import ts = require('typescript');
import { Visitor } from './visitor';
import { TranspilerContext } from './transpiler-context';
import { traverseAst } from './traverse-ast';
import { MutableSourceCode } from './mutable-source-code';

export interface CodeTransformer {
    transform(ast: ts.SourceFile): MutableSourceCode;
}

export class VisitorBasedTransformer implements CodeTransformer {
    constructor(private visitors: Visitor[], private languageServiceProvider: () => ts.LanguageService) {
    }

    transform(ast: ts.SourceFile): MutableSourceCode {
        const context: TranspilerContext = new TranspilerContext(ast.fileName, this.languageServiceProvider);
        this.visitors.forEach((visitor) => {
            context.halted || traverseAst(ast, visitor, context);
        });

        if (context.halted) {
            return null;
        } else {
            const mutable = new MutableSourceCode(ast);
            mutable.execute(context.actions);
            return mutable;
        }
    }
}