추가

frontend/composables/useWeekCalc.ts

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+/**
+ * ISO 8601 주차 계산 composable
+ */
+
+interface WeekInfo {
+  year: number
+  week: number
+  startDate: Date
+  endDate: Date
+  startDateStr: string
+  endDateStr: string
+  weekString: string  // "2026-W01" 형식
+}
+
+export function useWeekCalc() {
+  /**
+   * 특정 날짜의 ISO 주차 정보 반환
+   */
+  function getWeekInfo(date: Date = new Date()): WeekInfo {
+    const target = new Date(date)
+    target.setHours(0, 0, 0, 0)
+    
+    // 목요일 기준으로 연도 판단 (ISO 규칙)
+    const thursday = new Date(target)
+    thursday.setDate(target.getDate() - ((target.getDay() + 6) % 7) + 3)
+    
+    const year = thursday.getFullYear()
+    const firstThursday = new Date(year, 0, 4)
+    firstThursday.setDate(firstThursday.getDate() - ((firstThursday.getDay() + 6) % 7) + 3)
+    
+    const week = Math.ceil((thursday.getTime() - firstThursday.getTime()) / (7 * 24 * 60 * 60 * 1000)) + 1
+    
+    // 해당 주의 월요일
+    const monday = new Date(target)
+    monday.setDate(target.getDate() - ((target.getDay() + 6) % 7))
+    
+    // 해당 주의 일요일
+    const sunday = new Date(monday)
+    sunday.setDate(monday.getDate() + 6)
+    
+    return {
+      year,
+      week,
+      startDate: monday,
+      endDate: sunday,
+      startDateStr: formatDate(monday),
+      endDateStr: formatDate(sunday),
+      weekString: `${year}-W${week.toString().padStart(2, '0')}`
+    }
+  }
+
+  /**
+   * 이번 주 정보
+   */
+  function getCurrentWeekInfo(): WeekInfo {
+    return getWeekInfo(new Date())
+  }
+
+  /**
+   * 지난 주 정보
+   */
+  function getLastWeekInfo(): WeekInfo {
+    const lastWeek = new Date()
+    lastWeek.setDate(lastWeek.getDate() - 7)
+    return getWeekInfo(lastWeek)
+  }
+
+  /**
+   * 날짜 포맷 (YYYY-MM-DD)
+   */
+  function formatDate(date: Date): string {
+    return date.toISOString().split('T')[0]
+  }
+
+  /**
+   * 주차 문자열 파싱
+   */
+  function parseWeekString(weekStr: string): { year: number; week: number } | null {
+    const match = weekStr.match(/^(\d{4})-W(\d{2})$/)
+    if (!match) return null
+    return { year: parseInt(match[1]), week: parseInt(match[2]) }
+  }
+
+  /**
+   * 주차별 날짜 범위 텍스트
+   */
+  function getWeekRangeText(year: number, week: number): string {
+    // 해당 연도 첫 번째 목요일 찾기
+    const jan4 = new Date(year, 0, 4)
+    const firstThursday = new Date(jan4)
+    firstThursday.setDate(jan4.getDate() - ((jan4.getDay() + 6) % 7) + 3)
+    
+    // 해당 주차의 월요일
+    const monday = new Date(firstThursday)
+    monday.setDate(firstThursday.getDate() - 3 + (week - 1) * 7)
+    
+    const sunday = new Date(monday)
+    sunday.setDate(monday.getDate() + 6)
+    
+    return `${formatDateKr(monday)} ~ ${formatDateKr(sunday)}`
+  }
+
+  /**
+   * 한국어 날짜 포맷 (M월 D일)
+   */
+  function formatDateKr(date: Date): string {
+    return `${date.getMonth() + 1}월 ${date.getDate()}일`
+  }
+
+  return {
+    getWeekInfo,
+    getCurrentWeekInfo,
+    getLastWeekInfo,
+    formatDate,
+    parseWeekString,
+    getWeekRangeText,
+    formatDateKr
+  }
+}