/*******************************************************************************

    ηMatrix - a browser extension to black/white list requests.
    Copyright (C) 2014-2019 Raymond Hill
    Copyright (C) 2019-2020 Alessio Vanni

    This program 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.

    This program 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 this program.  If not, see {http://www.gnu.org/licenses/}.

    Home: https://libregit.spks.xyz/heckyel/ematrix
    uMatrix Home: https://github.com/gorhill/uMatrix
*/

'use strict';

(function () {
    let listDetails = {};
    let lastUpdateTemplateString = vAPI.i18n('hostsFilesLastUpdate');
    let hostsFilesSettingsHash;
    let reValidExternalList = /[a-z-]+:\/\/\S*\/\S+/;

    vAPI.messaging.addListener(function (msg) {
        switch (msg.what) {
        case 'assetUpdated':
            updateAssetStatus(msg);
            break;
        case 'assetsUpdated':
            document.body.classList.remove('updating');
            break;
        case 'loadHostsFilesCompleted':
            renderHostsFiles();
            break;
        default:
            break;
        }
    });

    let renderNumber = function (value) {
        return value.toLocaleString();
    };

    let renderHostsFiles = function (soft) {
        let listEntryTemplate = uDom('#templates .listEntry');
        let listStatsTemplate = vAPI.i18n('hostsFilesPerFileStats');
        let renderETTS = vAPI.i18n.renderElapsedTimeToString;
        let reExternalHostFile = /^https?:/;

        // Assemble a pretty list name if possible
        let listNameFromListKey = function (listKey) {
            let list =
                listDetails.current[listKey] || listDetails.available[listKey];
            let listTitle = list ? list.title : '';

            if (listTitle === '') {
                return listKey;
            }

            return listTitle;
        };

        let liFromListEntry = function (listKey, li) {
            let entry = listDetails.available[listKey];
            let elem;

            if (!li) {
                li = listEntryTemplate.clone().nodeAt(0);
            }

            if (li.getAttribute('data-listkey') !== listKey) {
                li.setAttribute('data-listkey', listKey);

                elem = li.querySelector('input[type="checkbox"]');
                elem.checked = (entry.off !== true);
                elem = li.querySelector('a:nth-of-type(1)');
                elem.setAttribute('href',
                                  'asset-viewer.html?url=' + encodeURI(listKey));
                elem.setAttribute('type', 'text/html');
                elem.textContent = listNameFromListKey(listKey);

                li.classList.remove('toRemove');

                if (entry.supportName) {
                    li.classList.add('support');
                    elem = li.querySelector('a.support');
                    elem.setAttribute('href', entry.supportURL);
                    elem.setAttribute('title', entry.supportName);
                } else {
                    li.classList.remove('support');
                }

                if (entry.external) {
                    li.classList.add('external');
                } else {
                    li.classList.remove('external');
                }

                if (entry.instructionURL) {
                    li.classList.add('mustread');
                    elem = li.querySelector('a.mustread');
                    elem.setAttribute('href', entry.instructionURL);
                } else {
                    li.classList.remove('mustread');
                }
            }

            // https://github.com/gorhill/uBlock/issues/1429
            if (!soft) {
                elem = li.querySelector('input[type="checkbox"]');
                elem.checked = entry.off !== true;
            }

            elem = li.querySelector('span.counts');

            let text = '';
            if (!isNaN(+entry.entryUsedCount) && !isNaN(+entry.entryCount)) {
                text = listStatsTemplate
                    .replace('{{used}}',
                             renderNumber(entry.off ? 0 : entry.entryUsedCount))
                    .replace('{{total}}',
                             renderNumber(entry.entryCount));
            }

            elem.textContent = text;

