const MS_PER_HOUR = 3600000;
const MS_PER_DAY = 86400000;

const FALSE_STORE_PATTERNS = [
  {
    code: 'question_mark',
    pattern: /[？?]\s*$/,
    message: 'Content ends with a question mark',
  },
  {
    code: 'what_is_question',
    pattern: /^(?:什么是|解释一下|介绍一下|请问|能不能|是否可以|怎么|如何|为什么|啥是)/u,
    message: 'Content looks like a question rather than a fact',
  },
  {
    code: 'imperative_only',
    pattern: /^(?:查一下|搜一下|看看|继续|下一步|帮我|请帮我)/u,
    message: 'Content looks like an instruction without durable facts',
  },
  {
    code: 'trivial_greeting',
    pattern: /^(?:你好|您好|谢谢|好的|可以|收到|再见|hi|hello|thanks)[！!。.\s]*$/iu,
    message: 'Content is a trivial greeting or acknowledgement',
  },
  {
    code: 'routing_leak',
    pattern: /(?:\[Memory Context\]|【Memind 任务编排】|agent_orchestration)/u,
    message: 'Content contains internal routing or memory envelope text',
  },
];

export function parseSinceArg(value, now = Date.now()) {
  const raw = String(value ?? '7d').trim().toLowerCase();
  const match = raw.match(/^(\d+)(h|d|w)$/);
  if (!match) {
    throw new Error(`Invalid --since value "${value}". Expected formats like 24h, 7d, 2w.`);
  }
  const amount = Number(match[1]);
  if (!Number.isFinite(amount) || amount <= 0) {
    throw new Error(`Invalid --since value "${value}". Amount must be positive.`);
  }
  const unit = match[2];
  const multiplier = unit === 'h' ? MS_PER_HOUR : unit === 'w' ? MS_PER_DAY * 7 : MS_PER_DAY;
  return {
    sinceMs: now - amount * multiplier,
    label: raw,
  };
}

export function detectFalseStoreCandidate(content) {
  const text = String(content ?? '').replace(/\s+/g, ' ').trim();
  if (!text) {
    return { suspicious: true, code: 'empty_content', message: 'Content is empty' };
  }
  for (const rule of FALSE_STORE_PATTERNS) {
    if (rule.pattern.test(text)) {
      return { suspicious: true, code: rule.code, message: rule.message };
    }
  }
  return { suspicious: false };
}

function normalizeCandidate(row) {
  return {
    id: String(row.id),
    userId: String(row.user_id ?? row.userId),
    sessionId: row.session_id == null ? null : String(row.session_id ?? row.sessionId),
    memoryType: String(row.memory_type ?? row.memoryType ?? ''),
    content: String(row.content ?? ''),
    status: String(row.status ?? ''),
    policyReason: String(row.policy_reason ?? row.policyReason ?? ''),
    confidence: Number(row.confidence ?? 0),
    importance: Number(row.importance ?? 0),
    createdAt: Number(row.created_at ?? row.createdAt ?? 0),
    updatedAt: Number(row.updated_at ?? row.updatedAt ?? 0),
  };
}

function normalizeMemoryItem(row) {
  return {
    id: String(row.id),
    userId: String(row.user_id ?? row.userId),
    label: String(row.label ?? ''),
    content: String(row.memory_text ?? row.content ?? ''),
    status: String(row.status ?? ''),
    createdAt: Number(row.created_at ?? row.createdAt ?? 0),
    updatedAt: Number(row.updated_at ?? row.updatedAt ?? 0),
  };
}

function countByField(items, field) {
  const counts = new Map();
  for (const item of items) {
    const key = String(item[field] ?? 'unknown');
    counts.set(key, (counts.get(key) ?? 0) + 1);
  }
  return Object.fromEntries([...counts.entries()].sort((a, b) => b[1] - a[1]));
}

function topEntries(counts, limit = 10) {
  return Object.entries(counts)
    .sort((a, b) => b[1] - a[1])
    .slice(0, limit)
    .map(([key, count]) => ({ key, count }));
}

export function auditMemoryV2Shadow({
  candidates = [],
  memoryItems = [],
  pgvectorMemoryIds = new Set(),
  pgvectorConfigured = false,
  agentMemoryEvents = [],
  sinceMs = 0,
  nowMs = Date.now(),
  falseStoreSampleLimit = 20,
  pgvectorLagSampleLimit = 20,
} = {}) {
  const normalizedCandidates = candidates.map(normalizeCandidate);
  const normalizedItems = memoryItems.map(normalizeMemoryItem);
  const inWindowCandidates = normalizedCandidates.filter((item) => item.createdAt >= sinceMs);
  const inWindowItems = normalizedItems.filter((item) => item.updatedAt >= sinceMs);

  const candidateStatusCounts = countByField(inWindowCandidates, 'status');
  const policyReasonCounts = countByField(inWindowCandidates, 'policyReason');
  const memoryTypeCounts = countByField(inWindowCandidates, 'memoryType');

  const suspiciousCandidates = inWindowCandidates
    .filter((item) => ['candidate', 'accepted'].includes(item.status))
    .map((item) => {
      const verdict = detectFalseStoreCandidate(item.content);
      if (!verdict.suspicious) return null;
      return {
        id: item.id,
        userId: item.userId,
        status: item.status,
        policyReason: item.policyReason,
        code: verdict.code,
        message: verdict.message,
        contentPreview: item.content.slice(0, 120),
        createdAt: item.createdAt,
      };
    })
    .filter(Boolean);

