/**
 * POP3 protocol - RFC1939 - https://www.ietf.org/rfc/rfc1939.txt
 *
 * Dependencies:
 * * poplib     - https://www.npmjs.com/package/poplib
 * * nodemailer - https://www.npmjs.com/package/nodemailer
 * * imap       - https://www.npmjs.com/package/imap
 * * mailparser - https://www.npmjs.com/package/mailparser
 */

module.exports = function(RED) {
    "use strict";
    var nodemailer = require("nodemailer");
    var Imap = require('imap');
    var POP3Client = require("poplib");
    var MailParser = require("mailparser").MailParser;
    var util = require("util");

    try {
        var globalkeys = RED.settings.email || require(process.env.NODE_RED_HOME+"/../emailkeys.js");
    } catch(err) {
    }

    function EmailNode(n) {
        RED.nodes.createNode(this,n);
        this.topic = n.topic;
        this.name = n.name;
        this.outserver = n.server;
        this.outport = n.port;
        var flag = false;
        if (this.credentials && this.credentials.hasOwnProperty("userid")) {
            this.userid = this.credentials.userid;
        } else {
            if (globalkeys) {
                this.userid = globalkeys.user;
                flag = true;
            } else {
                this.error(RED._("email.errors.nouserid"));
            }
        }
        if (this.credentials && this.credentials.hasOwnProperty("password")) {
            this.password = this.credentials.password;
        } else {
            if (globalkeys) {
                this.password = globalkeys.pass;
                flag = true;
            } else {
                this.error(RED._("email.errors.nopassword"));
            }
        }
        if (flag) {
            RED.nodes.addCredentials(n.id,{userid:this.userid, password:this.password, global:true});
        }
        var node = this;

        var smtpTransport = nodemailer.createTransport({
            host: node.outserver,
            port: node.outport,
            secure: true,
            auth: {
                user: node.userid,
                pass: node.password
            }
        });

        this.on("input", function(msg) {
            if (msg.hasOwnProperty("payload")) {
                if (smtpTransport) {
                    node.status({fill:"blue",shape:"dot",text:"email.status.sending"});
                    if (msg.to && node.name && (msg.to !== node.name)) {
                        node.warn(RED._("node-red:common.errors.nooverride"));
                    }
                    var sendopts = { from: ((msg.from) ? msg.from : node.userid) };   // sender address
                    sendopts.to = node.name || msg.to; // comma separated list of addressees
                    if (node.name === "") {
                        sendopts.cc = msg.cc;
                        sendopts.bcc = msg.bcc;
                    }
                    sendopts.subject = msg.topic || msg.title || "Message from Node-RED"; // subject line
                    if (msg.hasOwnProperty("envelope")) { sendopts.envelope = msg.envelope; }
                    if (Buffer.isBuffer(msg.payload)) { // if it's a buffer in the payload then auto create an attachment instead
                        if (!msg.filename) {
                            var fe = "bin";
                            if ((msg.payload[0] === 0xFF)&&(msg.payload[1] === 0xD8)) { fe = "jpg"; }
                            if ((msg.payload[0] === 0x47)&&(msg.payload[1] === 0x49)) { fe = "gif"; } //46
                            if ((msg.payload[0] === 0x42)&&(msg.payload[1] === 0x4D)) { fe = "bmp"; }
                            if ((msg.payload[0] === 0x89)&&(msg.payload[1] === 0x50)) { fe = "png"; } //4E
                            msg.filename = "attachment."+fe;
                        }
                        sendopts.attachments = [ { content: msg.payload, filename:(msg.filename.replace(/^.*[\\\/]/, '') || "file.bin") } ];
                        if (msg.hasOwnProperty("headers") && msg.headers.hasOwnProperty("content-type")) {
                            sendopts.attachments[0].contentType = msg.headers["content-type"];
                        }
                        // Create some body text..
                        sendopts.text = RED._("email.default-message",{filename:(msg.filename.replace(/^.*[\\\/]/, '') || "file.bin"),description:(msg.hasOwnProperty("description") ? "\n\n"+msg.description : "")});
                    }
                    else {
                        var payload = RED.util.ensureString(msg.payload);
                        sendopts.text = payload; // plaintext body
                        if (/<[a-z][\s\S]*>/i.test(payload)) { sendopts.html = payload; } // html body
                        if (msg.attachments) { sendopts.attachments = msg.attachments; } // add attachments
                    }
                    smtpTransport.sendMail(sendopts, function(error, info) {
                        if (error) {
                            node.error(error,msg);
                            node.status({fill:"red",shape:"ring",text:"email.status.sendfail"});
                        } else {
                            node.log(RED._("email.status.messagesent",{response:info.response}));
                            node.status({});
                        }
                    });
                }
                else { node.warn(RED._("email.errors.nocredentials")); }
            }
            else { node.warn(RED._("email.errors.nopayload")); }
        });
    }
    RED.nodes.registerType("e-mail",EmailNode,{
        credentials: {
            userid: {type:"text"},
            password: {type: "password"},
            global: { type:"boolean"}
        }
    });


