import json
from pathlib import Path

import click

import build_canonical_layer
import build_observed_products
from layer_helpers import stable_id, write_csv_rows


PROOF_FIELDS = [
    "proof_name",
    "canonical_product_id",
    "giant_observed_product_id",
    "costco_observed_product_id",
    "giant_example_item",
    "costco_example_item",
    "notes",
]


def read_rows(path):
    import csv

    with Path(path).open(newline="", encoding="utf-8") as handle:
        return list(csv.DictReader(handle))


def find_proof_pair(observed_rows):
    giant = None
    costco = None
    for row in observed_rows:
        if row["retailer"] == "giant" and row["representative_name_norm"] == "BANANA":
            giant = row
        if row["retailer"] == "costco" and row["representative_name_norm"] == "BANANA":
            costco = row
    return giant, costco


def merge_proof_pair(canonical_rows, link_rows, giant_row, costco_row):
    if not giant_row or not costco_row:
        return canonical_rows, link_rows, []

    proof_canonical_id = stable_id("gcan", "proof|banana")
    link_rows = [
        row
        for row in link_rows
        if row["observed_product_id"]
        not in {giant_row["observed_product_id"], costco_row["observed_product_id"]}
    ]
    canonical_rows = [
        row
        for row in canonical_rows
        if row["canonical_product_id"] != proof_canonical_id
    ]
    canonical_rows.append(
        {
            "canonical_product_id": proof_canonical_id,
            "canonical_name": "BANANA",
            "product_type": "banana",
            "brand": "",
            "variant": "",
            "size_value": "",
            "size_unit": "",
            "pack_qty": "",
            "measure_type": "weight",
            "normalized_quantity": "",
            "normalized_quantity_unit": "",
            "notes": "manual proof merge for cross-retailer validation",
            "created_at": "",
            "updated_at": "",
        }
    )
    for observed_row in [giant_row, costco_row]:
        link_rows.append(
            {
                "observed_product_id": observed_row["observed_product_id"],
                "canonical_product_id": proof_canonical_id,
                "link_method": "manual_proof_merge",
                "link_confidence": "medium",
                "review_status": "",
                "reviewed_by": "",
                "reviewed_at": "",
                "link_notes": "cross-retailer validation proof",
            }
        )

    proof_rows = [
        {
            "proof_name": "banana",
            "canonical_product_id": proof_canonical_id,
            "giant_observed_product_id": giant_row["observed_product_id"],
            "costco_observed_product_id": costco_row["observed_product_id"],
            "giant_example_item": giant_row["example_item_name"],
            "costco_example_item": costco_row["example_item_name"],
            "notes": "BANANA proof pair built from Giant and Costco enriched rows",
        }
    ]
    return canonical_rows, link_rows, proof_rows


@click.command()
@click.option(
    "--giant-items-enriched-csv",
    default="giant_output/items_enriched.csv",
    show_default=True,
)
@click.option(
    "--costco-items-enriched-csv",
    default="costco_output/items_enriched.csv",
    show_default=True,
)
@click.option(
    "--outdir",
    default="combined_output",
    show_default=True,
)
def main(giant_items_enriched_csv, costco_items_enriched_csv, outdir):
    outdir = Path(outdir)
    rows = read_rows(giant_items_enriched_csv) + read_rows(costco_items_enriched_csv)
    observed_rows = build_observed_products.build_observed_products(rows)
    canonical_rows, link_rows = build_canonical_layer.build_canonical_layer(observed_rows)
    giant_row, costco_row = find_proof_pair(observed_rows)
    if not giant_row or not costco_row:
        raise click.ClickException(
            "could not find BANANA proof pair across Giant and Costco observed products"
        )
    canonical_rows, link_rows, proof_rows = merge_proof_pair(
        canonical_rows, link_rows, giant_row, costco_row
    )

    write_csv_rows(
        outdir / "products_observed.csv",
        observed_rows,
        build_observed_products.OUTPUT_FIELDS,
    )
    write_csv_rows(
        outdir / "products_canonical.csv",
        canonical_rows,
        build_canonical_layer.CANONICAL_FIELDS,
    )
    write_csv_rows(
        outdir / "product_links.csv",
        link_rows,
        build_canonical_layer.LINK_FIELDS,
    )
    write_csv_rows(outdir / "proof_examples.csv", proof_rows, PROOF_FIELDS)
    click.echo(
        f"wrote combined outputs to {outdir} using {len(observed_rows)} observed rows"
    )


if __name__ == "__main__":
    main()