feat: 給与所得の源泉徴収票機能を追加

- 新規モジュール: backend/app/payroll/withholding_slip/
  - schemas.py: 源泉徴収票データモデル
  - service.py: 年間集計・給与所得控除・控除額計算ロジック
  - router.py: POST /payroll/withholding-slip/generate
- frontend/withholding-slip.html: 票面プレビュー・印刷(3部)ページ
- frontend/payroll.html: 源泉徴収票メニューカード追加
- backend/app/main.py: ルーター登録
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admin
2026-05-20 17:10:08 +09:00
parent a071a11df3
commit 63ac6bc99a
7 changed files with 1159 additions and 0 deletions

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"""
給与所得の源泉徴収票 計算サービス
"""
from decimal import Decimal, ROUND_DOWN
from datetime import date
from typing import List, Optional, Dict, Any
import logging
from app.core.database import get_connection
from .schemas import WithholdingSlipData, DependentInfo
logger = logging.getLogger(__name__)
# 通勤手当の非課税限度額月額150,000円
COMMUTE_TAX_FREE_MONTHLY = Decimal("150000")
def calc_kyuyo_shotoku(annual_income: Decimal) -> Decimal:
"""
給与所得控除後の金額を計算する(年末調整用)
給与所得控除額を差し引いた後、1円未満切り捨て
"""
income = int(annual_income)
if income <= 550_000:
# 給与所得は0
return Decimal("0")
elif income <= 1_625_000:
kojo = 550_000
elif income <= 1_800_000:
# income * 40% - 100,000 だが1円単位で計算
kojo = int(income * 0.4) - 100_000
elif income <= 3_600_000:
kojo = int(income * 0.3) + 80_000
elif income <= 6_600_000:
kojo = int(income * 0.2) + 440_000
elif income <= 8_500_000:
kojo = int(income * 0.1) + 1_100_000
else:
kojo = 1_950_000
shotoku = max(0, income - kojo)
return Decimal(str(shotoku))
def calc_basic_deduction(tax_year: int) -> Decimal:
"""
基礎控除額を計算する
令和7年(2025年)以降: 580,000円
令和2年(2020年)〜令和6年(2024年): 480,000円
"""
if tax_year >= 2025:
return Decimal("580000")
elif tax_year >= 2020:
return Decimal("480000")
else:
return Decimal("380000")
def get_age_at_year_end(birth_date: date, tax_year: int) -> int:
"""その年の12月31日時点の年齢を計算"""
year_end = date(tax_year, 12, 31)
age = year_end.year - birth_date.year
if (year_end.month, year_end.day) < (birth_date.month, birth_date.day):
age -= 1
return age
def calc_dependent_deduction(dep: Dict[str, Any], tax_year: int) -> tuple:
"""
扶養控除額を計算する
Returns: (deduction_type, deduction_amount)
"""
birth_date = dep.get("birth_date")
if birth_date is None:
return ("一般", Decimal("380000"))
age = get_age_at_year_end(birth_date, tax_year)
if age >= 70:
# 老人扶養親族 (同居老親等かどうかは不明なのでその他として扱う)
return ("老人扶養", Decimal("480000"))
elif 19 <= age <= 22:
# 特定扶養親族
return ("特定扶養", Decimal("630000"))
elif age >= 16:
# 一般扶養親族
return ("一般扶養", Decimal("380000"))
else:
# 16歳未満 - 控除なし
return ("年少", Decimal("0"))
def calc_spouse_deduction(spouse_income: Decimal, employee_income: Decimal, spouse_age: Optional[int]) -> tuple:
"""
配偶者控除・配偶者特別控除を計算する
Returns: (deduction_type, deduction_amount)
"""
spouse_inc = int(spouse_income)
emp_inc = int(employee_income)
# 納税者の合計所得金額が1,000万円超の場合は配偶者控除なし
# 給与所得として概算 (ここでは支払金額から控除後を算出)
emp_shotoku = int(calc_kyuyo_shotoku(employee_income))
if emp_shotoku > 10_000_000:
return (None, Decimal("0"))
# 配偶者の合計所得が48万円収入103万円相当以下 → 配偶者控除
if spouse_inc <= 480_000:
if spouse_age and spouse_age >= 70:
return ("老人配偶者控除", Decimal("480000"))
return ("配偶者控除", Decimal("380000"))
# 配偶者特別控除(配偶者の合計所得 48万1円〜133万円
elif spouse_inc <= 1_330_000:
# 段階的な配偶者特別控除
if spouse_inc <= 950_000:
return ("配偶者特別控除", Decimal("380000"))
elif spouse_inc <= 1_000_000:
return ("配偶者特別控除", Decimal("360000"))
elif spouse_inc <= 1_050_000:
return ("配偶者特別控除", Decimal("310000"))
elif spouse_inc <= 1_100_000:
return ("配偶者特別控除", Decimal("260000"))
elif spouse_inc <= 1_150_000:
return ("配偶者特別控除", Decimal("210000"))
elif spouse_inc <= 1_200_000:
return ("配偶者特別控除", Decimal("160000"))
elif spouse_inc <= 1_250_000:
return ("配偶者特別控除", Decimal("110000"))
elif spouse_inc <= 1_300_000:
return ("配偶者特別控除", Decimal("60000"))