            // https://github.com/chrisaljoudi/uBlock/issues/104
            let asset = listDetails.cache[listKey] || {};
            let remoteURL = asset.remoteURL;

            li.classList.toggle('unsecure',
                                typeof remoteURL === 'string'
                                && remoteURL.lastIndexOf('http:', 0) === 0);
            li.classList.toggle('failed', asset.error !== undefined);
            li.classList.toggle('obsolete', asset.obsolete === true);
            li.classList.toggle('cached',
                                asset.cached === true && asset.writeTime > 0);

            if (asset.cached) {
                li.querySelector('.status.cache')
                    .setAttribute('title',
                                  lastUpdateTemplateString
                                  .replace('{{ago}}',
                                           renderETTS(asset.writeTime)));
            }

            li.classList.remove('discard');
            return li;
        };

        let onListsReceived = function (details) {
            // Before all, set context vars
            listDetails = details;

            // Incremental rendering: this will allow us to easily discard unused
            // DOM list entries.
            uDom('#lists .listEntry').addClass('discard');

            let availableLists = details.available;
            let listKeys = Object.keys(details.available);

            // Sort works this way:
            // - Send /^https?:/ items at the end (custom hosts file URL)
            listKeys.sort(function (a, b) {
                let ta = availableLists[a].title || a;
                let tb = availableLists[b].title || b;

                if (reExternalHostFile.test(ta) === reExternalHostFile.test(tb)) {
                    return ta.localeCompare(tb);
                }

                return reExternalHostFile.test(tb) ? -1 : 1;
            });

            let ulList = document.querySelector('#lists');

            for (let i=0; i<listKeys.length; ++i) {
                let liEntry = liFromListEntry(listKeys[i], ulList.children[i]);
                if (liEntry.parentElement === null) {
                    ulList.appendChild(liEntry);
                }
            }

            uDom('#lists .listEntry.discard').remove();
            uDom('#listsOfBlockedHostsPrompt')
                .text(vAPI.i18n('hostsFilesStats')
                      .replace('{{blockedHostnameCount}}',
                               renderNumber(details.blockedHostnameCount)));
            uDom('#autoUpdate').prop('checked',
                                     listDetails.autoUpdate === true);

            if (!soft) {
                hostsFilesSettingsHash = hashFromCurrentFromSettings();
            }

            renderWidgets();
        };

        vAPI.messaging.send('hosts-files.js', {
            what: 'getLists'
        }, onListsReceived);
    };

    let renderWidgets = function () {
        let sel1 =
            'body:not(.updating) #lists .listEntry.obsolete '
            + '> input[type="checkbox"]:checked';
        let sel2 = '#lists .listEntry.cached';

        uDom('#buttonUpdate')
            .toggleClass('disabled', document.querySelector(sel1) === null);
        uDom('#buttonPurgeAll')
            .toggleClass('disabled', document.querySelector(sel2) === null);
        uDom('#buttonApply')
            .toggleClass('disabled',
                         hostsFilesSettingsHash ===
                         hashFromCurrentFromSettings());
    };

    let updateAssetStatus = function (details) {
        let li = document
            .querySelector('#lists .listEntry[data-listkey="'+details.key+'"]');
        if (li === null) {
            return;
        }

        li.classList.toggle('failed', !!details.failed);
        li.classList.toggle('obsolete', !details.cached);
        li.classList.toggle('cached', !!details.cached);

        if (details.cached) {
            let str = vAPI.i18n.renderElapsedTimeToString(Date.now());
            li.querySelector('.status.cache')
                .setAttribute('title',
                              lastUpdateTemplateString.replace('{{ago}}', str));
        }

        renderWidgets();
    };

    /**
       Compute a hash from all the settings affecting how filter lists are loaded
       in memory.
    **/
    let hashFromCurrentFromSettings = function () {
        let hash = [];
        let listHash = [];
        let sel = '#lists .listEntry[data-listkey]:not(.toRemove)';
        let ext = 'externalHostsFiles';
        let listEntries = document.querySelectorAll(sel);

        for (let i=listEntries.length-1; i>=0; --i) {
            let li = listEntries[i];
            if (li.querySelector('input[type="checkbox"]:checked') !== null) {
                listHash.push(li.getAttribute('data-listkey'));
            }
        }

        hash.push(listHash.sort().join(),
                  reValidExternalList.test(document.getElementById(ext).value),
                  document.querySelector('#lists .listEntry.toRemove') !== null);

