#!/usr/bin/env bash
# Monthly TVA déductible aggregation for Arcodange — the supplier-side
# counterpart to dolibarr-tva-reconciliation.
#
# Usage:
#   deductible-by-month.sh [--year YYYY] [--since YYYY-MM-DD] [--until YYYY-MM-DD]
#
# Groups every visible supplier invoice line by (year-month, tva_tx) and sums
# HT and TVA. The TVA figure feeds the CA3 lignes 19 / 20 (déductible).
#
# Mapping to French CA3:
#   - tva_tx == 20  → ligne 20 (TVA déductible normale 20 %)
#   - tva_tx == 10  → ligne 19 (taux intermédiaire)
#   - tva_tx == 5.5 → ligne 19 (taux réduit)
#   - tva_tx == 2.1 → ligne 19 (taux particulier)
#   - tva_tx == 0   → likely autoliquidation intra-UE (achats à l'étranger)
#                     → goes on ligne 17 (auto-collected) AND ligne 24 (déductible)
#                     run deductible-line-detail.sh for the per-supplier breakdown

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
DOL_CURL="${SCRIPT_DIR}/../../dolibarr/scripts/dol-curl.sh"

SINCE=""; UNTIL=""; YEAR=""
while [[ $# -gt 0 ]]; do
  case "$1" in
    --since) SINCE="$2"; shift 2 ;;
    --until) UNTIL="$2"; shift 2 ;;
    --year)  YEAR="$2"; SINCE="$2-01-01"; UNTIL="$2-12-31"; shift 2 ;;
    -h|--help) sed -n '2,20p' "$0" | sed 's/^# \{0,1\}//'; exit 0 ;;
    *) echo "deductible-by-month.sh: unknown arg: $1" >&2; exit 2 ;;
  esac
done

WORK="$(mktemp -d -t deduc.XXXXXX)"
trap 'rm -rf "${WORK}"' EXIT

"${DOL_CURL}" '/supplierinvoices?limit=500' > "${WORK}/inv.json"
IDS=$(python3 -c "import json,sys; print(' '.join(str(r['id']) for r in json.load(open(sys.argv[1])) if r.get('id')))" "${WORK}/inv.json")

mkdir -p "${WORK}/detail"
for id in ${IDS}; do "${DOL_CURL}" "/supplierinvoices/${id}" > "${WORK}/detail/${id}.json"; done

python3 - "${WORK}" "${SINCE}" "${UNTIL}" "${YEAR}" <<'PY'
import json, sys, os, collections, datetime
work, since, until, year_arg = sys.argv[1:5]

def in_window(ts):
    if not ts: return False
    d = datetime.date.fromtimestamp(int(ts))
    if since and d < datetime.date.fromisoformat(since): return False
    if until and d > datetime.date.fromisoformat(until): return False
    return True

agg = collections.defaultdict(lambda: {"ht":0.0,"tva":0.0,"count":0})
for fn in sorted(os.listdir(os.path.join(work,"detail"))):
    try: inv = json.load(open(os.path.join(work,"detail",fn)))
    except json.JSONDecodeError: continue
    ts = int(inv.get("date") or 0)
    if not in_window(ts): continue
    ym = datetime.date.fromtimestamp(ts).strftime("%Y-%m")
    lines = inv.get("lines") or []
    if lines:
        for line in lines:
            tx = round(float(line.get("tva_tx") or 0), 4)
            ht  = float(line.get("total_ht")  or 0)
            tva = float(line.get("total_tva") or 0)
            agg[(ym, tx)]["ht"]    += ht
            agg[(ym, tx)]["tva"]   += tva
            agg[(ym, tx)]["count"] += 1
    else:
        # Fallback: aggregate at invoice level (no lines available)
        # Derive an effective tva_tx if possible: TVA / HT × 100
        ht  = float(inv.get("total_ht")  or 0)
        tva = float(inv.get("total_tva") or 0)
        tx  = round((tva / ht * 100), 4) if ht else 0.0
        agg[(ym, tx)]["ht"]    += ht
        agg[(ym, tx)]["tva"]   += tva
        agg[(ym, tx)]["count"] += 1

def ca3_line(tx):
    if tx == 20:    return "ligne 20"
    if tx == 10:    return "ligne 19 (10 %)"
    if tx == 5.5:   return "ligne 19 (5,5 %)"
    if tx == 2.1:   return "ligne 19 (2,1 %)"
    if tx == 0:     return "ligne 17 + 24 (autoliquidation) — verify with line-detail"
    return f"manual @ {tx}%"

scope = f"window={since or '-inf'} → {until or '+inf'}"
if year_arg: scope = f"year {year_arg}"

print(f"# TVA déductible by month × rate — {scope}")
print()
print(f"{'month':<8}  {'tva_tx':>7}  {'count':>5}  {'basis HT':>12}  {'TVA ded':>10}  CA3 line")
print("-" * 78)
total_ht = total_tva = 0.0
for key in sorted(agg):
    ym, tx = key
    s = agg[key]
    print(f"{ym:<8}  {tx:>7.4f}  {s['count']:>5}  {s['ht']:>12.2f}  {s['tva']:>10.2f}  {ca3_line(tx)}")
    total_ht  += s["ht"]
    total_tva += s["tva"]
print("-" * 78)
print(f"{'TOTAL':>16}  {' ':>13}  {total_ht:>12.2f}  {total_tva:>10.2f}")
print()
print("# Notes:")
print("#   - This is TVA déductible (supplier side). For TVA collectée (customer side),")
print("#     use dolibarr-tva-reconciliation/scripts/tva-by-month.sh.")
print("#   - tva_tx==0 lines may be either truly exempt (e.g. La Poste timbres)")
print("#     or autoliquidation intra-UE (e.g. Wise). Run deductible-line-detail.sh.")
PY