/**
 * @license Licensed under the Apache License, Version 2.0 (the "License"):
 *          http://www.apache.org/licenses/LICENSE-2.0
 */

/**
 * @fileoverview Generating Arduino code for the Math blocks.
 *
 * TODO: Math on list needs lists to be implemented.
 *       math_constant and math_change needs to be tested in compiler.
 */
'use strict';

goog.provide('Blockly.Python.math');

goog.require('Blockly.Python');


/**
 * Generator for a numeric value (X).
 * Arduino code: loop { X }
 * @param {!Blockly.Block} block Block to generate the code from.
 * @return {array} Completed code with order of operation.
 */
Blockly.Python['math_number'] = function(block) {
  // Numeric value.
  var code = parseFloat(block.getFieldValue('NUM'));
  if (code == Infinity) {
    code = 'INFINITY';
  } else if (code == -Infinity) {
    code = '-INFINITY';
  }
  return [code, Blockly.Python.ORDER_ATOMIC];
};

/**
 * Generator for a basic arithmetic operators (X and Y) and power function
 * (X ^ Y).
 * Arduino code: loop { X operator Y }
 * @param {!Blockly.Block} block Block to generate the code from.
 * @return {array} Completed code with order of operation.
 */
Blockly.Python['math_arithmetic'] = function(block) {
  var OPERATORS = {
    ADD: [' + ', Blockly.Python.ORDER_ADDITIVE],
    MINUS: [' - ', Blockly.Python.ORDER_ADDITIVE],
    MULTIPLY: [' * ', Blockly.Python.ORDER_MULTIPLICATIVE],
    DIVIDE: [' / ', Blockly.Python.ORDER_MULTIPLICATIVE],
    POWER: [null, Blockly.Python.ORDER_NONE]  // Handle power separately.
  };
  var tuple = OPERATORS[block.getFieldValue('OP')];
  var operator = tuple[0];
  var order = tuple[1];
  var argument0 = Blockly.Python.valueToCode(block, 'A', order) || '0';
  var argument1 = Blockly.Python.valueToCode(block, 'B', order) || '0';
  var code;
  // Power in C++ requires a special case since it has no operator.
  if (!operator) {
    code = 'Math.pow(' + argument0 + ', ' + argument1 + ')';
    return [code, Blockly.Python.ORDER_UNARY_POSTFIX];
  }
  code = argument0 + operator + argument1;
  return [code, order];
};

/**
 * Generator for math operators that contain a single operand (X).
 * Arduino code: loop { operator(X) }
 * @param {!Blockly.Block} block Block to generate the code from.
 * @return {array} Completed code with order of operation.
 */
Blockly.Python['math_single'] = function(block) {
  var operator = block.getFieldValue('OP');
  var code;
  var arg;
  if (operator == 'NEG') {
    // Negation is a special case given its different operator precedents.
    arg = Blockly.Python.valueToCode(block, 'NUM',
        Blockly.Python.ORDER_UNARY_PREFIX) || '0';
    if (arg[0] == '-') {
      // --3 is not legal in C++ in this context.
      arg = ' ' + arg;
    }
    code = '-' + arg;
    return [code, Blockly.Python.ORDER_UNARY_PREFIX];
  }
  if (operator == 'ABS' || operator.substring(0, 5) == 'ROUND') {
    arg = Blockly.Python.valueToCode(block, 'NUM',
        Blockly.Python.ORDER_UNARY_POSTFIX) || '0';
  } else if (operator == 'SIN' || operator == 'COS' || operator == 'TAN') {
    arg = Blockly.Python.valueToCode(block, 'NUM',
        Blockly.Python.ORDER_MULTIPLICATIVE) || '0';
  } else {
    arg = Blockly.Python.valueToCode(block, 'NUM',
        Blockly.Python.ORDER_NONE) || '0';
  }
  // First, handle cases which generate values that don't need parentheses.
  switch (operator) {
    case 'ABS':
      code = 'abs(' + arg + ')';
      break;
    case 'ROOT':
      code = 'sqrt(' + arg + ')';
      break;
    case 'LN':
      code = 'log(' + arg + ')';
      break;
    case 'EXP':
      code = 'exp(' + arg + ')';
      break;
    case 'POW10':
      code = 'pow(10,' + arg + ')';
      break;
    case 'ROUND':
      code = 'round(' + arg + ')';
      break;
    case 'ROUNDUP':
      code = 'ceil(' + arg + ')';
      break;
    case 'ROUNDDOWN':
      code = 'floor(' + arg + ')';
      break;
    case 'SIN':
      code = 'sin(' + arg + ' / 180 * Math.PI)';
      break;
    case 'COS':
      code = 'cos(' + arg + ' / 180 * Math.PI)';
      break;
    case 'TAN':
      code = 'tan(' + arg + ' / 180 * Math.PI)';
      break;
  }
  if (code) {
    return [code, Blockly.Python.ORDER_UNARY_POSTFIX];
  }
  // Second, handle cases which generate values that may need parentheses.
  switch (operator) {
    case 'LOG10':
      code = 'log(' + arg + ') / log(10)';
      break;
    case 'ASIN':
      code = 'asin(' + arg + ') / M_PI * 180';
      break;
    case 'ACOS':
      code = 'acos(' + arg + ') / M_PI * 180';
      break;
    case 'ATAN':
      code = 'atan(' + arg + ') / M_PI * 180';
      break;
    default:
      throw 'Unknown math operator: ' + operator;
  }
  return [code, Blockly.Python.ORDER_MULTIPLICATIVE];
};

