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/report-materials-r4-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');
  return {
    source,
    file: ts.createSourceFile(filePath, source, ts.ScriptTarget.Latest, true, ts.ScriptKind.TS),
  };
}

function loadClass(relativePath, className) {
  const loaded = loadSource(relativePath);
  const declaration = loaded.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 {
    ...loaded,
    methods: new Map(
      declaration.members.filter(ts.isMethodDeclaration).map((method) => [
        method.name.getText(loaded.file),
        method,
      ]),
    ),
  };
}

const reverseReplacements = {
  officialExport: {
    'this.pending.findPendingItems': 'this.findPendingItems',
  },
  importReview: {
    'this.importParser.saveImportProfile': 'this.saveImportProfile',
  },
  batchGeneration: {
    'this.operations.claimBatchOperation': 'this.claimBatchOperation',
    'this.operations.completeBatchOperation': 'this.completeBatchOperation',
    'this.operations.failBatchOperation': 'this.failBatchOperation',
    'this.channelExport.exportChannelBatch': 'this.exportChannelBatch',
  },
};

function normalizedBody(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);
  }
  printed = printed
    .split("ReportBatchGenerationService['preflightBatch']")
    .join("ReportMaterialsService['preflightBatch']")
    .split("ReportBatchGenerationService['prepareBatchItem']")
    .join("ReportMaterialsService['prepareBatchItem']");
  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?.body) throw new Error(`Missing R4 domain method: ${domain}.${name}`);
    if (domainMethods.has(name)) throw new Error(`Duplicate R4 domain method: ${name}`);
    domainMethods.set(name, { domain, method, file: loaded.file });
  }
  if (loaded.methods.size !== definition.methods.length) {
    throw new Error(`Unexpected method found in R4 domain: ${domain}`);
  }
}

const expectedMethods = [...manifest.publicMethods, ...manifest.internalMethods];
for (const expected of expectedMethods) {
  const actual = domainMethods.get(expected.name);
  if (!actual) throw new Error(`R4 implementation missing: ${expected.name}`);
  if (actual.domain !== expected.domain) throw new Error(`${expected.name} moved to unexpected R4 domain`);
  if (sha256(normalizedBody(actual.domain, actual.method, actual.file)) !== expected.canonicalBodySha256) {
    throw new Error(`${expected.name} implementation changed during R4 split`);
  }
}
if (domainMethods.size !== expectedMethods.length) {
  throw new Error('Unexpected R4 implementation method found');
}

const facade = loadClass('api/src/report-materials/report-materials.service.ts', 'ReportMaterialsService');
for (const expected of manifest.publicMethods) {
  const method = facade.methods.get(expected.name);
  if (!method?.body) throw new Error(`ReportMaterialsService 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 (facade.methods.size !== manifest.publicMethods.length) {
  throw new Error('Unexpected ReportMaterialsService facade method found');
}

const contracts = loadSource('api/src/report-materials/report-materials.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).replace(/^export\s+/, '')),
    ]),
);
for (const expected of manifest.contracts) {
  if (actualContracts.get(expected.name) !== expected.sha256) {
    throw new Error(`Report-materials contract changed during R4 split: ${expected.name}`);
  }
}
if (actualContracts.size !== manifest.contracts.length) {
  throw new Error('Unexpected report-materials contract found');
}

const helpers = loadSource('api/src/report-materials/report-materials.helpers.ts');
const actualHelpers = new Map();
for (const statement of helpers.file.statements) {
  if (ts.isFunctionDeclaration(statement) || ts.isInterfaceDeclaration(statement) || ts.isTypeAliasDeclaration(statement)) {
    if (statement.name) {
      actualHelpers.set(statement.name.text, sha256(statement.getText(helpers.file).replace(/^export\s+/, '')));
    }
  } else if (ts.isVariableStatement(statement)) {
    for (const declaration of statement.declarationList.declarations) {
      actualHelpers.set(
        declaration.name.getText(helpers.file),
        sha256(statement.getText(helpers.file).replace(/^export\s+/, '')),
      );
    }
  }
}
for (const expected of manifest.helpers) {
  if (actualHelpers.get(expected.name) !== expected.sha256) {
    throw new Error(`Report-materials helper changed during R4 split: ${expected.name}`);
  }
}
if (actualHelpers.size !== manifest.helpers.length) {
  throw new Error('Unexpected report-materials helper found');
}

const controller = loadSource('api/src/report-materials/report-materials.controller.ts');
for (const statement of controller.file.statements.filter(ts.isImportDeclaration)) {
  if (!statement.moduleSpecifier.getText(controller.file).includes('report-materials.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('Mapping'))) {
    throw new Error('ReportMaterialsController still imports contracts from the implementation facade');
  }
}

console.log(
  `R4 report-materials facade verified: ${manifest.publicMethods.length} public methods, ${manifest.internalMethods.length} internal methods, ${manifest.contracts.length} contracts and ${manifest.helpers.length} helpers; implementations unchanged.`,
);