import { typeOf, isFunction } from './Type.js';
import { last, makeArray, slice, forEach, len, range } from './Array.js';

function asyncMap(forEachFn, collection, iterator, that, callback) {
    var type = typeOf(collection),
        results = type == 'object' ? {} : [];
    callback = last(arguments);
    that = arguments.length == 5 ? that : null;
    forEachFn(collection, function(value, key, collection, callback) {
        iterator(value, key, collection, function(value) {
            results[key] = value;
            callback();
        });
    }, that, function() {
        callback(type == 'string' ? results.join('') : results);
    });
}

export function asyncMapFn(array, iterator, that, callback) {
    array = makeArray(array);
    callback = last(arguments);
    that = arguments.length == 4 ? that : null;
    if (array.some(Array.isArray)) {
        serialMap(array, function(value, key, array, callback) {
            parallelMap(makeArray(value), iterator, callback);
        }, callback);
    } else {
        parallelMap(array, iterator, callback);
    }
}

/*@
Ox.nonblockingForEach <f> Non-blocking `forEach` with synchronous iterator
    (col, iterator[, that], callback[, ms]) -> <u> undefined
    collection <a|o|s> Collection
    iterator <f> Iterator function
        value <*> Value
        key <n|s> Key
        collection <a|o|s> The collection
    that <o> The iterator's `this` binding
    callback <f> Callback function
    ms <n> Number of milliseconds after which to insert a `setTimeout` call
@*/
export function nonblockingForEach(collection, iterator, that, callback, ms) {
    var i = 0, keys, lastArg = last(arguments),
        n, time, type = typeOf(collection);
    callback = isFunction(lastArg) ? lastArg : arguments[arguments.length - 2];
    collection = type == 'array' || type == 'object'
        ? collection : slice(collection);
    keys = type == 'object'
        ? Object.keys(collection) : range(collection.length);
    ms = ms || 1000;
    n = len(collection);
    that = arguments.length == 5 || (
        arguments.length == 4 && isFunction(lastArg)
    ) ? that : null;
    time = +new Date();
    iterate();
    function iterate() {
        forEach(keys.slice(i), function(key) {
            if (key in collection) {
                if (iterator.call(
                    that, collection[key], key, collection
                ) === false) {
                    i = n;
                    return false;
                }
            }
            i++;
            if (+new Date() >= time + ms) {
                return false; // break
            }
        });
        if (i < n) {
            setTimeout(function() {
                time = +new Date();
                iterate();
            }, 1);
        } else {
            callback();
        }
    }
}

/*@
Ox.nonblockingMap <f> Non-blocking `map` with synchronous iterator
    (collection, iterator[, that], callback[, ms]) -> <u> undefined
    collection <a|o|s> Collection
    iterator <f> Iterator function
    that <o> The iterator's `this` binding
    callback <f> Callback function
    ms <n> Number of milliseconds after which to insert a `setTimeout` call
    <script>
        // var time = +new Date();
        // Ox.nonblockingMap(
        //     Ox.range(1000000),
        //     function (value, index, array) {
        //         return +new Date() - time;
        //     },
        //     function(results) {
        //         Ox.print(results.length);
        //     },
        //     1000
        // );
    </script>
    > Ox.nonblockingMap(Ox.range(100000), Ox.identity, function(r) { Ox.test(r.length, 100000); })
    undefined
@*/
export function nonblockingMap(collection, iterator, that, callback, ms) {
    var lastArg = last(arguments),
        type = typeOf(collection),
        results = type == 'object' ? {} : [];
    callback = isFunction(lastArg) ? lastArg : arguments[arguments.length - 2];
    that = arguments.length == 5 || (
        arguments.length == 4 && isFunction(lastArg)
    ) ? that : null;
    nonblockingForEach(collection, function(value, key, collection) {
        results[key] = iterator.call(that, value, key, collection);
    }, function() {
        callback(type == 'string' ? results.join('') : results);
    }, ms);
}

/*@
Ox.parallelForEach <f> `forEach` with asynchronous iterator, running in parallel
    (collection, iterator[, that], callback) -> <u> undefined
    collection <a|o|s> Collection
    iterator <f> Iterator function
        value <*> Value
        key <n|s> Key
        collection <a|o|s> The collection
        callback <f> Callback function
    that <o> The iterator's this binding
    callback <f> Callback function
    <script>
        Ox.test.pfeNumber = 0;
        Ox.test.pfeIterator = function(value, index, array, callback) {
            if (index < 5) {
                Ox.test.pfeNumber++;
            }
            setTimeout(callback);
        };
    </script>
    > Ox.parallelForEach(Ox.range(10), Ox.test.pfeIterator, function() { Ox.test(Ox.test.pfeNumber, 5); })
    undefined
@*/
export function parallelForEach(collection, iterator, that, callback) {
    var i = 0, n, type = typeOf(collection);
    callback = callback || (arguments.length == 3 ? arguments[2] : function() {});
    collection = type == 'array' || type == 'object'
        ? collection : slice(collection);
    n = len(collection);
    that = arguments.length == 4 ? that : null;
    forEach(collection, function(value, key, collection) {
        iterator.call(that, value, key, collection, function() {
            ++i == n && callback();
        });
    });
}

