/*
  Automatically click all "Verify your email" links in the welcome e-mail from
  Nintendo Pokémon Trainer Club's signup e-mails.
  
  Only unread emails in inbox will be processed.
  All processed e-mails will be marked as read if verification was successful,
  and optionally moved to trash if it's enabled in your settings.
  
  How to use:
   1. Login to Gmail
   2. Go to https://script.google.com/
   3. Enter the code in Code.gs and index.html (if index.html doesn't exist, create it).
   4. Edit the settings at the top of index.html.
   5. In the editor, click on Resources > Advanced Google services and name your project.
   6. Enable "These services must also be enabled in the Google Developers Console".
   7. Enable GMail API for your new project in the Google Developers Console: https://console.developers.google.com/.
   8. Click Publish, then run as web app.
   9. You'll see the results on the page. Dev console can be used for debugging.
   10. Enjoy
*/

// Serve HTML file.
function doGet() {
    return HtmlService.createHtmlOutputFromFile('index.html');
}

function getAllEmailLinks(limit) {
    // Prepare response.
    var items = [];

    // Start.
    var threads = GmailApp.search('in:inbox -label:RM_EXPIRED -label:RM_PREACTIVATED is:unread subject:"Pokémon Trainer Club Activation"', 0, limit);
    Logger.log("Found " + threads.length + " threads.");

    threads.forEach(function (thread) {
        var messages = thread.getMessages();
        Logger.log("Found " + messages.length + " messages.");

        messages.forEach(function (msg) {
            // If we have a limit, follow it.
            if (limit > 0 && items.length >= limit) {
                return;
            }

            var value = msg.getBody()
                .match(/verify your email/m);

            if (msg.isInInbox() && value) {
                var messageId = msg.getId();

                var link = msg.getBody().match(/<a href="https:\/\/club.pokemon.com\/us\/pokemon-trainer-club\/activated\/([\w\d]+)"/);

                if (link) {
                    var url = 'https://club.pokemon.com/us/pokemon-trainer-club/activated/' + link[1];

                    // Add to list for front-end.
                    items.push({
                        'url': url,
                        'id': messageId
                    });
                }
            }
        });
    });

    Logger.log("Sent " + items.length + " URLs to front-end for verification.");

    return items;
}

function labelAsError(messageId, labelName) {
    try {
        modifyMessage('me', messageId, [ labelName ]);
        return {
            'success': true
        };
    } catch (e) {
        Logger.log(e);
        return {
            'success': false,
            'error': e
        };
    }
}

function markAsVerified(messageId, move_to_trash) {
    var msg = GmailApp.getMessageById(messageId);
    msg.markRead();

    if (move_to_trash) {
        msg.moveToTrash();
    }
}


/*
 * Below methods are Google Apps Script Gmail Utilities, by mogsdad:
 * https://gist.github.com/mogsdad/6515581
 */

/**
 * Modify the Labels a Message is associated with.
 * Throws if unsuccessful.
 * see https://developers.google.com/gmail/api/v1/reference/users/messages/modify
 *
 * @param  {String} userId         User's email address. The special value 'me'
 *                                 can be used to indicate the authenticated user.
 * @param  {String} messageId      ID of Message to modify.
 * @param  {String} labelsToAdd    Array of Label names to add.
 * @param  {String} labelsToRemove Array of Label names to remove.
 *
 * @returns {Object}               Users.messages resource, see reference. 
 */
function modifyMessage(userId, messageId, labelsToAdd, labelsToRemove) {
    labelsToAdd = labelsToAdd || [];
    labelsToRemove = labelsToRemove || [];
    // see https://developers.google.com/gmail/api/v1/reference/users/messages/modify
    var url = 'https://www.googleapis.com/gmail/v1/users/${userId}/messages/${id}/modify'
        .replace("${userId}", "me")
        .replace("${id}", messageId);
    var headers = {
        Authorization: 'Bearer ' + ScriptApp.getOAuthToken()
    };
    var addLabelIds = [];
    for (var i = 0; i < labelsToAdd.length; i++) {
        addLabelIds[i] = getLabelId(labelsToAdd[i]);
    }
    var removeLabelIds = [];
    for (var i = 0; i < labelsToRemove.length; i++) {
        removeLabelIds[i] = getLabelId(labelsToRemove[i], false);
    }
    var request = {
        'addLabelIds': addLabelIds,
        'removeLabelIds': removeLabelIds
    };
    var params = {
        method: "post",
        contentType: "application/json",
        headers: headers,
        payload: JSON.stringify(request),
        muteHttpExceptions: true
    };
    //var check = UrlFetchApp.getRequest(url, params); // for debugging
    var response = UrlFetchApp.fetch(url, params);

