module fahrplanparser;

import std.algorithm : filter, map, startsWith;
import std.array : array, empty, front, replace;
import std.conv : to;
import std.datetime : dur, TimeOfDay, Clock;
import std.format : format;
import std.json : JSONValue;
import std.regex : ctRegex, matchAll;
import std.string : strip;
import std.typecons : tuple;

import kxml.xml : readDocument, XmlNode;

import substitution;

public:

auto parseFahrplan(in string data)
{
    auto currentTime = Clock.currTime;
    JSONValue j = ["time" : "%02s:%02s".format(currentTime.hour, currentTime.minute)];
    j.object["departures"] = data.readDocument
            .parseXPath(`//table[@id="departureMonitor"]/tbody/tr`)[1 .. $]
            .getRowContents
            .filter!(row => !row.empty)
            .map!(a => ["departure" : a[0].parseTime[0].to!string[0 .. $ - 3],
                        "delay" : a[0].parseTime[1].total!"minutes".to!string,
                        "line" : a[1],
                        "direction" : a[2].substitute])
            .array.JSONValue;
    return j.toPrettyString.replace("\\/", "/");
}

private:

class BadTimeInputException : Exception
{
    this(string msg) @safe pure nothrow @nogc
    {
        super(msg);
    }

    this() @safe pure nothrow @nogc
    {
        this("");
    }
}

auto parseTime(in string input) @safe
{
    auto matches = matchAll(input, ctRegex!(`(?P<hours>\d{1,2}):(?P<minutes>\d{2})`));
    if (matches.empty)
        throw new BadTimeInputException();
    auto actualTime = TimeOfDay(matches.front["hours"].to!int, matches.front["minutes"].to!int);
    matches.popFront;
    if (!matches.empty)
    {
        auto expectedTime = TimeOfDay(matches.front["hours"].to!int,
                matches.front["minutes"].to!int);
        auto timeDiff = actualTime - expectedTime;

        if(timeDiff < dur!"minutes"(0))
            timeDiff = dur!"hours"(24) + timeDiff;

        return tuple(expectedTime, timeDiff);
    }
    return tuple(actualTime, dur!"minutes"(0));
}

@safe unittest
{
    import std.exception : assertThrown;
    assertThrown(parseTime(""));
    assertThrown(parseTime("lkeqf"));
    assertThrown(parseTime(":"));
    assertThrown(parseTime("00:0"));

    assert("00:00".parseTime == tuple(TimeOfDay(0, 0), dur!"minutes"(0)));
    assert("0:00".parseTime == tuple(TimeOfDay(0, 0), dur!"minutes"(0)));

    assert("00:00 00:00".parseTime == tuple(TimeOfDay(0, 0), dur!"minutes"(0)));

    assert("00:00 00:00 12:00".parseTime == tuple(TimeOfDay(0, 0), dur!"minutes"(0)));

    assert("12:3412:34".parseTime == tuple(TimeOfDay(12, 34), dur!"minutes"(0)));

    assert("ölqjfo12:34oieqf12:31ölqjf".parseTime == tuple(TimeOfDay(12, 31), dur!"minutes"(3)));

    assert("17:53 (planmäßig 17:51 Uhr)".parseTime == tuple(TimeOfDay(17, 51), dur!"minutes"(2)));

    assert("00:00 23:59".parseTime == tuple(TimeOfDay(23,59), dur!"minutes"(1)));
}

auto getRowContents(XmlNode[] rows)
{
    return rows.map!(row => row.parseXPath("//td")[1 .. $ - 1].map!((column) {
            auto link = column.parseXPath("//a");
            if (!link.empty)
                return link.front.getCData.replace("...", "");
            return column.getCData;}));
}