-- Praca s polom
-- Autor: Branislav Blaskovic
-- asi netreba rozsirenia :) snazil som sa

function strlen(slovo)

    local i;
    local typ;

    i = 0;

    -- overenie datoveho typu
    typ = type(slovo);
    if typ ~= "string" then
        write("CHYBA: Toto '",slovo,"' nie je string!\n");
        return nil;
    else end;

    -- zacnime pocitat
    local sub;

    while sub ~= "" do
        i = i + 1;
        sub = substr(slovo, i, i);
    end;

    -- posledny prechod
    i = i - 1;

    return i;

end

function array_valid(array, separator)

    -- overenie typu matice
    local typ;
    typ = type(array);
    if typ ~= "string" then write("CHYBA: Matica nie je string.\n"); return false; else end;
    -- overenie separatora
    local sep_len;
    local sep_typ;
    sep_len = strlen(separator);
    sep_typ = type(separator);
    if sep_typ ~= "string" then write("CHYBA: Separator nie je string.\n"); return false; else end;
    if sep_len ~= 1 then write("CHYBA: Separator musi mat 1 znak.\n"); return false; else end;

    -- vsetko ok
    return true;

end

function array_print(array, separator, return_len, get_value)

    -- return_len == ak nastavime na TRUE, nevypisujeme, ale vraciame velkost pola

    -- overenie validnosti
    local valid;
    valid = array_valid(array, separator);
    if valid ~= true then return false; else end;

    local pos;
    local array_len;
    local word;
    local i;
    local want_get_value;
    i = 0;

    -- chceme ziskat prvok? get_value je number
    local typ_get_value;
    typ_get_value = type(get_value);
    if typ_get_value == "number" then
        want_get_value = true;
    else
        want_get_value = false;
    end;

    -- prazdna matica
    array_len = strlen(array);
    if array_len == 0 then return 0; else end;

    -- aby to vbehlo do cyklu
    pos = 1;
    pos = find(array, separator);
    -- a ideme vypisovat
    while pos > 0 do
        pos = find(array, separator);
        pos = pos - 1;
        word = substr(array, 1, pos);
        if want_get_value == true then
            if get_value == i then

                return word;
            else end;
        else
            if return_len ~= true then
                write(i, ". ", word,"\n");
            else end;
        end;

        pos = pos + 2;
        array = substr(array, pos, array_len);
        pos = pos - 1;
        i = i + 1;
    end;

    if i == 0 then
        if array ~= "" then
            if return_len ~= true then
                write(i, ". ", array,"\n");
            else end;
        else end;
    else end;

    -- ak chceme velkost pola
    if return_len == true then

        if i == 0 then
            if array == "" then
                return 0;
            else
                return 1;
            end;
        end;

        return i;

    else end;

end

function array_get(array, separator, id)
    -- overenie validnosti
    local valid;
    valid = array_valid(array, separator);
    if valid ~= true then return array; else end;

    -- overenie pozicie
    local typ;
    typ = type(id);
    if typ ~= "number" then write("CHYBA: Pozicia nie je cislo!\n"); return array; else end;
    if id < 0 then write("CHYBA: Pozicia nemoze byt mensia ako 0!\n"); return array; else end;

    local value;

    value = array_print(array, separator, false, id);

    return value;

end

function array_add(array, separator, id, word)

    -- overenie validnosti
    local valid;
    valid = array_valid(array, separator);
    if valid ~= true then return array; else end;

    local typ;

    -- overenie vkladaneho slova
    typ = type(word);
    if typ ~= "string" then write("CHYBA: Nevkladate slovo!\n"); return array; else end;
    -- overenie pozicie
    typ = type(id);
    if typ ~= "number" then write("CHYBA: Pozicia nie je cislo!\n"); return array; else end;
    if id < 0 then write("CHYBA: Pozicia nemoze byt mensia ako 0!\n"); return array; else end;

    -- a zaciname
    local pos;
    local array_len;
    local i;
    local before;
    local after;
    local tmp;
    local array_num; -- pocet prvkov
    local want_num;
    local pom;
    want_num = true;
    i = 0;

    array_len = strlen(array);

    array_num = array_print(array, separator, want_num);
    -- ak mame prazdnu maticu
    if array == "" then
        if id == 0 then return word; else end;
    else end;
    -- ak ma matica 1 prvok a presne tam chcem vlozit, zmenime
    if array_num == 1 then

        if id == 0 then
            return word;
        else end;
    else end;

    -- vkladanie ZA maticu
    local dec;
    if array_num == 0 then
        dec = id;
        while dec > 0 do
            array = array .. separator;
            dec = dec - 1;
        end;
        array = array .. word;
        return array;
    else
        if (array_num-1) < id then
            dec = id;
            while dec > (array_num-1) do
                array = array .. separator;
                dec = dec - 1;
            end;
            array = array .. word;
            return array;
        else end;
    end;

    -- aby to vbehlo do cyklu
    pos = 1;
    pos = find(array, separator);

    before = "";
    after = "";

    -- a ideme pridavat
    while pos > 0 do
        pos = find(array, separator);

        -- ulozenie do before
        pos = pos - 1;
        tmp = substr(array, 1, pos);

        -- ulozenie do after
        pos = pos + 2;
        array = substr(array, pos, array_len);
        after = array;

        -- pre dalsi prechod (overenie konca)
        pos = find(array, separator);

        if i == id then
            -- separator nedame na zaciatok
            if i == 0 then
                before = word;
            else
                before = before .. separator .. word;
            end;
        else
            -- separator nedame na zaciatok
            if i == 0 then
                before = tmp;
            else
                before = before .. separator .. tmp;
            end;
        end;


        i = i + 1;
    end;

    local result;

    result = before .. separator .. after;

    return result;
end

function help()
    write("\n[ HELP ]\n");
    write("0: Vypisat help\n");
    write("1: Vypisat pole\n");
    write("2: Vlozit do pola\n");
    write("3: Ziskat hodnotu z pola\n");
    write("q: Ukoncit program\n");
end

function main()

    local a;
    local separator;
    local array;

    array = "";

    local pozicia;
    local slovo;
    local input;
    local typ;

    write("Zadajte separator: (1 znak, taky, ktory sa nebude nachadzat v data. Napriklad '@'): ");
    separator = read(1);

    a = help();

    while 1 do

        write("Prikaz $ ");
        input = read("*l");
        write("\n");

        -- moznosti
        if input == "1" then
            a = array_print(array, separator);
        else end;

        if input == "2" then

            write("\nZadajte text: ");
            slovo = read("*l");
            write("Zadajte poziciu: ");
            pozicia = read("*n");
            write(slovo, " - ", pozicia,"\n");
            array = array_add(array, separator, pozicia, slovo);
            write("\n... Vlozene ...\n");
        else end;

        if input == "3" then

            write("Zadajte poziciu: ");
            pozicia = read("*n");

            a = array_get(array, separator, pozicia);
            write("\nNa pozicii ", pozicia," sa nachadza: ", a,"\n");
        else end;

        if input == "0" then
            a = help();
        else end;

        if input == "q" then
            return 0;
        else end;

    end;
end;