from collections import defaultdict
from datetime import date

import click

from layer_helpers import compact_join, distinct_values, read_csv_rows, stable_id, write_csv_rows


OUTPUT_FIELDS = [
    "review_id",
    "queue_type",
    "retailer",
    "observed_product_id",
    "canonical_product_id",
    "reason_code",
    "priority",
    "raw_item_names",
    "normalized_names",
    "upc",
    "image_url",
    "example_prices",
    "seen_count",
    "status",
    "resolution_notes",
    "created_at",
    "updated_at",
]


def existing_review_state(path):
    try:
        rows = read_csv_rows(path)
    except FileNotFoundError:
        return {}
    return {row["review_id"]: row for row in rows}


def review_reasons(observed_row):
    reasons = []
    if (
        observed_row["is_fee"] == "true"
        or observed_row.get("is_discount_line") == "true"
        or observed_row.get("is_coupon_line") == "true"
    ):
        return reasons
    if observed_row["distinct_upcs_count"] not in {"", "0", "1"}:
        reasons.append(("multiple_upcs", "high"))
    if observed_row["distinct_item_names_count"] not in {"", "0", "1"}:
        reasons.append(("multiple_raw_names", "medium"))
    if not observed_row["representative_image_url"]:
        reasons.append(("missing_image", "medium"))
    if not observed_row["representative_upc"]:
        reasons.append(("missing_upc", "high"))
    if not observed_row["representative_name_norm"]:
        reasons.append(("missing_normalized_name", "high"))
    return reasons


def build_review_queue(observed_rows, item_rows, existing_rows, today_text):
    by_observed = defaultdict(list)
    for row in item_rows:
        observed_id = row.get("observed_product_id", "")
        if observed_id:
            by_observed[observed_id].append(row)

    queue_rows = []
    for observed_row in observed_rows:
        reasons = review_reasons(observed_row)
        if not reasons:
            continue

        related_items = by_observed.get(observed_row["observed_product_id"], [])
        raw_names = compact_join(distinct_values(related_items, "item_name"), limit=5)
        norm_names = compact_join(
            distinct_values(related_items, "item_name_norm"), limit=5
        )
        example_prices = compact_join(
            distinct_values(related_items, "line_total"), limit=5
        )

        for reason_code, priority in reasons:
            review_id = stable_id(
                "rvw",
                f"{observed_row['observed_product_id']}|{reason_code}",
            )
            prior = existing_rows.get(review_id, {})
            queue_rows.append(
                {
                    "review_id": review_id,
                    "queue_type": "observed_product",
                    "retailer": observed_row["retailer"],
                    "observed_product_id": observed_row["observed_product_id"],
                    "canonical_product_id": prior.get("canonical_product_id", ""),
                    "reason_code": reason_code,
                    "priority": priority,
                    "raw_item_names": raw_names,
                    "normalized_names": norm_names,
                    "upc": observed_row["representative_upc"],
                    "image_url": observed_row["representative_image_url"],
                    "example_prices": example_prices,
                    "seen_count": observed_row["times_seen"],
                    "status": prior.get("status", "pending"),
                    "resolution_notes": prior.get("resolution_notes", ""),
                    "created_at": prior.get("created_at", today_text),
                    "updated_at": today_text,
                }
            )

    queue_rows.sort(key=lambda row: (row["priority"], row["reason_code"], row["review_id"]))
    return queue_rows


def attach_observed_ids(item_rows, observed_rows):
    observed_by_key = {row["observed_key"]: row["observed_product_id"] for row in observed_rows}
    attached = []
    for row in item_rows:
        observed_key = "|".join(
            [
                row["retailer"],
                f"upc={row['upc']}",
                f"name={row['item_name_norm']}",
            ]
        ) if row.get("upc") else "|".join(
            [
                row["retailer"],
                f"retailer_item_id={row.get('retailer_item_id', '')}",
                f"name={row['item_name_norm']}",
                f"size={row['size_value']}",
                f"unit={row['size_unit']}",
                f"pack={row['pack_qty']}",
                f"measure={row['measure_type']}",
                f"store_brand={row['is_store_brand']}",
                f"fee={row['is_fee']}",
                f"discount={row.get('is_discount_line', 'false')}",
                f"coupon={row.get('is_coupon_line', 'false')}",
            ]
        )
        enriched = dict(row)
        enriched["observed_product_id"] = observed_by_key.get(observed_key, "")
        attached.append(enriched)
    return attached


@click.command()
@click.option(
    "--observed-csv",
    default="giant_output/products_observed.csv",
    show_default=True,
    help="Path to observed product rows.",
)
@click.option(
    "--items-enriched-csv",
    default="giant_output/items_enriched.csv",
    show_default=True,
    help="Path to enriched Giant item rows.",
)
@click.option(
    "--output-csv",
    default="giant_output/review_queue.csv",
    show_default=True,
    help="Path to review queue output.",
)
def main(observed_csv, items_enriched_csv, output_csv):
    observed_rows = read_csv_rows(observed_csv)
    item_rows = read_csv_rows(items_enriched_csv)
    item_rows = attach_observed_ids(item_rows, observed_rows)
    existing_rows = existing_review_state(output_csv)
    today_text = str(date.today())
    queue_rows = build_review_queue(observed_rows, item_rows, existing_rows, today_text)
    write_csv_rows(output_csv, queue_rows, OUTPUT_FIELDS)
    click.echo(f"wrote {len(queue_rows)} rows to {output_csv}")


if __name__ == "__main__":
    main()