import { describe, it } from "node:test";
import assert from "node:assert";
import { EventEmitter } from "node:events";
import { Readable } from "node:stream";
import {
  startJob,
  getJob,
  getJobResult,
  cancelJob,
  listJobs,
  cleanupJobs,
} from "../src/jobs.js";
import { JobNotFoundError, JobResultUnavailableError } from "../src/types.js";
import type { ClientName, JobRecord, JobStatus } from "../src/types.js";

interface MockScenario {
  stdout?: string;
  stderr?: string;
  exitCode?: number;
  error?: NodeJS.ErrnoException;
  hang?: boolean;
}

function createMockChildProcess(scenario: MockScenario): any {
  const child = new EventEmitter() as any;
  child.pid = 12345;
  child.stdout = Readable.from(
    scenario.stdout !== undefined ? [scenario.stdout] : []
  );
  child.stderr = Readable.from(
    scenario.stderr !== undefined ? [scenario.stderr] : []
  );
  child.killed = false;
  child.kill = (signal: string = "SIGTERM") => {
    child.killed = true;
    process.nextTick(() => {
      child.emit("exit", null, signal);
      child.emit("close", null, signal);
    });
    return true;
  };
  child.unref = () => {};

  let stdoutEnded = scenario.stdout === undefined;
  let stderrEnded = scenario.stderr === undefined;

  child.stdout.on("end", () => {
    stdoutEnded = true;
    maybeClose();
  });
  child.stderr.on("end", () => {
    stderrEnded = true;
    maybeClose();
  });

  function maybeClose() {
    if (stdoutEnded && stderrEnded && !scenario.hang && !scenario.error) {
      child.emit("exit", scenario.exitCode ?? 0, null);
      child.emit("close", scenario.exitCode ?? 0, null);
    }
  }

  process.nextTick(() => {
    if (scenario.error) {
      child.emit("error", scenario.error);
    }
  });

  return child;
}

function createMockFs() {
  const files = new Map<string, string>();
  const dirs = new Set<string>();

  const fs = {
    mkdirSync: (p: string, _opts?: any) => {
      dirs.add(p);
    },
    writeFileSync: (p: string, data: string) => {
      files.set(p, data);
    },
    readFileSync: (p: string, _opts?: any): string => {
      if (!files.has(p)) {
        const err = Object.assign(new Error(`ENOENT: ${p}`), { code: "ENOENT" });
        throw err;
      }
      return files.get(p)!;
    },
    readdirSync: (p: string): string[] => {
      const result: string[] = [];
      for (const f of files.keys()) {
        const dir = f.substring(0, f.lastIndexOf("/"));
        if (dir === p) {
          result.push(f.substring(f.lastIndexOf("/") + 1));
        }
      }
      return result;
    },
    existsSync: (p: string): boolean => {
      return files.has(p) || dirs.has(p);
    },
    statSync: (p: string): { mtimeMs: number; isFile: () => boolean } => {
      if (!files.has(p)) {
        const err = Object.assign(new Error(`ENOENT: ${p}`), { code: "ENOENT" });
        throw err;
      }
      const data = files.get(p)!;
      // Use startedAt from JSON for deterministic age tests
      try {
        const record = JSON.parse(data) as JobRecord;
        return { mtimeMs: new Date(record.startedAt).getTime(), isFile: () => true };
      } catch {
        return { mtimeMs: Date.now(), isFile: () => true };
      }
    },
    unlinkSync: (p: string) => {
      files.delete(p);
    },
    __files: files,
    __dirs: dirs,
  };

  return fs;
}

function mockSpawn(scenarios: Map<string, MockScenario>): any {
  return (cmd: string, args: string[], _opts: any): any => {
    const key = [cmd, ...args].join(" ");
    const scenario = scenarios.get(key);
    if (!scenario) {
      return createMockChildProcess({
        error: Object.assign(new Error("spawn ENOENT"), { code: "ENOENT" }),
      });
    }
    return createMockChildProcess(scenario);
  };
}

function readJobRecord(fs: ReturnType<typeof createMockFs>, path: string): JobRecord {
  return JSON.parse(fs.readFileSync(path)) as JobRecord;
}

function delay(ms: number): Promise<void> {
  return new Promise((r) => setTimeout(r, ms));
}

describe("startJob", () => {
  it("spawns a detached child process and returns a running Job", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo hello world", { stdout: "ok\n", exitCode: 0 }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job = await startJob("codex", "hello world", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });

    assert.strictEqual(job.client, "codex");
    assert.strictEqual(job.prompt, "hello world");
    assert.strictEqual(job.status, "running");
    assert.strictEqual(typeof job.id, "string");
    assert.ok(job.id.length > 0);
    assert.strictEqual(typeof job.pid, "number");
    assert.ok(typeof job.startedAt === "string");

