/*
    This file is part of FreeTube.

    FreeTube is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    FreeTube is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with FreeTube.  If not, see <http://www.gnu.org/licenses/>.
*/



/*
 * File for all functions related to subscriptions.
 */

let subscriptionTimer;
let forceTimer;
let checkSubscriptions = true;
let forceSubs = true;
let displaySubsLock = false;

/**
 * Add a channel to the user's subscription database.
 *
 * @param {string} channelId - The channel ID to add to the subscriptions database.
 *
 * @return {Void}
 */
function addSubscription(data, useToast = true, profile = '') {
    ft.log('Channel Data: ', data);

    let newSubscription = data;
    newSubscription.profile = [{
        value: profile
    }];

    if (profile === '') {
        newSubscription.profile = [{
            value: profileSelectView.activeProfile.name
        }];
    }

    subDb.find({
        channelId: data.channelId
    }, (err, docs) => {
        if (jQuery.isEmptyObject(docs)) {
            subDb.insert(newSubscription, (err, newDoc) => {
                if (useToast) {
                    showToast('Added ' + newSubscription.channelName + ' to subscriptions.');
                }
                // Refresh the list of subscriptions on the side navigation bar.
                displaySubs();
            });
        } else {
            subDb.update({
                channelId: data.channelId,
            }, {
                $push: {
                    profile: {
                        value: newSubscription.profile[0].value
                    }
                }
            }, (err, numAdded) => {
                // Refresh the list of subscriptions on the side navigation bar.
                displaySubs();
                showToast('Added ' + data.channelName + ' to subscriptions.');
            });
        }
    });
}

/**
 * Remove a channel from the subscriptions database.
 *
 * @param {string} channelId - The channel ID to be removed.
 *
 * @return {Void}
 */
function removeSubscription(channelId, profile = profileSelectView.activeProfile.name, displayToast = true) {
    subDb.find({
        channelId: channelId
    }, (err, docs) => {
        if (docs[0].profile.length > 1 && profile !== 'All Profiles') {
            subDb.update({
                channelId: channelId,
            }, {
                $pull: {
                    profile: {
                        value: profile
                    }
                }
            }, { multi: true },(err, numRemoved) => {
                // Refresh the list of subscriptions on the side navigation bar.
                displaySubs();
                if (displayToast) {
                  showToast('Removed channel from subscriptions.');
                }
            });
        } else {
            subDb.remove({
                channelId: channelId
            }, {}, (err, numRemoved) => {
                // Refresh the list of subscriptions on the side navigation bar.
                displaySubs();
                if (displayToast) {
                  showToast('Removed channel from subscriptions.');
                }
            });
        }
    });
}

/**
 * Load the recent uploads of the user's subscriptions.
 *
 * @return {Void}
 */
function loadSubscriptions() {
    if (checkSubscriptions === false && subscriptionView.videoList.length > 0) {
        ft.log('Will not load subscriptions. Timer still on.');
        loadingView.seen = false;
        return;
    } else {
        showToast('Refreshing Subscription List.  Please wait…');
        checkSubscriptions = false;
        progressView.seen = true;
        $('#reloadButton')[0].classList.add('fa-spin');
    }

    let videoList = [];

    const subscriptions = returnSubscriptions();

    subscriptions.then((results) => {
        let channelId = '';
        let videoList = [];

        if (results.length > 0) {
            let counter = 0;

            for (let i = 0; i < results.length; i++) {
                channelId = results[i]['channelId'];

                invidiousAPI('channels/latest', channelId, {}, (data) => {
                    data.forEach((video, index) => {
                        data[index].author = results[i]['channelName'];
                        data[index].profile = results[i]['profile'];
                        historyDb.findOne({
                            videoId: video.videoId
                        }, function (err, doc) {
                            if (doc === null) {
                                data[index].watched = false
                            } else {
                                data[index].watched = true;
                            }
                        });
                    });
                    videoList = videoList.concat(data);
                    counter = counter + 1;
                    progressView.progressWidth = (counter / results.length) * 100;

                    if (counter === results.length) {
                        addSubsToView(videoList);
                    }
                }, (errorData) => {
                    showToast('Unable to load channel: ' + results[i]['channelName']);
                    counter = counter + 1;
                    progressView.progressWidth = (counter / results.length) * 100;
                    if (counter === results.length) {
                        addSubsToView(videoList);
                    }
                });
            }
        } else {
            // User has no subscriptions. Display message.
            loadingView.seen = false;
            headerView.seen = false;
            noSubscriptions.seen = true;
            $('#reloadButton')[0].classList.remove('fa-spin');
        }
    });
}

function addSubsToView(videoList) {
    subscriptionView.fullVideoList = videoList;

