import fs from "node:fs/promises";
import { appendFileSync } from "node:fs";
import path from "node:path";
import { createHash, randomUUID } from "node:crypto";
import { authoringContext } from "./authoring-context.js";
import type { convergeAuthoring } from "./authoring-converge.js";
import { execFile as callback } from "node:child_process";
import { promisify } from "node:util";
import { buildImmutableCandidate, checkerIdentity } from "./checked-build.js";
import {
  planEvolution,
  reviewSemanticMajors,
  type WorkspaceRevision,
  type EvolutionReview,
} from "../capability-model/index.js";

export const checkRecordName = (directory: string) => createHash("sha256").update(directory).digest("hex") + ".json";
export async function checkAuthoring(
  start: string,
  output: string,
  options: { baseline?: string; reviews?: string; contractOnly?: boolean } = {},
) {
  const started = performance.now();
  const timings: Record<string, number> = {};
  const context = await authoringContext(start);
  const location = await fs.realpath(start);
  const directory = location === context.workbench ? "root" : path.relative(context.workbench, location);
  const resource = context.resources.find((entry) => entry.directory === directory);
  if (!resource) throw new Error("Run check from a registered repository root or the workbench");
  await fs.mkdir(output, { mode: 0o700 });
  const report: {
    directory: string;
    checker: string;
    candidateOnly: true;
    activationEvidence: false;
    commit?: string;
    artifactPath?: string;
    blockers: string[];
    phase: string;
    output: string;
    compilation?: "passed";
    runtime?: "execution";
    activationReadiness?: "preserve" | "migration-required" | "blocked";
    migrationRequired?: string[];
  } = {
    directory,
    checker: checkerIdentity(),
    candidateOnly: true,
    activationEvidence: false,
    blockers: [],
    phase: "convergence",
    output,
  };
  const progress = async (running = true) => {
    const file = path.join(output, "report.json"),
      temp = `${file}.tmp`;
    await fs.writeFile(temp, JSON.stringify({ ...report, timings, running }, null, 2));
    await fs.rename(temp, file);
  };
  await progress();
  try {
    console.error(`[${new Date().toISOString()}] Check: capture source and converge dependencies`);
    // Serialize only source capture, not the potentially slow Nix build.
    // Repository-scoped agents can check separate immutable candidates in parallel.
    const capture = promisify(callback)("quixos-qx", ["converge", context.workbench, directory], {
      maxBuffer: 4 * 1024 * 1024,
      env: { ...process.env, QUIXOS_JJ_NO_CHECKPOINT: "1", QUIXOS_TRACE_CAPTURE: "1", QUIXOS_TRACE_PROFILE: "1" },
    });
    console.error(`Capture details: ${path.join(output, "capture.log")}`);
    capture.child.stderr?.on("data", (chunk) => appendFileSync(path.join(output, "capture.log"), chunk));
    const captured = await capture.catch((error) => {
      if (typeof error.stdout === "string" && error.stdout.trim().startsWith("{")) return { stdout: error.stdout };
      throw error;
    });
    const converged = JSON.parse(captured.stdout) as Awaited<ReturnType<typeof convergeAuthoring>>;
    timings.captureMs = Math.round(performance.now() - started);
    console.error(`[${new Date().toISOString()}] Check: source captured in ${(timings.captureMs / 1000).toFixed(1)}s`);
    if (!converged.candidate) {
      report.phase = converged.worklist.find((entry) => entry.phase !== "dependency")?.phase ?? "convergence";
      throw new Error(
        converged.worklist.map((entry) => `${entry.directory} [${entry.phase}]: ${entry.message}`).join("\n"),
      );
    }
    report.commit = converged.candidate.commit;
    report.phase = "verification";
    await progress();
    const buildStarted = performance.now();
    console.error(
      `[${new Date().toISOString()}] Check: immutable Nix ${options.contractOnly ? "contract" : "verification"}; build output: ${path.join(output, "nix.log")}`,
    );
    try {
      report.artifactPath = await buildImmutableCandidate(
        converged.candidate,
        resource.kind,
        path.join(output, "nix.log"),
        options.contractOnly,
        (phase, ms) => {
          timings[phase] = ms;
        },
      );
    } finally {
      timings.immutableCheckMs = Math.round(performance.now() - buildStarted);
      console.error(
        `[${new Date().toISOString()}] Check: immutable phase ended after ${(timings.immutableCheckMs / 1000).toFixed(1)}s`,
