text: /**
   * @license
   * Copyright 2016 Google LLC
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  /**
   * @fileoverview Generating Lua for math blocks.
   * @author rodrigoq@google.com (Rodrigo Queiro)
   */
  'use strict';
  
  goog.provide('Blockly.Lua.math');
  
  goog.require('Blockly.Lua');
  
  
  Blockly.Lua['math_number'] = function(block) {
    // Numeric value.
      var code = Number(block.getFieldValue('NUM'));
    var order = code < 0 ? Blockly.Lua.ORDER_UNARY :
                Blockly.Lua.ORDER_ATOMIC;
    return [code, order];
  };
  
  Blockly.Lua['math_arithmetic'] = function(block) {
    // Basic arithmetic operators, and power.
    var OPERATORS = {
      ADD: [' + ', Blockly.Lua.ORDER_ADDITIVE],
      MINUS: [' - ', Blockly.Lua.ORDER_ADDITIVE],
      MULTIPLY: [' * ', Blockly.Lua.ORDER_MULTIPLICATIVE],
      DIVIDE: [' / ', Blockly.Lua.ORDER_MULTIPLICATIVE],
      POWER: [' ^ ', Blockly.Lua.ORDER_EXPONENTIATION]
    };
    var tuple = OPERATORS[block.getFieldValue('OP')];
    var operator = tuple[0];
    var order = tuple[1];
    var argument0 = Blockly.Lua.valueToCode(block, 'A', order) || '0';
    var argument1 = Blockly.Lua.valueToCode(block, 'B', order) || '0';
    var code = argument0 + operator + argument1;
    return [code, order];
  };
  
  Blockly.Lua['math_single'] = function(block) {
    // Math operators with single operand.
    var operator = block.getFieldValue('OP');
    var code;
    var arg;
    if (operator == 'NEG') {
      // Negation is a special case given its different operator precedence.
      arg = Blockly.Lua.valueToCode(block, 'NUM',
          Blockly.Lua.ORDER_UNARY) || '0';
      return ['-' + arg, Blockly.Lua.ORDER_UNARY];
    }
    if (operator == 'POW10') {
      arg = Blockly.Lua.valueToCode(block, 'NUM',
          Blockly.Lua.ORDER_EXPONENTIATION) || '0';
      return ['10 ^ ' + arg, Blockly.Lua.ORDER_EXPONENTIATION];
    }
    if (operator == 'ROUND') {
      arg = Blockly.Lua.valueToCode(block, 'NUM',
          Blockly.Lua.ORDER_ADDITIVE) || '0';
    } else {
      arg = Blockly.Lua.valueToCode(block, 'NUM',
          Blockly.Lua.ORDER_NONE) || '0';
    }
    switch (operator) {
      case 'ABS':
        code = 'math.abs(' + arg + ')';
        break;
      case 'ROOT':
        code = 'math.sqrt(' + arg + ')';
        break;
      case 'LN':
        code = 'math.log(' + arg + ')';
        break;
      case 'LOG10':
        code = 'math.log(' + arg + ', 10)';
        break;
      case 'EXP':
        code = 'math.exp(' + arg + ')';
        break;
      case 'ROUND':
        // This rounds up.  Blockly does not specify rounding direction.
        code = 'math.floor(' + arg + ' + .5)';
        break;
      case 'ROUNDUP':
        code = 'math.ceil(' + arg + ')';
        break;
      case 'ROUNDDOWN':
        code = 'math.floor(' + arg + ')';
        break;
      case 'SIN':
        code = 'math.sin(math.rad(' + arg + '))';
        break;
      case 'COS':
        code = 'math.cos(math.rad(' + arg + '))';
        break;
      case 'TAN':
        code = 'math.tan(math.rad(' + arg + '))';
        break;
      case 'ASIN':
        code = 'math.deg(math.asin(' + arg + '))';
        break;
      case 'ACOS':
        code = 'math.deg(math.acos(' + arg + '))';
        break;
      case 'ATAN':
        code = 'math.deg(math.atan(' + arg + '))';
        break;
      default:
        throw Error('Unknown math operator: ' + operator);
    }
    return [code, Blockly.Lua.ORDER_HIGH];
  };
  
