Agent-System/web/src/lib/squadCompletionObservation.ts

export const INFLIGHT_CHAT_STATUSES = ['pending', 'streaming_status', 'auto_retrying'] as const;
export const SUCCESS_TERMINAL_CHAT_STATUSES = ['completed', 'pending_author_confirmation'] as const;
export const ERROR_TERMINAL_CHAT_STATUSES = ['failed', 'cancelled', 'quality_failed'] as const;

export const SUCCESS_TERMINAL_STATUS_RE =
  /^(completed|pending_author_confirmation)$/;
export const ERROR_TERMINAL_STATUS_RE = /^(failed|cancelled|quality_failed)$/;
export const ANY_TERMINAL_STATUS_RE =
  /^(completed|pending_author_confirmation|failed|cancelled|quality_failed)$/;

export type SquadObservationFrame = {
  userPromptMatched: boolean;
  assistantAdjacent: boolean;
  status: string;
  hasVisibleError?: boolean;
};

export type SquadObservationVerdict = {
  action: 'accept' | 'wait' | 'reject';
  reason: string;
  sawInflight: boolean;
};

export function isInflightChatStatus(status: string): boolean {
  return (INFLIGHT_CHAT_STATUSES as readonly string[]).includes(status);
}

export function isSuccessTerminalChatStatus(status: string): boolean {
  return (SUCCESS_TERMINAL_CHAT_STATUSES as readonly string[]).includes(status);
}

export function isErrorTerminalChatStatus(status: string): boolean {
  return (ERROR_TERMINAL_CHAT_STATUSES as readonly string[]).includes(status);
}

/**
 * Decide whether a single observed assistant card is done, still running, or invalid.
 * Inflight is optional: a success terminal is accepted even if requireInflight is true
 * and no pending/streaming frame was seen (UI-11 fast-complete).
 */
export function evaluateSquadObservation(
  frame: SquadObservationFrame,
  ctx?: { requireInflight?: boolean; sawInflight?: boolean },
): SquadObservationVerdict {
  const sawInflight = Boolean(ctx?.sawInflight) || isInflightChatStatus(frame.status);
  if (!frame.userPromptMatched) {
    return { action: 'reject', reason: 'missing_user_prompt', sawInflight };
  }
  if (!frame.assistantAdjacent) {
    return { action: 'reject', reason: 'missing_adjacent_assistant', sawInflight };
  }
  if (frame.hasVisibleError) {
    return { action: 'reject', reason: 'visible_error', sawInflight };
  }
  if (isErrorTerminalChatStatus(frame.status)) {
    return { action: 'reject', reason: `error_terminal:${frame.status}`, sawInflight };
  }
  if (isSuccessTerminalChatStatus(frame.status)) {
    return {
      action: 'accept',
      reason: sawInflight && !isInflightChatStatus(frame.status)
        ? 'completed_after_inflight'
        : 'already_completed',
      sawInflight: Boolean(ctx?.sawInflight),
    };
  }
  if (isInflightChatStatus(frame.status)) {
    return { action: 'wait', reason: 'inflight', sawInflight: true };
  }
  return { action: 'wait', reason: 'wait_terminal', sawInflight: Boolean(ctx?.sawInflight) };
}

/** Replay a status timeline. Used by unit tests for direct-completed vs inflight paths. */
export function reduceSquadObservation(
  frames: SquadObservationFrame[],
  opts?: { requireInflight?: boolean },
): SquadObservationVerdict {
  let sawInflight = false;
  let last: SquadObservationVerdict = {
    action: 'wait',
    reason: 'empty_timeline',
    sawInflight: false,
  };
  for (const frame of frames) {
    if (isInflightChatStatus(frame.status)) {
      sawInflight = true;
    }
    last = evaluateSquadObservation(frame, {
      requireInflight: opts?.requireInflight,
      sawInflight,
    });
    if (last.action !== 'wait') {
      return last;
    }
  }
  return last;
}