar
        switch quest.scheduleMode {
        case .everyDay:
            return true
        case .weekdays:
            return quest.weekdays.contains(cal.component(.weekday, from: dayKey))
        case .monthDays:
            return quest.monthDays.contains(cal.component(.day, from: dayKey))
        case .ordinalWeekday:
            return cal.component(.weekday, from: dayKey) == quest.ordinalWeekday
                && cal.component(.weekdayOrdinal, from: dayKey) == quest.ordinalWeek
        }
    }

    func activeDayCount(in range: Range<Date>) -> Int {
        math.dayKeys(in: range).filter(isActiveDay).count
    }

    // MARK: 현재 주기 진행률

    /// 현재 주기의 실제 시각 범위. 하루 단위 다짐이 오늘 적용일이 아니면 nil.
    func currentPeriodRange(now: Date = .now) -> Range<Date>? {
        switch quest.period {
        case .daily:
            let key = math.dayKey(for: now)
            guard isActiveDay(key) else { return nil }
            return math.dayRange(forKey: key)
        case .weekly:
            return math.weekRange(containing: now)
        case .monthly:
            return math.monthRange(containing: now)
        case .custom:
            guard let start = quest.customStart, let end = quest.customEnd else { return nil }
            let cal = math.calendar
            let lower = math.dayRange(forKey: cal.startOfDay(for: start)).lowerBound
            let upper = math.dayRange(forKey: cal.startOfDay(for: end)).upperBound
            guard lower < upper else { return nil }
            return lower..<upper
        }
    }

    func value(in range: Range<Date>, now: Date = .now) -> Double {
        let agg = Aggregator(math: math)
        switch quest.measure {
        case .time: return agg.seconds(for: quest.targetActions, in: range, now: now)
        case .count: return Double(agg.count(for: quest.targetActions, in: range))
        }
    }

    /// 현재 주기의 진행률
    func current(now: Date = .now) -> QuestProgressResult? {
        guard let range = currentPeriodRange(now: now) else { return nil }
        return QuestProgressResult(
            value: value(in: range, now: now),
            target: quest.targetValue,
            direction: quest.direction
        )
    }

    // MARK: 하루/주간/월간 진행률 (CLAUDE.md §6.4 표시 구조)

    /// span 구간에서의 값과, 주기 목표량을 span에 맞게 환산한 목표
    func spanProgress(_ span: StatSpan, now: Date = .now) -> QuestProgressResult {
        let range: Range<Date>
        switch span {
        case .day: range = math.dayRange(containing: now)
        case .week: range = math.weekRange(containing: now)
        case .month: range = math.monthRange(containing: now)
        }
        return QuestProgressResult(
            value: value(in: range, now: now),
            target: scaledTarget(for: span, range: range, now: now),
            direction: quest.direction
        )
    }

    /// 주기 목표량을 span 길이에 맞춰 환산
    private func scaledTarget(for span: StatSpan, range: Range<Date>, now: Date) -> Double {
        let target = quest.targetValue
        let daysInRange = math.dayKeys(in: range).count
        switch quest.period {
        case .daily:
            switch span {
            case .day: return target
            case .week, .month: return target * Double(max(activeDayCount(in: range), 1))
            }
        case .weekly:
            switch span {
            case .day: return target / 7
            case .week: return target
            case .month: return target * Double(daysInRange) / 7
            }
        case .monthly:
            let daysInMonth = Double(math.dayKeys(in: math.monthRange(containing: now)).count)
            switch span {
            case .day: return target / daysInMonth
            case .week: return target * 7 / daysInMonth
            case .month: return target
            }
        case .custom:
            return target
        }
    }
}

// MARK: - 목표 평가

extension Goal {
    /// 종료일이 지났고 다짐이 있는 목표의 달성 여부를 판정해 상태를 갱신.
    /// (다짐 전체가 마지막 주기 기준으로 달성 상태이면 달성으로 처리)
    func evaluateIfEnded(math: DayMath = DayMath(), now: Date = .now) {
        guard status == .inProgress, isPastEndDate(asOf: now), !quests.isEmpty else { return }
        let allAchieved = quests.allSatisfy { quest in
            QuestProgress(quest: quest, math: math).current(now: now)?.isAchieved ?? true
        }
        status = allAchieved ? .achieved : .notAchieved
    }

    /// 수동 종료: 하위 다짐 전체 달성 여부로 판정 (다짐 없으면 nil 반환 → UI에서 직접 질문)
    func manualFinish(math: DayMath = DayMath(), now: Date = .now) -> GoalStatus? {
        guard !quests.isEmpty else { return nil }
        let allAchieved = quests.allSatisfy { quest in
            QuestProgress(quest: quest, math: math).current(now: now)?.isAchieved ?? true
        }
        status = allAchieved ? .achieved : .notAchieved
        return status
    }
}