  Blockly.Lua['math_constant'] = function(block) {
    // Constants: PI, E, the Golden Ratio, sqrt(2), 1/sqrt(2), INFINITY.
    var CONSTANTS = {
      PI: ['math.pi', Blockly.Lua.ORDER_HIGH],
      E: ['math.exp(1)', Blockly.Lua.ORDER_HIGH],
      GOLDEN_RATIO: ['(1 + math.sqrt(5)) / 2', Blockly.Lua.ORDER_MULTIPLICATIVE],
      SQRT2: ['math.sqrt(2)', Blockly.Lua.ORDER_HIGH],
      SQRT1_2: ['math.sqrt(1 / 2)', Blockly.Lua.ORDER_HIGH],
      INFINITY: ['math.huge', Blockly.Lua.ORDER_HIGH]
    };
    return CONSTANTS[block.getFieldValue('CONSTANT')];
  };
  
  Blockly.Lua['math_number_property'] = function(block) {
    // Check if a number is even, odd, prime, whole, positive, or negative
    // or if it is divisible by certain number. Returns true or false.
    var number_to_check = Blockly.Lua.valueToCode(block, 'NUMBER_TO_CHECK',
        Blockly.Lua.ORDER_MULTIPLICATIVE) || '0';
    var dropdown_property = block.getFieldValue('PROPERTY');
    var code;
    if (dropdown_property == 'PRIME') {
      // Prime is a special case as it is not a one-liner test.
      var functionName = Blockly.Lua.provideFunction_(
          'math_isPrime',
          ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(n)',
           '  -- https://en.wikipedia.org/wiki/Primality_test#Naive_methods',
           '  if n == 2 or n == 3 then',
           '    return true',
           '  end',
           '  -- False if n is NaN, negative, is 1, or not whole.',
           '  -- And false if n is divisible by 2 or 3.',
           '  if not(n > 1) or n % 1 ~= 0 or n % 2 == 0 or n % 3 == 0 then',
           '    return false',
           '  end',
           '  -- Check all the numbers of form 6k +/- 1, up to sqrt(n).',
           '  for x = 6, math.sqrt(n) + 1.5, 6 do',
           '    if n % (x - 1) == 0 or n % (x + 1) == 0 then',
           '      return false',
           '    end',
           '  end',
           '  return true',
           'end']);
      code = functionName + '(' + number_to_check + ')';
      return [code, Blockly.Lua.ORDER_HIGH];
    }
    switch (dropdown_property) {
      case 'EVEN':
        code = number_to_check + ' % 2 == 0';
        break;
      case 'ODD':
        code = number_to_check + ' % 2 == 1';
        break;
      case 'WHOLE':
        code = number_to_check + ' % 1 == 0';
        break;
      case 'POSITIVE':
        code = number_to_check + ' > 0';
        break;
      case 'NEGATIVE':
        code = number_to_check + ' < 0';
        break;
      case 'DIVISIBLE_BY':
        var divisor = Blockly.Lua.valueToCode(block, 'DIVISOR',
            Blockly.Lua.ORDER_MULTIPLICATIVE);
        // If 'divisor' is some code that evals to 0, Lua will produce a nan.
        // Let's produce nil if we can determine this at compile-time.
        if (!divisor || divisor == '0') {
          return ['nil', Blockly.Lua.ORDER_ATOMIC];
        }
        // The normal trick to implement ?: with and/or doesn't work here:
        //   divisor == 0 and nil or number_to_check % divisor == 0
        // because nil is false, so allow a runtime failure. :-(
        code = number_to_check + ' % ' + divisor + ' == 0';
        break;
    }
    return [code, Blockly.Lua.ORDER_RELATIONAL];
  };
  
