/*jshint node: true */
var express     = require('express'),
    request     = require('request'),
    db          = require('./db.js'),
    router      = express.Router();

function achievementSemester(course_id, teaching) {
    return new Promise(function(resolve, reject) {
        var error = {'status': -1, 'message': 'error'};
        var empty = {'status': 0, 'message': 'empty'};
        var sql = "SELECT abet_outcome, grade, lower, type, number FROM course_outcome_bound NATURAL JOIN course_outcome_source WHERE course_id = '" + course_id + "' AND year = '" + teaching.year + "' AND semester = '" + teaching.semester + "'";
        db.query(sql, function(err, result) {
            if (err) {
                reject(error);
            }
            if (result.length > 0) {
                var description = {};
                for (i = 0; i < result.length; i++) {
                    if (!(result[i].abet_outcome in description)) {
                        description[result[i].abet_outcome] = {};
                        description[result[i].abet_outcome].type = result[i].type;
                        description[result[i].abet_outcome].number = result[i].number;
                        description[result[i].abet_outcome].bound = {};
                    }
                    description[result[i].abet_outcome].bound[result[i].grade] = result[i].lower;
                }
                var sql = "SELECT class_id, type, scores FROM " + course_id + " WHERE year = '" + teaching.year + "' AND semester = '" + teaching.semester + "'";
                db.query(sql, function(err, result) {
                    if (err) {
                        reject(error);
                    }
                    if (result.length > 0) {
                        for (i = 0; i < result.length; i++) {
                            result[i].scores = result[i].scores.split(" ");
                        }
                        var data = result;
                        var result = {};
                        for (abet_outcome in description) {
                            result[abet_outcome] = {};
                            for (index in data) {
                                if (!result[abet_outcome][data[index].class_id]) {
                                    result[abet_outcome][data[index].class_id] = {};
                                    for (grade in description[abet_outcome].bound) {
                                        result[abet_outcome][data[index].class_id][grade] = 0;
                                    }
                                }
                                if (data[index].type == description[abet_outcome].type) {
                                    var number = description[abet_outcome].number;
                                    if (data[index].scores[number - 1] >= description[abet_outcome].bound.A) {
                                        result[abet_outcome][data[index].class_id].A++;
                                    } else if (data[index].scores[number - 1] >= description[abet_outcome].bound.B) {
                                        result[abet_outcome][data[index].class_id].B++;
                                    } else if (data[index].scores[number - 1] >= description[abet_outcome].bound.C) {
                                        result[abet_outcome][data[index].class_id].C++;
                                    } else if (data[index].scores[number - 1] >= description[abet_outcome].bound.D) {
                                        result[abet_outcome][data[index].class_id].D++;
                                    } else {
                                        result[abet_outcome][data[index].class_id].E++;
                                    }
                                }
                            }
                        }
                        var success = {'status': 1, 'message': result};
                        resolve(success);
                    } else {
                        resolve(empty);
                    }
                });
            } else {
                resolve(empty);
            }
        });
    });
}

function achievementABET(teaching) {
    return new Promise(function(resolve, reject) {
        var error = {'status': -1, 'message': 'error'};
        var empty = {'status': 0, 'message': 'empty'};
        var sql = "SELECT id FROM course";
        db.query(sql, function(err, result) {
            if (err) {
                reject(error);
            }
            var courses = result;
            var sql = "SELECT id FROM abet_outcome";
            db.query(sql, function(err, result) {
                if (err) {
                    reject(error);
                }
                var outcomes = result;
                var result = {};
                var promises = [];
                for (i = 0; i < courses.length; i++) {
                    promises.push(
                        achievementSemester(courses[i].id, teaching).then(function(body) {
                            body = body.message;
                            if (body != 'empty' && body != 'error') {
                                for (abet_outcome in body) {
                                    if (!result[abet_outcome]) {
                                        result[abet_outcome] = {};
                                        result[abet_outcome]['A'] = 0;
                                        result[abet_outcome]['B'] = 0;
                                        result[abet_outcome]['C'] = 0;
                                        result[abet_outcome]['D'] = 0;
                                        result[abet_outcome]['E'] = 0;
                                    }
                                    for (class_id in body[abet_outcome]) {
                                        for (grade in body[abet_outcome][class_id]) {
                                            result[abet_outcome][grade] += body[abet_outcome][class_id][grade];
                                        }
                                    }
                                }
                            }
                        })
                    );
                }
                Promise.all(promises).then(function() {
                    var success = {'status': 1, 'message': result};
                    resolve(success);
                }).catch(function(err) {
                    res.status(400).json({'status': -1, 'message': 'error'});
                });
            });
        });
    });
}

router.post('/semester', function(req, res) {
    var course_id = req.body.course_id;
    var teaching = req.body.teaching;
    achievementSemester(course_id, teaching).then(function(body) {
        res.status(200).json(body);
    }).catch(function(err) {
        res.status(400).json(body);
    });
});

router.post('/abetoutcome', function(req, res) {
    var teaching = req.body.teaching;
    achievementABET(teaching).then(function(body) {
        res.status(200).json(body);
    }).catch(function(err) {
        res.status(400).json(body);
    });
});

router.post('/total', function(req, res) {
    var teachings = [];
    for (year = 2013; year <= 2017; year++) {
        for (semester = 1; semester <= 2; semester++) {
            teachings.push({
                year: year,
                semester: semester
            });
        }
    }
    var result = {};
    var promises = [];
    for (i = 0; i < teachings.length; i++) {
        promises.push(
            achievementABET(teachings[i]).then(function(body) {
                body = body.message;
                if (body != 'empty' && body != 'error') {
                    for (abet_outcome in body) {
                        if (!result[abet_outcome]) {
                            result[abet_outcome] = {};
                            result[abet_outcome]['A'] = 0;
                            result[abet_outcome]['B'] = 0;
                            result[abet_outcome]['C'] = 0;
                            result[abet_outcome]['D'] = 0;
                            result[abet_outcome]['E'] = 0;
                        }
                        for (grade in body[abet_outcome]) {
                            result[abet_outcome][grade] += body[abet_outcome][grade];
                        }
                    }
                }
            })
        );
    }
    Promise.all(promises).then(function() {
        res.status(200).json({'status': 1, 'message': result});
    }).catch(function(err) {
        res.status(400).json({'status': -1, 'message': 'error'});
    });
});

module.exports = router;