var crypto = require('crypto');
var fs = require('fs');
var XMLHttpRequest = require('xmlhttprequest').XMLHttpRequest;
var moment = require('moment');
var locale = require('os-locale').sync();

var cal = {};

function fromIcal(string) {
    return new Date(
        parseInt(string.substr(0 , 4), 10),
        parseInt(string.substr(4 , 2), 10) - 1,
        parseInt(string.substr(6 , 2), 10),
        parseInt(string.substr(9, 2), 10),
        parseInt(string.substr(11, 2), 10),
        parseInt(string.substr(13, 2), 10)
    );
}

cal.Type = {
    CM:    1,
    CTD:   2,
    TD:    3,
    TP:    4,
    Other: {
        BE:     5,
        Examen: 6,
        Projet: 7,
        APP: 8,
    },
    Unknown: 9,
}

cal.getTypeName = function(type) {
    switch (type) {
        case cal.Type.TD:        return "TD";
        case cal.Type.TP:        return "TP";
        case cal.Type.CTD:       return "CTD";
        case cal.Type.CM:        return "CM";
        case cal.Type.Other.BE:
        case cal.Type.Other.Projet:
        case cal.Type.Other.Examen:
        case cal.Type.Other.APP:
            return "Other";
        default:                 return "Unknown";
    }
}

cal.getFactor = function(type) {
    switch (type) {
        case cal.Type.TD:
        case cal.Type.TP:
        case cal.Type.Other.BE: return 1;
        case cal.Type.Other.Projet: return 1;
        case cal.Type.Other.Examen: return 0;
        case cal.Type.Other.APP: return 1.5;
        case cal.Type.CTD: return 1.25;
        case cal.Type.CM:  return 1.5;
        default:           return 0;
    }
}

cal.getTypeFromName = function(name) {

    if (name.indexOf("CTD") !== -1) {
        return cal.Type.CTD;
    } else if (name.indexOf("TP") !== -1) {
        return cal.Type.TP;
    } else if (name.indexOf("TD") !== -1) {
        return cal.Type.TD;
    } else if (name.indexOf("CM") !== -1) {
        return cal.Type.CM;
    } else if (name.indexOf("BE") !== -1) {
        return cal.Type.Other.BE;
    } else if (name.toLowerCase().indexOf("exam") !== -1) {
        return cal.Type.Other.Examen;
    } else if (name.toLowerCase().indexOf("projet") !== -1) {
        return cal.Type.Other.Projet;
    } else if (name.indexOf("APP ") !== -1) {
        return cal.Type.Other.APP;
    } else {
        return cal.Type.Unkown;
    }

}

cal.Event = class {

    constructor(content, firstLineIndex = 0) {
        this.startTime = undefined;
        this.finishTime = undefined;
        this.name = undefined;
        this.location = undefined;
        this.type = cal.Type.Unkown;

        if (content !== undefined)
            this.setFromContent(content, firstLineIndex);
    }

    guessTypeFromName() {
        this.type = cal.getTypeFromName(this.name);
    }

    getDurationInHours() {
        return (this.finishTime - this.startTime) / (1000 * 60 * 60);
    }

    getTdEquivalent() {
        return this.getDurationInHours() * cal.getFactor(this.type);
    }

    setFromContent(content, firstLineIndex = 0) {
        let index = firstLineIndex;
        let lines = content.split('\n').map((a) => a.trim());

        for (let line of lines.slice(firstLineIndex)) {
            let split = line.split(':');

            switch (split[0]) {

                case 'END'     : if (split[1] === 'VEVENT')            return index;
                case 'DTSTART' : this.startTime  = fromIcal(split[1]); break;
                case 'DTEND'   : this.finishTime = fromIcal(split[1]); break;
                case 'LOCATION':
                    this.location = split[1].replace('\\','');
                    break;
                case 'SUMMARY' :
                    this.name = split[1];
                    this.guessTypeFromName();
                    break;