  Blockly.Lua['math_change'] = function(block) {
    // Add to a variable in place.
    var argument0 = Blockly.Lua.valueToCode(block, 'DELTA',
        Blockly.Lua.ORDER_ADDITIVE) || '0';
    var varName = Blockly.Lua.variableDB_.getName(
        block.getFieldValue('VAR'), Blockly.Variables.NAME_TYPE);
    return varName + ' = ' + varName + ' + ' + argument0 + '\n';
  };
  
  // Rounding functions have a single operand.
  Blockly.Lua['math_round'] = Blockly.Lua['math_single'];
  // Trigonometry functions have a single operand.
  Blockly.Lua['math_trig'] = Blockly.Lua['math_single'];
  
  Blockly.Lua['math_on_list'] = function(block) {
    // Math functions for lists.
    var func = block.getFieldValue('OP');
    var list = Blockly.Lua.valueToCode(block, 'LIST',
        Blockly.Lua.ORDER_NONE) || '{}';
    var functionName;
  
    // Functions needed in more than one case.
    function provideSum() {
      return Blockly.Lua.provideFunction_(
          'math_sum',
          ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t)',
           '  local result = 0',
           '  for _, v in ipairs(t) do',
           '    result = result + v',
           '  end',
           '  return result',
           'end']);
    }
  
    switch (func) {
      case 'SUM':
        functionName = provideSum();
        break;
  
      case 'MIN':
        // Returns 0 for the empty list.
        functionName = Blockly.Lua.provideFunction_(
            'math_min',
            ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t)',
             '  if #t == 0 then',
             '    return 0',
             '  end',
             '  local result = math.huge',
             '  for _, v in ipairs(t) do',
             '    if v < result then',
             '      result = v',
             '    end',
             '  end',
             '  return result',
             'end']);
        break;
  
      case 'AVERAGE':
        // Returns 0 for the empty list.
        functionName = Blockly.Lua.provideFunction_(
            'math_average',
            ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t)',
             '  if #t == 0 then',
             '    return 0',
             '  end',
             '  return ' + provideSum() + '(t) / #t',
             'end']);
        break;
  
      case 'MAX':
        // Returns 0 for the empty list.
        functionName = Blockly.Lua.provideFunction_(
            'math_max',
            ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t)',
             '  if #t == 0 then',
             '    return 0',
             '  end',
             '  local result = -math.huge',
             '  for _, v in ipairs(t) do',
             '    if v > result then',
             '      result = v',
             '    end',
             '  end',
             '  return result',
             'end']);
        break;
  
      case 'MEDIAN':
        functionName = Blockly.Lua.provideFunction_(
            'math_median',
            // This operation excludes non-numbers.
            ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t)',
             '  -- Source: http://lua-users.org/wiki/SimpleStats',
             '  if #t == 0 then',
             '    return 0',
             '  end',
             '  local temp={}',
             '  for _, v in ipairs(t) do',
             '    if type(v) == "number" then',
             '      table.insert(temp, v)',
             '    end',
             '  end',
             '  table.sort(temp)',
             '  if #temp % 2 == 0 then',
             '    return (temp[#temp/2] + temp[(#temp/2)+1]) / 2',
             '  else',
             '    return temp[math.ceil(#temp/2)]',
             '  end',
             'end']);
        break;
  
      case 'MODE':
        functionName = Blockly.Lua.provideFunction_(
            'math_modes',
            // As a list of numbers can contain more than one mode,
            // the returned result is provided as an array.
            // The Lua version includes non-numbers.
            ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t)',
             '  -- Source: http://lua-users.org/wiki/SimpleStats',
             '  local counts={}',
             '  for _, v in ipairs(t) do',
             '    if counts[v] == nil then',
             '      counts[v] = 1',
             '    else',
             '      counts[v] = counts[v] + 1',
             '    end',
             '  end',
             '  local biggestCount = 0',
             '  for _, v  in pairs(counts) do',
             '    if v > biggestCount then',
             '      biggestCount = v',
             '    end',
             '  end',
             '  local temp={}',
             '  for k, v in pairs(counts) do',
             '    if v == biggestCount then',
             '      table.insert(temp, k)',
             '    end',
             '  end',
             '  return temp',
             'end']);
        break;
  
