from __future__ import annotations

from app.repositories.pricing import list_price_rules
from app.repositories.scheme_groups import list_scheme_version_groups
from app.repositories.scheme_seats import list_scheme_version_seats
from app.repositories.scheme_sectors import list_scheme_version_sectors


async def build_pricing_rule_diagnostics(
    *,
    scheme_id: str,
    scheme_version_id: str,
) -> dict:
    rules = await list_price_rules(scheme_id)
    seats = await list_scheme_version_seats(scheme_version_id)
    sectors = await list_scheme_version_sectors(scheme_version_id)
    groups = await list_scheme_version_groups(scheme_version_id)

    sector_ids = {row.sector_id for row in sectors if row.sector_id}
    group_ids = {row.group_id for row in groups if row.group_id}
    seat_ids = {row.seat_id for row in seats if row.seat_id}

    items: list[dict] = []
    matched_seats_total = 0
    orphan_rules_count = 0

    for rule in rules:
        matched_seat_ids: list[str] = []
        orphan = False
        orphan_reason: str | None = None

        if rule.target_type == "seat":
            if rule.target_ref not in seat_ids:
                orphan = True
                orphan_reason = "target_seat_not_found"
            else:
                matched_seat_ids = [
                    seat.seat_id
                    for seat in seats
                    if seat.seat_id and seat.seat_id == rule.target_ref
                ]

        elif rule.target_type == "group":
            if rule.target_ref not in group_ids:
                orphan = True
                orphan_reason = "target_group_not_found"
            else:
                matched_seat_ids = [
                    seat.seat_id
                    for seat in seats
                    if seat.seat_id and seat.group_id == rule.target_ref
                ]

        elif rule.target_type == "sector":
            if rule.target_ref not in sector_ids:
                orphan = True
                orphan_reason = "target_sector_not_found"
            else:
                matched_seat_ids = [
                    seat.seat_id
                    for seat in seats
                    if seat.seat_id and seat.sector_id == rule.target_ref
                ]
        else:
            orphan = True
            orphan_reason = "unsupported_target_type"

        if orphan:
            orphan_rules_count += 1

        matched_seats_total += len(matched_seat_ids)

        items.append(
            {
                "price_rule_id": rule.price_rule_id,
                "pricing_category_id": rule.pricing_category_id,
                "target_type": rule.target_type,
                "target_ref": rule.target_ref,
                "amount": str(rule.amount),
                "currency": rule.currency,
                "matched_seats_count": len(matched_seat_ids),
                "matched_seat_ids": matched_seat_ids,
                "orphan": orphan,
                "orphan_reason": orphan_reason,
            }
        )

    return {
        "scheme_id": scheme_id,
        "scheme_version_id": scheme_version_id,
        "summary": {
            "total_rules": len(items),
            "orphan_rules_count": orphan_rules_count,
            "active_rules_count": len(items) - orphan_rules_count,
            "matched_seats_total": matched_seats_total,
        },
        "items": items,
    }