"use strict";

var db = require("app/db");

var Base = require("./Base");
var Chunk = require("./Chunk");

/**
 * Attachments for {{#crossLink "models.server.Ticket"}}{{/crossLink}}
 *
 * @namespace models.server
 * @extends models.server.Base
 * @class Attachment
 */
var Attachment = Base.extend({

    tableName: "attachments",

    defaults: function() {
        return {
            createdAt: new Date(),
            updatedAt: new Date()
        };
    },

    /**
     * Get attachment content-type ensuring utf-8 if it is a text type
     * charset=utf-8
     *
     * @method getContentType
     * @return {String}
     */
    getContentType: function(){
        var type = this.get("dataType");
        if (type === "text/plain") {
            return type + "; charset=utf-8";
        }
        return type;
    },

    /**
     * @method chunks
     * @return {Bookshelf.Collection} Collection of model.server.Chunk
     */
    chunks: function() {
        var self = this;
        return Chunk.collection().query(function(q) {
            q.where({ fileId: self.getUniqueId() });
            q.orderBy("sequence", "asc");
        });
    },

    /**
     * @method isStillUploading
     * @return {Boolean}
     */
    isStillUploading: function() {
        return this.get("size") === -1;
    },

    /**
     * @method getFileId
     * @return {String}
     */
    getFileId: function(){
        var id = this.get("fileId");
        if (!id) throw new Error("File id null for " + this.get("id"));
        return id;
    },

    /**
     * @method getComputedFileId
     * @return {String}
     */
    getComputedFileId: function(){
        return "attachmentfile:" + this.getUniqueId();
    },

    /**
     * Write readable stream to this attachment. The returned promise is
     * resolved when the stream has been fully written.
     *
     * @method writeStream
     * @param {stream.Readable} stream Node.js readable stream
     * @return {Bluebird.Promise}
     */
    writeStream: function(stream) {
        var self = this;
        if (this.get("fileId")) {
            throw new Error("Attachment " + this.get("id") + " already has a file written");
        }
        var fileId = this.getComputedFileId();
        return db.gridSQL.write(fileId, stream)
        .then(function(info) {
            return self.set({
                fileId: fileId,
                size: info.bytesWritten,
                chunkCount: info.chunkCount
            }).save();
        });
    },

    /**
     * Return readable stream for this ticket data
     *
     * @method readStream
     * @return {stream.Readable}
     */
    readStream: function() {
        return db.gridSQL.read(this.getFileId());
    },

    /**
     * Fetch content of this attachment
     *
     * @method fetchContent
     * @return {Bluebird.Promise} with data of the attachment in a buffer
     */
    fetchContent: function() {
        return this.chunks().fetch()
            .then(function(chunks) {
                console.log("sending count chunks", chunks.length);

                var b =Buffer.concat(chunks.pluck("chunk")); 
                console.log("data size", b.length);
                return b;
            });
    },

});

module.exports = Attachment;