else:
return ("配偶者特別控除", Decimal("30000"))
else:
return (None, Decimal("0"))
def get_withholding_slip_data(tax_year: int, employee_id: int) -> Optional[WithholdingSlipData]:
"""
指定年度・従業員の源泉徴収票データを計算して返す
"""
with get_connection() as conn:
with conn.cursor() as cur:
# 1. 従業員情報を取得
cur.execute(
"""
SELECT employee_id, employee_code, name, name_kana,
address, birth_date, my_number
FROM employees
WHERE employee_id = %s
""",
(employee_id,)
)
emp = cur.fetchone()
if not emp:
return None
# 2. 月次給与データを集計(その年のすべての月)
cur.execute(
"""
SELECT
COUNT(*) as month_count,
COALESCE(SUM(total_payment), 0) as total_payment,
COALESCE(SUM(commute_allowance), 0) as total_commute,
COALESCE(SUM(health_insurance), 0) as health_ins,
COALESCE(SUM(care_insurance), 0) as care_ins,
COALESCE(SUM(pension_insurance), 0) as pension_ins,
COALESCE(SUM(employment_insurance), 0) as emp_ins,
COALESCE(SUM(income_tax), 0) as income_tax
FROM monthly_payroll
WHERE employee_id = %s
AND payroll_year = %s
""",
(employee_id, tax_year)
)
salary_summary = cur.fetchone()
# 3. 賞与データを集計(その年のすべての賞与)
cur.execute(
"""
SELECT
COUNT(*) as bonus_count,
COALESCE(SUM(total_bonus), 0) as total_bonus,
COALESCE(SUM(health_insurance), 0) as health_ins,
COALESCE(SUM(care_insurance), 0) as care_ins,
COALESCE(SUM(pension_insurance), 0) as pension_ins,
COALESCE(SUM(employment_insurance), 0) as emp_ins,
COALESCE(SUM(income_tax), 0) as income_tax
FROM bonus_payments
WHERE employee_id = %s
AND bonus_year = %s
""",
(employee_id, tax_year)
)
bonus_summary = cur.fetchone()
# 4. 扶養親族情報を取得その年の12月31日時点で有効なもの
cur.execute(
"""
SELECT d.dependent_id, d.name, d.relationship, d.birth_date,
d.is_spouse, d.is_disabled, d.income_amount, d.mynumber
FROM dependents d
WHERE d.employee_id = %s
AND d.valid_from <= %s
AND (d.valid_to IS NULL OR d.valid_to >= %s)
ORDER BY d.is_spouse DESC, d.birth_date
""",
(employee_id,
date(tax_year, 12, 31),
date(tax_year, 12, 31))
)
dep_rows = cur.fetchall()
# 5. 集計データを整理
s = salary_summary or {}
b = bonus_summary or {}
def to_dec(v) -> Decimal:
if v is None:
return Decimal("0")
return Decimal(str(v))
salary_total = to_dec(s.get("total_payment", 0))
salary_commute = to_dec(s.get("total_commute", 0))
bonus_total = to_dec(b.get("total_bonus", 0))
# 通勤手当の非課税額月150,000円上限は支払金額から除外
# 簡易計算:通勤手当全額を非課税として除外(厳密には上限チェックが必要)
commute_taxable = Decimal("0") # 通勤手当は非課税として全額除外
# 源泉徴収票の「支払金額」= 給与+賞与の総支給額(通勤手当を除く)
# 実務上は通勤手当を除いた金額を記載することが多い
total_pay_for_slip = salary_total - salary_commute + bonus_total
# 社会保険料合計
health_ins = to_dec(s.get("health_ins", 0)) + to_dec(b.get("health_ins", 0))
care_ins = to_dec(s.get("care_ins", 0)) + to_dec(b.get("care_ins", 0))
pension_ins = to_dec(s.get("pension_ins", 0)) + to_dec(b.get("pension_ins", 0))
emp_ins = to_dec(s.get("emp_ins", 0)) + to_dec(b.get("emp_ins", 0))
social_ins_total = health_ins + care_ins + pension_ins + emp_ins
# 源泉徴収税額合計
income_tax_total = to_dec(s.get("income_tax", 0)) + to_dec(b.get("income_tax", 0))
# 6. 給与所得控除後の金額を計算
kyuyo_shotoku = calc_kyuyo_shotoku(total_pay_for_slip)
# 7. 基礎控除
basic_deduction = calc_basic_deduction(tax_year)
# 8. 扶養親族の処理
birth_date_emp = emp.get("birth_date") if isinstance(emp, dict) else None
dependents_over16 = []
dependents_under16 = []
dependent_deduction_total = Decimal("0")
spouse_info = None
spouse_deduction_amount = Decimal("0")
has_spouse_deduction = False
spouse_deduction_type = None
for dep in dep_rows:
if isinstance(dep, dict):
d = dep
else:
d = {
"dependent_id": dep[0], "name": dep[1], "relationship": dep[2],
"birth_date": dep[3], "is_spouse": dep[4], "is_disabled": dep[5],
"income_amount": dep[6], "mynumber": dep[7]
}
dep_birth = d.get("birth_date")
dep_age = get_age_at_year_end(dep_birth, tax_year) if dep_birth else None
