(function () {
    'use strict';

    angular.module('ariaNg').factory('aria2TaskService', ['$q', '$translate', 'aria2RpcService', function ($q, $translate, aria2RpcService) {
        var getFileNameFromPath = function (path) {
            if (!path) {
                return path;
            }

            var index = path.lastIndexOf('/');

            if (index <= 0 || index == path.length) {
                return path;
            }

            return path.substring(index + 1);
        };

        var calculateDownloadRemainTime = function (remainBytes, downloadSpeed) {
            if (downloadSpeed == 0) {
                return 0;
            }

            return remainBytes / downloadSpeed;
        };

        var getTaskName = function (task) {
            var taskName = "";

            if (task.bittorrent && task.bittorrent.info) {
                taskName = task.bittorrent.info.name;
            }

            if (!taskName && task.files && task.files.length >= 1) {
                taskName = getFileNameFromPath(task.files[0].path);
            }

            if (!taskName && task.files && task.files.length >= 1 && task.files[0].uris && task.files[0].uris.length >= 1) {
                taskName = getFileNameFromPath(task.files[0].uris[0].uri);
            }

            if (!taskName) {
                taskName = $translate.instant('Unknown');
            }

            return taskName;
        };

        var processDownloadTask = function (task) {
            if (!task) {
                return task;
            }

            task.totalLength = parseInt(task.totalLength);
            task.completedLength = parseInt(task.completedLength);
            task.completePercent = (task.totalLength > 0 ? task.completedLength / task.totalLength * 100 : 0);
            task.remainLength = task.totalLength - task.completedLength;
            task.remainPercent = 100 - task.completePercent;

            task.uploadSpeed = parseInt(task.uploadSpeed);
            task.downloadSpeed = parseInt(task.downloadSpeed);

            task.taskName = getTaskName(task);
            task.idle = task.downloadSpeed == 0;

            task.remainTime = calculateDownloadRemainTime(task.remainLength, task.downloadSpeed);

            if (task.files) {
                for (var i = 0; i < task.files.length; i++) {
                    var file = task.files[i];
                    file.fileName = getFileNameFromPath(file.path);
                    file.length = parseInt(file.length);
                    file.completedLength = parseInt(file.completedLength);
                    file.completePercent = (file.length > 0 ? file.completedLength / file.length * 100 : 0);
                }
            }

            return task;
        };

        var estimateCompletedPercentFromBitField = function (bitfield) {
            var totalLength = bitfield.length * 0xf;
            var completedLength = 0;

            if (totalLength == 0) {
                return 0;
            }

            for (var i = 0; i < bitfield.length; i++) {
                var num = parseInt(bitfield[i], 16);
                completedLength += num;
            }

            return completedLength / totalLength;
        };

        return {
            getTaskList: function (type, full, callback, silent) {
                var invokeMethod = null;

                if (type == 'downloading') {
                    invokeMethod = aria2RpcService.tellActive;
                } else if (type == 'waiting') {
                    invokeMethod = aria2RpcService.tellWaiting;
                } else if (type == 'stopped') {
                    invokeMethod = aria2RpcService.tellStopped;
                } else {
                    return;
                }

                return invokeMethod({
                    requestParams: full ? aria2RpcService.getFullTaskParams() : aria2RpcService.getBasicTaskParams(),
                    silent: !!silent,
                    callback: function (result) {
                        if (!callback) {
                            return;
                        }

                        callback(result);
                    }
                });
            },
            getTaskStatus: function (gid, callback, silent) {
                return aria2RpcService.tellStatus({
                    gid: gid,
                    silent: !!silent,
                    callback: function (result) {
                        if (!callback) {
                            return;
                        }

                        var task = processDownloadTask(result);
                        callback(task);
                    }
                });
            },
            getTaskOptions: function (gid, callback) {
                return aria2RpcService.getOption({
                    gid: gid,
                    callback: callback
                });
            },
            setTaskOption: function (gid, key, value, callback) {
                var data = {};
                data[key] = value;

                return aria2RpcService.changeOption({
                    gid: gid,
                    options: data,
                    callback: callback
                });
            },
            getBtTaskPeers: function (gid, callback, silent) {
                return aria2RpcService.getPeers({
                    gid: gid,
                    silent: !!silent,
                    callback: function (result) {
                        if (!callback) {
                            return;
                        }

