"""記事 returns-credit-invoice-calc(返品・値引きの返還インボイス、月次で税額はいくら変わる?)の計算と図。すべて架空のデータ。
架空の1か月:14回の納品(8%と10%が混在)と、返品・値引き・リベートの返還伝票4枚(元の請求・債権は3つ)。
売上と返還の差し引きの税額(納める側から見た「売上の税額 − 返還の税額」)を、4通りの単位で計算する。
A 明細ごとに丸めて合計(国税庁 Q&A 問57 の注の考え方で認められない。比べるためだけに計算)
B 書類ごと:納品書ごとに税率ごとに1回(売上)と、返還伝票ごとに税率ごとに1回(返還)を別々に出して引く
C 月まとめの請求書1枚に別建てで書く:売上を税率ごとに1回、返還を税率ごとに1回(問62の1つ目の書き方)
D 売上から返還を控除した金額で税率ごとに1回(問62の2つ目の書き方、基通1-8-20。注に「税率ごとに1回の端数処理」)
あわせて、返還伝票の「1万円未満」の判定を、伝票ごと(誤り)と元の請求・債権ごと(基通1-8-17)で比べる。
返還の消費税額等は消費税法57条の4第3項5号が「第1項第5号に準じて」計算するとしているので、売上と同じ税率ごと1回の考え方で計算した(筆者の読み)。
使い方: python scripts/figs/returns_credit_calc.py (fields/sales-management-app/ で実行。標準ライブラリだけ)
出力: 標準出力に JSON、public/img/articles/returns-credit-invoice-calc-4ways.svg(図1。frontmatter の image とアイキャッチ)、
scripts/figs/.out/rcc_fig2_flow.svg(図2。記事にインラインで貼る処理の流れ図)
"""
import json, math, pathlib, random, sys
from decimal import Decimal, ROUND_HALF_UP
sys.stdout.reconfigure(encoding='utf-8')
ROOT = pathlib.Path(__file__).resolve().parents[2]
SEED = 20261016
FONT = "'Hiragino Sans','Yu Gothic','Meiryo',sans-serif"
# ---------- 売上:14回の納品 ----------
rng = random.Random(SEED)
deliveries = []
for _ in range(14):
lines = []
for _ in range(rng.randint(2, 6)):
rate = 8 if rng.random() < 0.7 else 10
price = rng.choice([128, 198, 248, 356, 480, 615, 742, 980, 1260, 1580, 2380, 3150])
lines.append((rate, price * rng.randint(1, 24)))
deliveries.append(lines)
# ---------- 返還:伝票4枚(元の請求・債権は X・Y・Z の3つ)。明細は (税率, 税抜の金額) ----------
slips = [
{'id': 'R1', 'kind': '返品', 'claim': 'X', 'lines': [(8, 2380), (8, 1980), (10, 1580)]},
{'id': 'R2', 'kind': '返品', 'claim': 'X', 'lines': [(8, 3150), (10, 1260), (10, 742)]},
{'id': 'R3', 'kind': '値引き', 'claim': 'Y', 'lines': [(10, 1800), (10, 1260)]},
{'id': 'R4', 'kind': 'リベート', 'claim': 'Z', 'lines': [(8, 2480), (8, 2480), (8, 2480), (8, 2480), (8, 2480), (10, 1580), (10, 1580), (10, 1580), (10, 1580)]},
]
def rnd(x100, mode='floor'):
q = Decimal(x100) / 100
if mode == 'floor': return math.floor(q)
if mode == 'ceil': return math.ceil(q)
return int(q.quantize(Decimal('1'), rounding=ROUND_HALF_UP))
def by_rate(lines):
s = {8: 0, 10: 0}
for r, a in lines: s[r] += a
return s
def compute(mode):
S_lines = [x for d in deliveries for x in d]
R_lines = [x for s in slips for x in s['lines']]
Sb, Rb = by_rate(S_lines), by_rate(R_lines)
res = {}
# A 明細ごと
sA = sum(rnd(a * r, mode) for r, a in S_lines); rA = sum(rnd(a * r, mode) for r, a in R_lines)
res['A'] = dict(sales=sA, ret=rA, net=sA - rA, ops=len(S_lines) + len(R_lines))
# B 書類ごと
sB = rB = opsB = 0
for d in deliveries:
b = by_rate(d)
for r in (8, 10):
if b[r]: sB += rnd(b[r] * r, mode); opsB += 1
for s in slips:
b = by_rate(s['lines'])
for r in (8, 10):
if b[r]: rB += rnd(b[r] * r, mode); opsB += 1
res['B'] = dict(sales=sB, ret=rB, net=sB - rB, ops=opsB)
# C 月まとめ別建て
sC = sum(rnd(Sb[r] * r, mode) for r in (8, 10)); rC = sum(rnd(Rb[r] * r, mode) for r in (8, 10))
res['C'] = dict(sales=sC, ret=rC, net=sC - rC, ops=4)
# D 控除後で1回
nD = sum(rnd((Sb[r] - Rb[r]) * r, mode) for r in (8, 10))
res['D'] = dict(sales=None, ret=None, net=nD, ops=2)
