"""Invoice sync: pushes approved invoices from the finance export CSV into the billing API.

python sync.py data/input/invoices.csv   (runs every hour from Task Scheduler)
"""
import csv
import logging
import os
import sys
import time
from datetime import datetime
from pathlib import Path

import requests
from dotenv import load_dotenv

ROOT = Path(__file__).parent
load_dotenv(ROOT / ".env")
API = os.environ.get("BILLING_API_URL", "https://billing.example.test/api/v2")
HEADERS = {"Authorization": f"Bearer {os.environ.get('BILLING_API_KEY', '')}"}
RETRIES = 5
TIMEOUT_S = 30
REQUIRED = ["invoice_no", "customer_id", "amount", "currency"]

logging.basicConfig(filename=ROOT / "logs" / "sync.log", level=logging.INFO,
                    format="%(asctime)s %(levelname)s %(message)s")
log = logging.getLogger("sync")


def validate(row):
    missing = [f for f in REQUIRED if not row.get(f)]
    if missing:
        return f"missing {', '.join(missing)}"
    try:
        if float(row["amount"]) <= 0:
            return "amount must be positive"
    except ValueError:
        return f"amount '{row['amount']}' is not a number"
    return ""


def exists(invoice_no):
    r = requests.get(f"{API}/invoices/{invoice_no}", headers=HEADERS, timeout=TIMEOUT_S)
    return r.status_code == 200


def push(row):
    """Returns (status, message). Retries 429 and 5xx with backoff; checks for a duplicate before each retry."""
    for attempt in range(1, RETRIES + 1):
        try:
            r = requests.post(f"{API}/invoices", json=row, headers=HEADERS, timeout=TIMEOUT_S)
        except requests.RequestException as e:
            print(f"network error on {row['invoice_no']}: {e}")
            r = None
        if r is not None and r.status_code in (200, 201, 207):
            return "Synced", "Created" if r.status_code != 207 else "Created (some lines rejected)"
        if r is not None and r.status_code == 409:
            return "Duplicate", "Invoice already exists in billing"
        if r is not None and r.status_code == 422:
            return "Invalid", r.json().get("detail", "Rejected by billing")
        if exists(row["invoice_no"]):
            return "Synced", "Created (confirmed after retry)"
        time.sleep(2 ** attempt)
    return "Failed", f"No success after {RETRIES} tries"


def main(path):
    (ROOT / "BOT_WAS_RUN").write_text("1")
    report = ROOT / "data" / "output" / f"sync_report_{datetime.now():%Y%m%d_%H%M}.csv"
    with open(path, newline="", encoding="utf-8") as f, open(report, "w", newline="", encoding="utf-8") as out:
        w = csv.writer(out)
        w.writerow(["invoice_no", "customer", "Status", "Message"])
        for row in csv.DictReader(f):
            problem = validate(row)
            status, msg = ("Invalid", problem) if problem else push(row)
            log.info("%s %s", row.get("invoice_no"), status)
            w.writerow([row.get("invoice_no"), row.get("customer_name"), status, msg])
    log.info("run done -> %s", report.name)


if __name__ == "__main__":
    try:
        main(sys.argv[1])
    except Exception as e:
        print(f"CRASH: {e!r}")
        raise