import * as ts from 'typescript';
import * as Lint from 'tslint';
import { ScopedSymbolTrackingWalker } from './ScopedSymbolTrackingWalker';

import { AstUtils } from './AstUtils';

/**
 * A walker that creates failures whenever it detects a string parameter is being passed to a certain constructor. .
 */
export class NoStringParameterToFunctionCallWalker extends ScopedSymbolTrackingWalker {
    private failureString: string;
    private targetFunctionName: string;

    public constructor(sourceFile: ts.SourceFile, targetFunctionName: string, options: Lint.IOptions, program?: ts.Program) {
        super(sourceFile, options, program);
        this.targetFunctionName = targetFunctionName;
        this.failureString = 'Forbidden ' + targetFunctionName + ' string parameter: ';
    }

    protected visitCallExpression(node: ts.CallExpression) {
        this.validateExpression(node);
        super.visitCallExpression(node);
    }

    private validateExpression(node: ts.CallExpression): void {
        const functionName: string = AstUtils.getFunctionName(node);
        const firstArg: ts.Expression = node.arguments[0];
        if (functionName === this.targetFunctionName && firstArg != null) {
            if (!this.isExpressionEvaluatingToFunction(firstArg)) {
                const msg: string =
                    this.failureString +
                    firstArg
                        .getFullText()
                        .trim()
                        .substring(0, 40);
                this.addFailureAt(node.getStart(), node.getWidth(), msg);
            }
        }
    }
}