const expectData = {
  ageLt18: [
    { name: "Uktg", age: 17 },
    { name: "3U5", age: 17 },
    { name: "Hu8M", age: 17 },
    { name: "Z2d", age: 17 },
    { name: "n0ap", age: 17 },
    { name: "ptTc", age: 17 },
    { name: "Hqn", age: 17 },
    { name: "QC3", age: 17 }
  ],
  males: [
    { sex: "M", name: "vyo", age: 18, grade: 72 },
    { sex: "M", name: "Uktg", age: 17, grade: 86 },
    { sex: "M", name: "3U5", age: 17, grade: 82 },
    { sex: "M", name: "OVfZ", age: 19, grade: 54 },
    { sex: "M", name: "5Rx", age: 18, grade: 92 },
    { sex: "M", name: "8GPC", age: 18, grade: 79 },
    { sex: "M", name: "Z2d", age: 17, grade: 82 },
    { sex: "M", name: "QyKY", age: 19, grade: 59 },
    { sex: "M", name: "VT1", age: 19, grade: 89 },
    { sex: "M", name: "ptTc", age: 17, grade: 65 },
    { sex: "M", name: "Xvhf", age: 18, grade: 65 },
    { sex: "M", name: "wOR", age: 19, grade: 78 },
    { sex: "M", name: "Hqn", age: 17, grade: 74 }
  ],
  top10: [
    { name: "5Rx", grade: 92 },
    { name: "VT1", grade: 89 },
    { name: "gZW", grade: 87 },
    { name: "Uktg", grade: 86 },
    { name: "3U5", grade: 82 },
    { name: "Z2d", grade: 82 },
    { name: "NqXw", grade: 79 },
    { name: "8GPC", grade: 79 },
    { name: "wOR", grade: 78 },
    { name: "jXgh", grade: 77 }
  ]
};

const data = [
  {
    sex: "M",
    name: "vyo",
    age: 18,
    grade: 72
  },
  {
    sex: "M",
    name: "Uktg",
    age: 17,
    grade: 86
  },
  {
    sex: "F",
    name: "gZW",
    age: 18,
    grade: 87
  },
  {
    sex: "F",
    name: "NqXw",
    age: 19,
    grade: 79
  },
  {
    sex: "M",
    name: "3U5",
    age: 17,
    grade: 82
  },
  {
    sex: "M",
    name: "OVfZ",
    age: 19,
    grade: 54
  },
  {
    sex: "F",
    name: "Hu8M",
    age: 17,
    grade: 62
  },
  {
    sex: "M",
    name: "5Rx",
    age: 18,
    grade: 92
  },
  {
    sex: "M",
    name: "8GPC",
    age: 18,
    grade: 79
  },
  {
    sex: "M",
    name: "Z2d",
    age: 17,
    grade: 82
  },
  {
    sex: "M",
    name: "QyKY",
    age: 19,
    grade: 59
  },
  {
    sex: "M",
    name: "VT1",
    age: 19,
    grade: 89
  },
  {
    sex: "F",
    name: "n0ap",
    age: 17,
    grade: 58
  },
  {
    sex: "M",
    name: "ptTc",
    age: 17,
    grade: 65
  },
  {
    sex: "M",
    name: "Xvhf",
    age: 18,
    grade: 65
  },
  {
    sex: "F",
    name: "uMe1",
    age: 18,
    grade: 56
  },
  {
    sex: "F",
    name: "jXgh",
    age: 18,
    grade: 77
  },
  {
    sex: "M",
    name: "wOR",
    age: 19,
    grade: 78
  },
  {
    sex: "M",
    name: "Hqn",
    age: 17,
    grade: 74
  },
  {
    sex: "F",
    name: "QC3",
    age: 17,
    grade: 59
  }
];
const { curry, pipe, filter, prop } = R;
// code here
/*
 *  ex1 
 */
// :: String -> Number -> Object -> Boolean
const propLt = curry((p, c) => R.pipe(R.prop(p), R.lt(R.__, c)));

// :: Object ->  Boolean
const ageUnder18 = propLt("age", 18);

// :: [a] -> b 
const getAgeUnder18 = R.pipe(
  R.filter(ageUnder18),
  R.map(R.pickAll(["name", "age"]))
);

/*
 *  ex2
 */

// :: String -> [a] -> [a]
const getSex = sex => R.filter((R.propEq("sex", sex)));
// :: [a] -> [a]
const getMales = getSex("M");
const getFemales = getSex("F");

/*
 *  ex3 
 */

// :: String -> (String -> String -> a -> Object -> Object)
const updatePropBy = curry((byProp, updateProp, match, newValue, obj) => 
                           R.when(R.propEq(byProp, match), R.assoc(updateProp, newValue))(obj));

// 如果上面的理解有困难，可以类比到下面这个函数：
const updatePropBy_2 = curry((byProp, updateProp, match, newValue, obj) => {
  if (obj[byProp] === match) {
    let newObj = {...obj };
    newObj[updateProp] = newValue;
    return newObj;
  }
  return ({...obj})
});

                           
// :: String -> (String -> a -> Object -> Object)
const updatePropByName = updatePropBy('name');

// :: String -> (a -> Object -> Object)
const updateGradeByName = updatePropByName('grade');
const updateAgeByName = updatePropByName('age');

// :: String -> Number -> [Object] -> [Object]
const updateUsersGradeByName = curry((name, value, arr) => R.map(updateGradeByName(name, value), arr));
// :: String -> Number -> [Object] -> [Object]
const updateUsersAgeByName = curry((name, age, arr) => R.map(updateAgeByName(name, age), arr));


/*
 *  ex4
 */

// :: String -> [a] -> [a]
const desc = x => R.sort(R.descend(R.prop(x)));

// :: [a] -> [b]
const getGradeTop10 = R.pipe(
  desc("grade"),
  R.take(10),
  R.map(R.pickAll(["name", "grade"]))
);



mocha.setup("bdd");
var assert = chai.assert;

describe("Test", function() {
  it("1. 获取所有年龄小于18岁的对象，并返回他们的名称和年龄", function() {
    const result = getAgeUnder18(data);
    assert.deepEqual(result, expectData.ageLt18);
  });

  it("2. 查找所有男性用户", function() {
    const result = getMales(data);
    assert.deepEqual(result, expectData.males);
  });
  
  
  it("3. 更新一个指定名称用户的成绩", function() {
    const result = updateUsersGradeByName('QC3', 100, data);
    const getGrade = R.pipe(R.find(R.propEq('name', 'QC3')), R.prop('grade'));
    assert.deepEqual(getGrade(result), 100);
  });
  

  it("4. 取出成绩最高的10名，并返回他们的名称和分数", function() {
    const result = getGradeTop10(data);
    assert.deepEqual(result, expectData.top10);
  });

});

mocha.run();