/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */

/** Template string function that can be used to strip indentation from a given string literal. */
export function dedent(strings: TemplateStringsArray, ...values: any[]) {
  let joinedString = '';
  for (let i = 0; i < values.length; i++) {
    joinedString += `${strings[i]}${values[i]}`;
  }
  joinedString += strings[strings.length - 1];
  const lines = joinedString.split('\n');
  while (isBlank(lines[0])) {
    lines.shift();
  }
  while (isBlank(lines[lines.length - 1])) {
    lines.pop();
  }
  let minWhitespacePrefix = lines.reduce(
      (min, line) => Math.min(min, numOfWhiteSpaceLeadingChars(line)), Number.MAX_SAFE_INTEGER);
  return lines.map((line) => line.substring(minWhitespacePrefix)).join('\n');
}

/**
 * Tests to see if the line is blank.
 *
 * A blank line is such which contains only whitespace.
 * @param text string to test for blank-ness.
 */
function isBlank(text: string): boolean {
  return /^\s*$/.test(text);
}

/**
 * Returns number of whitespace leading characters.
 *
 * @param text
 */
function numOfWhiteSpaceLeadingChars(text: string): number {
  return text.match(/^\s*/)![0].length;
}


/**
 * Jasmine AsymmetricMatcher which can be used to assert `.debug` properties.
 *
 * ```
 * expect(obj).toEqual({
 *   create: debugMatch('someValue')
 * })
 * ```
 *
 * In the above example it will assert that `obj.create.debug === 'someValue'`.
 *
 * @param expected Expected value.
 */
export function debugMatch<T>(expected: T): any {
  const matcher = function() {};
  let actual: any = null;

  matcher.asymmetricMatch = function(objectWithDebug: any) {
    return jasmine.matchersUtil.equals(actual = objectWithDebug.debug, expected);
  };
  matcher.jasmineToString = function() {
    return `<${JSON.stringify(actual)} != ${JSON.stringify(expected)}>`;
  };
  return matcher;
}