    // Wait for child to finish
    await delay(50);

    const record = readJobRecord(fs, `${jobDir}/${job.id}.json`);
    assert.strictEqual(record.status, "completed");
    assert.strictEqual(record.stdout, "ok\n");
    assert.strictEqual(record.result?.exitCode, 0);
    assert.ok(typeof record.completedAt === "string");
  });

  it("generates unique ids for concurrent jobs", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo a", { stdout: "a", exitCode: 0 }],
      ["codex exec --yolo b", { stdout: "b", exitCode: 0 }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job1 = await startJob("codex", "a", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });
    const job2 = await startJob("codex", "b", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });

    assert.notStrictEqual(job1.id, job2.id);
  });

  it("sets status to timed_out when timeout is exceeded", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo slow", { hang: true }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job = await startJob("codex", "slow", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
      timeoutMs: 20,
    });

    // Wait for timeout + processing
    await delay(100);

    const record = readJobRecord(fs, `${jobDir}/${job.id}.json`);
    assert.strictEqual(record.status, "timed_out");
  });

  it("sets status to failed on non-zero exit code", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo fail", { stdout: "", stderr: "err", exitCode: 1 }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job = await startJob("codex", "fail", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });

    await delay(50);

    const record = readJobRecord(fs, `${jobDir}/${job.id}.json`);
    assert.strictEqual(record.status, "failed");
    assert.strictEqual(record.result?.exitCode, 1);
    assert.strictEqual(record.stderr, "err");
  });

  it("sets status to failed on spawn ENOENT", async () => {
    const scenarios = new Map<string, MockScenario>();
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job = await startJob("codex", "hello", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });

    await delay(50);

    const record = readJobRecord(fs, `${jobDir}/${job.id}.json`);
    assert.strictEqual(record.status, "failed");
    assert.ok(record.error);
  });
});

describe("getJob", () => {
  it("returns the current Job state from disk", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo hello", { stdout: "ok", exitCode: 0 }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job = await startJob("codex", "hello", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });

    const fetched = getJob(job.id, { jobDir, fs });
    assert.strictEqual(fetched.id, job.id);
    assert.strictEqual(fetched.status, "running");

    await delay(50);

    const after = getJob(job.id, { jobDir, fs });
    assert.strictEqual(after.status, "completed");
    assert.strictEqual(after.result?.exitCode, 0);
  });

  it("throws JobNotFoundError for nonexistent job", () => {
    const fs = createMockFs();
    assert.throws(
      () => getJob("missing", { jobDir: "/tmp/jobs", fs }),
      (err: unknown) => err instanceof JobNotFoundError
    );
  });
});

describe("getJobResult", () => {
  it("returns ExecResult when job is completed", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo hello", { stdout: "ok", exitCode: 0 }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job = await startJob("codex", "hello", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });

    await delay(50);

    const result = getJobResult(job.id, { jobDir, fs });
    assert.strictEqual(result.stdout, "ok");
    assert.strictEqual(result.exitCode, 0);
  });

  it("throws JobResultUnavailableError when job is still running", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo hello", { hang: true }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job = await startJob("codex", "hello", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
      timeoutMs: 50,
    });

    assert.throws(
      () => getJobResult(job.id, { jobDir, fs }),
      (err: unknown) => err instanceof JobResultUnavailableError
    );
  });

  it("throws JobResultUnavailableError when job failed", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo fail", { stdout: "", stderr: "err", exitCode: 1 }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job = await startJob("codex", "fail", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });

    await delay(50);

    assert.throws(
      () => getJobResult(job.id, { jobDir, fs }),
      (err: unknown) => err instanceof JobResultUnavailableError
    );
  });

  it("throws JobNotFoundError for nonexistent job", () => {
    const fs = createMockFs();
    assert.throws(
      () => getJobResult("missing", { jobDir: "/tmp/jobs", fs }),
      (err: unknown) => err instanceof JobNotFoundError
    );
  });
});

describe("cancelJob", () => {
  it("sends SIGTERM and updates status to cancelled", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo hello", { hang: true }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job = await startJob("codex", "hello", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });

    cancelJob(job.id, { jobDir, fs });

    await delay(50);

    const record = readJobRecord(fs, `${jobDir}/${job.id}.json`);
    assert.strictEqual(record.status, "cancelled");
  });

