var shallowClone = require('../clone').shallow;

var Token = require('../../tokenizer/token');
var Marker = require('../../tokenizer/marker');

function isInheritOnly(values) {
  for (var i = 0, l = values.length; i < l; i++) {
    var value = values[i][1];

    if (value != 'inherit' && value != Marker.COMMA && value != Marker.FORWARD_SLASH) { return false; }
  }

  return true;
}

function background(property, configuration, lastInMultiplex) {
  var components = property.components;
  var restored = [];
  var needsOne, needsBoth;

  function restoreValue(component) {
    Array.prototype.unshift.apply(restored, component.value);
  }

  function isDefaultValue(component) {
    var descriptor = configuration[component.name];

    if (descriptor.doubleValues && descriptor.defaultValue.length == 1) {
      return component.value[0][1] == descriptor.defaultValue[0]
        && (component.value[1]
          ? component.value[1][1] == descriptor.defaultValue[0]
          : true);
    } if (descriptor.doubleValues && descriptor.defaultValue.length != 1) {
      return component.value[0][1] == descriptor.defaultValue[0]
      && ((component.value[1] ? component.value[1][1] : component.value[0][1])
        == descriptor.defaultValue[1]);
    }
    return component.value[0][1] == descriptor.defaultValue;
  }

  for (var i = components.length - 1; i >= 0; i--) {
    var component = components[i];
    var isDefault = isDefaultValue(component);

    if (component.name == 'background-clip') {
      var originComponent = components[i - 1];
      var isOriginDefault = isDefaultValue(originComponent);

      needsOne = component.value[0][1] == originComponent.value[0][1];

      needsBoth = !needsOne && (
        (isOriginDefault && !isDefault)
        || (!isOriginDefault && !isDefault)
        || (!isOriginDefault && isDefault && component.value[0][1] != originComponent.value[0][1]));

      if (needsOne) {
        restoreValue(originComponent);
      } else if (needsBoth) {
        restoreValue(component);
        restoreValue(originComponent);
      }

      i--;
    } else if (component.name == 'background-size') {
      var positionComponent = components[i - 1];
      var isPositionDefault = isDefaultValue(positionComponent);

      needsOne = !isPositionDefault && isDefault;

      needsBoth = !needsOne
        && (isPositionDefault && !isDefault || !isPositionDefault && !isDefault);

      if (needsOne) {
        restoreValue(positionComponent);
      } else if (needsBoth) {
        restoreValue(component);
        restored.unshift([Token.PROPERTY_VALUE, Marker.FORWARD_SLASH]);
        restoreValue(positionComponent);
      } else if (positionComponent.value.length == 1) {
        restoreValue(positionComponent);
      }

      i--;
    } else {
      if (isDefault || configuration[component.name].multiplexLastOnly && !lastInMultiplex) { continue; }

      restoreValue(component);
    }
  }

  if (restored.length === 0 && property.value.length == 1 && property.value[0][1] == '0') { restored.push(property.value[0]); }

  if (restored.length === 0) { restored.push([Token.PROPERTY_VALUE, configuration[property.name].defaultValue]); }

  if (isInheritOnly(restored)) { return [restored[0]]; }

  return restored;
}

function borderRadius(property) {
  if (property.multiplex) {
    var horizontal = shallowClone(property);
    var vertical = shallowClone(property);

    for (var i = 0; i < 4; i++) {
      var component = property.components[i];

      var horizontalComponent = shallowClone(property);
      horizontalComponent.value = [component.value[0]];
      horizontal.components.push(horizontalComponent);

      var verticalComponent = shallowClone(property);
      // FIXME: only shorthand compactor (see breakup#borderRadius) knows that border radius
      // longhands have two values, whereas tokenizer does not care about populating 2nd value
      // if it's missing, hence this fallback
      verticalComponent.value = [component.value[1] || component.value[0]];
      vertical.components.push(verticalComponent);
    }

    var horizontalValues = fourValues(horizontal);
    var verticalValues = fourValues(vertical);

    if (horizontalValues.length == verticalValues.length
        && horizontalValues[0][1] == verticalValues[0][1]
        && (horizontalValues.length > 1 ? horizontalValues[1][1] == verticalValues[1][1] : true)
        && (horizontalValues.length > 2 ? horizontalValues[2][1] == verticalValues[2][1] : true)
        && (horizontalValues.length > 3 ? horizontalValues[3][1] == verticalValues[3][1] : true)) {
      return horizontalValues;
    }
    return horizontalValues.concat([[Token.PROPERTY_VALUE, Marker.FORWARD_SLASH]]).concat(verticalValues);
  }
  return fourValues(property);
}

function font(property, configuration) {
  var components = property.components;
  var restored = [];
  var component;
  var componentIndex = 0;
  var fontFamilyIndex = 0;

  if (property.value[0][1].indexOf(Marker.INTERNAL) === 0) {
    property.value[0][1] = property.value[0][1].substring(Marker.INTERNAL.length);
    return property.value;
  }

