import { appendFile, mkdir } from "node:fs/promises";
import { dirname } from "node:path";
import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import { expandHomePath } from "../../src/core/paths";
import { configLoader } from "../../src/shared/config";
import {
  GUARDRAILS_ACTION_BLOCKED_EVENT,
  GUARDRAILS_ACTION_PROMPTED_EVENT,
  GUARDRAILS_APPROVAL_REPLY_EVENT,
  GUARDRAILS_APPROVAL_REQUEST_EVENT,
  GUARDRAILS_RISK_DETECTED_EVENT,
  GUARDRAILS_YOLO_CHANGED_EVENT,
} from "../../src/shared/events";

export interface AuditEntry {
  kind:
    | "blocked"
    | "prompted"
    | "risk"
    | "approval-request"
    | "approval-reply"
    | "yolo";
  timestamp: string;
  cwd: string;
  feature?: string;
  reason?: string;
  tool?: string;
  blockSource?: string;
  requestId?: string;
  decision?: string;
  command?: string;
  yoloEnabled?: boolean;
}

export function toAuditEntry(
  kind: AuditEntry["kind"],
  data: unknown,
): AuditEntry {
  const payload = (data ?? {}) as Record<string, unknown>;
  const context = payload.context as { toolName?: string } | undefined;
  const block = payload.block as { source?: string } | undefined;
  const risk = payload.risk as { reason?: string } | undefined;
  return {
    kind,
    timestamp:
      typeof payload.timestamp === "string"
        ? payload.timestamp
        : new Date().toISOString(),
    cwd: process.cwd(),
    ...(typeof payload.feature === "string"
      ? { feature: payload.feature }
      : {}),
    ...(typeof payload.reason === "string"
      ? { reason: payload.reason }
      : typeof risk?.reason === "string"
        ? { reason: risk.reason }
        : {}),
    ...(typeof context?.toolName === "string"
      ? { tool: context.toolName }
      : {}),
    ...(typeof block?.source === "string" ? { blockSource: block.source } : {}),
    ...(typeof payload.requestId === "string"
      ? { requestId: payload.requestId }
      : {}),
    ...(typeof payload.decision === "string"
      ? { decision: payload.decision }
      : {}),
    ...(typeof payload.command === "string"
      ? { command: payload.command }
      : {}),
    ...(typeof payload.enabled === "boolean"
      ? { yoloEnabled: payload.enabled }
      : {}),
  };
}

/**
 * Append guardrails decisions (blocks, prompts, detected risks) to a JSONL
 * audit log so the user can review what the agent attempted. Auditing must
 * never break the session: all failures are swallowed.
 */
export function registerAuditLog(pi: ExtensionAPI): void {
  const record = (kind: AuditEntry["kind"]) => (data: unknown) => {
    void (async () => {
      try {
        const config = configLoader.getConfig();
        if (!config.enabled || !config.audit.enabled) return;
        const path = expandHomePath(config.audit.path);
        await mkdir(dirname(path), { recursive: true });
        await appendFile(
          path,
          `${JSON.stringify(toAuditEntry(kind, data))}\n`,
          "utf8",
        );
      } catch {
        // Never let auditing interfere with the session.
      }
    })();
  };

  pi.events.on(GUARDRAILS_ACTION_BLOCKED_EVENT, record("blocked"));
  pi.events.on(GUARDRAILS_ACTION_PROMPTED_EVENT, record("prompted"));
  pi.events.on(GUARDRAILS_RISK_DETECTED_EVENT, record("risk"));
  pi.events.on(GUARDRAILS_APPROVAL_REQUEST_EVENT, record("approval-request"));
  pi.events.on(GUARDRAILS_APPROVAL_REPLY_EVENT, record("approval-reply"));
  pi.events.on(GUARDRAILS_YOLO_CHANGED_EVENT, record("yolo"));
}