/**
 * Code generation of the index file to pull together all the other documentation
 */
'use strict';
var Handlebars = require('handlebars');
var fs = require('fs');
var os = require('os');

//
// Define the exports
//
module.exports = {
    GenerateIndex: docgen
};

/**
 * Function to generate the index AsciiDoc document for all files
 *
 * @param {Object} options          - The docgen options
 *
 * @returns {Promise}   Promise that is resolved/rejected on success/failure
 */
function docgen(options) {
    return new Promise(function(resolve, reject) {
        //
        // Register some Handlebars helpers
        //
        registerHandlebarsHelpers();

        //
        // Register Handlebars partials
        //
        var handlebarsOpts = {noEscape: true};
        registerHandlebarsPartials(options.indexdocs.options, handlebarsOpts);

        //
        // Process the templates with all the config info
        //
        var templateData = {
            options: options
        };

        try {
            var indexOptions = options.indexdocs.options;

            for (var name in indexOptions.pages) {
                var dest = indexOptions.dest + name + '.adoc';
                console.log('Building %s -> %s', indexOptions.pages[name], dest);

                var templateText = fs.readFileSync(indexOptions.pages[name], 'utf-8');
                var func = Handlebars.compile(templateText, handlebarsOpts);
                var result = func(templateData);
                fs.writeFileSync(dest, result);
            }

            //
            // Resolve the promise to report success
            //
            resolve();
        } catch (err) {
            reject(err);
        }

    });
}

/**
 * Register handlebars partials
 *
 * @param {Object} options          - configuration options
 * @param {Object} handlebarsOpts   - options for handlebars
 */
function registerHandlebarsPartials(options, handlebarsOpts) {
    for (var name in options.templates) {
        registerHandlebarsPartial(options.templates[name], name, handlebarsOpts);
    }
}

function registerHandlebarsPartial(file, name, handlebarsOpts) {
    var templateText = fs.readFileSync(file, 'utf-8');
    var template = Handlebars.compile(templateText, handlebarsOpts);

    Handlebars.registerPartial(name, template);
}

/**
 * Registers handlebars helper functions
 */
function registerHandlebarsHelpers() {
    Handlebars.registerHelper('filenameify', filenameify);
}

/**
 * Handlebars helper function to replace all '/' with '-' to make a single
 * filename rather than a nested path
 *
 * @param {Object} item - the item to look at.
 *
 * @return {Object}     - a safestring of the type string
 */
function filenameify(item) {
    var result = item.replace(/\//g, '-');
    return new Handlebars.SafeString(result);
}