import * as Lint from "tslint/lib";

import * as ts from "typescript";

export class Rule extends Lint.Rules.AbstractRule {

public static FAILURE_STRING = "The '|' and '&' operators must be surrounded by single spaces";

public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] {

return this.applyWithFunction(sourceFile, walk);

}

}

function walk(ctx: Lint.WalkContext<void>): void {

const { sourceFile } = ctx;

ts.forEachChild(sourceFile, recur);

function recur(node: ts.Node): void {

if (node.kind === ts.SyntaxKind.UnionType || node.kind === ts.SyntaxKind.IntersectionType) {

check((node as ts.UnionOrIntersectionTypeNode).types);

}

ts.forEachChild(node, recur);

}

function check(types: ts.TypeNode[]): void {

let expectedStart = types[0].end + 2; // space, | or &

for (let i = 1; i < types.length; i++) {

const currentType = types[i];

if (expectedStart !== currentType.pos || currentType.getLeadingTriviaWidth() !== 1) {

const previousTypeEndPos = sourceFile.getLineAndCharacterOfPosition(types[i - 1].end);

const currentTypeStartPos = sourceFile.getLineAndCharacterOfPosition(currentType.pos);

if (previousTypeEndPos.line === currentTypeStartPos.line) {

ctx.addFailureAtNode(currentType, Rule.FAILURE_STRING);

}

}

expectedStart = currentType.end + 2;

}

}

}