    //
    // EmailInNode
    //
    // Setup the EmailInNode
    function EmailInNode(n) {
        var imap;

        RED.nodes.createNode(this,n);
        this.name = n.name;
        this.repeat = n.repeat * 1000 || 300000;
        this.inserver = n.server || (globalkeys && globalkeys.server) || "imap.gmail.com";
        this.inport = n.port || (globalkeys && globalkeys.port) || "993";
        this.box = n.box || "INBOX";
        this.useSSL= n.useSSL;
        this.protocol = n.protocol || "IMAP";
        this.disposition = n.disposition || "None"; // "None", "Delete", "Read"

        var flag = false;

        if (this.credentials && this.credentials.hasOwnProperty("userid")) {
            this.userid = this.credentials.userid;
        } else {
            if (globalkeys) {
                this.userid = globalkeys.user;
                flag = true;
            } else {
                this.error(RED._("email.errors.nouserid"));
            }
        }
        if (this.credentials && this.credentials.hasOwnProperty("password")) {
            this.password = this.credentials.password;
        } else {
            if (globalkeys) {
                this.password = globalkeys.pass;
                flag = true;
            } else {
                this.error(RED._("email.errors.nopassword"));
            }
        }
        if (flag) {
            RED.nodes.addCredentials(n.id,{userid:this.userid, password:this.password, global:true});
        }

        var node = this;
        this.interval_id = null;

        // Process a new email message by building a Node-RED message to be passed onwards
        // in the message flow.  The parameter called `msg` is the template message we
        // start with while `mailMessage` is an object returned from `mailparser` that
        // will be used to populate the email.
        // DCJ NOTE: - heirachical multipart mime parsers seem to not exist - this one is barely functional.
        function processNewMessage(msg, mailMessage) {
            msg = JSON.parse(JSON.stringify(msg)); // Clone the message
            // Populate the msg fields from the content of the email message
            // that we have just parsed.
            msg.payload = mailMessage.text;
            msg.topic = mailMessage.subject;
            msg.date = mailMessage.date;
            if (mailMessage.html) { msg.html = mailMessage.html; }
            if (mailMessage.to && mailMessage.from.to > 0) { msg.to = mailMessage.to; }
            if (mailMessage.cc && mailMessage.from.cc > 0) { msg.cc = mailMessage.cc; }
            if (mailMessage.bcc && mailMessage.from.bcc > 0) { msg.bcc = mailMessage.bcc; }
            if (mailMessage.from && mailMessage.from.length > 0) { msg.from = mailMessage.from[0].address; }
            if (mailMessage.attachments) { msg.attachments = mailMessage.attachments; }
            else { msg.attachments = []; }
            node.send(msg); // Propagate the message down the flow
        } // End of processNewMessage

        // Check the POP3 email mailbox for any new messages.  For any that are found,
        // retrieve each message, call processNewMessage to process it and then delete
        // the messages from the server.
        function checkPOP3(msg) {
            var currentMessage;
            var maxMessage;

            // Form a new connection to our email server using POP3.
            var pop3Client = new POP3Client(
                node.inport, node.inserver,
                {enabletls: node.useSSL} // Should we use SSL to connect to our email server?
            );

            // If we have a next message to retrieve, ask to retrieve it otherwise issue a
            // quit request.
            function nextMessage() {
                if (currentMessage > maxMessage) {
                    pop3Client.quit();
                    return;
                }
                pop3Client.retr(currentMessage);
                currentMessage++;
            } // End of nextMessage

            pop3Client.on("stat", function(status, data) {
                // Data contains:
                // {
                //   count: <Number of messages to be read>
                //   octect: <size of messages to be read>
                // }
                if (status) {
                    currentMessage = 1;
                    maxMessage = data.count;
                    nextMessage();
                } else {
                    node.log(util.format("stat error: %s %j", status, data));
                }
            });

            pop3Client.on("error", function(err) {
                node.log("We caught an error: " + JSON.stringify(err));
            });

            pop3Client.on("connect", function() {
                //node.log("We are now connected");
                pop3Client.login("kolban@test.com", "password");
            });

            pop3Client.on("login", function(status, rawData) {
                //node.log("login: " + status + ", " + rawData);
                if (status) {
                    pop3Client.stat();
                } else {
                    node.log(util.format("login error: %s %j", status, rawData));
                    pop3Client.quit();
                }
            });

            pop3Client.on("retr", function(status, msgNumber, data, rawData) {
                node.log(util.format("retr: status=%s, msgNumber=%d, data=%j", status, msgNumber, data));
                if (status) {

                    // We have now received a new email message.  Create an instance of a mail parser
                    // and pass in the email message.  The parser will signal when it has parsed the message.
                    var mailparser = new MailParser();
                    mailparser.on("end", function(mailObject) {
                        //node.log(util.format("mailparser: on(end): %j", mailObject));
                        processNewMessage(msg, mailObject);
                    });
                    mailparser.write(data);
                    mailparser.end();
                    pop3Client.dele(msgNumber);
                }
                else {
                    node.log(util.format("retr error: %s %j", status, rawData));
                    pop3Client.quit();
                }
            });

            pop3Client.on("invalid-state", function(cmd) {
                node.log("Invalid state: " + cmd);
            });

            pop3Client.on("locked", function(cmd) {
                node.log("We were locked: " + cmd);
            });

