// http://wiki.commonjs.org/wiki/Unit_Testing/1.0
//
// THIS IS NOT TESTED NOR LIKELY TO WORK OUTSIDE V8!
//
// Originally from narwhal.js (http://narwhaljs.org)
// Copyright (c) 2009 Thomas Robinson <280north.com>
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the “Software”), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
// ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

// UTILITY

var pSlice = Array.prototype.slice;

// 1. The assert module provides functions that throw
// AssertionError's when particular conditions are not met. The
// assert module must conform to the following interface.

var assert = exports;

// 2. The AssertionError is defined in assert.
// new assert.AssertionError({message: message, actual: actual, expected: expected})

assert.AssertionError = function AssertionError(options) {
    this.name = "AssertionError";
    this.message = options.message;
    this.actual = options.actual;
    this.expected = options.expected;
    this.operator = options.operator;
    //v8 specific
    if(Error.captureStackTrace){
        Error.captureStackTrace(this,fail);
        //node specific, removes the node machinery stack frames
        if(typeof(__filename) !== undefined){
            var stack = this.stack.split('\n');
            for (var i = stack.length - 1; i >= 0; i--) {
                if(stack[i].indexOf(__filename) != -1){
                    this.stack = stack.slice(0,i+2).join('\n');
                    break;
                }
            }
        }
    }
};

assert.AssertionError.prototype.toString = function(){
    if(this.message)
        return [this.name+":", this.message].join(' ');
    else
        return [this.name+":", JSON.stringify(this.expected ), this.operator , JSON.stringify(this.actual)].join(" ");
}

// assert.AssertionError instanceof Error

assert.AssertionError.__proto__ = Error.prototype;

// At present only the three keys mentioned above are used and
// understood by the spec. Implementations or sub modules can pass
// other keys to the AssertionError's constructor - they will be
// ignored.

// 3. All of the following functions must throw an AssertionError
// when a corresponding condition is not met, with a message that
// may be undefined if not provided.  All assertion methods provide
// both the actual and expected values to the assertion error for
// display purposes.

function fail(actual, expected, message, operator) {
    throw new assert.AssertionError({
        message: message,
        actual: actual,
        expected: expected,
        operator: operator
    });
}

// EXTENSION! allows for well behaved errors defined elsewhere.
assert.fail = fail;

// 4. Pure assertion tests whether a value is truthy, as determined
// by !!guard.
// assert.ok(guard, message_opt);
// This statement is equivalent to assert.equal(true, guard,
// message_opt);. To test strictly for the value true, use
// assert.strictEqual(true, guard, message_opt);.

assert.ok = function ok(value, message) {
    if (!!!value)
        fail(value, true, message, "==");
};

// 5. The equality assertion tests shallow, coercive equality with
// ==.
// assert.equal(actual, expected, message_opt);

assert.equal = function equal(actual, expected, message) {
    if (actual != expected)
        fail(actual, expected, message, "==");
};


// 6. The non-equality assertion tests for whether two objects are not equal
// with != assert.notEqual(actual, expected, message_opt);

assert.notEqual = function notEqual(actual, expected, message) {
    if (actual == expected)
        fail(actual, expected, message, "!=");
};

// 7. The equivalence assertion tests a deep equality relation.
// assert.deepEqual(actual, expected, message_opt);

exports.deepEqual = function deepEqual(actual, expected, message) {
    if (!_deepEqual(actual, expected))
        fail(actual, expected, message, "deepEqual");
};

function _deepEqual(actual, expected) {
    // 7.1. All identical values are equivalent, as determined by ===.
    if (actual === expected) {
        return true;

    // 7.2. If the expected value is a Date object, the actual value is
    // equivalent if it is also a Date object that refers to the same time.
    } else if (actual instanceof Date
            && expected instanceof Date) {
        return actual.getTime() === expected.getTime();

    // 7.3. Other pairs that do not both pass typeof value == "object",
    // equivalence is determined by ==.
    } else if (typeof actual != 'object'
            && typeof expected != 'object') {
        return actual == expected;