/**
 * Generator for math constants (PI, E, the Golden Ratio, sqrt(2), 1/sqrt(2),
 * INFINITY).
 * Arduino code: loop { constant }
 * TODO: Might need to include "#define _USE_MATH_DEFINES"
 *       The arduino header file already includes math.h
 * @param {!Blockly.Block} block Block to generate the code from.
 * @return {string} Completed code.
 */
Blockly.Python['math_constant'] = function(block) {
  var CONSTANTS = {
    'PI': ['M_PI', Blockly.Python.ORDER_UNARY_POSTFIX],
    'E': ['M_E', Blockly.Python.ORDER_UNARY_POSTFIX],
    'GOLDEN_RATIO': ['(1 + sqrt(5)) / 2', Blockly.Python.ORDER_MULTIPLICATIVE],
    'SQRT2': ['M_SQRT2', Blockly.Python.ORDER_UNARY_POSTFIX],
    'SQRT1_2': ['M_SQRT1_2', Blockly.Python.ORDER_UNARY_POSTFIX],
    'INFINITY': ['INFINITY', Blockly.Python.ORDER_ATOMIC]
  };
  return CONSTANTS[block.getFieldValue('CONSTANT')];
};

/**
 * Generator for math checks: if a number is even, odd, prime, whole, positive,
 * negative, or if it is divisible by certain number. Returns true or false.
 * Arduino code: complex code, can create external functions.
 * @param {!Blockly.Block} block Block to generate the code from.
 * @return {array} Completed code with order of operation.
 */
Blockly.Python['math_number_property'] = function(block) {
  var number_to_check = Blockly.Python.valueToCode(block, 'NUMBER_TO_CHECK',
      Blockly.Python.ORDER_MULTIPLICATIVE) || '0';
  var dropdown_property = block.getFieldValue('PROPERTY');
  var code;
  if (dropdown_property == 'PRIME') {
    var func = [
        'boolean ' + Blockly.Python.DEF_FUNC_NAME + '(int n) {',
        '  // https://en.wikipedia.org/wiki/Primality_test#Naive_methods',
        '  if (n == 2 || n == 3) {',
        '    return true;',
        '  }',
        '  // False if n is NaN, negative, is 1.',
        '  // And false if n is divisible by 2 or 3.',
        '  if (isnan(n) || (n <= 1) || (n == 1) || (n % 2 == 0) || ' +
            '(n % 3 == 0)) {',
        '    return false;',
        '  }',
        '  // Check all the numbers of form 6k +/- 1, up to sqrt(n).',
        '  for (int x = 6; x <= sqrt(n) + 1; x += 6) {',
        '    if (n % (x - 1) == 0 || n % (x + 1) == 0) {',
        '      return false;',
        '    }',
        '  }',
        '  return true;',
        '}'];
    var funcName = Blockly.Python.addFunction('mathIsPrime', func.join('\n'));
    Blockly.Python.addInclude('math', '#include <math.h>');
    code = funcName + '(' + number_to_check + ')';
    return [code, Blockly.Python.ORDER_UNARY_POSTFIX];
  }
  switch (dropdown_property) {
    case 'EVEN':
      code = number_to_check + ' % 2 == 0';
      break;
    case 'ODD':
      code = number_to_check + ' % 2 == 1';
      break;
    case 'WHOLE':
      Blockly.Python.addInclude('math', '#include <math.h>');
      code = '(floor(' + number_to_check + ') == ' + number_to_check + ')';
      break;
    case 'POSITIVE':
      code = number_to_check + ' > 0';
      break;
    case 'NEGATIVE':
      code = number_to_check + ' < 0';
      break;
    case 'DIVISIBLE_BY':
      var divisor = Blockly.Python.valueToCode(block, 'DIVISOR',
          Blockly.Python.ORDER_MULTIPLICATIVE) || '0';
      code = number_to_check + ' % ' + divisor + ' == 0';
      break;
  }
  return [code, Blockly.Python.ORDER_EQUALITY];
};