    videoList = videoList.filter(a => {
        return !a.premium;
    });

    if (hideWatchedSubs) {
        videoList = videoList.filter(a => {
            return !a.watched;
        });
    }

    if (profileSelectView.activeProfile.name !== 'All Channels') {
      videoList = videoList.filter(a => {
        return a.profile.map(x => x.value).indexOf(profileSelectView.activeProfile.name) !== -1
      });
    }

    videoList.sort((a, b) => {
        return b.published - a.published;
    });

    subscriptionView.videoList = [];

    if (videoList.length > 100) {
        for (let i = 0; i < 100; i++) {
            displayVideo(videoList[i], 'subscriptions');
        }
    } else {
        videoList.forEach((video) => {
            displayVideo(video, 'subscriptions');
        });
    }

    loadingView.seen = false;
    progressView.seen = false;
    progressView.progressWidth = 0;
    $('#reloadButton')[0].classList.remove('fa-spin');

    subscriptionTimer = window.setTimeout(() => {
        checkSubscriptions = true;
    }, 7200000);

    ft.log('Done');
}

function forceSubscriptions() {
    if (progressView.progressWidth > 0) {
        showToast('Please wait for subscriptions to finish loading before trying again.');
        return;
    } else if (forceSubs === false) {
        showToast('Too many attempts.  Please wait before loading subscriptions again.');
        return;
    } else {
        window.clearTimeout(subscriptionTimer);
        checkSubscriptions = true;
        loadSubscriptions();
        forceSubs = false;
    }
    forceTimer = window.setTimeout(() => {
        forceSubs = true;
    }, 300000);
}

/**
 * Get the list of subscriptions from the user's subscription database.
 *
 * @return {promise} The list of subscriptions.
 */
function returnSubscriptions() {
    return new Promise((resolve, reject) => {
        subDb.find({}, (err, subs) => {
            resolve(subs);
        });
    });
}

/**
 * Display the list of subscriptions on the side navigation bar.
 *
 * @return {Void}
 */
function displaySubs() {
    if (displaySubsLock) {
        return;
    }

    displaySubsLock = true;

    const subList = document.getElementById('subscriptions');

    subList.innerHTML = '';

    // Sort alphabetically
    subDb.find().sort({
        channelName: 1
    }).exec((err, subs) => {
        let subFilter;
        if (profileSelectView.activeProfile.name === 'All Channels' || typeof(profileSelectView.activeProfile.name) === 'undefined') {
          subFilter = subs;
        }
        else {
          subFilter = subs.filter(a => {
              return a.profile.find((name) => {return name.value === profileSelectView.activeProfile.name });
          });
        }

        subFilter.forEach((channel) => {
            // Grab subscriptions.html to be used as a template.
            const subsTemplate = require('./templates/subscriptions.html')
            mustache.parse(subsTemplate);
            const rendered = mustache.render(subsTemplate, {
                channelIcon: channel['channelThumbnail'],
                channelName: channel['channelName'],
                channelId: channel['channelId'],
            });
            // Render template to page.
            const subscriptionsHtml = $('#subscriptions').html();
            $('#subscriptions').html(subscriptionsHtml + rendered);
        });

        displaySubsLock = false;
    });

    // Add onclick function
    $('#subscriptions .fa-times').onClick = removeSubscription;
}

/**
 * Adds / Removes a subscription based on if the channel is in the database or not.
 * @param {string} channelId - The channel ID to check
 *
 * @return {Void}
 */
function toggleSubscription(data) {
    event.stopPropagation();

    const checkIfSubscribed = isSubscribed(data.channelId);

    checkIfSubscribed.then((results) => {

        if (results === false) {
            playerView.subscribedText = 'UNSUBSCRIBE';
            channelView.subButtonText = 'UNSUBSCRIBE';
            addSubscription(data);
        } else {
            playerView.subscribedText = 'SUBSCRIBE';
            channelView.subButtonText = 'SUBSCRIBE';
            removeSubscription(data.channelId);
        }
    });
}

/**
 * Check if the user is subscribed to a channel or not.
 *
 * @param {string} channelId - The channel ID to check
 *
 * @return {promise} - A boolean value if the channel is currently subscribed or not.
 */
function isSubscribed(channelId, profile = profileSelectView.activeProfile.name) {
    return new Promise((resolve, reject) => {
        subDb.find({
            $and: [{
                    channelId: channelId
                },
                {
                    profile: {
                        $elemMatch: {
                            value: profile
                        }
                    }
                },
            ]
        }, (err, docs) => {
            if (jQuery.isEmptyObject(docs)) {
                resolve(false);
            } else {
                resolve(true);
            }
        });
    });
}