      );
    }
    const candidateText = await fs.readFile(path.join(report.artifactPath, "candidate.json"), "utf8");
    await fs.writeFile(path.join(output, "candidate.json"), candidateText);
    report.compilation = "passed";
    try {
      await fs.access(path.join(report.artifactPath, "execution-plan.json"));
      report.runtime = "execution";
    } catch (error) {
      if ((error as NodeJS.ErrnoException).code !== "ENOENT") throw error;
    }
    if (resource.kind === "workspace" && !options.contractOnly && report.runtime === "execution") {
      report.phase = "semantic-review";
      if (options.reviews && !options.baseline)
        throw new Error("Execution semantic reviews require an explicit --baseline candidate");
      const baseline = options.baseline
        ? (JSON.parse(await fs.readFile(options.baseline, "utf8")) as WorkspaceRevision)
        : null;
      const receipts = options.reviews
        ? (JSON.parse(await fs.readFile(options.reviews, "utf8")) as EvolutionReview[])
        : [];
      const review = reviewSemanticMajors(baseline, JSON.parse(candidateText), receipts);
      await fs.writeFile(path.join(output, "semantic-review.json"), JSON.stringify(review, null, 2));
      report.blockers.push(...review.blockers);
    } else if (resource.kind === "workspace" && !options.contractOnly) {
      report.phase = "evolution";
      await progress();
      let baseline = options.baseline;
      if (!baseline) {
        try {
          const host = JSON.parse(await fs.readFile("/etc/quixos/workspace-source.json", "utf8"));
          if ((await fs.realpath(host.workbenchRoot)) === context.workbench)
            baseline = JSON.parse(
              await fs.readFile(path.join(host.runtimeClosureRoot, "manifest.json"), "utf8"),
            ).workspacePlanPath;
        } catch (error) {
          if ((error as NodeJS.ErrnoException).code !== "ENOENT") throw error;
        }
      }
      const before = baseline ? (JSON.parse(await fs.readFile(baseline, "utf8")) as WorkspaceRevision) : null;
      const reviews = options.reviews
        ? (JSON.parse(await fs.readFile(options.reviews, "utf8")) as EvolutionReview[])
        : [];
      const evolution = planEvolution(before, JSON.parse(candidateText), { reviews });
      await fs.writeFile(path.join(output, "evolution.json"), JSON.stringify(evolution, null, 2));
      report.blockers.push(...evolution.blockers);
      report.migrationRequired = evolution.migrationRequired;
      report.activationReadiness = evolution.blockers.length
        ? "blocked"
        : evolution.migrationRequired.length
          ? "migration-required"
          : "preserve";
      if (evolution.migrationRequired.length)
        report.blockers.push(
          `Explicit migration required for: ${evolution.migrationRequired.join(", ")}. Compilation passed; supply a migration path before cutover.`,
        );
    }
    if (!report.blockers.length) report.phase = options.contractOnly ? "contract-only" : "checked";
  } catch (error) {
    report.blockers.push(String(error instanceof Error ? error.message : error));
  }
  timings.totalMs = Math.round(performance.now() - started);
  Object.assign(report, { timings });
  await progress(false);
  if (options.contractOnly) return report;
  const records = path.join(context.workbench, ".quixos/checks");
  await fs.mkdir(records, { recursive: true });
  const remember = async (value: typeof report) => {
    const filename = path.join(records, checkRecordName(value.directory)),
      temporary = `${filename}.${randomUUID()}.tmp`;
    await fs.writeFile(temporary, JSON.stringify(value, null, 2), { flag: "wx", mode: 0o600 });
    await fs.rename(temporary, filename);
  };
  if (report.artifactPath && report.compilation === "passed" && !report.blockers.length) {
    const graph = JSON.parse(await fs.readFile(path.join(report.artifactPath, "graph.json"), "utf8"));
    for (const checked of graph.resources) {
      const managed = context.resources.find(
        (entry) => entry.kind === checked.kind && entry.source?.repository === checked.source.repository,
      );
      if (managed && managed.directory !== directory)
        await remember({
          ...report,
          directory: managed.directory,
          commit: checked.source.commit,
          blockers: [],
          phase: "checked",
        });
    }
  }
  await remember(report);
  return report;
}