res['base'] = {'sales': Sb, 'ret': Rb, 'net': {r: Sb[r] - Rb[r] for r in (8, 10)}}
res['exact_net'] = str(sum(Decimal((Sb[r] - Rb[r]) * r) / 100 for r in (8, 10)))
return res
out = {'seed': SEED, 'deliveries': len(deliveries), 'salesLines': sum(len(d) for d in deliveries),
'slips': len(slips), 'returnLines': sum(len(s['lines']) for s in slips)}
out['floor'] = compute('floor'); out['half_up'] = compute('half_up'); out['ceil'] = compute('ceil')
# 返還の税込(伝票ごと・元の請求ごと)と1万円未満の判定
def incl(lines): return sum(rnd(a * (100 + r), 'floor') if False else a for r, a in lines) # 置き場所のための関数(下で使わない)
def tax_incl(lines):
b = by_rate(lines)
return sum(b[r] + rnd(b[r] * r, 'floor') for r in (8, 10))
judge = {'slip': {s['id']: tax_incl(s['lines']) for s in slips}}
claims = {}
for s in slips: claims.setdefault(s['claim'], []).append(s)
judge['claim'] = {c: tax_incl([x for s in v for x in s['lines']]) for c, v in claims.items()}
judge['slipExempt'] = [k for k, v in judge['slip'].items() if v < 10000]
judge['claimExempt'] = [k for k, v in judge['claim'].items() if v < 10000]
out['judge'] = judge
# 申告で控除する返還の消費税額(国税分):原則(消費税法38条1項、返還した税込価額×7.8/110・軽減は6.24/108)と、
# 交付した適格返還請求書の写しを保存している場合の特例(消費税法施行令58条1項、記載した消費税額等×78/100)。月まとめ別建て(C)の数字で比べる
Rb = f_rb = by_rate([x for s in slips for x in s['lines']])
inc = {r: Rb[r] + rnd(Rb[r] * r, 'floor') for r in (8, 10)}
out['controlTax'] = {'taxIncl': inc, 'principle': round(inc[8] * 6.24 / 108 + inc[10] * 7.8 / 110, 2),
'tsumiage': round(out['floor']['C']['ret'] * 78 / 100, 2)}
print(json.dumps(out, ensure_ascii=False, indent=1))
# ---------- 図1:4通りの差し引き税額(切り捨て) ----------
f = out['floor']
vals = [('明細ごと(不可)', f['A']['net'], '#a8a8a8', '#444444'),
('書類ごと', f['B']['net'], '#b5cc8e', '#111111'),
('月まとめに別建て', f['C']['net'], '#678b2c', '#ffffff'),
('控除後で1回', f['D']['net'], '#557323', '#ffffff')]
W, H = 720, 340; x0, x1 = 210, 650
lo = min(v[1] for v in vals) - 80; hi = max(v[1] for v in vals) + 10
X = lambda v: x0 + (v - lo) / (hi - lo) * (x1 - x0)
s = [f"")
(ROOT / 'public/img/articles').mkdir(parents=True, exist_ok=True)
(ROOT / 'public/img/articles/returns-credit-invoice-calc-4ways.svg').write_text(''.join(s), encoding='utf-8')
# ---------- 図2:処理の流れ図(金額は上の計算値) ----------
j = out['judge']
def box(x, y, w, h, head, lines_, fill='#fff', stroke='#678b2c', hfill='#b5cc8e', htc='#111111'):
t = [f"",
f"",
f"{head}"]
for k, l in enumerate(lines_):
t.append(f"{l}")
return ''.join(t)
def arrow(x, y1, y2):
return f""
fl = [""]
od = ROOT / 'scripts/figs/.out'; od.mkdir(parents=True, exist_ok=True)
(od / 'rcc_fig2_flow.svg').write_text(''.join(fl), encoding='utf-8')
# ---------- 図3:丸め方(切り捨て・四捨五入・切り上げ)ごとの差し引き税額 ----------
rows = [('明細ごと(不可)', 'A'), ('書類ごと', 'B'), ('月まとめに別建て', 'C'), ('控除後で1回', 'D')]
modes = [('floor', '切り捨て', '#678b2c'), ('half_up', '四捨五入', '#c6a47e'), ('ceil', '切り上げ', '#111111')]
allv = [out[m][k]['net'] for m, _, _ in modes for _, k in rows]
lo, hi = min(allv) - 6, max(allv) + 6
W, H = 720, 320; x0, x1 = 190, 680
X = lambda v: x0 + (v - lo) / (hi - lo) * (x1 - x0)
ex = float(out['floor']['exact_net'])
g = [f"")
(od / 'rcc_fig3_modes.svg').write_text(''.join(g), encoding='utf-8')