"""Rapport des écarts entre catalogue et inventaire agrégé."""

import csv
from pathlib import Path
from typing import Dict, Iterable, List

from lib.filesystem import ensure_parent_dir

def load_sets(sets_path: Path) -> List[dict]:
    """Charge les sets filtrés pour l'analyse."""
    with sets_path.open() as sets_file:
        reader = csv.DictReader(sets_file)
        return list(reader)


def index_sets_by_num(sets: Iterable[dict]) -> Dict[str, dict]:
    """Crée un index des sets par numéro complet."""
    return {row["set_num"]: row for row in sets}


def compute_inventory_totals(parts_path: Path, include_spares: bool) -> Dict[str, int]:
    """Calcule le total de pièces par set, avec ou sans rechanges."""
    totals: Dict[str, int] = {}
    with parts_path.open() as parts_file:
        reader = csv.DictReader(parts_file)
        for row in reader:
            if not include_spares and row["is_spare"] == "true":
                continue
            set_num = row["set_num"]
            totals[set_num] = totals.get(set_num, 0) + int(row["quantity_in_set"])
    return totals


def compute_inventory_gaps(sets_path: Path, parts_path: Path) -> List[dict]:
    """Liste les sets dont le total de pièces diffère du catalogue."""
    sets = load_sets(sets_path)
    totals_with_spares = compute_inventory_totals(parts_path, include_spares=True)
    totals_without_spares = compute_inventory_totals(parts_path, include_spares=False)
    gaps: List[dict] = []
    for set_row in sets:
        expected_parts = int(set_row["num_parts"])
        inventory_parts_with_spares = totals_with_spares[set_row["set_num"]]
        inventory_parts_non_spare = totals_without_spares[set_row["set_num"]]
        if expected_parts != inventory_parts_with_spares:
            gaps.append(
                {
                    "set_num": set_row["set_num"],
                    "set_id": set_row["set_id"],
                    "expected_parts": expected_parts,
                    "inventory_parts": inventory_parts_with_spares,
                    "inventory_parts_non_spare": inventory_parts_non_spare,
                    "delta": abs(expected_parts - inventory_parts_with_spares),
                    "delta_non_spare": abs(expected_parts - inventory_parts_non_spare),
                    "in_collection": set_row["in_collection"],
                }
            )
    return gaps


def write_inventory_gaps_csv(destination_path: Path, gaps: Iterable[dict]) -> None:
    """Écrit un CSV listant les sets en écart d'inventaire."""
    ensure_parent_dir(destination_path)
    with destination_path.open("w", newline="") as csv_file:
        fieldnames = [
            "set_num",
            "set_id",
            "expected_parts",
            "inventory_parts",
            "inventory_parts_non_spare",
            "delta",
            "delta_non_spare",
            "in_collection",
        ]
        writer = csv.DictWriter(csv_file, fieldnames=fieldnames)
        writer.writeheader()
        for row in gaps:
            writer.writerow(row)


def build_instructions_url(set_id: str) -> str:
    """Construit un lien direct vers la page d'instructions LEGO du set."""
    return f"https://www.lego.com/service/buildinginstructions/{set_id}"


def write_inventory_gaps_markdown(
    destination_path: Path,
    gaps: Iterable[dict],
    sets_by_num: Dict[str, dict],
) -> None:
    """Génère un tableau Markdown listant les sets en écart d'inventaire."""
    ensure_parent_dir(destination_path)
    with destination_path.open("w") as markdown_file:
        markdown_file.write(
            "| set_id | name | year | delta (spares inclus) | delta (spares exclus) | expected_parts | inventory_parts | inventory_parts_non_spare | in_collection | instructions |\n"
        )
        markdown_file.write("| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |\n")
        for row in gaps:
            if row["delta_non_spare"] == 0:
                continue
            set_row = sets_by_num[row["set_num"]]
            set_link = f"[{row['set_id']}]({set_row['rebrickable_url']})"
            instructions_link = f"[PDF]({build_instructions_url(row['set_id'])})"
            markdown_file.write(
                f"| {set_link} | {set_row['name']} | {set_row['year']} | {row['delta']} | {row['delta_non_spare']} | "
                f"{row['expected_parts']} | {row['inventory_parts']} | {row['inventory_parts_non_spare']} | "
                f"{row['in_collection']} | {instructions_link} |\n"
            )