#!/usr/bin/env node
/**
 * Mosaic mission/task layer (M2, host-side only).
 *
 * Operations:
 *   validate <file>   Strictly validate a task (and its referenced mission);
 *                     print the resolved task on success. Writes nothing.
 *   run <taskFile>    Execute the task through the config-driven container
 *                     path; record an immutable run under <dataRoot>/runs/.
 *   list              List runs recorded under <dataRoot>/runs/.
 *
 * Exit codes:
 *   0 success (run: status "succeeded")
 *   1 run failed (mismatch, nonzero exit, timeout) — result.json still written
 *   2 invalid task/mission data
 *   3 configuration problem
 *   4 file/environment problem
 *
 * M2 scope: mission directives are validated and snapshotted into run
 * records for provenance; they are NOT yet injected into the runtime
 * system prompt (capability/policy layer comes later).
 *
 * Invariants carried over from the configuration layer:
 *   - Strict schemas; unknown keys rejected; versions pinned at 1.
 *   - Validation never writes.
 *   - Run records are write-once and never rewritten by a later run.
 *   - No secrets in mission/task data or run records.
 */

import fs from "node:fs";
import path from "node:path";
import process from "node:process";
import { randomBytes } from "node:crypto";
import { spawnSync } from "node:child_process";
import { fileURLToPath } from "node:url";

const PROJECT_ROOT = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
const RUNS_DIRNAME = "runs";
const ID_PATTERN = /^[a-z0-9][a-z0-9._-]{0,63}$/;
const DEFAULT_TIMEOUT_SECONDS = 120;

function fail(exitCode, message) {
  process.stderr.write(`mosaic-task: ${message}\n`);
  process.exit(exitCode);
}

function isPlainObject(value) {
  return typeof value === "object" && value !== null && !Array.isArray(value);
}

function rejectUnknownKeys(object, allowed, where) {
  for (const key of Object.keys(object)) {
    if (!allowed.includes(key)) fail(2, `unsupported ${where} key: "${key}"`);
  }
}

function readJsonFile(file, what) {
  let stat;
  try {
    stat = fs.lstatSync(file);
  } catch {
    fail(4, `${what} not found: ${file}`);
  }
  if (!stat.isFile() || stat.isSymbolicLink()) {
    fail(4, `${what} must be a regular, non-symbolic-link file: ${file}`);
  }
  let document;
  try {
    document = JSON.parse(fs.readFileSync(file, "utf8"));
  } catch (error) {
    fail(2, `${what} is not valid JSON (${file}): ${error.message}`);
  }
  return document;
}

function validateId(value, what) {
  if (typeof value !== "string" || !ID_PATTERN.test(value)) {
    fail(2, `${what} must match ${ID_PATTERN} (got ${JSON.stringify(value)})`);
  }
  return value;
}

function validateMission(document, file) {
  if (!isPlainObject(document)) fail(2, "mission must be a JSON object");
  rejectUnknownKeys(document, ["missionVersion", "id", "objective", "directives"], "mission");
  if (document.missionVersion !== 1) {
    fail(2, `unsupported missionVersion: ${JSON.stringify(document.missionVersion)} (supported: 1)`);
  }
  validateId(document.id, "mission id");
  if (typeof document.objective !== "string" || document.objective.trim().length === 0 || document.objective.length > 4000) {
    fail(2, "mission objective must be a non-empty string of at most 4000 characters");
  }
  let directives = [];
  if (document.directives !== undefined) {
    if (!Array.isArray(document.directives)) fail(2, "mission directives must be an array of strings");
    directives = document.directives.map((d, i) => {
      if (typeof d !== "string" || d.trim().length === 0 || d.length > 2000 || d.includes("\0")) {
        fail(2, `mission directive ${i} must be a non-empty string of at most 2000 characters`);
      }
      return d;
    });
  }
  return { missionVersion: document.missionVersion, id: document.id, objective: document.objective, directives };
}

function validateTask(document, file) {
  if (!isPlainObject(document)) fail(2, "task must be a JSON object");
  rejectUnknownKeys(document, ["taskVersion", "id", "prompt", "mission", "expectExact", "timeoutSeconds"], "task");
  if (document.taskVersion !== 1) {
    fail(2, `unsupported taskVersion: ${JSON.stringify(document.taskVersion)} (supported: 1)`);
  }
  validateId(document.id, "task id");