/**
 * Generator to add (Y) to a variable (X).
 * If variable X has not been declared before this block it will be declared as
 * a (not initialised) global int, however globals are 0 initialised in C/C++.
 * Arduino code: loop { X += Y; }
 * @param {!Blockly.Block} block Block to generate the code from.
 * @return {array} Completed code with order of operation.
 */
Blockly.Python['math_change'] = function(block) {
  var argument0 = Blockly.Python.valueToCode(block, 'DELTA',
      Blockly.Python.ORDER_ADDITIVE) || '0';
  var varName = Blockly.Python.variableDB_.getName(
      block.getFieldValue('VAR'), Blockly.Variables.NAME_TYPE);
  return varName + ' += ' + argument0 + ';\n';
};

/** Rounding functions have a single operand. */
Blockly.Python['math_round'] = Blockly.Python['math_single'];

/** Trigonometry functions have a single operand. */
Blockly.Python['math_trig'] = Blockly.Python['math_single'];

/**
 * Generator for the math function to a list.
 * Arduino code: ???
 * TODO: List have to be implemented first. Removed from toolbox for now.
 * @param {!Blockly.Block} block Block to generate the code from.
 * @return {array} Completed code with order of operation.
 */
Blockly.Python['math_on_list'] = Blockly.Python.noGeneratorCodeInline;

/**
 * Generator for the math modulo function (calculates remainder of X/Y).
 * Arduino code: loop { X % Y }
 * @param {!Blockly.Block} block Block to generate the code from.
 * @return {array} Completed code with order of operation.
 */
Blockly.Python['math_modulo'] = function(block) {
  var argument0 = Blockly.Python.valueToCode(block, 'DIVIDEND',
      Blockly.Python.ORDER_MULTIPLICATIVE) || '0';
  var argument1 = Blockly.Python.valueToCode(block, 'DIVISOR',
      Blockly.Python.ORDER_MULTIPLICATIVE) || '0';
  var code = argument0 + ' % ' + argument1;
  return [code, Blockly.Python.ORDER_MULTIPLICATIVE];
};

/**
 * Generator for clipping a number(X) between two limits (Y and Z).
 * Arduino code: loop { (X < Y ? Y : ( X > Z ? Z : X)) }
 * @param {!Blockly.Block} block Block to generate the code from.
 * @return {array} Completed code with order of operation.
 */
Blockly.Python['math_constrain'] = function(block) {
  // Constrain a number between two limits.
  var argument0 = Blockly.Python.valueToCode(block, 'VALUE',
      Blockly.Python.ORDER_NONE) || '0';
  var argument1 = Blockly.Python.valueToCode(block, 'LOW',
      Blockly.Python.ORDER_NONE) || '0';
  var argument2 = Blockly.Python.valueToCode(block, 'HIGH',
      Blockly.Python.ORDER_NONE) || '0';
  var code = '(' + argument0 + ' < ' + argument1 + ' ? ' + argument1 +
      ' : ( ' + argument0 + ' > ' + argument2 + ' ? ' + argument2 + ' : ' +
      argument0 + '))';
  return [code, Blockly.Python.ORDER_UNARY_POSTFIX];
};

/**
 * Generator for a random integer between two numbers (X and Y).
 * Arduino code: loop { math_random_int(X, Y); }
 *               and an aditional math_random_int function
 * @param {!Blockly.Block} block Block to generate the code from.
 * @return {array} Completed code with order of operation.
 */
Blockly.Python['math_random_int'] = function(block) {
  var argument0 = Blockly.Python.valueToCode(block, 'FROM',
      Blockly.Python.ORDER_NONE) || '0';
  var argument1 = Blockly.Python.valueToCode(block, 'TO',
      Blockly.Python.ORDER_NONE) || '0';
  var functionName = Blockly.Python.variableDB_.getDistinctName(
      'math_random_int', Blockly.Generator.NAME_TYPE);
  Blockly.Python.math_random_int.random_function = functionName;
  var func = [
      'int ' + Blockly.Python.DEF_FUNC_NAME + '(int min, int max) {',
      '  if (min > max) {',
      '    // Swap min and max to ensure min is smaller.',
      '    int temp = min;',
      '    min = max;',
      '    max = temp;',
      '  }',
      '  return min + (rand() % (max - min + 1));',
      '}'];
  var funcName = Blockly.Python.addFunction('mathRandomInt', func.join('\n'));
  var code = funcName + '(' + argument0 + ', ' + argument1 + ')';
  return [code, Blockly.Python.ORDER_UNARY_POSTFIX];
};

/**
 * Generator for a random float from 0 to 1.
 * Arduino code: loop { (rand() / RAND_MAX) }
 * @param {!Blockly.Block} block Block to generate the code from.
 * @return {string} Completed code.
 */
Blockly.Python['math_random_float'] = function(block) {
  return ['(rand() / RAND_MAX)', Blockly.Python.ORDER_UNARY_POSTFIX];
};