exception CannotExtractName;

let getName =
  fun
  | Typescript.FunctionDeclaration({name: Identifier({text})}) => text
  | Typescript.InterfaceDeclaration({name: Identifier({text})}) => text
  | Typescript.Parameter({name: Identifier({text})}) => text
  | Typescript.Identifier({text}) => text
  | Typescript.TypeParameter({name: Identifier({text})}) => text
  | _ => raise(CannotExtractName);

let getNamesOfArray = names => names |> Array.to_list |> List.map(getName);

let rec memberToObjectProperty =
  fun
  | Typescript.PropertySignature(prop) => (
      getName(prop.name),
      typescriptAstToBsType(prop.type_),
      switch (prop.questionToken) {
      | Some(_) => true
      | None => false
      },
    )
  | _ => raise(Not_found)
and typescriptAstToBsType =
  fun
  | Typescript.Parameter(parameter) => typescriptAstToBsType(parameter.type_)
  | Typescript.NumberKeyword(_) => BsTypeAst.Number
  | Typescript.StringKeyword(_) => BsTypeAst.String
  | Typescript.TypeLiteral(literal) =>
    BsTypeAst.Object(
      literal.members |> Array.to_list |> List.map(memberToObjectProperty),
    )
  | Typescript.TypeReference(typeRef) =>
    BsTypeAst.Named([], getName(typeRef.typeName), None)
  | _ => BsTypeAst.Any;

let rec typescriptAstToBsTypeAst =
  fun
  | Typescript.SourceFile(sourceFile) =>
    if (Array.length(sourceFile.parseDiagnostics) > 0) {
      raise(Diagnostic.Error(Diagnostic.diagnosticOfTs(sourceFile)));
    } else {
      BsTypeAst.ModuleDecl(
        "\"" ++ Genutils.normalize_name(sourceFile.fileName) ++ "\"",
        sourceFile.statements
        |> Array.to_list
        |> List.map(typescriptAstToBsTypeAst),
      );
    }
  | Typescript.FunctionDeclaration(func) =>
    BsTypeAst.FuncDecl(
      getName(func.name),
      BsTypeAst.Function({
        typeParams: getNamesOfArray(func.typeParameters),
        formalParams:
          func.parameters
          |> Array.to_list
          |> List.map(param =>
               (getName(param), typescriptAstToBsType(param))
             ),
        restParam: None,
        returnType: typescriptAstToBsType(func.type_),
      }),
    )
  | Typescript.InterfaceDeclaration(interface) =>
    BsTypeAst.InterfaceDecl(
      getName(interface.name),
      getNamesOfArray(interface.typeParameters),
      BsTypeAst.Object(
        interface.members |> Array.to_list |> List.map(memberToObjectProperty),
      ),
    )
  | Typescript.TypeAliasDeclaration(decl) =>
    BsTypeAst.TypeDecl(
      getName(decl.name),
      getNamesOfArray(decl.typeParameters),
      typescriptAstToBsType(decl.type_),
    )
  | _ => BsTypeAst.Noop;