        return hash.join();
    };

    let onHostsFilesSettingsChanged = function () {
        renderWidgets();
    };

    let onRemoveExternalHostsFile = function (ev) {
        let liEntry = uDom(this).ancestors('[data-listkey]');
        let listKey = liEntry.attr('data-listkey');

        if (listKey) {
            liEntry.toggleClass('toRemove');
            renderWidgets();
        }

        ev.preventDefault();
    };

    let onPurgeClicked = function () {
        let button = uDom(this);
        let liEntry = button.ancestors('[data-listkey]');
        let listKey = liEntry.attr('data-listkey');

        if (!listKey) {
            return;
        }

        vAPI.messaging.send('hosts-files.js', {
            what: 'purgeCache',
            assetKey: listKey
        });

        liEntry.addClass('obsolete');
        liEntry.removeClass('cached');

        if (liEntry.descendants('input').first().prop('checked')) {
            renderWidgets();
        }
    };

    let selectHostsFiles = function (callback) {
        // Hosts files to select
        let toSelect = [];
        let sel = '#lists .listEntry[data-listkey]:not(.toRemove)';
        let sel2 = '#lists .listEntry.toRemove[data-listkey]';
        let liEntries = document.querySelectorAll(sel);

        for (let i=liEntries.length-1; i>=0; --i) {
            let li  = liEntries[i];
            if (li.querySelector('input[type="checkbox"]:checked') !== null) {
                toSelect.push(li.getAttribute('data-listkey'));
            }
        }

        // External hosts files to remove
        let toRemove = [];
        liEntries = document.querySelectorAll(sel2);

        for (let i=liEntries.length-1; i>=0; --i) {
            toRemove.push(liEntries[i].getAttribute('data-listkey'));
        }

        // External hosts files to import
        let externalListsElem = document.getElementById('externalHostsFiles');
        let toImport = externalListsElem.value.trim();

        externalListsElem.value = '';

        vAPI.messaging.send('hosts-files.js', {
            what: 'selectHostsFiles',
            toSelect: toSelect,
            toImport: toImport,
            toRemove: toRemove
        }, callback);

        hostsFilesSettingsHash = hashFromCurrentFromSettings();
    };

    let buttonApplyHandler = function () {
        uDom('#buttonApply').removeClass('enabled');
        selectHostsFiles(function () {
            vAPI.messaging.send('hosts-files.js', {
                what: 'reloadHostsFiles'
            });
        });

        renderWidgets();
    };

    let buttonUpdateHandler = function () {
        uDom('#buttonUpdate').removeClass('enabled');
        selectHostsFiles(function () {
            document.body.classList.add('updating');
            vAPI.messaging.send('hosts-files.js', {
                what: 'forceUpdateAssets'
            });
            renderWidgets();
        });
        renderWidgets();
    };

    let buttonPurgeAllHandler = function () {
        uDom('#buttonPurgeAll').removeClass('enabled');
        vAPI.messaging.send('hosts-files.js', {
            what: 'purgeAllCaches'
        }, function () {
            renderHostsFiles(true);
        });
    };

    let autoUpdateCheckboxChanged = function () {
        vAPI.messaging.send('hosts-files.js', {
            what: 'userSettings',
            name: 'autoUpdate',
            value: this.checked
        });
    };

    uDom('#autoUpdate').on('change', autoUpdateCheckboxChanged);
    uDom('#buttonApply').on('click', buttonApplyHandler);
    uDom('#buttonUpdate').on('click', buttonUpdateHandler);
    uDom('#buttonPurgeAll').on('click', buttonPurgeAllHandler);
    uDom('#lists').on('change', '.listEntry > input',
                      onHostsFilesSettingsChanged);
    uDom('#lists').on('click', '.listEntry > a.remove',
                      onRemoveExternalHostsFile);
    uDom('#lists').on('click', 'span.cache', onPurgeClicked);
    uDom('#externalHostsFiles').on('input', onHostsFilesSettingsChanged);

    renderHostsFiles();
})();