import { DatabaseConnection } from '../db/index';
import { QueryBuilder } from '../utils/QueryBuilder';
import type { ScoreResult, SignalSnapshotRow } from '../types';

/**
 * Signal snapshot ledger (PRODUCT.md P0.1).
 *
 * Persists one row per ticker per day on every /api/screen call so the
 * product builds a verifiable signal track record. This data cannot be
 * backfilled — the backtest dashboard (Phase 10.5e), thesis review (10.6d),
 * and calibration features all depend on it accumulating from day one.
 *
 * Recording is best-effort: failures are logged by the caller and must never
 * fail the screen request itself.
 */

export interface SnapshotInput {
  ticker: string;
  assetType: string;
  price: number | null;
  signal: string;
  fundamental: ScoreResult;
  inflated: ScoreResult;
  rateRegime?: string | null;
}

export class SignalSnapshotRepository {
  constructor(private readonly db: DatabaseConnection) {}

  /**
   * Upsert today's snapshot for a batch of screened assets.
   * Repeated screens on the same day keep the latest result.
   */
  recordBatch(inputs: SnapshotInput[], date = SignalSnapshotRepository.today()): number {
    let written = 0;
    for (const input of inputs) {
      this.record(input, date);
      written++;
    }
    return written;
  }

  record(input: SnapshotInput, date = SignalSnapshotRepository.today()): void {
    const { ticker, assetType, price, signal, fundamental, inflated, rateRegime } = input;
    const coverage = fundamental.audit?.coverage ?? inflated.audit?.coverage ?? null;
    const riskFlags = fundamental.audit?.riskFlags ?? inflated.audit?.riskFlags ?? null;

    const qb = new QueryBuilder('SIGNAL_SNAPSHOT_QUERIES.UPSERT', [
      ticker.toUpperCase(),
      date,
      assetType,
      price,
      signal,
      fundamental.tier,
      fundamental.score,
      fundamental.label,
      inflated.tier,
      inflated.score,
      inflated.label,
      coverage?.active ?? null,
      coverage?.total ?? null,
      riskFlags ? JSON.stringify(riskFlags) : null,
      rateRegime ?? null,
      new Date().toISOString(),
    ]);
    this.db.run(qb);
  }

  /** Full history for one ticker, oldest first. */
  history(ticker: string): SignalSnapshotRow[] {
    const qb = new QueryBuilder('SIGNAL_SNAPSHOT_QUERIES.SELECT_BY_TICKER', [ticker.toUpperCase()]);
    return this.db.all<SignalSnapshotRow>(qb);
  }

  /** All snapshots for a given day (YYYY-MM-DD). */
  byDate(date: string): SignalSnapshotRow[] {
    const qb = new QueryBuilder('SIGNAL_SNAPSHOT_QUERIES.SELECT_BY_DATE', [date]);
    return this.db.all<SignalSnapshotRow>(qb);
  }

  /** Latest snapshot per ticker strictly before a date — for daily diffing. */
  latestBefore(date: string): SignalSnapshotRow[] {
    const qb = new QueryBuilder('SIGNAL_SNAPSHOT_QUERIES.SELECT_LATEST_BEFORE', [date]);
    return this.db.all<SignalSnapshotRow>(qb);
  }

  private static today(): string {
    return new Date().toISOString().slice(0, 10);
  }
}