/*
 * p4bio.c — целевая проба bank_read_page()/bank_write_page().
 *
 * Проверяет перенос 4096 байт через одну EMM-страницу без полноразмерного
 * near-буфера, восстановление W3, контроль границ и отсутствие утечки EMM.
 * Временный файл создаётся только на тестовой дискете A: и удаляется.
 */

#include <stdio.h>
#include <stdint.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <conio.h>
#include <sprinter.h>
#include <sprinter_mem.h>

#define TEST_PATH  "A:\\P4BIO.TMP"
#define TEST_SIZE  4096u
#define READ_OFFSET 4096u

static uint8_t chunk[256];

static uint8_t pattern(uint16_t pos)
{
    return (uint8_t)((uint8_t)(pos * 37u) + (uint8_t)(pos >> 8) + 0x5Au);
}

static void prepare_page(uint8_t page)
{
    uint16_t base;
    uint16_t i;

    for (base = 0u; base < TEST_SIZE; base += (uint16_t)sizeof(chunk)) {
        for (i = 0u; i < (uint16_t)sizeof(chunk); i++) {
            chunk[i] = pattern((uint16_t)(base + i));
        }
        bank_write(page, base, chunk, (uint16_t)sizeof(chunk));
    }
}

static uint8_t verify_page(uint8_t page)
{
    uint16_t i;

    for (i = 0u; i < TEST_SIZE; i++) {
        if (bank_load_byte(page, (uint16_t)(READ_OFFSET + i)) != pattern(i)) {
            return 0u;
        }
    }
    return 1u;
}

int main(void)
{
    uint16_t total_before;
    uint16_t free_before;
    uint16_t total_after;
    uint16_t free_after;
    uint8_t block = 0u;
    uint8_t page = 0u;
    uint8_t w3_before;
    uint8_t write_w3_ok = 0u;
    uint8_t read_w3_ok = 0u;
    uint8_t data_ok = 0u;
    uint8_t range_ok = 0u;
    uint8_t cleanup_ok;
    int fd = -1;
    int written = -1;
    int loaded = -1;

    (void)settextmode(TEXT_MODE_80x32);
    clrscr_attr(0x17u);
    gotoxy(0u, 0u);
    textattr(0x1Fu);
    cputs("P4 bank page file I/O diagnostic\r\n\r\n");
    textattr(0x17u);

    (void)unlink(TEST_PATH);
    mem_info(&total_before, &free_before);
    block = mem_alloc_pages(1u);
    page = block ? mem_get_page(block, 0u) : 0u;
    if (!block || !page) goto cleanup;

    prepare_page(page);
    fd = open(TEST_PATH, O_WRONLY | O_CREAT | O_EXCL);
    if (fd < 0) goto cleanup;
    w3_before = _io_page_w3;
    written = bank_write_page(fd, page, 0u, TEST_SIZE);
    write_w3_ok = (_io_page_w3 == w3_before);
    if (close(fd) != 0) goto cleanup;
    fd = -1;
    if (written != TEST_SIZE) goto cleanup;

    fd = open(TEST_PATH, O_RDONLY);
    if (fd < 0) goto cleanup;
    w3_before = _io_page_w3;
    loaded = bank_read_page(fd, page, READ_OFFSET, TEST_SIZE);
    read_w3_ok = (_io_page_w3 == w3_before);
    if (close(fd) != 0) goto cleanup;
    fd = -1;
    if (loaded != TEST_SIZE) goto cleanup;

    data_ok = verify_page(page);
    errno = 0;
    w3_before = _io_page_w3;
    range_ok = bank_write_page(-1, page, 0x3FFFu, 2u) == -1 &&
               errno == EINVAL && _io_page_w3 == w3_before;

cleanup:
    if (fd >= 0) (void)close(fd);
    (void)unlink(TEST_PATH);
    if (block != 0u) mem_free_block(block);
    mem_info(&total_after, &free_after);
    cleanup_ok = total_before == total_after && free_before == free_after;

    printf("page=%02X write=%d read=%d data=%u\n",
           (unsigned)page, written, loaded, (unsigned)data_ok);
    printf("W3: write=%u read=%u range=%u errno=%d\n",
           (unsigned)write_w3_ok, (unsigned)read_w3_ok,
           (unsigned)range_ok, errno);
    printf("EMM: before=%u after=%u restored=%u\n",
           (unsigned)free_before, (unsigned)free_after,
           (unsigned)cleanup_ok);

    textattr((written == TEST_SIZE && loaded == TEST_SIZE && data_ok &&
              write_w3_ok && read_w3_ok && range_ok && cleanup_ok) ?
             0x1Eu : 0x4Fu);
    cputs((written == TEST_SIZE && loaded == TEST_SIZE && data_ok &&
           write_w3_ok && read_w3_ok && range_ok && cleanup_ok) ?
          "\r\nPASS: bank page file I/O is intact." :
          "\r\nFAIL: bank page file I/O violation.");
    textattr(0x1Eu);
    cputs("\r\nProbe stopped; MAME test will take a snapshot.");
    for (;;) (void)getkey();
}