  // first four components are optional
  while (componentIndex < 4) {
    component = components[componentIndex];

    if (component.value[0][1] != configuration[component.name].defaultValue) {
      Array.prototype.push.apply(restored, component.value);
    }

    componentIndex++;
  }

  // then comes font-size
  Array.prototype.push.apply(restored, components[componentIndex].value);
  componentIndex++;

  // then may come line-height
  if (components[componentIndex].value[0][1] != configuration[components[componentIndex].name].defaultValue) {
    Array.prototype.push.apply(restored, [[Token.PROPERTY_VALUE, Marker.FORWARD_SLASH]]);
    Array.prototype.push.apply(restored, components[componentIndex].value);
  }

  componentIndex++;

  // then comes font-family
  while (components[componentIndex].value[fontFamilyIndex]) {
    restored.push(components[componentIndex].value[fontFamilyIndex]);

    if (components[componentIndex].value[fontFamilyIndex + 1]) {
      restored.push([Token.PROPERTY_VALUE, Marker.COMMA]);
    }

    fontFamilyIndex++;
  }

  if (isInheritOnly(restored)) {
    return [restored[0]];
  }

  return restored;
}

function fourValues(property) {
  var components = property.components;
  var value1 = components[0].value[0];
  var value2 = components[1].value[0];
  var value3 = components[2].value[0];
  var value4 = components[3].value[0];

  if (value1[1] == value2[1] && value1[1] == value3[1] && value1[1] == value4[1]) {
    return [value1];
  } if (value1[1] == value3[1] && value2[1] == value4[1]) {
    return [value1, value2];
  } if (value2[1] == value4[1]) {
    return [value1, value2, value3];
  }
  return [value1, value2, value3, value4];
}

function multiplex(restoreWith) {
  return function(property, configuration) {
    if (!property.multiplex) { return restoreWith(property, configuration, true); }

    var multiplexSize = 0;
    var restored = [];
    var componentMultiplexSoFar = {};
    var i, l;

    // At this point we don't know what's the multiplex size, e.g. how many background layers are there
    for (i = 0, l = property.components[0].value.length; i < l; i++) {
      if (property.components[0].value[i][1] == Marker.COMMA) { multiplexSize++; }
    }

    for (i = 0; i <= multiplexSize; i++) {
      var _property = shallowClone(property);

      // We split multiplex into parts and restore them one by one
      for (var j = 0, m = property.components.length; j < m; j++) {
        var componentToClone = property.components[j];
        var _component = shallowClone(componentToClone);
        _property.components.push(_component);

        // The trick is some properties has more than one value, so we iterate over values looking for
        // a multiplex separator - a comma
        for (var k = componentMultiplexSoFar[_component.name] || 0, n = componentToClone.value.length; k < n; k++) {
          if (componentToClone.value[k][1] == Marker.COMMA) {
            componentMultiplexSoFar[_component.name] = k + 1;
            break;
          }

          _component.value.push(componentToClone.value[k]);
        }
      }

      // No we can restore shorthand value
      var lastInMultiplex = i == multiplexSize;
      var _restored = restoreWith(_property, configuration, lastInMultiplex);
      Array.prototype.push.apply(restored, _restored);

      if (i < multiplexSize) { restored.push([Token.PROPERTY_VALUE, Marker.COMMA]); }
    }

    return restored;
  };
}

function withoutDefaults(property, configuration) {
  var components = property.components;
  var restored = [];

  for (var i = components.length - 1; i >= 0; i--) {
    var component = components[i];
    var descriptor = configuration[component.name];

    if (component.value[0][1] != descriptor.defaultValue || ('keepUnlessDefault' in descriptor) && !isDefault(components, configuration, descriptor.keepUnlessDefault)) {
      restored.unshift(component.value[0]);
    }
  }

  if (restored.length === 0) { restored.push([Token.PROPERTY_VALUE, configuration[property.name].defaultValue]); }

  if (isInheritOnly(restored)) { return [restored[0]]; }

  return restored;
}

function isDefault(components, configuration, propertyName) {
  var component;
  var i, l;

  for (i = 0, l = components.length; i < l; i++) {
    component = components[i];

    if (component.name == propertyName && component.value[0][1] == configuration[propertyName].defaultValue) {
      return true;
    }
  }

  return false;
}

module.exports = {
  background: background,
  borderRadius: borderRadius,
  font: font,
  fourValues: fourValues,
  multiplex: multiplex,
  withoutDefaults: withoutDefaults
};