    var result = response.getResponseCode();
    if (result == '200') { // OK
        return JSON.parse(response.getContentText());
    } else {
        // This is only needed when muteHttpExceptions == true
        var err = JSON.parse(response.getContentText());
        throw new Error('Error (' + result + ") " + err.error.message);
    }
}

/**
 * Get the Label ID for the given LabelName. If Label isn't found, it will be created
 * depending on the state of ok2Create.
 * Throws if unsuccessful.
 * See https://developers.google.com/gmail/api/v1/reference/users/messages/modify.
 *
 * @param {String}   labelName        Immutable Gmail Message ID to modify
 * @param {Boolean}  ok2Create        (optional) Set true if a label should be created when not found.
 *                                    Default is true.
 *
 * @returns {String}                  ID of Label, or null if not found or created.
 */
function getLabelId(labelName, ok2Create) {
    if (typeof ok2Create == 'undefined') ok2Create = true;

    var id = null;
    // see https://developers.google.com/gmail/api/v1/reference/users/labels/list
    var url = 'https://www.googleapis.com/gmail/v1/users/${userId}/labels'
        .replace("${userId}", "me") // The user's email address. The special value me can be used to indicate the authenticated user.
    var headers = {
        Authorization: 'Bearer ' + ScriptApp.getOAuthToken()
    };
    var params = {
        method: "get",
        contentType: "application/json",
        headers: headers,
        muteHttpExceptions: true
    };

    //var check = UrlFetchApp.getRequest(url, params); // for debugging
    var response = UrlFetchApp.fetch(url, params);

    var result = response.getResponseCode();
    if (result == '200') { // OK
        var labels = JSON.parse(response.getContentText()).labels;
        var found = false;
        for (var i = 0; i < labels.length & !found; i++) {
            if (labels[i].name == labelName) {
                found = true;
                id = labels[i].id;
            }
        }
        if (!found && ok2Create) {
            id = createLabel(labelName);
        }
        return id;
    } else {
        // This is only needed when muteHttpExceptions == true
        var err = JSON.parse(response.getContentText());
        throw new Error('Error (' + result + ") " + err.error.message);
    }
}

/**
 * Create Label given LabelName.
 * Throws if unsuccessful.
 * See https://developers.google.com/gmail/api/v1/reference/users/messages/modify.
 *
 * @param {String}   labelName        Immutable Gmail Message ID to modify
 *
 * @returns {String}                  ID of Label.
 */
function createLabel(labelName) {
    var id = null;
    // see https://developers.google.com/gmail/api/v1/reference/users/labels/create
    var url = 'https://www.googleapis.com/gmail/v1/users/${userId}/labels'
        .replace("${userId}", "me") // The user's email address. The special value me can be used to indicate the authenticated user.
    var headers = {
        Authorization: 'Bearer ' + ScriptApp.getOAuthToken()
    };
    var request = {
        'name': labelName
    };
    var params = {
        method: "post",
        contentType: "application/json",
        headers: headers,
        payload: JSON.stringify(request),
        muteHttpExceptions: true
    };

    //var check = UrlFetchApp.getRequest(url, params); // for debugging
    var response = UrlFetchApp.fetch(url, params);

    var result = response.getResponseCode();
    if (result == '200') { // OK
        var label = JSON.parse(response.getContentText());
        id = label.id;
        return id;
    } else {
        // This is only needed when muteHttpExceptions == true
        var err = JSON.parse(response.getContentText());
        throw new Error('Error (' + result + ") " + err.error.message);
    }
}