# =============================================================================
# QWHPI — Quebec Weekly Housing Price Index
# Author  : Simon-Pierre Boucher
# Contact : contact@spboucher.ai
# File    : api/app/routers/maps.py
# Purpose : Choropleth data endpoint — one metric across geographies.
# =============================================================================
"""Map data endpoints (region choropleth + assessment gap)."""

from __future__ import annotations

import polars as pl
from fastapi import APIRouter, HTTPException, Query, Request, Response

from app.deps import etag_for
from app.schemas import MapCell, MapResponse
from app.services import data

router = APIRouter()

METRICS = {
    "yoy": "yoy_pct",
    "six_month": "six_month_pct",
    "three_month": "three_month_pct",
    "index_level": "index_smoothed",
}


@router.get("/map", response_model=MapResponse)
def map_data(
    request: Request,
    response: Response,
    metric: str = Query("yoy", description=f"one of {sorted(METRICS)} or assessment_gap"),
    level: str = Query("region", pattern="^(region|municipality)$"),
    type: str = Query("all"),
    period: str | None = None,
):
    """One metric per geography for choropleth rendering."""
    c = data.canonical().filter(
        (pl.col("geography_level") == level) & (pl.col("property_type") == type))
    if period is None:
        period = c.filter(~pl.col("is_partial_month"))["period"].max()
    if metric == "assessment_gap":
        gap = data.assessment_gap().filter(
            (pl.col("property_type") == type) & (pl.col("period") == period)
            & pl.col("geography_id").str.starts_with("region-" if level == "region" else ""))
        c_wk = c.filter(pl.col("period") == period).select(
            "geography_id", "geography_name", "reliability_grade", "transactions")
        j = c_wk.join(gap, on="geography_id", how="left")
        cells = [MapCell(geography_id=r["geography_id"],
                         geography_name=r["geography_name"],
                         value=r["median_ratio"],
                         reliability_grade=r["reliability_grade"],
                         transactions=r["transactions"])
                 for r in j.iter_rows(named=True)]
    else:
        if metric not in METRICS:
            raise HTTPException(422, f"metric must be one of {sorted(METRICS)} or assessment_gap")
        col = METRICS[metric]
        wk = c.filter(pl.col("period") == period)
        if wk.height == 0:
            raise HTTPException(404, f"no data for period {period}")
        cells = [MapCell(geography_id=r["geography_id"],
                         geography_name=r["geography_name"],
                         value=r[col],
                         reliability_grade=r["reliability_grade"],
                         transactions=r["transactions"])
                 for r in wk.iter_rows(named=True)]
    if etag_for(request, response, metric, level, type, str(period)):
        return Response(status_code=304)
    return MapResponse(metric=metric, level=level, property_type=type,
                       period=str(period), cells=cells)