module.exports = function(RED) {
    var https = require('https');
    var http = require('http');
    var url = require('url');

    var OPERATIONS = {
        'account:list':        { method: 'GET',  path: '/ocs/v2.php/apps/mail/account/list' },
        'message:get':         { method: 'GET',  path: '/ocs/v2.php/apps/mail/message/{id}' },
        'message:getRaw':      { method: 'GET',  path: '/ocs/v2.php/apps/mail/message/{id}/raw' },
        'message:attachment':  { method: 'GET',  path: '/ocs/v2.php/apps/mail/message/{id}/attachment/{attachmentId}' },
        'mailbox:list':        { method: 'GET',  path: '/ocs/v2.php/apps/mail/ocs/mailboxes', query: ['accountId'] },
        'mailbox:messages':    { method: 'GET',  path: '/ocs/v2.php/apps/mail/ocs/mailboxes/{mailboxId}/messages', query: ['cursor','filter','limit','view'] },
        'message:send':        { method: 'POST', path: '/ocs/v2.php/apps/mail/message/send',
            body: ['accountId','fromEmail','subject','body','isHtml','to','cc','bcc','references'] }
    };

    function MailNode(config) {
        RED.nodes.createNode(this, config);
        var node = this;
        this.configNode = RED.nodes.getNode(config.nextcloud);
        this.operation = config.operation || 'account:list';
        this.messageId = config.messageId;
        this.attachmentId = config.attachmentId;
        this.mailboxId = config.mailboxId;
        this.bodyAccountId = config.bodyAccountId;
        this.bodyFromEmail = config.bodyFromEmail;
        this.bodySubject = config.bodySubject;
        this.bodyBody = config.bodyBody;
        this.bodyIsHtml = config.bodyIsHtml;
        this.bodyTo = config.bodyTo;
        this.bodyCc = config.bodyCc;
        this.bodyBcc = config.bodyBcc;
        this.bodyReferences = config.bodyReferences;

        if (!this.configNode) { node.error("No Nextcloud configuration node selected"); return; }

        node.on('input', function(msg) {
            var op = OPERATIONS[msg.operation || node.operation];
            if (!op) { node.error("Unknown operation: " + (msg.operation || node.operation), msg); return; }

            var baseUrl = (node.configNode.baseUrl || '').replace(/\/+$/, '');
            var username = node.configNode.credentials.username;
            var password = node.configNode.credentials.password;

            var path = op.path
                .replace('{id}', msg.messageId || node.messageId || '')
                .replace('{attachmentId}', msg.attachmentId || node.attachmentId || '')
                .replace('{mailboxId}', msg.mailboxId || node.mailboxId || '');

            var queryParts = [];
            if (op.query) {
                op.query.forEach(function(q) {
                    var v = msg[q] !== undefined ? msg[q] : getField(node, q);
                    if (v !== undefined && v !== '') queryParts.push(encodeURIComponent(q) + '=' + encodeURIComponent(v));
                });
            }
            var fullUrl = baseUrl + path + (queryParts.length ? '?' + queryParts.join('&') : '');
            var parsedUrl = url.parse(fullUrl);

            var headers = {
                'OCS-APIRequest': 'true', 'Accept': 'application/json',
                'Authorization': 'Basic ' + Buffer.from(username + ':' + password).toString('base64')
            };

            var bodyObj = {};
            if (op.body) {
                op.body.forEach(function(b) {
                    var v = msg[b] !== undefined ? msg[b] : getField(node, b);
                    if (v !== undefined && v !== '') bodyObj[b] = v;
                });
            }
            // Handle complex send fields: to/cc/bcc can be msg arrays
            if (msg.to && Array.isArray(msg.to)) bodyObj.to = msg.to;
            if (msg.cc && Array.isArray(msg.cc)) bodyObj.cc = msg.cc;
            if (msg.bcc && Array.isArray(msg.bcc)) bodyObj.bcc = msg.bcc;

            var bodyStr = null;
            if (Object.keys(bodyObj).length > 0) {
                headers['Content-Type'] = 'application/json';
                bodyStr = JSON.stringify(bodyObj);
            }

            var opts = {
                hostname: parsedUrl.hostname,
                port: parsedUrl.port || (parsedUrl.protocol === 'https:' ? 443 : 80),
                path: parsedUrl.path, method: op.method, headers: headers, rejectUnauthorized: false
            };

            node.log(op.method + ' ' + fullUrl);

            var transport = parsedUrl.protocol === 'https:' ? https : http;
            var req = transport.request(opts, function(res) {
                var body = '';
                res.on('data', function(chunk) { body += chunk; });
                res.on('end', function() {
                    msg.statusCode = res.statusCode; msg.operation = msg.operation || node.operation;
                    try { msg.payload = JSON.parse(body); } catch(e) { msg.payload = body; }
                    node.send(msg);
                });
            });
            req.on('error', function(err) { msg.error = err.message; node.error(op.method + ' ' + fullUrl + ' — ' + err.message, msg); });
            if (bodyStr) req.write(bodyStr);
            req.end();
        });
    }

    function getField(node, name) {
        var m = { 'accountId': node.bodyAccountId, 'fromEmail': node.bodyFromEmail,
            'subject': node.bodySubject, 'body': node.bodyBody, 'isHtml': node.bodyIsHtml,
            'references': node.bodyReferences, 'cursor': node.bodyCursor, 'filter': node.bodyFilter,
            'limit': node.bodyLimit, 'view': node.bodyView };
        return m[name];
    }

    RED.nodes.registerType("mail", MailNode);
};