// Build the choropleth payload from a GameState: every region key (see
// public/region-keys.json) maps to its owning nation plus that nation's stable
// color (see shared.nationColor). The client merges this onto the sub-national
// regions.geo.json (resolving each feature by its own region key) and calls
// source.setData(). Format-agnostic: it maps whatever keys sit in territory.
//
// A key ABSENT from the returned map is unowned (no nation's territory holds
// it) — this covers both regions a preset never assigned and regions released
// to no man's land mid-game (v0.22, #16 P3). The map deliberately does NOT
// distinguish the two: the visible no-man's-land grey vs the faint
// preset-unassigned look is decided by the client from `GameState.unowned`
// (see shared/protocol.ts's regionFillStyle).
import { nationColor, type RegionMap } from '../shared/protocol';
import type { GameState } from '../shared/types';

export function buildRegionMap(state: GameState): RegionMap {
  const map: RegionMap = {};
  for (const [id, nation] of Object.entries(state.nations)) {
    const color = nationColor(id);
    for (const key of nation.territory) {
      map[key] = { color, owner: nation.name, ownerId: id };
    }
  }
  return map;
}