  if (typeof document.prompt !== "string" || document.prompt.length === 0 || document.prompt.length > 20000 || document.prompt.includes("\0")) {
    fail(2, "task prompt must be a non-empty string of at most 20000 characters");
  }

  let mission = null;
  let missionId = null;
  let missionSnapshot = null;
  if (document.mission !== undefined && document.mission !== null) {
    if (typeof document.mission !== "string" || document.mission.length === 0) {
      fail(2, 'task "mission" must be a path string when present');
    }
    const missionPath = path.resolve(path.dirname(path.resolve(file)), document.mission);
    missionSnapshot = validateMission(readJsonFile(missionPath, "mission file"), missionPath);
    mission = document.mission;
    missionId = missionSnapshot.id;
  }

  let expectExact = null;
  if (document.expectExact !== undefined && document.expectExact !== null) {
    if (typeof document.expectExact !== "string" || document.expectExact.length === 0 || document.expectExact.length > 500 || /[^\P{C}\t\n]/u.test(document.expectExact)) {
      fail(2, "task expectExact must be a non-empty string of at most 500 characters without control characters (tab/newline allowed)");
    }
    expectExact = document.expectExact;
  }

  let timeoutSeconds = DEFAULT_TIMEOUT_SECONDS;
  if (document.timeoutSeconds !== undefined && document.timeoutSeconds !== null) {
    if (!Number.isInteger(document.timeoutSeconds) || document.timeoutSeconds < 5 || document.timeoutSeconds > 600) {
      fail(2, "task timeoutSeconds must be an integer between 5 and 600");
    }
    timeoutSeconds = document.timeoutSeconds;
  }

  return {
    taskVersion: document.taskVersion,
    id: document.id,
    prompt: document.prompt,
    mission,
    missionId,
    missionSnapshot,
    expectExact,
    timeoutSeconds,
  };
}

function loadConfig() {
  const proc = spawnSync(process.execPath, [path.join(PROJECT_ROOT, "scripts", "mosaic-config.mjs"), "validate"], {
    cwd: PROJECT_ROOT,
    encoding: "utf8",
    maxBuffer: 1024 * 1024,
  });
  if (proc.status !== 0) {
    fail(3, `configuration problem (exit ${proc.status}); run scripts/bootstrap.sh or fix config.json`);
  }
  return JSON.parse(proc.stdout);
}

function runsRoot(resolvedConfig) {
  return path.join(resolvedConfig.dataRoot, RUNS_DIRNAME);
}

function utcStamp() {
  return new Date().toISOString().replace(/[-:]/g, "").replace(/\.\d+Z$/, "Z");
}

function writeOnce(file, content) {
  const fd = fs.openSync(file, "wx", 0o644); // exclusive: never overwrite
  try {
    fs.writeFileSync(fd, content);
  } finally {
    fs.closeSync(fd);
  }
}

function runTask(taskFile) {
  const resolved = JSON.parse(
    spawnSync(process.execPath, [path.join(PROJECT_ROOT, "scripts", "mosaic-config.mjs"), "validate"], {
      cwd: PROJECT_ROOT,
      encoding: "utf8",
      maxBuffer: 1024 * 1024,
    }).stdout,
  );

  const task = validateTask(readJsonFile(taskFile, "task file"), path.resolve(taskFile));
  const runId = `r-${utcStamp()}-${randomBytes(3).toString("hex")}`;
  const runDir = path.join(runsRoot(resolved), runId);

  fs.mkdirSync(runDir, { recursive: true });

  // Immutable input snapshots (evidence of exactly what was executed).
  const rawTask = fs.readFileSync(path.resolve(taskFile), "utf8");
  writeOnce(path.join(runDir, "task.json"), rawTask);
  if (task.missionSnapshot) {
    const missionPath = path.resolve(path.dirname(path.resolve(taskFile)), task.mission);
    writeOnce(path.join(runDir, "mission.json"), fs.readFileSync(missionPath, "utf8"));
  }

  const startedAt = new Date();
  const stderrFile = path.join(runDir, "stderr.txt");

