/**
 * Author: Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 * Project: Groupe Ka / Ka Maps
 *
 * Ka Lens — statistiques d'une sélection géographique. Calcule sur les
 * MapProperty réellement chargées (viewport ou polygone) ; seules les
 * métriques dont les données existent sont renseignées — jamais de
 * valeurs inventées. Les agrégats temporels (7 j/30 j/1 an) relèvent des
 * API d'agrégation des apps (GeographicMarketSummary) quand elles
 * existeront.
 */

import type { BBox, KaLensStats, MapProperty } from "../types/index.js";
import { bboxContainsPoint } from "./geo.js";
import { median } from "./format.js";

/** Statistiques Ka Lens sur un ensemble de propriétés. */
export function computeLensStats(properties: MapProperty[]): KaLensStats {
  const count = properties.length;
  const prices = properties
    .map((p) => p.price)
    .filter((v): v is number => Number.isFinite(v as number));
  const estimates = properties
    .map((p) => p.estimatedValue)
    .filter((v): v is number => Number.isFinite(v as number));
  const dom = properties
    .map((p) => p.daysOnMarket)
    .filter((v): v is number => Number.isFinite(v as number));
  const cuts = properties.filter(
    (p) => typeof p.priceChange === "number" && p.priceChange < 0,
  ).length;
  const stale = properties.filter(
    (p) => typeof p.daysOnMarket === "number" && p.daysOnMarket > 90,
  ).length;

  const typeCounts = new Map<string, number>();
  for (const p of properties) {
    if (!p.propertyType) continue;
    typeCounts.set(p.propertyType, (typeCounts.get(p.propertyType) ?? 0) + 1);
  }
  const typed = [...typeCounts.values()].reduce((a, b) => a + b, 0);

  const stats: KaLensStats = { count };
  const medPrice = median(prices);
  if (medPrice !== undefined) stats.medianPrice = medPrice;
  const medEst = median(estimates);
  if (medEst !== undefined) stats.medianEstimatedValue = medEst;
  const medDom = median(dom);
  if (medDom !== undefined) stats.medianDaysOnMarket = medDom;
  if (dom.length > 0) stats.stale90dShare = stale / dom.length;
  if (properties.some((p) => typeof p.priceChange === "number")) {
    stats.priceCutShare = count > 0 ? cuts / count : 0;
  }
  if (typed > 0) {
    stats.typeMix = Object.fromEntries(
      [...typeCounts.entries()]
        .sort((a, b) => b[1] - a[1])
        .map(([k, v]) => [k, v / typed]),
    );
  }
  return stats;
}

/** Sous-ensemble des propriétés dans un rectangle (sélection visible). */
export function propertiesInBBox(
  properties: MapProperty[],
  bbox: BBox,
): MapProperty[] {
  return properties.filter((p) =>
    bboxContainsPoint(bbox, p.latitude, p.longitude),
  );
}

/** Sous-ensemble dans un polygone GeoJSON (Ka Lens dessiné) — ray casting. */
export function propertiesInPolygon(
  properties: MapProperty[],
  polygon: GeoJSON.Polygon,
): MapProperty[] {
  const ring = polygon.coordinates[0];
  if (!ring || ring.length < 4) return [];
  return properties.filter((p) => pointInRing(ring, p.longitude, p.latitude));
}

function pointInRing(ring: GeoJSON.Position[], x: number, y: number): boolean {
  let inside = false;
  for (let i = 0, j = ring.length - 1; i < ring.length; j = i++) {
    const xi = ring[i]![0]!;
    const yi = ring[i]![1]!;
    const xj = ring[j]![0]!;
    const yj = ring[j]![1]!;
    if (yi > y !== yj > y && x < ((xj - xi) * (y - yi)) / (yj - yi) + xi) {
      inside = !inside;
    }
  }
  return inside;
}