                        if (result) {
                            for (var i = 0; i < result.length; i++) {
                                var peer = result[i];
                                peer.completePercent = estimateCompletedPercentFromBitField(peer.bitfield) * 100;
                            }
                        }

                        callback(result);
                    }
                });
            },
            startTasks: function (gids, callback) {
                return aria2RpcService.unpauseMulti({
                    gids: gids,
                    callback: callback
                });
            },
            pauseTasks: function (gids, callback) {
                return aria2RpcService.forcePauseMulti({
                    gids: gids,
                    callback: callback
                });
            },
            removeTasks: function (tasks, callback) {
                var runningTaskGids = [];
                var stoppedTaskGids = [];
                
                for (var i = 0; i < tasks.length; i++) {
                    if (tasks[i].status == 'complete' || tasks[i].status == 'error' || tasks[i].status == 'removed') {
                        stoppedTaskGids.push(tasks[i].gid);
                    } else {
                        runningTaskGids.push(tasks[i].gid);
                    }
                }
                
                var promises = [];
                var results = {
                    runningResult: null, 
                    stoppedResult: null
                };
                
                if (runningTaskGids.length > 0) {
                    promises.push(aria2RpcService.forceRemoveMulti({
                        gids: runningTaskGids,
                        callback: function (result) {
                            results.runningResult = result;
                        }
                    }));
                }
                
                if (stoppedTaskGids.length > 0) {
                    promises.push(aria2RpcService.removeDownloadResultMulti({
                        gids: stoppedTaskGids,
                        callback: function (result) {
                            results.stoppedResult = result;
                        }
                    }));
                }

                return $q.all(promises).then(function () {
                    if (callback) {
                        callback(results);
                    }
                });
            },
            changeTaskPosition: function (gid, position, callback) {
                return aria2RpcService.changePosition({
                    gid: gid,
                    pos: position,
                    how: 'POS_SET',
                    callback: callback
                })
            },
            clearStoppedTasks: function (callback) {
                return aria2RpcService.purgeDownloadResult({
                    callback: callback
                });
            },
            processDownloadTasks: function (tasks) {
                if (!angular.isArray(tasks)) {
                    return;
                }

                for (var i = 0; i < tasks.length; i++) {
                    processDownloadTask(tasks[i]);
                }
            },
            estimateHealthPercentFromPeers: function (task, peers) {
                if (peers.length < 1) {
                    return task.completePercent;
                }

                var bitfieldCompletedArr = new Array(task.bitfield.length);
                var bitfieldPieceArr = new Array(task.bitfield.length);
                var totalLength = task.bitfield.length * 0xf;
                var healthBitCount = 0;

                for (var i = 0; i < task.bitfield.length; i++) {
                    var num = parseInt(task.bitfield[i], 16);
                    bitfieldCompletedArr[i] = 0;
                    bitfieldPieceArr[i] = 0;

                    if (num == 0xf) {
                        bitfieldCompletedArr[i] = num;
                    } else {
                        bitfieldPieceArr[i] = num;
                    }
                }

                for (var i = 0; i < peers.length; i++) {
                    var peer = peers[i];
                    var bitfield = peer.bitfield;

                    for (var j = 0; j < bitfield.length; j++) {
                        var num = parseInt(bitfield[j], 16);

                        if (num == 0xf) {
                            bitfieldCompletedArr[j] += num;
                        } else {
                            bitfieldPieceArr[j] = Math.max(bitfieldPieceArr[j], num);
                        }
                    }
                }

                for (var i = 0; i < bitfieldCompletedArr.length; i++) {
                    bitfieldCompletedArr[i] += bitfieldPieceArr[i];
                }

                while (true) {
                    var completed = true;

                    for (var i = 0; i < bitfieldCompletedArr.length; i++) {
                        var bitCount = Math.min(bitfieldCompletedArr[i], 0xf);
                        healthBitCount += bitCount;
                        bitfieldCompletedArr[i] -= bitCount;

                        if (bitCount < 0xf) {
                            completed = false;
                        }
                    }

                    if (!completed) {
                        break;
                    }
                }

                var healthPercent = healthBitCount / totalLength * 100;

                if (healthPercent < task.completePercent) {
                    healthPercent = task.completePercent;
                }

                return healthPercent;
            }
        };
    }]);
})();