export type AgentExecutionReport = {
  responses: { id: string; text: string }[];
  activities: { id: string; title: string; detail?: string; status: "running" | "completed" | "error" }[];
};

const record = (value: unknown): Record<string, unknown> | null =>
  value !== null && typeof value === "object" && !Array.isArray(value) ? value as Record<string, unknown> : null;

export function updateExecutionReportProgress(report: AgentExecutionReport, value: unknown): AgentExecutionReport {
  const progress = record(value);
  // The report contains public execution facts, not the model's reasoning stream.
  if (!progress || !["tool", "start", "execution_plan"].includes(String(progress.phase)) ||
    typeof progress.id !== "string" || typeof progress.title !== "string" ||
    !["running", "completed", "error"].includes(String(progress.status))) return report;
  const activity = {
    id: progress.id, title: progress.title,
    detail: typeof progress.detail === "string" ? progress.detail : undefined,
    status: progress.status as "running" | "completed" | "error"
  };
  const existing = report.activities.findIndex((item) => item.id === activity.id);
  return { ...report, activities: existing < 0 ? [...report.activities, activity].slice(-8) :
    report.activities.map((item, index) => index === existing ? activity : item) };
}

export function readExecutionReport(messages: unknown[]): AgentExecutionReport {
  let report: AgentExecutionReport = { responses: [], activities: [] };
  messages.forEach((value, index) => {
    const message = record(value);
    if (!message || message.role !== "assistant") return;
    const parts = Array.isArray(message.parts) ? message.parts.map(record).filter((part) => part !== null) : [];
    const text = parts.filter((part) => part.type === "text" && typeof part.text === "string").map((part) => part.text).join("") ||
      (typeof message.content === "string" ? message.content : "");
    report.responses.push({ id: typeof message.id === "string" ? message.id : `response-${index}`, text });
    for (const progress of Array.isArray(message.progress) ? message.progress : []) report = updateExecutionReportProgress(report, progress);
    for (const part of parts) if (part.type === "data-progress") report = updateExecutionReportProgress(report, part.data);
  });
  return { ...report, responses: report.responses.slice(-3) };
}

export function appendExecutionReportText(report: AgentExecutionReport, value: unknown): AgentExecutionReport {
  const data = record(value);
  if (!data || typeof data.content !== "string") return report;
  const id = typeof data.message_id === "string" ? data.message_id : "current-response";
  const matching = report.responses.findIndex((response) => response.id === id);
  // Active-run snapshots and UI stream chunks currently use different assistant IDs.
  const existing = matching < 0 ? report.responses.length - 1 : matching;
  return { ...report, responses: existing < 0 ? [...report.responses, { id, text: data.content }].slice(-3) :
    report.responses.map((response, index) => index === existing ? { ...response, id, text: response.text + data.content } : response) };
}