  it("throws JobNotFoundError for nonexistent job", () => {
    const fs = createMockFs();
    assert.throws(
      () => cancelJob("missing", { jobDir: "/tmp/jobs", fs }),
      (err: unknown) => err instanceof JobNotFoundError
    );
  });
});

describe("listJobs", () => {
  it("returns all jobs sorted by startedAt desc", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo a", { stdout: "a", exitCode: 0 }],
      ["codex exec --yolo b", { stdout: "b", exitCode: 0 }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job1 = await startJob("codex", "a", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });
    await delay(20);
    const job2 = await startJob("codex", "b", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });

    await delay(50);

    const jobs = listJobs({ jobDir, fs });
    assert.strictEqual(jobs.length, 2);
    assert.strictEqual(jobs[0].id, job2.id);
    assert.strictEqual(jobs[1].id, job1.id);
  });

  it("filters jobs by status when filter is provided", () => {
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const now = new Date().toISOString();
    const runningRecord: JobRecord = {
      id: "job-running",
      client: "codex",
      prompt: "run",
      status: "running",
      startedAt: now,
      stdout: "",
      stderr: "",
    };
    const completedRecord: JobRecord = {
      id: "job-completed",
      client: "claude",
      prompt: "done",
      status: "completed",
      startedAt: now,
      completedAt: now,
      stdout: "ok",
      stderr: "",
      result: {
        stdout: "ok",
        stderr: "",
        exitCode: 0,
        client: "claude",
        durationMs: 100,
      },
    };
    const failedRecord: JobRecord = {
      id: "job-failed",
      client: "opencode",
      prompt: "fail",
      status: "failed",
      startedAt: now,
      completedAt: now,
      stdout: "",
      stderr: "err",
      result: {
        stdout: "",
        stderr: "err",
        exitCode: 1,
        client: "opencode",
        durationMs: 100,
      },
    };

    fs.mkdirSync(jobDir, { recursive: true });
    fs.writeFileSync(`${jobDir}/job-running.json`, JSON.stringify(runningRecord));
    fs.writeFileSync(`${jobDir}/job-completed.json`, JSON.stringify(completedRecord));
    fs.writeFileSync(`${jobDir}/job-failed.json`, JSON.stringify(failedRecord));

    const all = listJobs({ jobDir, fs });
    assert.strictEqual(all.length, 3);

    const running = listJobs({ jobDir, fs, filter: "running" });
    assert.strictEqual(running.length, 1);
    assert.strictEqual(running[0].id, "job-running");

    const completed = listJobs({ jobDir, fs, filter: "completed" });
    assert.strictEqual(completed.length, 1);
    assert.strictEqual(completed[0].id, "job-completed");

    const failed = listJobs({ jobDir, fs, filter: "failed" });
    assert.strictEqual(failed.length, 1);
    assert.strictEqual(failed[0].id, "job-failed");
  });
});

describe("cleanupJobs", () => {
  it("deletes job files older than maxAgeMs", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo old", { stdout: "old", exitCode: 0 }],
      ["codex exec --yolo new", { stdout: "new", exitCode: 0 }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    // Create an old job by manipulating startedAt after creation
    const oldJob = await startJob("codex", "old", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });
    await delay(50);

    const newJob = await startJob("codex", "new", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });
    await delay(50);

    // Make old job appear 25h old by patching its record
    const oldPath = `${jobDir}/${oldJob.id}.json`;
    const oldRecord = readJobRecord(fs, oldPath);
    oldRecord.startedAt = new Date(Date.now() - 25 * 60 * 60 * 1000).toISOString();
    fs.writeFileSync(oldPath, JSON.stringify(oldRecord));

    cleanupJobs({ jobDir, fs, maxAgeMs: 24 * 60 * 60 * 1000 });

    assert.strictEqual(fs.existsSync(oldPath), false);
    assert.strictEqual(fs.existsSync(`${jobDir}/${newJob.id}.json`), true);
  });

  it("uses default maxAge of 24 hours", async () => {
    const scenarios = new Map<string, MockScenario>([
      ["codex exec --yolo old", { stdout: "old", exitCode: 0 }],
    ]);
    const fs = createMockFs();
    const jobDir = "/tmp/jobs";

    const job = await startJob("codex", "old", {
      jobDir,
      spawn: mockSpawn(scenarios),
      fs,
    });
    await delay(50);

    const path = `${jobDir}/${job.id}.json`;
    const record = readJobRecord(fs, path);
    record.startedAt = new Date(Date.now() - 25 * 60 * 60 * 1000).toISOString();
    fs.writeFileSync(path, JSON.stringify(record));

    cleanupJobs({ jobDir, fs });

    assert.strictEqual(fs.existsSync(path), false);
  });
});