import { access, mkdir, readFile, writeFile } from "node:fs/promises";
import path from "node:path";
import { pathToFileURL } from "node:url";

/** @param {string} name @param {string} fallback */
function argumentValue(name, fallback) {
  const index = process.argv.indexOf(name);
  return index >= 0 && process.argv[index + 1] ? process.argv[index + 1] : fallback;
}

const governancePath = argumentValue(
  "--governance",
  "config/contracts/registry-governance.json",
);
const artifactPath = argumentValue(
  "--artifact",
  "artifacts/quality/registries.json",
);
const governance = JSON.parse(
  await readFile(governancePath, "utf8"),
);
const failures = [];
const owners = new Map();
const snapshots = [];
const rowsByRegistry = new Map();
const registryExtensions = [".js", ".jsx", ".mjs", ".ts", ".tsx", ".mts"];

/** @param {string} declaredPath */
async function resolveRegistrySource(declaredPath) {
  const extension = path.extname(declaredPath);
  const basePath = extension
    ? declaredPath.slice(0, -extension.length)
    : declaredPath;
  const candidates = [];
  for (const candidateExtension of registryExtensions) {
    const candidate = `${basePath}${candidateExtension}`;
    try {
      await access(candidate);
      candidates.push(candidate);
    } catch {
      // A migration may legitimately replace the declared extension.
    }
  }
  if (candidates.length > 1) {
    failures.push(
      `ambiguous registry source ${declaredPath}: ${candidates.join(", ")}`,
    );
    return null;
  }
  return candidates[0] ?? null;
}

for (const specification of governance.registries) {
  if (owners.has(specification.registryId)) {
    failures.push(`duplicate owner for ${specification.registryId}`);
  }
  owners.set(specification.registryId, specification.owner);

  let rows = specification.declaredRows;
  const sourcePath = await resolveRegistrySource(specification.path);
  try {
    if (!sourcePath) throw new Error("missing registry source");
    const module = await import(
      `${pathToFileURL(path.resolve(sourcePath)).href}?registry-check=${Date.now()}`
    );
    rows = module[specification.exportName];
  } catch {
    if (!rows) failures.push(`missing registry source ${specification.path}`);
  }

  if (!rows || typeof rows !== "object" || Array.isArray(rows)) {
    failures.push(`${specification.registryId} is not an object registry`);
    continue;
  }

  rowsByRegistry.set(specification.registryId, rows);

  for (const [rowName, row] of Object.entries(rows)) {
    if (!row || typeof row !== "object" || Array.isArray(row)) {
      failures.push(`${specification.registryId}.${rowName} is not an object`);
      continue;
    }
    for (const field of specification.requiredFields) {
      if (!(field in row)) {
        failures.push(`${specification.registryId}.${rowName} missing ${field}`);
      }
    }
  }

  for (const field of specification.uniqueFields ?? []) {
    const values = new Map();
    for (const [rowName, row] of Object.entries(rows)) {
      if (!row || typeof row !== "object" || Array.isArray(row)) continue;
      const value = row[field];
      if (value === undefined) continue;
      if (values.has(value)) {
        failures.push(
          `${specification.registryId}.${rowName} duplicates ${field}=${String(value)} from ${values.get(value)}`,
        );
      } else {
        values.set(value, rowName);
      }
    }
  }

  snapshots.push({
    registryId: specification.registryId,
    owner: specification.owner,
    source: sourcePath ?? specification.path,
    rowCount: Object.keys(rows).length,
    rows,
  });
}

for (const specification of governance.registries) {
  const rows = rowsByRegistry.get(specification.registryId);
  if (!rows) continue;
  for (const reference of specification.references ?? []) {
    const targetRows = rowsByRegistry.get(reference.registryId);
    if (!targetRows) {
      failures.push(
        `${specification.registryId} references unknown registry ${reference.registryId}`,
      );
      continue;
    }
    const targetValues = new Set(
      Object.values(targetRows)
        .filter((row) => row && typeof row === "object" && !Array.isArray(row))
        .map((row) => row[reference.targetField])
        .filter((value) => value !== undefined),
    );
    for (const [rowName, row] of Object.entries(rows)) {
      if (!row || typeof row !== "object" || Array.isArray(row)) continue;
      const value = row[reference.field];
      if (value !== undefined && !targetValues.has(value)) {
        failures.push(
          `${specification.registryId}.${rowName}.${reference.field} references unknown ${reference.registryId}.${reference.targetField}=${String(value)}`,
        );
      }
    }
  }
}

const sourceFiles = governance.sourceDirectories ?? [
  "src/application",
  "src/presentation",
  "src/domain",
];
const adHocPatterns = [
  { name: "direct fetch", expression: /\bfetch\s*\(/ },
  { name: "direct localStorage", expression: /\blocalStorage\.(?:get|set|remove)Item/ },
  { name: "direct import.meta.env", expression: /\bimport\.meta\.env\./ },
  { name: "raw API path", expression: /["']\/api\// },
];

/** @param {string} directory */
async function scanDirectory(directory) {
  const entries = await import("node:fs/promises").then(({ readdir }) =>
    readdir(directory, { withFileTypes: true }),
  );
  for (const entry of entries) {
    const target = path.join(directory, entry.name);
    if (entry.isDirectory()) {
      await scanDirectory(target);
      continue;
    }
    if (!/\.(js|jsx|mjs|ts|tsx|mts)$/.test(entry.name)) continue;
    const content = await readFile(target, "utf8");
    for (const pattern of adHocPatterns) {
      if (pattern.expression.test(content)) {
        failures.push(`ad-hoc ${pattern.name} in ${target}`);
      }
    }
  }
}

for (const sourceDirectory of sourceFiles) {
  await scanDirectory(sourceDirectory);
}

await mkdir("artifacts/quality", { recursive: true });
await writeFile(
  artifactPath,
  `${JSON.stringify(
    {
      schemaVersion: 1,
      generatedAt: new Date().toISOString(),
      compatibilityImpact: governance.compatibilityImpact.current,
      failures,
      registries: snapshots,
    },
    null,
    2,
  )}\n`,
);

if (failures.length > 0) {
  process.stderr.write(`Registry governance failed:\n${failures.join("\n")}\n`);
  process.exit(1);
}
process.stdout.write(`Registry governance: ${snapshots.length} registries PASS\n`);