            }

            index++
        }

        return index;
    }

};

cal.Calendar = class {

    constructor(content) {
        this.events = [];

        if (content !== undefined)
            this.setFromContent(content);
    }

    setFromContent(content) {
        let index = 0;
        let lines = content.split('\n').map((a) => a.trim());

        while (index < lines.length) {

            let split = lines[index].split(':');

            if (split[0] === 'BEGIN' && split[1] === 'VEVENT') {
                let event = new cal.Event();
                index = event.setFromContent(content, index);
                this.events.push(event);
            } else {
                index++;
            }

        }

        this.events.sort((a,b) => {
            if (a.startTime < b.startTime)
                return -1
            else if (a.startTime > b.startTime)
                return 1
            else
                return 0;
        });
    }

    setFromUrl(url, callback) {

        let xhr = new XMLHttpRequest();
        xhr.open("get", url, true);
        xhr.onreadystatechange = (e) => {
            if (xhr.readyState === 4) {
                if (xhr.responseText.indexOf('<html>') === -1) {
                    this.setFromContent(xhr.responseText);
                    callback(this);
                }
            }
        };
        xhr.send();

        if (xhr.responseText.indexOf('<html>') === -1) {
            this.setFromContent(xhr.responseText);
        }

    }

};

function dateToString(dt) {
    return dt.getFullYear() + "-" + (dt.getMonth() + 1) + "-" + dt.getDate();
}

cal.getUrlFromUser = function(user, firstDate = new Date(), lastDate = new Date(), calType = "ical") {

    if (firstDate instanceof Date) {
        firstDate = dateToString(firstDate);
    }

    if (lastDate instanceof Date) {
        lastDate = dateToString(lastDate);
    }

    let baseUrl = "https://edt.inp-toulouse.fr/jsp/custom/modules/plannings/anonymous_cal.jsp?";
    let resourcesParam = `resources=${user._resources.value}`;
    let projectIdParam = `projectId=${user._projectId.value}`;
    let firstDateParam = `firstDate=${firstDate}`;
    let lastDateParam = `lastDate=${lastDate}`;
    let calTypeParam = `calType=${calType}`;
    let parameters = [resourcesParam, projectIdParam, firstDateParam, lastDateParam, calTypeParam].join("&");

    return baseUrl + parameters;

};

cal.getCalendar = function(user, firstDate = new Date(), lastDate = new Date(), calType, callback) {

    if (typeof calType === 'function') {
        callback = calType;
        calType = "iCal";
    }

    let calendar = new cal.Calendar();
    let url = cal.getUrlFromUser(user, firstDate, lastDate, calType);
    calendar.setFromUrl(url, cal => {
        callback(cal);
    });

};

cal.getTotal = function(user, callback) {
    let firstDate = new Date(2000, 8, 1);
    let lastDate = new Date(3000, 8, 1);

    cal.getCalendar(user, firstDate, lastDate, (calendar) => {
        let res = {};

        for (let event of calendar.events) {

            let hours = event.getDurationInHours();
            let td = event.getTdEquivalent();

            if (res[event.name] === undefined) {
                res[event.name] = {
                    time: 0,
                    tdEquivalent: 0,
                    type: cal.getTypeName(event.type) +
                        ' (x' + cal.getFactor(event.type) + ')',
                };
            }

            res[event.name].time += hours;
            res[event.name].tdEquivalent += td;

        }

        callback(res);
    });

}

cal.getTotalByCourse = function(user, callback) {

    let firstDate = new Date(2000, 8, 1);
    let lastDate = new Date(3000, 8, 1);

    cal.getCalendar(user, firstDate, lastDate, (calendar) => {
        let res = {};

        for (let event of calendar.events) {
            // Guess name of event, last element of split('-');
            let split = event.name.split(' -').map(x => x.trim());
            let name = split[split.length - 1];

            if (res[name] === undefined) {
                res[name] = {}
                for (let type in cal.Type) {
                    res[name][type] = 0;
                }
                res[name].totalTdEquivalent = 0;
            }

            let type = event.type;
            let typeName;
            if (type in cal.Type.Other) {
                typeName = "Other";
            } else {
                typeName = cal.getTypeName(type);
            }
            res[name][typeName]++;
            res[name].totalTdEquivalent += event.getTdEquivalent();
        }

        callback(res);
    });
}

module.exports = cal;