import { spawnSync } from "node:child_process";
import { writeFileSync, unlinkSync } from "node:fs";
import { join } from "node:path";
import { tmpdir } from "node:os";

type JsonRecord = Record<string, unknown>;

function assertCondition(condition: unknown, message: string, detail: JsonRecord = {}): void {
  if (!condition) throw new Error(`${message}: ${JSON.stringify(detail)}`);
}

function runCli(args: string[], stdin?: string): { status: number | null; stdout: string; stderr: string; json: JsonRecord | null } {
  const result = spawnSync("bun", ["scripts/cli.ts", ...args], {
    cwd: process.cwd(),
    input: stdin,
    encoding: "utf8",
  });
  const stdout = String(result.stdout || "");
  let json: JsonRecord | null = null;
  try {
    json = JSON.parse(stdout) as JsonRecord;
  } catch {
    json = null;
  }
  return {
    status: result.status,
    stdout,
    stderr: String(result.stderr || ""),
    json,
  };
}

function nestedRecord(value: unknown, path: string[]): JsonRecord {
  let current: unknown = value;
  for (const key of path) {
    assertCondition(current !== null && typeof current === "object" && !Array.isArray(current), "expected object while traversing JSON", { path, key, current });
    current = (current as JsonRecord)[key];
  }
  assertCondition(current !== null && typeof current === "object" && !Array.isArray(current), "expected nested object", { path, current });
  return current as JsonRecord;
}

function stringArray(value: unknown): string[] {
  return Array.isArray(value) ? value.map((item) => String(item)) : [];
}

function assertDryRunPrompt(response: JsonRecord, expectedText: string): void {
  assertCondition(response.ok === true, "CLI dry-run should succeed", response);
  const data = nestedRecord(response.data, []);
  assertCondition(data.dryRun === true, "dry-run response should expose dryRun=true", data);
  const prompt = nestedRecord(response.data, ["request", "body", "prompt"]);
  assertCondition(prompt.text === expectedText, "dry-run prompt text mismatch", prompt);
  assertCondition(prompt.chars === expectedText.length, "dry-run prompt char count mismatch", prompt);
  assertCondition(prompt.truncated === false, "dry-run prompt must not truncate", prompt);
}

export function runCodeQueueCliSteerContract(): JsonRecord {
  const positional = runCli(["codex", "steer", "codex_test_task", "correct the running task", "--dry-run"]);
  assertDryRunPrompt(positional.json ?? {}, "correct the running task");

  const stdin = runCli(["codex", "steer", "codex_test_task", "--prompt-stdin", "--dry-run"], "stdin steer prompt\n");
  assertDryRunPrompt(stdin.json ?? {}, "stdin steer prompt\n");

  const promptFile = join(tmpdir(), `unidesk-code-queue-steer-${process.pid}.txt`);
  writeFileSync(promptFile, "file steer prompt", "utf8");
  try {
    const fromFile = runCli(["codex", "steer", "codex_test_task", "--prompt-file", promptFile, "--dry-run"]);
    assertDryRunPrompt(fromFile.json ?? {}, "file steer prompt");
  } finally {
    unlinkSync(promptFile);
  }

  const duplicateSource = runCli(["codex", "steer", "codex_test_task", "positional", "--prompt-stdin", "--dry-run"], "stdin\n");
  assertCondition(duplicateSource.status !== 0, "duplicate prompt source should fail", duplicateSource.json ?? { stdout: duplicateSource.stdout });
  const duplicateMessage = String(nestedRecord(duplicateSource.json, ["error"]).message || "");
  assertCondition(duplicateMessage.includes("exactly one prompt source"), "duplicate prompt source error should be explicit", { duplicateMessage });

  const unknownOption = runCli(["codex", "steer", "codex_test_task", "--queue", "default", "prompt", "--dry-run"]);
  assertCondition(unknownOption.status !== 0, "unknown steer option should fail", unknownOption.json ?? { stdout: unknownOption.stdout });
  const unknownMessage = String(nestedRecord(unknownOption.json, ["error"]).message || "");
  assertCondition(unknownMessage.includes("unsupported codex steer option: --queue"), "unknown option error should name option", { unknownMessage });

  const help = runCli(["codex", "help"]);
  assertCondition(help.status === 0 && help.json?.ok === true, "codex help should succeed", help.json ?? { stdout: help.stdout });
  const usage = stringArray(nestedRecord(help.json?.data, []).usage);
  assertCondition(usage.some((line) => line.includes("codex steer <taskId>")), "codex help should list steer", { usage });

  return {
    ok: true,
    checks: [
      "steer positional dry-run",
      "steer stdin dry-run",
      "steer prompt-file dry-run",
      "duplicate prompt source failure",
      "unsupported option failure",
      "codex help lists steer",
    ],
  };
}

if (import.meta.main) {
  const result = runCodeQueueCliSteerContract();
  process.stdout.write(`${JSON.stringify(result, null, 2)}\n`);
}