/**
 * SnapshotToolsNudge — mid-run reminder when the user asked to update test
 * snapshots but no snapshot-update-shaped exec has run yet.
 *
 * Soft: max 1 fire. Pairs with evaluateInventedSnapshotCompletionGate.
 */

export const SNAPSHOT_TOOLS_NUDGE_MAX_ATTEMPTS = 1;

const SNAPSHOT_USER_RE =
  /(?:\bupdate(?:\s+the)?\s+snapshots?\b|\bsnapshots?\s+update\b|\bjest\s+-u\b|\bvitest\s+-u\b|--updateSnapshot|更新 snapshot|更新快照)/iu;

const EXEC_TOOLS = new Set(['exec', 'exec_background']);

export interface SnapshotToolsNudgeRequest {
  userText: string;
  toolCallsByName: Record<string, number>;
  messages?: Array<{ role?: string; content?: unknown }>;
  totalToolCalls: number;
  attempts: number;
}

export type SnapshotToolsNudgeResult =
  | { fire: false }
  | { fire: true; correction: string };

function sawSnapshotExec(
  messages: Array<{ role?: string; content?: unknown }> | undefined,
): boolean {
  if (!messages?.length) return false;
  for (const m of messages) {
    if (!m || m.role !== 'assistant' || !Array.isArray(m.content)) continue;
    for (const block of m.content) {
      const b = block as { type?: string; name?: string; input?: unknown };
      if (b?.type !== 'tool_use' || !b.name || !EXEC_TOOLS.has(b.name)) continue;
      const input = b.input;
      if (!input || typeof input !== 'object') continue;
      const o = input as Record<string, unknown>;
      let cmd = '';
      for (const key of ['command', 'cmd', 'input'] as const) {
        if (typeof o[key] === 'string' && String(o[key]).trim()) {
          cmd = String(o[key]);
          break;
        }
      }
      if (
        /\b(?:jest|vitest)\b[^\n]*\s-u\b/i.test(cmd) ||
        /\b--update(?:Snapshot|s)?\b/i.test(cmd) ||
        /\bupdate[- ]?snapshots?\b/i.test(cmd) ||
        /\bnpm run (?:test:)?update-?snapshots?\b/i.test(cmd)
      ) {
        return true;
      }
    }
  }
  return false;
}

export function evaluateSnapshotToolsNudge(
  request: SnapshotToolsNudgeRequest,
): SnapshotToolsNudgeResult {
  if (request.attempts >= SNAPSHOT_TOOLS_NUDGE_MAX_ATTEMPTS) return { fire: false };
  if (request.totalToolCalls < 1) return { fire: false };
  if (sawSnapshotExec(request.messages)) return { fire: false };

  const user = (request.userText || '').trim();
  if (!user || !SNAPSHOT_USER_RE.test(user)) return { fire: false };

  return {
    fire: true,
    correction:
      '[System] The user asked to update test snapshots, and tools have already run without a snapshot-update command ' +
      '(`jest -u`, `vitest -u`, `--updateSnapshot`, etc.). ' +
      'Run the real snapshot update via `exec` and report its output, or clearly say snapshots were not updated. ' +
      'Do not invent snapshot updates.',
  };
}