import { createHash } from 'node:crypto';
import { readFileSync } from 'node:fs';
import { resolve } from 'node:path';
import ts from '../../api/node_modules/typescript/lib/typescript.js';

const root = process.cwd();
const manifest = JSON.parse(
  readFileSync(resolve(root, 'docs/contracts/sms-config-r3-methods.json'), 'utf8'),
);
const printer = ts.createPrinter({ newLine: ts.NewLineKind.LineFeed });
const sha256 = (value) => createHash('sha256').update(value).digest('hex');

function loadSource(relativePath) {
  const filePath = resolve(root, relativePath);
  const source = readFileSync(filePath, 'utf8');
  const file = ts.createSourceFile(filePath, source, ts.ScriptTarget.Latest, true, ts.ScriptKind.TS);
  return { source, file };
}

function loadClass(relativePath, className) {
  const { source, file } = loadSource(relativePath);
  const declaration = file.statements.find(
    (statement) => ts.isClassDeclaration(statement) && statement.name?.text === className,
  );
  if (!declaration || !ts.isClassDeclaration(declaration)) {
    throw new Error(`${className} not found in ${relativePath}`);
  }
  return {
    source,
    file,
    methods: new Map(
      declaration.members.filter(ts.isMethodDeclaration).map((method) => [
        method.name.getText(file),
        method,
      ]),
    ),
  };
}

const reverseReplacements = {
  application: {
    'this.lifecycle.markTimedOutDownstreamConnections': 'this.markTimedOutDownstreamConnections',
    'this.lifecycle.getApplicationDeactivationPreview': 'this.getApplicationDeactivationPreview',
    'this.lifecycle.writeOperationLog': 'this.writeOperationLog',
  },
  signature: {
    'this.reportValidation.validateSignatureReportValues': 'this.validateSignatureReportValues',
    'this.reportValidation.withReportRequirementSnapshot': 'this.withReportRequirementSnapshot',
    'this.reportValidation.syncSignatureReportValues': 'this.syncSignatureReportValues',
    'this.audit.createAuditRecord': 'this.createAuditRecord',
  },
  drainage: {
    'this.reportValidation.validateDrainageReportValues': 'this.validateDrainageReportValues',
    'this.reportValidation.activateDrainageReporting': 'this.activateDrainageReporting',
    'this.reportValidation.suspendDrainageReporting': 'this.suspendDrainageReporting',
    'this.audit.createAuditRecord': 'this.createAuditRecord',
    'this.audit.reviewDrainageInfo': 'this.reviewDrainageInfo',
  },
  template: {
    'this.audit.createAuditRecord': 'this.createAuditRecord',
  },
  audit: {
    'this.lifecycle.writeOperationLog': 'this.writeOperationLog',
    'this.reportValidation.activateDrainageReporting': 'this.activateDrainageReporting',
    'this.reportValidation.suspendDrainageReporting': 'this.suspendDrainageReporting',
  },
  reportValidation: {
    'this.applications.getApplicationReportFields': 'this.getApplicationReportFields',
  },
};

function normalizeDomainBody(domain, method, file) {
  let printed = printer.printNode(ts.EmitHint.Unspecified, method.body, file);
  for (const [current, original] of Object.entries(reverseReplacements[domain] ?? {})) {
    printed = printed.split(current).join(original);
  }
  if (method.name.getText(file) === 'finalizeDisablingApplication') {
    printed = printed
      .split("SmsApplicationLifecycleService['getApplicationDeactivationPreview']")
      .join("SmsConfigService['getApplicationDeactivationPreview']");
  }
  return printed;
}

const domainMethods = new Map();
for (const [domain, definition] of Object.entries(manifest.domains)) {
  const loaded = loadClass(definition.file, definition.className);
  for (const name of definition.methods) {
    const method = loaded.methods.get(name);
    if (!method || !method.body) throw new Error(`Missing R3 domain method: ${domain}.${name}`);
    if (domainMethods.has(name)) throw new Error(`Duplicate R3 domain method: ${name}`);
    domainMethods.set(name, { domain, method, file: loaded.file, source: loaded.source });
  }
  if (loaded.methods.size !== definition.methods.length) {
    throw new Error(`Unexpected method found in R3 domain: ${domain}`);
  }
}

