var util = require("util");
var path = require("path");
var Q = require("q");
var _ = require("lodash");
var exec = require('child_process').exec;

var fs = require('graceful-fs');
var parse = require("../../parse");
var BaseGenerator = require("../page");
var stringUtils = require("../../utils/string");

var Generator = function() {
    BaseGenerator.apply(this, arguments);
};
util.inherits(Generator, BaseGenerator);

Generator.prototype.finish = function() {
    var that = this;

    return BaseGenerator.prototype.finish.apply(this)
    .then(function() {
        var d = Q.defer();
        var format = that.options.extension || path.extname(that.options.output).replace("\.", "") || "pdf";

        if (!that.options.cover && fs.existsSync(path.join(that.options.output, "cover.jpg"))) {
            that.options.cover = path.join(that.options.output, "cover.jpg");
        }

        var _options = {
            "--cover": that.options.cover,
            "--title": that.options.title,
            "--comments": that.options.description,
            "--isbn": that.options.isbn,
            "--authors": that.options.author,
            "--publisher": "GitBook",
            "--chapter": "descendant-or-self::*[contains(concat(' ', normalize-space(@class), ' '), ' book-chapter ')]",
            "--chapter-mark": "pagebreak",
            "--page-breaks-before": "/",
            "--level1-toc": "descendant-or-self::*[contains(concat(' ', normalize-space(@class), ' '), ' book-chapter-1 ')]",
            "--level2-toc": "descendant-or-self::*[contains(concat(' ', normalize-space(@class), ' '), ' book-chapter-2 ')]",
            "--level3-toc": "descendant-or-self::*[contains(concat(' ', normalize-space(@class), ' '), ' book-chapter-3 ')]",
            "--no-chapters-in-toc": true,
            "--max-levels": "1",
            "--breadth-first": true
        };

        if (format == "pdf") {
            var pdfOptions = that.options.pdf;

            _.extend(_options, {
                "--margin-left": String(pdfOptions.margin.left),
                "--margin-right": String(pdfOptions.margin.right),
                "--margin-top": String(pdfOptions.margin.top),
                "--margin-bottom": String(pdfOptions.margin.bottom),
                "--pdf-default-font-size": String(pdfOptions.fontSize),
                "--pdf-mono-font-size": String(pdfOptions.fontSize),
                "--paper-size": String(pdfOptions.paperSize),
                "--pdf-page-numbers": Boolean(pdfOptions.pageNumbers),
                "--pdf-header-template": String(pdfOptions.headerTemplate),
                "--pdf-footer-template": String(pdfOptions.footerTemplate)
            });
        }
        
        return Q()
            .then(function() {
                return that.callHook("ebook:before", _options);
            })
            .then(function(_options) {
                var command = [
                    "ebook-convert",
                    path.join(that.options.output, "SUMMARY.html"),
                    path.join(that.options.output, "index."+format),
                    stringUtils.optionsToShellArgs(_options)
                ].join(" ");

                exec(command, function (error, stdout, stderr) {
                    if (error) {
                        if (error.code == 127) {
                            error.message = "Need to install ebook-convert from Calibre";
                        } else {
                            error.message = error.message + " "+stdout;
                        }
                        return d.reject(error);
                    }
                    d.resolve();
                });

                return d.promise;

            }).then(function(_promise) {
                that.callHook("ebook:after");
                return _promise;
            });
    });
};

module.exports = Generator;