    // 7.4. For all other Object pairs, including Array objects, equivalence is
    // determined by having the same number of owned properties (as verified
    // with Object.prototype.hasOwnProperty.call), the same set of keys
    // (although not necessarily the same order), equivalent values for every
    // corresponding key, and an identical "prototype" property. Note: this
    // accounts for both named and indexed properties on Arrays.
    } else {
        return objEquiv(actual, expected);
    }
}

function isUndefinedOrNull (value) {
    return value === null || value === undefined;
}

function isArguments (object){
    return Object.prototype.toString.call(object) == '[object Arguments]';
}

function objEquiv (a, b) {
    if (isUndefinedOrNull(a) || isUndefinedOrNull(b))
        return false;
    // an identical "prototype" property.
    if (a.prototype !== b.prototype) return false;
    //~~~I've managed to break Object.keys through screwy arguments passing.
    //   Converting to array solves the problem.
    if(isArguments(a)){
        if(!isArguments(b)){
            return false;
        }
        a = pSlice.call(a);
        b = pSlice.call(b);
        return _deepEqual(a,b);
    }
    try{
        var ka = Object.keys(a),
            kb = Object.keys(b),
            key, i;
    } catch (e) {//happens when one is a string literal and the other isn't
        return false;
    }
    // having the same number of owned properties (keys incorporates hasOwnProperty)
    if(ka.length != kb.length)
        return false;
    //the same set of keys (although not necessarily the same order),
    ka.sort();
    kb.sort();
    //~~~cheap key test
    for (i = ka.length - 1; i >= 0; i--) {
        if(ka[i] != kb[i])
            return false;
    }
    //equivalent values for every corresponding key, and
    //~~~possibly expensive deep test
    for (i = ka.length - 1; i >= 0; i--) {
        key = ka[i];
        if(!_deepEqual(a[key], b[key] ))
           return false;
    }
    return true;
}

// 8. The non-equivalence assertion tests for any deep inequality.
// assert.notDeepEqual(actual, expected, message_opt);

exports.notDeepEqual = function notDeepEqual(actual, expected, message) {
    if (_deepEqual(actual, expected))
        fail(actual, expected, message, "notDeepEqual");
};

// 9. The strict equality assertion tests strict equality, as determined by ===.
// assert.strictEqual(actual, expected, message_opt);

assert.strictEqual = function strictEqual(actual, expected, message) {
    if (actual !== expected)
        fail(actual, expected, message, "===");
};

// 10. The strict non-equality assertion tests for strict inequality, as determined by !==.
// assert.notStrictEqual(actual, expected, message_opt);

assert.notStrictEqual = function notStrictEqual(actual, expected, message) {
    if (actual === expected)
        fail(actual, expected, message, "!==");
};

// 11. Expected to throw an error:
// assert.throws(block, Error_opt, message_opt);

assert.throws = function(block, /*optional*/error, /*optional*/message){
    var args = [true]
    _throws.apply(this, args.concat(pSlice.call(arguments)));
}

// EXTENSION! This is annoying to write outside this module.
assert.doesNotThrow = function(block, /*optional*/error, /*optional*/message){
    var args = [false]
    _throws.apply(this, args.concat(pSlice.call(arguments)));
}

var _throws = function (shouldThrow, block, err, message) {
    var exception = null
        threw = false
        typematters = true;
    message = message || "";

    //handle optional arguments
    if(arguments.length == 3){
        if(typeof(err) == "string"){
            message = err;
            typematters = false;
        }
    } else if(arguments.length == 2) {
        typematters = false;
    }

    try {
        block();
    } catch (e) {
        threw = true;
        exception = e;
    }

    if(shouldThrow && !threw){
        fail("Missing expected exception"+
             (err && err.name ? " ("+err.name+")." : '.') +
             (message ? " " + message : ""));
    }
    if(!shouldThrow && threw && typematters && exception instanceof err){
        fail("Got unwanted exception" +
             (err && err.name ? " ("+err.name+")." : '.') +
             (message ? " " + message : ""));
    }
    if((shouldThrow && threw && typematters && !(exception instanceof err)) ||
       (!shouldThrow && threw)){
        throw exception;
    }
};
