var nthCheck = require("./"),
    assert = require("assert");

var invalid = [
    "-",
    "- 1n",
    "-1 n",
    "2+0",
    "2n+-0",
    "an+b",
    "asdf",
    "b",
    "expr",
    "odd|even|x"
];

function parseInvalid() {
    invalid.forEach(function(formula) {
        assert.throws(
            function() {
                nthCheck.parse(formula);
            },
            SyntaxError,
            formula
        );
    });
}

var valid = {
    "1": [0, 1],
    "2": [0, 2],
    "3": [0, 3],
    "5": [0, 5],
    " 1 ": [0, 1],
    " 5 ": [0, 5],
    "+2n + 1": [2, 1],
    "-1": [0, -1],
    "-1n + 3": [-1, 3],
    "-1n+3": [-1, 3],
    "-n+2": [-1, 2],
    "-n+3": [-1, 3],
    "0n+3": [0, 3],
    "1n": [1, 0],
    "1n+0": [1, 0],
    "2n": [2, 0],
    "2n + 1": [2, 1],
    "2n+1": [2, 1],
    "3n": [3, 0],
    "3n+0": [3, 0],
    "3n+1": [3, 1],
    "3n+2": [3, 2],
    "3n+3": [3, 3],
    "3n-1": [3, -1],
    "3n-2": [3, -2],
    "3n-3": [3, -3],
    even: [2, 0],
    n: [1, 0],
    "n+2": [1, 2],
    odd: [2, 1],

    //surprisingly, neither sizzle, qwery or nwmatcher cover these cases
    "-4n+13": [-4, 13],
    "-2n + 12": [-2, 12]
};

function parseValid() {
    Object.keys(valid).forEach(function(formula) {
        assert.deepEqual(nthCheck.parse(formula), valid[formula], formula);
    });
}

function testValid() {
    Object.keys(valid).forEach(function(formula) {
        testFormula(valid[formula], formula);
    });
}

var valArray = Array.apply(null, Array(2e3)).map(function(_, i) {
    return i;
});

function testFormula(formula, name) {
    var filtered = valArray.filter(nthCheck.compile(formula)),
        iterated = stupidNth(formula);

    try {
        assert.deepEqual(filtered, iterated, name);
    } catch (e) {
        e.expected = JSON.stringify(iterated) + " " + name;
        e.actual = JSON.stringify(filtered) + " " + name;
        throw e;
    }
}

function stupidNth(formula, limit) {
    var a = formula[0],
        b = formula[1];

    if (a === 0 && b > 0) return [b - 1];

    //taken from qwery
    return valArray.filter(function(val) {
        for (var i = b, l = valArray.length; a > 0 ? i <= l : i >= 1; i += a) {
            if (val === valArray[i - 1]) return true;
        }
    });
}

process.stdout.write("- parser");
process.stdout.write("\n  - parse invalid:\t");
parseInvalid();
process.stdout.write("X\n  - parse valid:\t");
parseValid();
process.stdout.write("X\n- check values:  \t");
testValid();
process.stdout.write("X\n");