import type { XiaobaoRiskLevel } from './xiaobao-risk';

export interface XiaobaoRiskSnapshot {
  versionId: string;
  date: string;
  riskScore: number;
  riskLevel: XiaobaoRiskLevel;
  forecastReleaseDate?: string;
  openBugCount: number;
  failedTestCount: number;
  blockedCount: number;
  silentRiskCount: number;
  confidence: number;
  createdAt: string;
}

export interface RiskTrendSummary {
  direction: 'up' | 'down' | 'flat' | 'unknown';
  delta: number;
  summary: string;
  pattern: 'continuous_rising' | 'continuous_falling' | 'score_delta' | 'stable' | 'unknown';
}

export function summarizeRiskTrend(snapshots: XiaobaoRiskSnapshot[]): RiskTrendSummary {
  const sorted = [...snapshots].sort((a, b) => getSnapshotTime(a) - getSnapshotTime(b));
  if (sorted.length < 2) {
    return { direction: 'unknown', delta: 0, summary: 'No historical risk snapshots yet.', pattern: 'unknown' };
  }

  const first = sorted[0];
  const latest = sorted[sorted.length - 1];
  const delta = clampScore(latest.riskScore) - clampScore(first.riskScore);
  const recentThree = sorted.slice(-3);

  if (recentThree.length === 3) {
    const [a, b, c] = recentThree.map((snapshot) => clampScore(snapshot.riskScore));
    if (a < b && b < c) {
      return {
        direction: 'up',
        delta,
        summary: `Risk rose continuously from ${a} to ${c}.`,
        pattern: 'continuous_rising',
      };
    }
    if (a > b && b > c) {
      return {
        direction: 'down',
        delta,
        summary: `Risk fell continuously from ${a} to ${c}.`,
        pattern: 'continuous_falling',
      };
    }
  }

  if (delta >= 10) {
    return { direction: 'up', delta, summary: `Risk rose by ${delta} points.`, pattern: 'score_delta' };
  }
  if (delta <= -10) {
    return { direction: 'down', delta, summary: `Risk fell by ${Math.abs(delta)} points.`, pattern: 'score_delta' };
  }
  return { direction: 'flat', delta, summary: 'Risk is stable.', pattern: 'stable' };
}

export function summarizeRiskTrendWithCurrent(
  snapshots: XiaobaoRiskSnapshot[] = [],
  current: XiaobaoRiskSnapshot,
): RiskTrendSummary {
  return summarizeRiskTrend([...snapshots, current]);
}

export function buildRiskSignature(snapshot: XiaobaoRiskSnapshot): string {
  return [
    snapshot.versionId,
    snapshot.date,
    clampScore(snapshot.riskScore),
    snapshot.riskLevel,
    snapshot.forecastReleaseDate ?? '',
    snapshot.openBugCount,
    snapshot.failedTestCount,
    snapshot.blockedCount,
    snapshot.silentRiskCount,
    clampScore(snapshot.confidence),
  ].join('|');
}

function getSnapshotTime(snapshot: XiaobaoRiskSnapshot): number {
  const date = new Date(snapshot.createdAt || snapshot.date).getTime();
  return Number.isFinite(date) ? date : 0;
}

function clampScore(score: number): number {
  return Math.max(0, Math.min(100, Math.round(score)));
}