import { readFileSync } from 'node:fs';
import { createHash } from 'node:crypto';

const read = (path) => readFileSync(new URL(`../${path}`, import.meta.url), 'utf8');
const semver = /^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-([0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*))?(?:\+[0-9A-Za-z-]+(?:\.[0-9A-Za-z-]+)*)?$/;
const contract = JSON.parse(read('contracts/api-contract.json'));
const fail = (message) => {
  console.error(`API contract check failed: ${message}`);
  process.exit(1);
};

const dtoSources = ['server/src/WebDrop.Api/Json/ApiJson.cs', 'server/src/WebDrop.Core/Channels/Dtos.cs', 'server/src/WebDrop.Core/Channels/Settings.cs', 'server/src/WebDrop.Core/Common/Enums.cs', 'server/src/WebDrop.Core/Spaces/Workspace.cs', 'server/src/WebDrop.Core/Accounts/AccountProfile.cs', 'server/src/WebDrop.Api/Passkeys/PasskeyDtos.cs', 'server/src/WebDrop.Core/Spaces/WorkspaceCrypto.cs', 'server/src/WebDrop.Api/Endpoints/Endpoints.WorkspaceCrypto.cs'];
const dtoDigest = createHash('sha256').update(dtoSources.map(path => `${path}\n${read(path).replace(/\r\n/g, '\n')}\n`).join('')).digest('hex');
const generatedDigest = /backend-contract-sha256: ([a-f0-9]{64})/.exec(read('web/src/api/generated.ts'))?.[1];
if (generatedDigest !== dtoDigest) fail('Backend DTOs changed. Regenerate with dotnet run --project tools/ContractGenerator -- .');
if (JSON.parse(read('contracts/api.schemas.json'))['x-backend-contract-sha256'] !== dtoDigest) fail('Generated API schemas are stale. Run ContractGenerator.');

if (typeof contract.version !== 'string' || !semver.test(contract.version)) {
  fail('contracts/api-contract.json must contain a SemVer version.');
}

const apiMajor = Number(contract.version.split('.')[0]);
const openapi = read('docs/openapi.yaml');
const openapiVersion = /^info:\s*\r?\n(?:.*\r?\n)*?\s+version:\s*([^\s#]+)/m.exec(openapi)?.[1];
if (openapiVersion !== contract.version) fail(`OpenAPI version ${openapiVersion ?? '(missing)'} differs from ${contract.version}.`);

const backend = read('server/src/WebDrop.Api/Hosting/ApiContract.cs');
const backendVersion = /const string Version = "([^"]+)"/.exec(backend)?.[1];
if (backendVersion !== contract.version) fail(`backend version ${backendVersion ?? '(missing)'} differs from ${contract.version}.`);

const frontend = read('web/src/api/contract.ts');
const supportedMajor = Number(/SUPPORTED_API_CONTRACT_MAJOR\s*=\s*(\d+)/.exec(frontend)?.[1]);
if (supportedMajor !== apiMajor) {
  fail(`backend contract is ${contract.version}; frontend still supports API major ${supportedMajor || '(missing)'}. Update web/src/api/contract.ts.`);
}

const tag = process.argv[2];
if (tag !== undefined) {
  if (!tag.startsWith('v')) fail(`release tag ${tag} must start with v.`);
  const releaseVersion = tag.slice(1);
  if (!semver.test(releaseVersion) || releaseVersion.includes('+')) {
    fail(`release tag ${tag} must be a SemVer version usable as an OCI image tag (expected vMAJOR.MINOR.PATCH[-prerelease]).`);
  }
}

console.log(`API contract ${contract.version}: backend, OpenAPI, and frontend major ${supportedMajor} agree.`);