import pc from "picocolors";

function safeJsonParse(text: string): unknown {
  try {
    return JSON.parse(text);
  } catch {
    return null;
  }
}

function asRecord(value: unknown): Record<string, unknown> | null {
  if (typeof value !== "object" || value === null || Array.isArray(value)) return null;
  return value as Record<string, unknown>;
}

function asString(value: unknown, fallback = ""): string {
  return typeof value === "string" ? value : fallback;
}

function asNumber(value: unknown, fallback = 0): number {
  return typeof value === "number" && Number.isFinite(value) ? value : fallback;
}

function errorText(value: unknown): string {
  if (typeof value === "string") return value;
  const rec = asRecord(value);
  if (!rec) return "";
  const data = asRecord(rec.data);
  const message =
    asString(rec.message) ||
    asString(data?.message) ||
    asString(rec.name) ||
    "";
  if (message) return message;
  try {
    return JSON.stringify(rec);
  } catch {
    return "";
  }
}

export function printOpenCodeStreamEvent(raw: string, _debug: boolean): void {
  const line = raw.trim();
  if (!line) return;

  const parsed = asRecord(safeJsonParse(line));
  if (!parsed) {
    console.log(line);
    return;
  }

  const type = asString(parsed.type);

  if (type === "step_start") {
    const sessionId = asString(parsed.sessionID);
    console.log(pc.blue(`step started${sessionId ? ` (session: ${sessionId})` : ""}`));
    return;
  }

  if (type === "text") {
    const part = asRecord(parsed.part);
    const text = asString(part?.text).trim();
    if (text) console.log(pc.green(`assistant: ${text}`));
    return;
  }

  if (type === "reasoning") {
    const part = asRecord(parsed.part);
    const text = asString(part?.text).trim();
    if (text) console.log(pc.gray(`thinking: ${text}`));
    return;
  }

  if (type === "tool_use") {
    const part = asRecord(parsed.part);
    const tool = asString(part?.tool, "tool");
    const state = asRecord(part?.state);
    const status = asString(state?.status);
    const summary = `tool_${status || "event"}: ${tool}`;
    const isError = status === "error";
    console.log((isError ? pc.red : pc.yellow)(summary));
    const input = state?.input;
    if (input !== undefined) {
      try {
        console.log(pc.gray(JSON.stringify(input, null, 2)));
      } catch {
        console.log(pc.gray(String(input)));
      }
    }
    const output = asString(state?.output) || asString(state?.error);
    if (output) console.log((isError ? pc.red : pc.gray)(output));
    return;
  }

  if (type === "step_finish") {
    const part = asRecord(parsed.part);
    const tokens = asRecord(part?.tokens);
    const cache = asRecord(tokens?.cache);
    const input = asNumber(tokens?.input, 0);
    const output = asNumber(tokens?.output, 0) + asNumber(tokens?.reasoning, 0);
    const cached = asNumber(cache?.read, 0);
    const cost = asNumber(part?.cost, 0);
    const reason = asString(part?.reason, "step");
    console.log(pc.blue(`step finished (${reason}) tokens: in=${input} out=${output} cached=${cached} cost=$${cost.toFixed(6)}`));
    return;
  }

  if (type === "error") {
    const message = errorText(parsed.error ?? parsed.message);
    if (message) console.log(pc.red(`error: ${message}`));
    return;
  }

  console.log(line);
}