"""
Archidekt collection importer.

Supports two export formats:
  - CSV  (Collection -> Export -> CSV)
  - JSON (Collection -> Export -> JSON)

CSV columns (current Archidekt format, as of 2024):
  Quantity, Foil Quantity, Card Name, Set Code, Collector Number, ...

JSON format (array of card objects):
  [{"quantity": 1, "foilQuantity": 0, "card": {"name": "...", "set": {"code": "..."}, "collectorNumber": "..."}}]
"""
import csv
import io
import json
from typing import Union

import chardet

from app.services.imports.models import RawCardRow

SOURCE = "archidekt"

# CSV column name aliases — Archidekt has changed these over time
_NAME_COLS    = {"card name", "name", "cardname"}
_QTY_COLS     = {"quantity", "qty", "count", "amount"}
_FOIL_COLS    = {"foil quantity", "foil qty", "foilqty", "foilcount", "foils"}
_SET_COLS     = {"set code", "set", "setcode", "edition"}
_COLLECTOR_COLS = {"collector number", "collector #", "collectornumber", "number"}


def parse(raw_bytes: bytes) -> list[RawCardRow]:
    """
    Auto-detect CSV vs JSON and dispatch to the appropriate parser.
    Raises ValueError with a human-readable message on unrecognised format.
    """
    # Detect encoding
    detected = chardet.detect(raw_bytes)
    encoding = detected.get("encoding") or "utf-8"
    text = raw_bytes.decode(encoding, errors="replace").strip()

    if text.startswith("[") or text.startswith("{"):
        return _parse_json(text)
    else:
        return _parse_csv(text)


def _parse_csv(text: str) -> list[RawCardRow]:
    reader = csv.DictReader(io.StringIO(text))
    if not reader.fieldnames:
        raise ValueError("Archidekt CSV appears to be empty or has no header row")

    # Normalise header names
    headers = {h.strip().lower(): h for h in reader.fieldnames if h}

    name_col     = _find_col(headers, _NAME_COLS,      "Card Name")
    qty_col      = _find_col(headers, _QTY_COLS,       "Quantity")
    foil_col     = _find_col(headers, _FOIL_COLS,      None, required=False)
    set_col      = _find_col(headers, _SET_COLS,       None, required=False)
    collect_col  = _find_col(headers, _COLLECTOR_COLS, None, required=False)

    rows: list[RawCardRow] = []
    for i, row in enumerate(reader, start=2):  # start=2 because row 1 is header
        name = row.get(name_col, "").strip()
        if not name:
            continue

        try:
            qty = int(float(row.get(qty_col, "1") or "1"))
        except (ValueError, TypeError):
            qty = 1

        try:
            foil_qty = int(float(row.get(foil_col, "0") or "0")) if foil_col else 0
        except (ValueError, TypeError):
            foil_qty = 0

        rows.append(RawCardRow(
            card_name=name,
            set_code=(row.get(set_col, "") or "").strip().lower() if set_col else "",
            collector_number=(row.get(collect_col, "") or "").strip() if collect_col else "",
            quantity=qty,
            foil_quantity=foil_qty,
            import_source=SOURCE,
            raw=dict(row),
        ))

    if not rows:
        raise ValueError("Archidekt CSV contained no card rows")

    return rows


def _parse_json(text: str) -> list[RawCardRow]:
    try:
        data = json.loads(text)
    except json.JSONDecodeError as e:
        raise ValueError(f"Archidekt JSON is malformed: {e}")

    # Handle both bare array and {"cards": [...]} wrapper
    if isinstance(data, dict):
        data = data.get("cards") or data.get("collection") or []
    if not isinstance(data, list):
        raise ValueError("Archidekt JSON must be an array of card objects")

    rows: list[RawCardRow] = []
    for item in data:
        card = item.get("card") or item  # nested or flat
        name = (
            card.get("name")
            or card.get("cardName")
            or card.get("card_name")
            or ""
        ).strip()
        if not name:
            continue

        qty = int(item.get("quantity") or item.get("qty") or 1)
        foil_qty = int(item.get("foilQuantity") or item.get("foil_quantity") or 0)

        set_obj = card.get("set") or {}
        set_code = (
            set_obj.get("code") if isinstance(set_obj, dict) else str(set_obj)
        ).lower().strip()

        collector = str(card.get("collectorNumber") or card.get("collector_number") or "").strip()

        rows.append(RawCardRow(
            card_name=name,
            set_code=set_code,
            collector_number=collector,
            quantity=qty,
            foil_quantity=foil_qty,
            import_source=SOURCE,
            raw=item,
        ))

    if not rows:
        raise ValueError("Archidekt JSON contained no card entries")

    return rows


def _find_col(
    headers: dict[str, str],
    aliases: set[str],
    fallback: str | None,
    required: bool = True,
) -> str | None:
    for alias in aliases:
        if alias in headers:
            return headers[alias]
    if fallback and fallback.lower() in headers:
        return headers[fallback.lower()]
    if required:
        raise ValueError(
            f"Could not find required column. Expected one of: {sorted(aliases)}"
        )
    return None