  // Sanctioned mission injection: point the container at the run snapshot's
  // CONTAINER path (dataRoot maps to /var/lib/mosaic in the image).
  const spawnEnv = { ...process.env };
  spawnEnv.MOSAIC_ADAPTER = resolved.execution.adapter;
  if (task.missionSnapshot) {
    const relative = path.relative(resolved.dataRoot, runDir);
    if (relative.startsWith("..") || path.isAbsolute(relative)) {
      fail(4, `run directory is outside the configured dataRoot: ${runDir}`);
    }
    spawnEnv.MOSAIC_MISSION_FILE = `/var/lib/mosaic/${relative.split(path.sep).join("/")}/mission.json`;
  }

  const proc = spawnSync(
    "docker",
    ["compose", "run", "--rm", "-T", "mosaic-agent", task.prompt],
    {
      cwd: PROJECT_ROOT,
      env: spawnEnv,
      input: "", // stdin detached: print mode must never wait on a terminal (see issue #5)
      encoding: "utf8",
      maxBuffer: 16 * 1024 * 1024,
      timeout: task.timeoutSeconds * 1000,
      killSignal: "SIGKILL",
    },
  );
  const finishedAt = new Date();

  fs.writeFileSync(stderrFile, proc.stderr ?? "", { flag: "wx" });

  const response = (proc.stdout ?? "").replace(/^[^\S\n]+/, "").replace(/[^\S\n]+$/, "").trim();
  let status = "succeeded";
  let reason = null;
  let expected = task.expectExact;

  if (proc.error && proc.error.code === "ETIMEDOUT") {
    status = "failed";
    reason = "timeout";
  } else if (proc.error) {
    status = "failed";
    reason = `spawn-error: ${proc.error.code ?? proc.error.message}`;
  } else if (proc.status !== 0) {
    status = "failed";
    reason = "exit-nonzero";
  } else if (expected !== null && response !== expected) {
    status = "failed";
    reason = "expect-mismatch";
  }

  const result = {
    runVersion: 1,
    runId,
    taskId: task.id,
    missionId: task.missionId,
    status,
    reason,
    request: task.prompt,
    response,
    expectedExact: expected,
    exitCode: proc.status,
    signal: proc.signal ?? null,
    provider: resolved.execution.provider,
    model: resolved.execution.model,
    startedAt: startedAt.toISOString(),
    finishedAt: finishedAt.toISOString(),
    durationMs: finishedAt.getTime() - startedAt.getTime(),
  };

  writeOnce(path.join(runDir, "result.json"), `${JSON.stringify(result, null, 2)}\n`);

  process.stdout.write(`run: ${runId}\nstatus: ${status}${reason ? ` (${reason})` : ""}\nresponse: ${response}\n`);
  process.exit(status === "succeeded" ? 0 : 1);
}

function listRuns() {
  const resolved = loadConfig();
  const root = runsRoot(resolved);
  let entries = [];
  try {
    entries = fs.readdirSync(root).filter((name) => name.startsWith("r-")).sort();
  } catch {
    // No runs yet.
  }
  for (const runId of entries) {
    let status = "unknown";
    let taskId = "-";
    try {
      const result = JSON.parse(fs.readFileSync(path.join(root, runId, "result.json"), "utf8"));
      status = result.status;
      taskId = result.taskId;
    } catch {
      // Incomplete run record; report as unknown.
    }
    process.stdout.write(`${runId}  ${status.padEnd(9)}  ${taskId}\n`);
  }
}

const operation = process.argv[2];
const target = process.argv[3];

switch (operation) {
  case "validate": {
    if (!target) fail(4, "usage: mosaic-task.mjs validate <taskFile>");
    const file = path.resolve(target);
    const task = validateTask(readJsonFile(file, "task file"), file);
    const { missionSnapshot, ...rest } = task;
    process.stdout.write(`${JSON.stringify(rest, null, 2)}\n`);
    process.exit(0);
  }
  case "run":
    if (!target) fail(4, "usage: mosaic-task.mjs run <taskFile>");
    runTask(path.resolve(target));
    break;
  case "list":
    listRuns();
    process.exit(0);
  default:
    fail(4, `unknown operation: ${JSON.stringify(operation ?? "")} (expected validate | run | list)`);
}