'use strict';

var Command = require('ember-cli/lib/models/command');

var path    = require('path');

var Q       = require('q');

var request = require('request');

var _       = require('lodash');

var fs      = require('fs');

var chalk   = require('chalk');

// taken from http://stackoverflow.com/a/17238793

// `condition` is a function that returns a boolean

// `body` is a function that returns a promise

// returns a promise for the completion of the loop

function promiseWhile(condition, body) {

    var done = Q.defer();

    function loop(res) {

        // When the result of calling `condition` is no longer true, we are

        // done.

        if (!condition()) return done.resolve(res);

        // Use `when`, in case `body` does not return a promise.

        // When it completes loop again otherwise, if it fails, reject the

        // done promise

        Q.when(body(), loop, done.reject);

    }

    // Start running the loop in the next tick so that this function is

    // completely async. It would be unexpected if `body` was called

    // synchronously the first time.

    Q.nextTick(loop);

    // The promise

    return done.promise;

}

module.exports = Command.extend({

    name: 'dl-fixtures',

    description: 'Download fixtures',

    works: 'everywhere',

    availableOptions: [

        { name: 'type', type: String, default: 'documents', aliases: ['t'], description: 'type of obejcts to downloads' },

        { name: 'url',  type: String, aliases: ['u'], description: 'Source url' },

        { name: 'dest', type: String, aliases: ['d'], description: 'File destination'  },

        { name: 'page', type: Number, default: 1 , aliases: ['p'], description: 'number of page to download'},

        { name: 'format', type: String, default: 'es6' , aliases: ['f'], description: 'Format for module export, es6 or require'},

        { name: 'extra', type: String, default: '', aliases: ['e'], description: 'additionnal data to download (comma separated list of document ids)'}

    ],

    dl_countmap: function(commandOptions, rootKey) {

        var done = Q.defer();

        var that = this;

        request.get({url: commandOptions.url, json: true}, function (err, res, body) {

            var objectList = _.reduce(

                _.keys(body[rootKey]),

                function(res, objKey) {

                    var objValue = body[rootKey][objKey];

                    res.push({id: objKey, count: objValue.count, label: objValue.label});

                    return res;

                },

                []

            );

            var prefix = (that.format==='es6')?'export default ':'module.exports = ';

            fs.writeFile(that.dest, prefix + JSON.stringify(objectList,null,2) + ';', function(err) {

                if(err) {

                    return done.reject(err);

                }

                done.resolve();

            });

        });

        return done.promise;

    },

    dl_discourses: function(commandOptions) {

        return this.dl_countmap(commandOptions, 'discourses');

    },

    dl_themes: function(commandOptions) {

        return this.dl_countmap(commandOptions, 'themes');

    },

    dl_documents_ids: function(commandOptions, rawArgs, ui) {

        var pageIndex = 1;

        var ids = commandOptions.extra?_.map(commandOptions.extra.split(','), function(id) { return { id: id};}):[];

        return promiseWhile(

            function() { return pageIndex <= commandOptions.page && nextPageUrl; },

            function() {

                var deferred = Q.defer();

                ui.writeLine(chalk.yellow('Download Documents : getting page ' + pageIndex));

                request.get({url: nextPageUrl, json: true}, function (err, res, body) {

                    if (err) {

                        return deferred.reject(err);

                    } else if (res.statusCode !== 200) {

                        err = new Error('Unexpected status code: ' + res.statusCode);

                        err.res = res;

                        return deferred.reject(err);

                    }

                    pageIndex++;

                    ids = _.reduce(

                        body.documents,

                        function(res, doc) {

                            res.push(doc);

                            return res;

                        },

                        ids

                    );

                    deferred.resolve(ids);

                });

                return deferred.promise;

            }

        );

    },

    dl_transcripts: function(commandOptions, rawArgs, ui) {  // eslint-disable-line no-unused-vars

        return this.dl_documents_ids(commandOptions, rawArgs, ui).then(function(docs) {

            return Q.all(_.map(docs, function(doc) {

                var id = doc.id;

                var deferred = Q.defer();

                request.get({url: commandOptions.url + encodeURIComponent(encodeURIComponent(id)) + '/transcript', json: true}, function (err, res, body) {

                    ui.writeLine(chalk.green('Download transcripts : getting transcript ' + id));

                    if (err) {

                        return deferred.reject(err);