  const activeItems = normalizedItems.filter((item) => item.status === 'active');
  const pgvectorLagUsers = new Map();
  const pgvectorMissingSamples = [];
  if (pgvectorConfigured) {
    for (const item of activeItems) {
      if (pgvectorMemoryIds.has(item.id)) continue;
      pgvectorLagUsers.set(item.userId, (pgvectorLagUsers.get(item.userId) ?? 0) + 1);
      if (pgvectorMissingSamples.length < pgvectorLagSampleLimit) {
        pgvectorMissingSamples.push({
          memoryId: item.id,
          userId: item.userId,
          label: item.label,
          updatedAt: item.updatedAt,
          contentPreview: item.content.slice(0, 120),
        });
      }
    }
  }

  const resolvedEvents = agentMemoryEvents.filter((event) => {
    const createdAt = Number(event.created_at ?? event.createdAt ?? 0);
    return createdAt >= sinceMs;
  });
  const resolvedWithHits = resolvedEvents.filter((event) => {
    const data = event.data_json ?? event.data ?? {};
    const count = Number(data.count ?? data.memoryCount ?? data.memories?.length ?? 0);
    return count > 0;
  });

  const acceptedCount = candidateStatusCounts.accepted ?? 0;
  const candidateCount = candidateStatusCounts.candidate ?? 0;
  const reviewedCount = acceptedCount + (candidateStatusCounts.rejected ?? 0);
  const autoAcceptRate = reviewedCount > 0 ? acceptedCount / reviewedCount : null;
  const falseStoreRate = inWindowCandidates.length > 0
    ? suspiciousCandidates.length / inWindowCandidates.length
    : null;
  const resolveHitRate = resolvedEvents.length > 0
    ? resolvedWithHits.length / resolvedEvents.length
    : null;

  const thresholds = {
    falseStoreRateMax: 0.05,
    pgvectorLagUsersMax: 0,
  };

  const issues = [];
  if (falseStoreRate != null && falseStoreRate > thresholds.falseStoreRateMax) {
    issues.push({
      code: 'false_store_rate_high',
      message: `False-store sample rate ${(falseStoreRate * 100).toFixed(1)}% exceeds ${thresholds.falseStoreRateMax * 100}%`,
    });
  }
  if (pgvectorConfigured && pgvectorLagUsers.size > thresholds.pgvectorLagUsersMax) {
    issues.push({
      code: 'pgvector_sync_lag',
      message: `${pgvectorLagUsers.size} user(s) have active memories missing from pgvector`,
    });
  }

  return {
    ok: issues.length === 0,
    generatedAt: nowMs,
    window: {
      sinceMs,
      untilMs: nowMs,
      candidateCount: inWindowCandidates.length,
      memoryItemCount: inWindowItems.length,
      agentMemoryResolvedEvents: resolvedEvents.length,
    },
    summary: {
      candidateStatusCounts,
      policyReasonCounts,
      memoryTypeCounts,
      autoAcceptRate,
      falseStoreRate,
      resolveHitRate,
      suspiciousCandidateCount: suspiciousCandidates.length,
      pgvectorLagUserCount: pgvectorConfigured ? pgvectorLagUsers.size : null,
      activeMemoryCount: activeItems.length,
      pgvectorMemoryCount: pgvectorConfigured ? pgvectorMemoryIds.size : null,
    },
    topPolicyReasons: topEntries(policyReasonCounts),
    pgvectorLagUsers: [...pgvectorLagUsers.entries()]
      .sort((a, b) => b[1] - a[1])
      .slice(0, pgvectorLagSampleLimit)
      .map(([userId, missingCount]) => ({ userId, missingCount })),
    sampleFalseStores: suspiciousCandidates.slice(0, falseStoreSampleLimit),
    pgvectorMissingSamples,
    issues,
  };
}

export function formatMemoryV2ShadowAuditReport(report) {
  const lines = [
    `memory v2 shadow audit: ${report.ok ? 'ok' : 'issues found'}`,
    `window: ${new Date(report.window.sinceMs).toISOString()} -> ${new Date(report.window.untilMs).toISOString()}`,
    `candidates: ${report.window.candidateCount}`,
    `memory items updated: ${report.window.memoryItemCount}`,
    `agent_memory_resolved events: ${report.window.agentMemoryResolvedEvents}`,
    '',
    'summary:',
    JSON.stringify(report.summary, null, 2),
  ];

  if (report.topPolicyReasons.length > 0) {
    lines.push('', 'top policy reasons:');
    for (const item of report.topPolicyReasons) {
      lines.push(`- ${item.key}: ${item.count}`);
    }
  }

  if (report.pgvectorLagUsers.length > 0) {
    lines.push('', 'pgvector lag users:');
    for (const item of report.pgvectorLagUsers) {
      lines.push(`- ${item.userId}: ${item.missingCount} missing`);
    }
  }

  if (report.sampleFalseStores.length > 0) {
    lines.push('', 'sample false stores:');
    for (const item of report.sampleFalseStores) {
      lines.push(`- [${item.code}] ${item.id} (${item.policyReason}): ${item.contentPreview}`);
    }
  }

  if (report.issues.length > 0) {
    lines.push('', 'issues:');
    for (const item of report.issues) {
      lines.push(`- ${item.code}: ${item.message}`);
    }
  }

  return lines.join('\n');
}