      case 'STD_DEV':
        functionName = Blockly.Lua.provideFunction_(
            'math_standard_deviation',
            ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t)',
             '  local m',
             '  local vm',
             '  local total = 0',
             '  local count = 0',
             '  local result',
             '  m = #t == 0 and 0 or ' + provideSum() + '(t) / #t',
             '  for _, v in ipairs(t) do',
             "    if type(v) == 'number' then",
             '      vm = v - m',
             '      total = total + (vm * vm)',
             '      count = count + 1',
             '    end',
             '  end',
             '  result = math.sqrt(total / (count-1))',
             '  return result',
             'end']);
        break;
  
      case 'RANDOM':
        functionName = Blockly.Lua.provideFunction_(
            'math_random_list',
            ['function ' + Blockly.Lua.FUNCTION_NAME_PLACEHOLDER_ + '(t)',
             '  if #t == 0 then',
             '    return nil',
             '  end',
             '  return t[math.random(#t)]',
             'end']);
        break;
  
      default:
        throw Error('Unknown operator: ' + func);
    }
    return [functionName + '(' + list + ')', Blockly.Lua.ORDER_HIGH];
  };
  
  Blockly.Lua['math_modulo'] = function(block) {
    // Remainder computation.
    var argument0 = Blockly.Lua.valueToCode(block, 'DIVIDEND',
        Blockly.Lua.ORDER_MULTIPLICATIVE) || '0';
    var argument1 = Blockly.Lua.valueToCode(block, 'DIVISOR',
        Blockly.Lua.ORDER_MULTIPLICATIVE) || '0';
    var code = argument0 + ' % ' + argument1;
    return [code, Blockly.Lua.ORDER_MULTIPLICATIVE];
  };
  
  Blockly.Lua['math_constrain'] = function(block) {
    // Constrain a number between two limits.
    var argument0 = Blockly.Lua.valueToCode(block, 'VALUE',
        Blockly.Lua.ORDER_NONE) || '0';
    var argument1 = Blockly.Lua.valueToCode(block, 'LOW',
        Blockly.Lua.ORDER_NONE) || '-math.huge';
    var argument2 = Blockly.Lua.valueToCode(block, 'HIGH',
        Blockly.Lua.ORDER_NONE) || 'math.huge';
    var code = 'math.min(math.max(' + argument0 + ', ' + argument1 + '), ' +
        argument2 + ')';
    return [code, Blockly.Lua.ORDER_HIGH];
  };
  
  Blockly.Lua['math_random_int'] = function(block) {
    // Random integer between [X] and [Y].
    var argument0 = Blockly.Lua.valueToCode(block, 'FROM',
        Blockly.Lua.ORDER_NONE) || '0';
    var argument1 = Blockly.Lua.valueToCode(block, 'TO',
        Blockly.Lua.ORDER_NONE) || '0';
    var code = 'math.random(' + argument0 + ', ' + argument1 + ')';
    return [code, Blockly.Lua.ORDER_HIGH];
  };
  
  Blockly.Lua['math_random_float'] = function(block) {
    // Random fraction between 0 and 1.
    return ['math.random()', Blockly.Lua.ORDER_HIGH];
  };
  
  Blockly.Lua['math_atan2'] = function(block) {
    // Arctangent of point (X, Y) in degrees from -180 to 180.
    var argument0 = Blockly.Lua.valueToCode(block, 'X',
        Blockly.Lua.ORDER_NONE) || '0';
    var argument1 = Blockly.Lua.valueToCode(block, 'Y',
        Blockly.Lua.ORDER_NONE) || '0';
    return ['math.deg(math.atan2(' + argument1 + ', ' + argument0 + '))',
        Blockly.Lua.ORDER_HIGH];
  };
  