dep_income = to_dec(d.get("income_amount", 0))
if d.get("is_spouse"):
# 配偶者処理
spouse_age = dep_age
sp_type, sp_amount = calc_spouse_deduction(dep_income, total_pay_for_slip, spouse_age)
if sp_type:
has_spouse_deduction = True
spouse_deduction_amount = sp_amount
spouse_deduction_type = sp_type
spouse_deduction_total = sp_amount
else:
spouse_deduction_total = Decimal("0")
spouse_info = DependentInfo(
name=d.get("name", ""),
relationship="配偶者",
birth_date=str(dep_birth) if dep_birth else None,
is_spouse=True,
is_disabled=bool(d.get("is_disabled", False)),
income_amount=dep_income,
my_number=d.get("mynumber"),
deduction_type=sp_type,
deduction_amount=spouse_deduction_amount
)
else:
# 扶養親族
dep_type, dep_amount = calc_dependent_deduction(d, tax_year)
dep_obj = DependentInfo(
name=d.get("name", ""),
relationship=d.get("relationship", ""),
birth_date=str(dep_birth) if dep_birth else None,
is_spouse=False,
is_disabled=bool(d.get("is_disabled", False)),
income_amount=dep_income,
my_number=d.get("mynumber"),
deduction_type=dep_type,
deduction_amount=dep_amount
)
if dep_age is not None and dep_age < 16:
dependents_under16.append(dep_obj)
else:
dependents_over16.append(dep_obj)
dependent_deduction_total += dep_amount
# 9. 所得控除の額の合計額
total_deduction_amount = (
social_ins_total
+ basic_deduction
+ spouse_deduction_amount
+ dependent_deduction_total
)
# 10. 摘要(社会保険料の内訳)
remarks_parts = []
if health_ins > 0:
remarks_parts.append(f"健康保険料{int(health_ins):,}")
if care_ins > 0:
remarks_parts.append(f"介護保険料{int(care_ins):,}")
if pension_ins > 0:
remarks_parts.append(f"厚生年金{int(pension_ins):,}")
if emp_ins > 0:
remarks_parts.append(f"雇用保険{int(emp_ins):,}")
remarks = " ".join(remarks_parts) if remarks_parts else None
months_with_salary = int(s.get("month_count", 0)) if s else 0
months_with_bonus = int(b.get("bonus_count", 0)) if b else 0
return WithholdingSlipData(
employee_id=emp.get("employee_id") if isinstance(emp, dict) else emp[0],
employee_code=emp.get("employee_code", "") if isinstance(emp, dict) else emp[1],
employee_name=emp.get("name", "") if isinstance(emp, dict) else emp[2],
employee_name_kana=emp.get("name_kana") if isinstance(emp, dict) else emp[3],
employee_address=emp.get("address") if isinstance(emp, dict) else emp[4],
employee_birth_date=str(emp.get("birth_date")) if (isinstance(emp, dict) and emp.get("birth_date")) else None,
my_number=emp.get("my_number") if isinstance(emp, dict) else emp[6],
tax_year=tax_year,
total_payment=salary_total + bonus_total,
total_payment_excl_commute=total_pay_for_slip,
kyuyo_shotoku=kyuyo_shotoku,
social_insurance_total=social_ins_total,
health_insurance_total=health_ins,
care_insurance_total=care_ins,
pension_total=pension_ins,
employment_insurance_total=emp_ins,
basic_deduction=basic_deduction,
has_spouse_deduction=has_spouse_deduction,
spouse_deduction_amount=spouse_deduction_amount,
spouse_name=spouse_info.name if spouse_info else None,
spouse_name_kana=spouse_info.name_kana if spouse_info else None,
spouse_income=spouse_info.income_amount if spouse_info else Decimal("0"),
spouse_deduction_type=spouse_deduction_type,
dependents_over16=dependents_over16,
dependents_under16=dependents_under16,
dependent_deduction_total=dependent_deduction_total,
total_deduction_amount=total_deduction_amount,
income_tax_withheld=income_tax_total,
months_with_salary=months_with_salary,
months_with_bonus=months_with_bonus,
remarks=remarks,
)
def get_withholding_slips(tax_year: int, employee_ids: List[int]) -> List[WithholdingSlipData]:
"""複数従業員の源泉徴収票データを取得"""
results = []
for eid in employee_ids:
try:
slip = get_withholding_slip_data(tax_year, eid)
if slip:
results.append(slip)
except Exception as e:
logger.error(f"源泉徴収票計算エラー employee_id={eid}: {e}")
return results