#include "tdkpin_command_line.h"

/*
 * 1020:0871 — scan one DOS command-tail token.
 * Bytes <= space are separators. A zero starting index intentionally wraps to
 * ffff after the first token and counts until the zero-length terminal scan.
 */
BorlandCommandToken borland_scan_command_token(uint16_t index)
{
    Win16FarPtr cursor = g_borland_command_line;
    while (true) {
        uint8_t value;
        do {
            value = win16_read_u8(cursor);
            cursor = win16_far_add_offset(cursor, 1);
        } while (value != 0 && value <= 0x20);

        cursor = win16_far_add_offset(cursor, 0xffff);
        Win16FarPtr token = cursor;
        do {
            value = win16_read_u8(cursor);
            cursor = win16_far_add_offset(cursor, 1);
        } while (value > 0x20);
        cursor = win16_far_add_offset(cursor, 0xffff);
        uint16_t length =
            (uint16_t)(win16_far_offset(cursor) - win16_far_offset(token));
        if (length == 0) {
            return (BorlandCommandToken){token, 0, index};
        }
        index--;
        if (index == 0) {
            return (BorlandCommandToken){token, length, index};
        }
    }
}

/* 1020:0866 — CX=0 scan followed by XCHG/NEG returns the token count. */
uint16_t borland_parameter_count(void)
{
    BorlandCommandToken terminal = borland_scan_command_token(0);
    return (uint16_t)(0 - terminal.remaining_index);
}

/*
 * 1020:082e — ParamStr with a hidden far ShortString result.
 * For command tokens, AL becomes the length byte while REP MOVSB retains the
 * complete uint16 token length; this deliberately preserves >255 overflow.
 */
void borland_parameter_string(uint16_t index, Win16FarPtr destination)
{
    if (index == 0) {
        uint16_t length = GetModuleFileNameFar16(
            g_win16_instance,
            win16_far_add_offset(destination, 1),
            0xff);
        win16_write_u8(destination, (uint8_t)length);
        return;
    }
    BorlandCommandToken token = borland_scan_command_token(index);
    win16_write_u8(destination, (uint8_t)token.length);
    for (uint16_t offset = 0; offset < token.length; offset++) {
        win16_write_u8(
            win16_far_add_offset(destination, (uint16_t)(offset + 1)),
            win16_read_u8(win16_far_add_offset(token.token, offset)));
    }
}