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'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.flip = flip;

var _convert = require('./convert');

var _convert2 = _interopRequireDefault(_convert);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function reduce(node, precision) {
  if (node.type === "MathExpression") return reduceMathExpression(node, precision);

  return node;
}

function isEqual(left, right) {
  return left.type === right.type && left.value === right.value;
}

function isValueType(type) {
  switch (type) {
    case 'LengthValue':
    case 'AngleValue':
    case 'TimeValue':
    case 'FrequencyValue':
    case 'ResolutionValue':
    case 'EmValue':
    case 'ExValue':
    case 'ChValue':
    case 'RemValue':
    case 'VhValue':
    case 'VwValue':
    case 'VminValue':
    case 'VmaxValue':
    case 'PercentageValue':
    case 'Value':
      return true;
  }
  return false;
}

function convertMathExpression(node, precision) {
  var nodes = (0, _convert2.default)(node.left, node.right, precision);
  var left = reduce(nodes.left, precision);
  var right = reduce(nodes.right, precision);

  if (left.type === "MathExpression" && right.type === "MathExpression") {

    if (left.operator === '/' && right.operator === '*' || left.operator === '-' && right.operator === '+' || left.operator === '*' && right.operator === '/' || left.operator === '+' && right.operator === '-') {

      if (isEqual(left.right, right.right)) nodes = (0, _convert2.default)(left.left, right.left, precision);else if (isEqual(left.right, right.left)) nodes = (0, _convert2.default)(left.left, right.right, precision);

      left = reduce(nodes.left, precision);
      right = reduce(nodes.right, precision);
    }
  }

  node.left = left;
  node.right = right;
  return node;
}

function flip(operator) {
  return operator === '+' ? '-' : '+';
}

function flipValue(node) {
  if (isValueType(node.type)) node.value = -node.value;else if (node.type == 'MathExpression') {
    node.left = flipValue(node.left);
    node.right = flipValue(node.right);
  }
  return node;
}

function reduceAddSubExpression(node, precision) {
  var _node = node,
      left = _node.left,
      right = _node.right,
      op = _node.operator;


  if (left.type === 'CssVariable' || right.type === 'CssVariable') return node;

  // something + 0 => something
  // something - 0 => something
  if (right.value === 0) return left;

  // 0 + something => something
  if (left.value === 0 && op === "+") return right;

  // 0 - something => -something
  if (left.value === 0 && op === "-") return flipValue(right);

  // value + value
  // value - value
  if (left.type === right.type && isValueType(left.type)) {
    node = Object.assign({}, left);
    if (op === "+") node.value = left.value + right.value;else node.value = left.value - right.value;
  }

  // value <op> (expr)
  if (isValueType(left.type) && (right.operator === '+' || right.operator === '-') && right.type === 'MathExpression') {
    // value + (value + something) => (value + value) + something
    // value + (value - something) => (value + value) - something
    // value - (value + something) => (value - value) - something
    // value - (value - something) => (value - value) + something
    if (left.type === right.left.type) {
      node = Object.assign({}, node);
      node.left = reduce({
        type: 'MathExpression',
        operator: op,
        left: left,
        right: right.left
      }, precision);
      node.right = right.right;
      node.operator = op === '-' ? flip(right.operator) : right.operator;
      return reduce(node, precision);
    }
    // value + (something + value) => (value + value) + something
    // value + (something - value) => (value - value) + something
    // value - (something + value) => (value - value) - something
    // value - (something - value) => (value + value) - something
    else if (left.type === right.right.type) {
        node = Object.assign({}, node);
        node.left = reduce({
          type: 'MathExpression',
          operator: op === '-' ? flip(right.operator) : right.operator,
          left: left,
          right: right.right
        }, precision);
        node.right = right.left;
        return reduce(node, precision);
      }
  }

  // (expr) <op> value
  if (left.type === 'MathExpression' && (left.operator === '+' || left.operator === '-') && isValueType(right.type)) {
    // (value + something) + value => (value + value) + something
    // (value - something) + value => (value + value) - something
    // (value + something) - value => (value - value) + something
    // (value - something) - value => (value - value) - something
    if (right.type === left.left.type) {
      node = Object.assign({}, left);
      node.left = reduce({
        type: 'MathExpression',
        operator: op,
        left: left.left,
        right: right
      }, precision);
      return reduce(node, precision);
    }
    // (something + value) + value => something + (value + value)
    // (something - value1) + value2 => something - (value2 - value1)
    // (something + value) - value => something + (value - value)
    // (something - value) - value => something - (value + value)
    else if (right.type === left.right.type) {
        node = Object.assign({}, left);
        if (left.operator === '-') {
          node.right = reduce({
            type: 'MathExpression',
            operator: op === '-' ? '+' : '-',
            left: right,
            right: left.right
          }, precision);
          node.operator = op === '-' ? '-' : '+';
        } else {
          node.right = reduce({
            type: 'MathExpression',
            operator: op,
            left: left.right,
            right: right
          }, precision);
        }
        if (node.right.value < 0) {
          node.right.value *= -1;
          node.operator = node.operator === '-' ? '+' : '-';
        }
        return reduce(node, precision);
      }
  }
  return node;
}

function reduceDivisionExpression(node, precision) {
  if (!isValueType(node.right.type)) return node;

  if (node.right.type !== 'Value') throw new Error('Cannot divide by "' + node.right.unit + '", number expected');

  if (node.right.value === 0) throw new Error('Cannot divide by zero');

  // (expr) / value
  if (node.left.type === 'MathExpression') {
    if (isValueType(node.left.left.type) && isValueType(node.left.right.type)) {
      node.left.left.value /= node.right.value;
      node.left.right.value /= node.right.value;
      return reduce(node.left, precision);
    }
    return node;
  }
  // something / value
  else if (isValueType(node.left.type)) {
      node.left.value /= node.right.value;
      return node.left;
    }
  return node;
}

function reduceMultiplicationExpression(node) {
  // (expr) * value
  if (node.left.type === 'MathExpression' && node.right.type === 'Value') {
    if (isValueType(node.left.left.type) && isValueType(node.left.right.type)) {
      node.left.left.value *= node.right.value;
      node.left.right.value *= node.right.value;
      return node.left;
    }
  }
  // something * value
  else if (isValueType(node.left.type) && node.right.type === 'Value') {
      node.left.value *= node.right.value;
      return node.left;
    }
    // value * (expr)
    else if (node.left.type === 'Value' && node.right.type === 'MathExpression') {
        if (isValueType(node.right.left.type) && isValueType(node.right.right.type)) {
          node.right.left.value *= node.left.value;
          node.right.right.value *= node.left.value;
          return node.right;
        }
      }
      // value * something
      else if (node.left.type === 'Value' && isValueType(node.right.type)) {
          node.right.value *= node.left.value;
          return node.right;
        }
  return node;
}

function reduceMathExpression(node, precision) {
  node = convertMathExpression(node, precision);

  switch (node.operator) {
    case "+":
    case "-":
      return reduceAddSubExpression(node, precision);
    case "/":
      return reduceDivisionExpression(node, precision);
    case "*":
      return reduceMultiplicationExpression(node);
  }
  return node;
}

exports.default = reduce;