                    } else if (res.statusCode === 404) {

                        deferred.resolve({'id': id, 'transcript': undefined});

                    } else if (res.statusCode !== 200) {

                        err = new Error('Unexpected status code: ' + res.statusCode);

                        err.res = res;

                        return deferred.reject(err);

                    } else {

                        deferred.resolve({'id': id, 'transcript': body});

                    }

                });

                return deferred.promise;

            }));

        }).then(function(res) {

            var deferred = Q.defer();

            var prefix = (this.format==='es6')?'export default ':'module.exports = ';

            fs.writeFile(this.dest, prefix + JSON.stringify(res,null,2) + ';', function(err) {

                if(err) {

                    return deferred.reject(err);

                }

                deferred.resolve();

            });

            return deferred.promise;

        }.bind(this));

    },

    dl_documents: function(commandOptions, rawArgs, ui) { // eslint-disable-line no-unused-vars

        var destFiles = {

            docs: this.dest

        };

        return this.dl_documents_ids(commandOptions, rawArgs, ui).then(function(docs) {

            return Q.all(_.map(docs, function(doc) {

                var deferred = Q.defer();

                if(Object.keys(doc).length === 1) {

                    var id = doc.id;

                    request.get(

                        {

                            url: commandOptions.url + encodeURIComponent(encodeURIComponent(id)),

                            qs: {short: true},

                            json: true

                        },

                        function (err, res, body) {

                            ui.writeLine(chalk.green('Download documents : completing doc ' + id));

                            if (err) {

                                return deferred.reject(err);

                            } else if (res.statusCode !== 200) {

                                err = new Error('Unexpected status code: ' + res.statusCode);

                                err.res = res;

                                return deferred.reject(err);

                            }

                            deferred.resolve(body.document);

                        }

                    );

                }

                else {

                    deferred.resolve(doc);

                }

                return deferred.promise;

            }));

        }).then(function(docs) {

            var docsdeferred = Q.defer();

            Q.all(_.map(docs, function(docu) {

                var id = docu.id;

                var deferred = Q.defer();

                request.get({url: commandOptions.url + encodeURIComponent(encodeURIComponent(id)), json: true}, function (err, res, body) {

                    ui.writeLine(chalk.green('Download documents : getting doc ' + id));

                    if (err) {

                        return deferred.reject(err);

                    } else if (res.statusCode !== 200) {

                        err = new Error('Unexpected status code: ' + res.statusCode);

                        err.res = res;

                        return deferred.reject(err);

                    }

                    deferred.resolve(body.document);

                });

                return deferred.promise;

            })).then(

                function(downloadedDocs) {

                    docsdeferred.resolve({list: docs, docs: downloadedDocs});

                },

                function(err) {

                    return docsdeferred.reject(err);

                }

            );

            return docsdeferred.promise;

        }).then(function(resList) {

            var format = this.format;

            return Q.all(_.map(resList, function(res, key) {

                var deferred = Q.defer();

                if(key in destFiles) {

                    ui.writeLine(chalk.green('Writing ' + key + ' in file ' + destFiles[key]));

                    var prefix = (format==='es6')?'export default ':'module.exports = ';

                    fs.writeFile(destFiles[key], prefix + JSON.stringify(res,null,2) + ';', function(err) {

                        if(err) {

                            return deferred.reject(err);

                        }

                        deferred.resolve();

                    });

                } else {

                    deferred.resolve();

                }

                return deferred.promise;

            }));

        }.bind(this));

    },

    run: function(commandOptions, rawArgs) { // eslint-disable-line no-unused-vars

        var type = commandOptions.type || 'documents';

        this.dest = commandOptions.dest || '.' + path.sep + type + '.js';

        this.format = commandOptions.format || 'es6';

        return this['dl_' + type](commandOptions, rawArgs, this.ui);

    }

});