import type {
  API,
  ASTPath,
  Collection,
  FileInfo,
  ImportDeclaration,
  JSCodeshift,
  JSXAttribute,
  JSXMemberExpression,
  JSXOpeningElement,
} from 'jscodeshift';

const TARGET_COMPONENTS = new Set([
  'TextLink',
  'Menu',
  'GNBList.Item',
]);

const DESIGN_SYSTEM_PACKAGE = '@wishket/design-system';
const NEXT_LINK_PACKAGE = 'next/link';
const NEXT_LINK_LOCAL_NAME = 'Link';

export default function transformer(file: FileInfo, api: API): string {
  const j: JSCodeshift = api.jscodeshift;
  const root = j(file.source);

  const dsImport: Collection<ImportDeclaration> = root.find(
    j.ImportDeclaration,
    {
      source: { value: DESIGN_SYSTEM_PACKAGE },
    },
  );
  if (dsImport.size() === 0) return file.source;

  let didChange = false;

  root
    .find(j.JSXOpeningElement)
    .forEach((path: ASTPath<JSXOpeningElement>) => {
      const name = getJSXName(path.node);
      if (!name || !TARGET_COMPONENTS.has(name)) return;

      const attrs = path.node.attributes ?? [];

      const hasAs = attrs.some(
        (attr): attr is JSXAttribute =>
          attr.type === 'JSXAttribute' &&
          attr.name.type === 'JSXIdentifier' &&
          attr.name.name === 'as',
      );
      if (hasAs) return;

      const hasHref = attrs.some(
        (attr): attr is JSXAttribute =>
          attr.type === 'JSXAttribute' &&
          attr.name.type === 'JSXIdentifier' &&
          attr.name.name === 'href',
      );
      if (!hasHref) return;

      const asAttr = j.jsxAttribute(
        j.jsxIdentifier('as'),
        j.jsxExpressionContainer(j.identifier(NEXT_LINK_LOCAL_NAME)),
      );
      path.node.attributes = [asAttr, ...attrs];
      didChange = true;
    });

  if (!didChange) return file.source;

  const hasNextLinkImport =
    root
      .find(j.ImportDeclaration, {
        source: { value: NEXT_LINK_PACKAGE },
      })
      .size() > 0;

  if (!hasNextLinkImport) {
    const newImport = j.importDeclaration(
      [j.importDefaultSpecifier(j.identifier(NEXT_LINK_LOCAL_NAME))],
      j.literal(NEXT_LINK_PACKAGE),
    );
    root.get().node.program.body.unshift(newImport);
  }

  return root.toSource({ quote: 'single' });
}

function getJSXName(node: JSXOpeningElement): string | null {
  const { name } = node;
  if (name.type === 'JSXIdentifier') return name.name;
  if (name.type === 'JSXMemberExpression') {
    return memberExpressionToString(name);
  }
  return null;
}

function memberExpressionToString(
  expr: JSXMemberExpression,
): string | null {
  const right = expr.property.name;
  if (expr.object.type === 'JSXIdentifier') {
    return `${expr.object.name}.${right}`;
  }
  if (expr.object.type === 'JSXMemberExpression') {
    const left = memberExpressionToString(expr.object);
    return left ? `${left}.${right}` : null;
  }
  return null;
}