var express = require("express")
  , HTTPResult = require("../util/http-result")
  , cryptoken = require("../util/crypto-token")
  , etags = require("../util/etags")
  , _ = require('underscore')
  ;

module.exports = function(couch,schema) {
    var exports = {};

    var util = require('./util')(couch,schema);
    var responses = require('./responses')(couch,schema);
    var app = exports.app = express();

    app.get('/',
        util.ensureMIME(util.JSON_MIME),
        function(req,res) {
            var qs = {reduce:false,include_docs:true};
            var now = new Date().toISOString();
            var hr;
            if ( 'current' in req.query ) {
                // we make the assumption that there will be fewer
                // runs with no or a future enddate than with a
                // startdate in the past, i.e. we assume fewer future
                // surveys are planned than past surveys are run.
                hr = couch.get('_design/surveyRuns/_view/by_end_date',{
                    query: {startkey:now,reduce:false,include_docs:true}
                }).handle({
                    '-1': _.identity,
                    200: function(result) {
                        return _.filter(
                            util.handleRowDocs(result),
                            function(doc){
                                return !doc.startDate ||
                                       doc.startDate <= now;
                            });
                    },
                    default: util.handleUnknownResponse
                });
            } else if ( 'future' in req.query ) {
                hr = couch.get('_design/surveyRuns/_view/by_start_date',{
                    query: {startkey:now,reduce:false,include_docs:true}
                }).handle({
                    '-1': _.identity,
                    200: util.handleRowDocs,
                    default: util.handleUnknownResponse
                });
            } else if ( 'past' in req.query ) {
                hr = couch.get('_design/surveyRuns/_view/by_end_date',{
                    query: {endkey:now,reduce:false,include_docs:true}
                }).handle({
                    '-1': _.identity,
                    200: util.handleRowDocs,
                    default: util.handleUnknownResponse
                });
            } else {
                hr = util.getDocumentsOfType('SurveyRun');
            }
            hr.handle({'-1': util.handleException})
            .handle(res.send.bind(res));
        });
    app.post('/',
        util.ensureMIME(util.JSON_MIME),
        function(req,res) {
            var doc = req.body;
            var hr;
            if ( !util.isDocPublished(doc.survey) ) {
                hr = new HTTPResult(400,{error:"Cannot run unpublished survey."});
            } else {
                hr = cryptoken()
                .then(function(token) {
                    doc.secret = token;
                    return util.postDocument('SurveyRun',doc);
                });
            }
            hr.handle({'-1': util.handleException})
              .handle(res.send.bind(res));
        });
    app.get('/:id',
        util.ensureMIME(util.JSON_MIME),
        util.makeDocGet_id('SurveyRun'));
    app.put('/:id',
        util.ensureMIME(util.JSON_MIME),
        function (req,res) {
            var id = req.params.id;
            var doc = req.body;
            var rev = etags.parse(req.header('If-Match'))[0] || (doc && doc._rev);
            var hr;
            if ( !util.isDocPublished(doc.survey) ) {
                hr = new HTTPResult(400,{error:"Cannot run unpublished survey."});
            } else if ( typeof doc.secret === 'undefined' ) {
                hr = cryptoken()
                .then(function(token) {
                    doc.secret = token;
                    return util.putDocument(id,rev,'SurveyRun',doc);
                });
            } else {
                hr = util.putDocument(id,rev,'SurveyRun',doc);
            }
            hr.handle({'-1': util.handleException})
              .handle(res.send.bind(res));
        });
    app.delete('/:id',
        util.ensureMIME(util.JSON_MIME),
        function(req,res) {
            var id = req.params.id;
            var doc = req.body;
            var rev = etags.parse(req.header('If-Match'))[0] || (doc && doc._rev);
            responses.getResponsesBySurveyRunId(id)
            .handle({
                200: function(responses) {
                    if ( responses.length > 0 ) {
                        return new HTTPResult(403,{error:"Cannot delete run that has responses."});
                    } else {
                        return util.deleteDocument(id,rev);
                    }
                }
            })
            .handle({'-1': util.handleException})
            .handle(res.send.bind(res));
        });
    app.get('/:id/responses',
        util.ensureMIME(util.JSON_MIME),
        function(req,res) {
            var id = req.params.id;
            responses.getResponsesBySurveyRunId(id)
            .handle({'-1': util.handleException})
            .handle(res.send.bind(res));
        });
    app.get('/:id/responses.csv',
        util.ensureMIME(util.CSV_MIME),
        function(req, res) {
            var id = req.params.id;
            responses.getResponsesBySurveyRunId(id)
            .handle({
                '-1': function(result) {
                    util.handleException(result)
                    .handle(res.send.bind(res));
                },
                200: function(responses) {
                    var answers = _.map(responses,function(response){
                        return response.answers;
                    });
                    res.set({
                        'Content-Disposition': 'attachment; filename=surveyRun-'+id+'-responses.csv'
                    });
                    res.status(200);
                    util.writeObjectsToCSVStream(answers, res);
                    res.end();
                },
                default: res.send.bind(res)
            });
        });
    return exports;
};