import os
import threading
import time
import requests
from fastapi import FastAPI, HTTPException, Security, Depends
from fastapi.security.api_key import APIKeyHeader
from openpyxl import load_workbook
from io import BytesIO
from dotenv import load_dotenv

load_dotenv()
API_KEY = os.getenv("API_KEY", "change-me")
EXCEL_URL = os.getenv(
    "EXCEL_URL",
    "https://files.constantcontact.com/d8c838c7001/d68c2f97-5cd3-40c9-b0df-04296ccdcc7b.xlsx",
)
REFRESH_HOURS = int(os.getenv("REFRESH_HOURS", "6"))

app = FastAPI(title="MTZ Stock API", version="1.0.0")


def safe_int(value, default):
    if value is None:
        return default
    if isinstance(value, (int, float)):
        return int(value)
    try:
        return int(str(value).strip())
    except (ValueError, TypeError):
        return default


def safe_float(value, default):
    if value is None:
        return default
    if isinstance(value, (int, float)):
        return float(value)
    try:
        return float(str(value).strip())
    except (ValueError, TypeError):
        return default


products_cache = []
last_refresh = None
rows_processed = 0
rows_skipped = 0
cache_lock = threading.Lock()
api_key_header = APIKeyHeader(name="X-API-Key")


def verify_key(key: str = Security(api_key_header)):
    if key != API_KEY:
        raise HTTPException(status_code=403, detail="Invalid API Key")
    return key


def download_and_parse():
    global products_cache, last_refresh, rows_processed, rows_skipped
    resp = requests.get(EXCEL_URL, timeout=60)
    resp.raise_for_status()
    # read_only=True would stop at the sheet's declared <dimension ref> attribute,
    # silently missing any rows added beyond the original range.
    wb = load_workbook(BytesIO(resp.content), data_only=True)
    ws = wb.active
    rows = list(ws.iter_rows(min_row=6, values_only=True))
    parsed = []
    skipped = 0
    for row in rows:
        if row[1] is None:  # col B (index 1) = item_code — empty row
            skipped += 1
            continue
        ean_raw = row[3]  # col D
        if ean_raw is None:
            ean = ""
        elif isinstance(ean_raw, (int, float)):
            ean = str(int(ean_raw))
        else:
            ean = str(ean_raw).strip()

        # Skip products with blank or non-numeric EAN codes
        if not ean or not ean.isdigit():
            skipped += 1
            continue

        brand_raw = row[9]  # col J
        brand = str(brand_raw) if brand_raw is not None else ""
        min_box_raw = row[10]  # col K
        parsed.append(
            {
                "item_code": safe_int(row[1], 0),
                "ean": ean,
                "description": str(row[2] or ""),
                "price_usd": safe_float(row[4], 0.0),
                "stock": safe_int(row[5], 0),
                "brand": brand,
                "min_box_qty": safe_int(min_box_raw, 1),
            }
        )
    with cache_lock:
        products_cache = parsed
        rows_processed = len(rows)
        rows_skipped = skipped
        last_refresh = time.time()
    wb.close()


def background_refresh():
    while True:
        time.sleep(REFRESH_HOURS * 3600)
        try:
            download_and_parse()
        except Exception as e:
            print(f"Background refresh failed: {e}")


@app.on_event("startup")
def startup():
    download_and_parse()
    t = threading.Thread(target=background_refresh, daemon=True)
    t.start()


@app.get("/api/health")
def health():
    with cache_lock:
        return {
            "status": "ok",
            "product_count": len(products_cache),
            "rows_processed": rows_processed,
            "rows_skipped": rows_skipped,
            "last_refresh": last_refresh,
        }


@app.get("/api/products", dependencies=[Depends(verify_key)])
def get_products():
    with cache_lock:
        return products_cache


@app.post("/api/refresh", dependencies=[Depends(verify_key)])
def refresh():
    download_and_parse()
    with cache_lock:
        return {
            "status": "ok",
            "product_count": len(products_cache),
            "rows_processed": rows_processed,
            "rows_skipped": rows_skipped,
        }