/**
 * Loads character dossiers at boot time.
 *
 * Dossiers live as JSON files at ./dossiers/{id}.json — one per character.
 * They are generated by apps/api/scripts/generate-who-dossiers.ts (a strong
 * cloud LLM does the research) and then consumed at runtime by the small
 * model (gemma3:4b) in carefully staged chunks to keep gameplay coherent.
 *
 * This loader:
 *  1. Reads every {id}.json under ./dossiers/
 *  2. Validates each against CharacterDossierSchema (Zod)
 *  3. Sanity-checks that the dossier id matches the filename
 *  4. Builds a Map<id, dossier> for O(1) runtime lookup
 *
 * Missing dossiers are NOT a hard error — the prompt builder falls back to
 * the legacy `personality` string on the WhoCharacter so the module keeps
 * working during the rollout. We only warn at boot.
 */

/* eslint-disable no-console */
import { readdirSync, readFileSync, existsSync } from 'node:fs';
import { join, dirname } from 'node:path';
import { fileURLToPath } from 'node:url';
import { CharacterDossierSchema, type CharacterDossier } from './dossier-types';
import { CHARACTERS } from './characters';

const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);
const DOSSIER_DIR = join(__dirname, 'dossiers');

let dossierCache: Map<number, CharacterDossier> | null = null;

function loadDossiers(): Map<number, CharacterDossier> {
	const map = new Map<number, CharacterDossier>();

	if (!existsSync(DOSSIER_DIR)) {
		console.warn(
			`[who] dossier directory missing at ${DOSSIER_DIR} — falling back to legacy personality strings for all characters. Run: bun run apps/api/scripts/generate-who-dossiers.ts`
		);
		return map;
	}

	const files = readdirSync(DOSSIER_DIR).filter(
		(f) => f.endsWith('.json') && !f.endsWith('.raw.json')
	);

	for (const file of files) {
		const path = join(DOSSIER_DIR, file);
		try {
			const raw = readFileSync(path, 'utf8');
			const parsed = JSON.parse(raw);
			const dossier = CharacterDossierSchema.parse(parsed);

			// Filename must match the dossier id (catches accidental copies)
			const expectedId = Number(file.replace('.json', ''));
			if (dossier.id !== expectedId) {
				console.warn(
					`[who] dossier ${file}: id mismatch (file=${expectedId}, content=${dossier.id}) — skipping`
				);
				continue;
			}

			map.set(dossier.id, dossier);
		} catch (err) {
			console.warn(
				`[who] failed to load dossier ${file}: ${err instanceof Error ? err.message : String(err)}`
			);
		}
	}

	// Report coverage so devs notice gaps quickly during rollout
	const missing = CHARACTERS.filter((c) => !map.has(c.id));
	if (missing.length > 0) {
		console.warn(
			`[who] ${map.size}/${CHARACTERS.length} dossiers loaded; missing ids: ${missing
				.map((c) => `${c.id}(${c.name})`)
				.join(', ')}`
		);
	} else {
		console.log(`[who] loaded ${map.size}/${CHARACTERS.length} character dossiers`);
	}

	return map;
}

/** Returns the dossier for a character id, or undefined if not generated yet. */
export function getDossier(id: number): CharacterDossier | undefined {
	if (!dossierCache) {
		dossierCache = loadDossiers();
	}
	return dossierCache.get(id);
}

/** Test/dev helper: force a reload from disk. */
export function reloadDossiers(): void {
	dossierCache = null;
}