// tests/unit/chatcore-stream-error-result.test.ts
// Characterization of isSemaphoreCapacityError / createStreamingErrorResult /
// getUpstreamErrorIdentifier — streaming error-result helpers extracted from handleChatCore
// (chatCore god-file decomposition, #3501). Locks the semaphore code matching, the SSE error
// envelope shape (status, headers, `data: {...}\n\ndata: [DONE]\n\n` body, optional code/type), and
// the string-code extraction.
import { test } from "node:test";
import assert from "node:assert/strict";
import {
  isSemaphoreCapacityError,
  createStreamingErrorResult,
  getUpstreamErrorIdentifier,
} from "../../open-sse/handlers/chatCore/streamErrorResult.ts";

test("isSemaphoreCapacityError matches the two semaphore codes only", () => {
  assert.equal(isSemaphoreCapacityError({ code: "SEMAPHORE_TIMEOUT" }), true);
  assert.equal(isSemaphoreCapacityError({ code: "SEMAPHORE_QUEUE_FULL" }), true);
  assert.equal(isSemaphoreCapacityError({ code: "OTHER" }), false);
  assert.equal(isSemaphoreCapacityError(null), false);
  assert.equal(isSemaphoreCapacityError("SEMAPHORE_TIMEOUT"), false);
});

test("createStreamingErrorResult builds an SSE error envelope with [DONE] terminator", async () => {
  const result = createStreamingErrorResult(503, "boom");
  assert.equal(result.success, false);
  assert.equal(result.status, 503);
  assert.equal(result.error, "boom");
  assert.equal(result.response.status, 503);
  assert.equal(result.response.headers.get("Content-Type"), "text/event-stream");
  assert.equal(result.response.headers.get("X-Accel-Buffering"), "no");
  const body = await result.response.text();
  assert.ok(body.startsWith("data: "));
  assert.ok(body.endsWith("data: [DONE]\n\n"));
  const json = JSON.parse(body.slice("data: ".length, body.indexOf("\n\n")));
  assert.equal(json.error.message, "boom");
});

test("createStreamingErrorResult attaches optional code and type", async () => {
  const result = createStreamingErrorResult(429, "slow down", "rate_limited", "rate_limit_error");
  const body = await result.response.text();
  const json = JSON.parse(body.slice("data: ".length, body.indexOf("\n\n")));
  assert.equal(json.error.code, "rate_limited");
  assert.equal(json.error.type, "rate_limit_error");
});

test("createStreamingErrorResult sanitizes code and type at the SSE boundary", async () => {
  const result = createStreamingErrorResult(
    502,
    "upstream failed",
    "sk-live-secret-value",
    "server_error\nX-Leak: yes"
  );
  const body = await result.response.text();
  const json = JSON.parse(body.slice("data: ".length, body.indexOf("\n\n"))) as {
    error: { code: string; type: string };
  };

  assert.equal(json.error.code, "bad_gateway");
  assert.equal(json.error.type, "server_error");
  assert.doesNotMatch(body, /sk-live-secret-value|X-Leak/);
});

test("getUpstreamErrorIdentifier returns a non-empty string code or undefined", () => {
  assert.equal(getUpstreamErrorIdentifier({ code: "ECONNRESET" }), "ECONNRESET");
  assert.equal(getUpstreamErrorIdentifier({ code: "" }), undefined);
  assert.equal(getUpstreamErrorIdentifier({ code: 123 }), undefined);
  assert.equal(getUpstreamErrorIdentifier(null), undefined);
  assert.equal(getUpstreamErrorIdentifier("ECONNRESET"), undefined);
});

test("non-streaming runNonStreamingProviderLeg is inside a try that maps semaphore errors", async () => {
  const fs = await import("node:fs");
  const src = fs.readFileSync("open-sse/handlers/chatCore.ts", "utf8");
  // `let`, not `const`, since 6077b9dd (#12867) made the finalization step reassign
  // legResult. The guard is about the try/catch that wraps the call, not the keyword.
  const idx = src.search(/(?:const|let) legResult = await runNonStreamingProviderLeg/);
  assert.ok(idx >= 0, "non-streaming branch must exist");
  const start = src.lastIndexOf("if (!stream)", idx);
  const end = src.indexOf("// Streaming response", idx);
  assert.ok(start >= 0 && end > start, "non-stream block bounds");
  const block = src.slice(start, end);
  assert.match(
    block,
    /try\s*\{[\s\S]*runNonStreamingProviderLeg/,
    "non-stream leg must sit in a try so SEMAPHORE_TIMEOUT cannot escape handleChatCore"
  );
  assert.match(
    block,
    /isSemaphoreCapacityError/,
    "same catch that maps stream semaphore errors must cover the non-stream leg"
  );
});