import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import { MESSAGE_TYPE_PROCESS_UPDATE, type ProcessInfo } from "../constants";
import type { ProcessManager } from "../manager";
import { formatRuntime, sanitizeLine, truncateCmd } from "../utils";

interface ProcessUpdateDetails {
  processId: string;
  processName: string;
  command: string;
  status: "exited" | "killed";
  exitCode: number | null;
  success: boolean;
  runtime: string;
}

export function setupProcessEndHook(pi: ExtensionAPI, manager: ProcessManager) {
  manager.onEvent((event) => {
    if (event.type !== "process_ended") return;

    // Tool-initiated kills already return a tool result. Do not enqueue a
    // custom message while the agent is streaming; even triggerTurn=false would
    // otherwise be delivered as steering by Pi.
    if (!event.triggerAgentTurn) return;

    const info: ProcessInfo = event.info;
    const runtime = formatRuntime(info.startTime, info.endTime);

    // Build message
    let summary: string;

    const processName = sanitizeLine(info.name);
    if (info.status === "killed") {
      summary = `Process "${processName}" (${info.id}) was terminated after ${runtime}.`;
    } else if (info.success) {
      summary = `Process "${processName}" (${info.id}) completed successfully after ${runtime}.`;
    } else {
      summary = `Process "${processName}" (${info.id}) crashed with exit code ${info.exitCode ?? "?"} after ${runtime}.`;
    }

    const message = buildAgentMessage(summary, info, manager);

    // Send the message to the conversation - displayed via custom renderer in UI.
    const details: ProcessUpdateDetails = {
      processId: info.id,
      processName: info.name,
      command: info.command,
      status: info.status as "exited" | "killed",
      exitCode: info.exitCode,
      success: info.success ?? false,
      runtime,
    };

    pi.sendMessage(
      {
        customType: MESSAGE_TYPE_PROCESS_UPDATE,
        content: message,
        display: true,
        details,
      },
      { triggerTurn: true, deliverAs: "steer" },
    );
  });
}

function buildAgentMessage(
  summary: string,
  info: ProcessInfo,
  manager: ProcessManager,
): string {
  const lines = [
    summary,
    `Command: ${truncateCmd(sanitizeLine(info.command), 160)}`,
  ];

  const recentOutput = manager.getCombinedOutput(info.id, 20) ?? [];
  if (recentOutput.length > 0) {
    lines.push("", "Recent output:");
    for (const line of recentOutput) {
      const prefix = line.type === "stderr" ? "stderr" : "stdout";
      lines.push(`${prefix}: ${truncateCmd(sanitizeLine(line.text), 500)}`);
    }
  }

  lines.push(
    "",
    "This is the automatic process-end notification. Do not call process list/output/logs just to check whether it finished; use process output once only if you need more logs for debugging.",
  );

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