/*@
Ox.parallelMap <f> Parallel `map` with asynchronous iterator
    (collection, iterator[, that], callback) -> <u> undefined
    collection <a|o|s> Collection
    iterator <f> Iterator function
        value <*> Value
        key <n|s> Key
        collection <a|o|s> The collection
        callback <f> Callback function
    that <o> The iterator's this binding
    callback <f> Callback function
        results <a|o|s> Results
    <script>
        // var time = +new Date();
        // Ox.parallelMap(
        //     Ox.range(10),
        //     function (value, index, array, callback) {
        //         setTimeout(function() {
        //             callback(+new Date() - time);
        //         }, Ox.random(1000));
        //     },
        //     function(results) {
        //         Ox.print(results);
        //     }
        // );
        Ox.test.pmIterator = function(value, index, array, callback) {
            setTimeout(callback(value - index));
        };
    </script>
    > Ox.parallelMap(Ox.range(10), Ox.test.pmIterator, function(r) { Ox.test(Ox.sum(r), 0); })
    undefined
@*/
export function parallelMap() {
    asyncMap.apply(null, [parallelForEach].concat(slice(arguments)));
}

/*@
Ox.serialForEach <f> `forEach` with asynchronous iterator, run serially
    (collection, iterator[, that], callback) -> <u> undefined
    collection <a|o|s> Collection
    iterator <f> Iterator function
        value <*> Value
        key <n|s> Key
        collection <a|o|s> The collection
        callback <f> Callback function
    that <o> The iterator's this binding
    callback <f> Callback function
    <script>
        Ox.test.sfeNumber = 0;
        Ox.test.sfeIterator = function(value, index, array, callback) {
            Ox.test.sfeNumber++;
            setTimeout(function() {
                callback(index < 4);
            });
        };
    </script>
    > Ox.serialForEach(Ox.range(10), Ox.test.sfeIterator, function() { Ox.test(Ox.test.sfeNumber, 5); })
    undefined
@*/
export function serialForEach(collection, iterator, that, callback) {
    var i = 0, keys, n, type = typeOf(collection);
    callback = callback || (arguments.length == 3 ? arguments[2] : function() {});
    collection = type == 'array' || type == 'object'
        ? collection : slice(collection);
    keys = type == 'object'
        ? Object.keys(collection) : range(collection.length);
    n = len(collection);
    that = arguments.length == 4 ? that : null;
    iterate();
    function iterate(value) {
        if (value !== false) {
            if (keys[i] in collection) {
                iterator.call(
                    that,
                    collection[keys[i]],
                    keys[i],
                    collection,
                    ++i < n ? iterate : callback
                );
            } else {
                ++i < n ? iterate() : callback();
            }
        } else {
            callback();
        }
    }
}

/*@
Ox.serialMap <f> Serial `map` with asynchronous iterator
    (collection, iterator[, that], callback) -> <u> undefined
    collection <a|o|s> Collection
    iterator <f> Iterator function
        value <*> Value
        key <n|s> Key
        collection <a|o|s> The collection
        callback <f> Callback function
    that <o> The iterator's this binding
    callback <f> Callback function
        results <a|o|s> Results
    <script>
        // var time = +new Date();
        // Ox.serialMap(
        //     Ox.range(10),
        //     function (value, index, array, callback) {
        //         setTimeout(function() {
        //             callback(+new Date() - time);
        //         }, Ox.random(1000));
        //     },
        //     function(results) {
        //         Ox.print(results);
        //     }
        // );
        Ox.test.smIterator = function(value, index, array, callback) {
            setTimeout(callback(value - index));
        };
    </script>
    > Ox.serialMap(Ox.range(10), Ox.test.smIterator, function(r) { Ox.test(Ox.sum(r), 0); })
    undefined
@*/
export function serialMap(collection, iterator, that, callback) {
    asyncMap.apply(null, [serialForEach].concat(slice(arguments)));
}
// FIXME: The above test with 10000 iterations blows the stack