const expectedMethods = [...manifest.publicMethods, ...manifest.internalMethods];
for (const expected of expectedMethods) {
  const actual = domainMethods.get(expected.name);
  if (!actual) throw new Error(`R3 implementation missing: ${expected.name}`);
  if (actual.domain !== expected.domain) {
    throw new Error(`${expected.name} moved to unexpected R3 domain`);
  }
  const bodyHash = sha256(normalizeDomainBody(actual.domain, actual.method, actual.file));
  if (bodyHash !== expected.canonicalBodySha256) {
    throw new Error(`${expected.name} implementation changed during R3 split`);
  }
}
if (domainMethods.size !== expectedMethods.length) {
  throw new Error('Unexpected R3 implementation method found');
}

const facade = loadClass('api/src/sms-config/sms-config.service.ts', 'SmsConfigService');
const facadePublicMethods = new Map(
  [...facade.methods].filter(([, method]) =>
    !method.modifiers?.some((modifier) => modifier.kind === ts.SyntaxKind.PrivateKeyword),
  ),
);
for (const expected of manifest.publicMethods) {
  const method = facadePublicMethods.get(expected.name);
  if (!method || !method.body) throw new Error(`SmsConfigService facade method missing: ${expected.name}`);
  const signature = facade.source.slice(method.getStart(facade.file), method.body.getStart(facade.file)).trim();
  if (signature !== expected.signature) throw new Error(`${expected.name} facade signature changed`);
}
if (facadePublicMethods.size !== manifest.publicMethods.length) {
  throw new Error('Unexpected SmsConfigService facade method found');
}

const contracts = loadSource('api/src/sms-config/sms-config.contracts.ts');
const actualContracts = new Map(
  contracts.file.statements
    .filter((statement) => ts.isInterfaceDeclaration(statement) || ts.isTypeAliasDeclaration(statement))
    .map((statement) => [statement.name.text, sha256(statement.getText(contracts.file))]),
);
for (const expected of manifest.contracts) {
  if (actualContracts.get(expected.name) !== expected.sha256) {
    throw new Error(`SMS config contract changed during R3 split: ${expected.name}`);
  }
}
if (actualContracts.size !== manifest.contracts.length) {
  throw new Error('Unexpected SMS config contract found');
}

const helpers = loadSource('api/src/sms-config/sms-config.helpers.ts');
const actualHelpers = new Map(
  helpers.file.statements
    .filter(
      (statement) =>
        ts.isInterfaceDeclaration(statement) ||
        ts.isTypeAliasDeclaration(statement) ||
        ts.isFunctionDeclaration(statement) ||
        ts.isVariableStatement(statement),
    )
    .map((statement) => [
      ts.isVariableStatement(statement)
        ? statement.declarationList.declarations[0].name.getText(helpers.file)
        : statement.name.text,
      sha256(statement.getText(helpers.file).replace(/^export\s+/, '')),
    ]),
);
for (const expected of [...manifest.helpers, ...manifest.sharedDeclarations]) {
  if (actualHelpers.get(expected.name) !== expected.sha256) {
    throw new Error(`SMS config helper changed during R3 split: ${expected.name}`);
  }
}
if (actualHelpers.size !== manifest.helpers.length + manifest.sharedDeclarations.length) {
  throw new Error('Unexpected SMS config helper found');
}

for (const controller of [
  'api/src/sms-config/admin-sms-config.controller.ts',
  'api/src/sms-config/client-sms-config.controller.ts',
  'api/src/send-chain/gateway-events.controller.ts',
]) {
  const loaded = loadSource(controller);
  for (const statement of loaded.file.statements.filter(ts.isImportDeclaration)) {
    if (!statement.moduleSpecifier.getText(loaded.file).includes('sms-config.service')) continue;
    const names = statement.importClause?.namedBindings && ts.isNamedImports(statement.importClause.namedBindings)
      ? statement.importClause.namedBindings.elements.map((element) => element.name.text)
      : [];
    if (names.some((name) => name.endsWith('Dto') || name.endsWith('ListQuery'))) {
      throw new Error(`${controller} still imports DTOs from the implementation facade`);
    }
  }
}

console.log(
  `R3 SMS configuration facade verified: ${manifest.publicMethods.length} public methods, ${manifest.internalMethods.length} internal methods, ${manifest.contracts.length} contracts and ${manifest.helpers.length + manifest.sharedDeclarations.length} helpers/constants; implementations unchanged.`,
);