            // When we have deleted the last processed message, we can move on to
            // processing the next message.
            pop3Client.on("dele", function(status, msgNumber) {
                nextMessage();
            });
        } // End of checkPOP3


        //
        // checkIMAP
        //
        // Check the email sever using the IMAP protocol for new messages.
        function checkIMAP(msg) {
            node.log("Checking IMAP for new messages");
            // We get back a 'ready' event once we have connected to imap
            imap.once("ready", function() {
                node.status({fill:"blue", shape:"dot", text:"email.status.fetching"});
                //console.log("> ready");
                // Open the inbox folder
                imap.openBox(node.box, // Mailbox name
                    false, // Open readonly?
                    function(err, box) {
                    //console.log("> Inbox open: %j", box);
                    imap.search([ 'UNSEEN' ], function(err, results) {
                        if (err) {
                            node.status({fill:"red", shape:"ring", text:"email.status.foldererror"});
                            node.error(RED._("email.errors.fetchfail", {folder:node.box}),err);
                            imap.end();
                            return;
                        }
                        //console.log("> search - err=%j, results=%j", err, results);
                        if (results.length === 0) {
                            //console.log(" [X] - Nothing to fetch");
                            node.status({});
                            imap.end();
                            return;
                        }

                        var marks = false;
                        if (this.disposition === "Read") { marks = true; }
                        // We have the search results that contain the list of unseen messages and can now fetch those messages.
                        var fetch = imap.fetch(results, {
                            bodies: '',
                            struct: true,
                            markSeen: marks
                        });

                        // For each fetched message returned ...
                        fetch.on('message', function(imapMessage, seqno) {
                            //node.log(RED._("email.status.message",{number:seqno}));
                            var messageText = "";
                            //console.log("> Fetch message - msg=%j, seqno=%d", imapMessage, seqno);
                            imapMessage.on('body', function(stream, info) {
                                //console.log("> message - body - stream=?, info=%j", info);
                                stream.on('data', function(chunk) {
                                    //console.log("> stream - data - chunk=??");
                                    messageText += chunk.toString('utf8');
                                });
                                stream.once('end', function() {
                                    var mailParser = new MailParser();
                                    mailParser.on('end', function(mailMessage) {
                                        processNewMessage(msg, mailMessage);
                                    });
                                    mailParser.write(messageText);
                                    mailParser.end();
                                }); // End of msg->end
                            }); // End of msg->body
                        }); // End of fetch->message

                        // When we have fetched all the messages, we don't need the imap connection any more.
                        fetch.on('end', function() {
                            var cleanup = function() {
                                node.status({});
                                imap.end();
                            };
                            if (this.disposition === "Delete") {
                                imap.addFlags(results, "\Deleted", cleanup);
                            } else if (this.disposition === "Read") {
                                imap.addFlags(results, "\Seen", cleanup);
                            } else {
                                cleanup();
                            }
                        });

                        fetch.once('error', function(err) {
                            console.log('Fetch error: ' + err);
                        });
                    }); // End of imap->search
                }); // End of imap->openInbox
            }); // End of imap->ready
            imap.connect();
            node.status({fill:"grey",shape:"dot",text:"node-red:common.status.connecting"});
        } // End of checkIMAP


        // Perform a check of the email inboxes using either POP3 or IMAP
        function checkEmail(msg) {
            if (node.protocol === "POP3") {
                checkPOP3(msg);
            } else if (node.protocol === "IMAP") {
                checkIMAP(msg);
            }
        }  // End of checkEmail

        if (node.protocol === "IMAP") {
            imap = new Imap({
                user: node.userid,
                password: node.password,
                host: node.inserver,
                port: node.inport,
                tls: node.useSSL,
                tlsOptions: { rejectUnauthorized: false },
                connTimeout: node.repeat,
                authTimeout: node.repeat
            });
            imap.on('error', function(err) {
                if (err.errno !== "ECONNRESET") {
                    node.log(err);
                    node.status({fill:"red",shape:"ring",text:"email.status.connecterror"});
                }
            });
        }

        this.on("input", function(msg) {
            checkEmail(msg);
        });

        this.on("close", function() {
            if (this.interval_id != null) {
                clearInterval(this.interval_id);
            }
            if (imap) { imap.destroy(); }
        });

        // Set the repetition timer as needed
        if (!isNaN(this.repeat) && this.repeat > 0) {
            this.interval_id = setInterval( function() {
                node.emit("input",{});
            }, this.repeat );
        }

        node.emit("input",{});
    }

    RED.nodes.registerType("e-mail in",EmailInNode,{
        credentials: {
            userid: { type:"text" },
            password: { type: "password" },
            global: { type:"boolean" }
        }
    });
};