/**
 * @file test_crc32.c
 * @brief CRC32 Test Suite
 */

#include "protocol.h"
#include <stdio.h>
#include <string.h>

static int passed = 0;
static int failed = 0;

#define TEST_ASSERT(cond, msg) do { \
    if (cond) { \
        printf("[PASS] %s\n", msg); \
        passed++; \
    } else { \
        printf("[FAIL] %s\n", msg); \
        failed++; \
    } \
} while(0)

/* Test vector from IEEE 802.3 */
static void test_crc32_basic(void) {
    printf("\n--- CRC32 Basic Tests ---\n");
    
    /* Test 1: Empty data */
    uint32_t crc = chunk_crc32(NULL, 0);
    TEST_ASSERT(crc == 0x00000000UL, "Empty data CRC = 0x00000000");
    
    /* Test 2: Single byte */
    uint8_t data1[] = {0x41};  /* 'A' */
    crc = chunk_crc32(data1, 1);
    TEST_ASSERT(crc == 0xD3D99E8BUL, "Single byte 'A' CRC = 0xD3D99E8B");
    
    /* Test 3: "foobar" */
    uint8_t data2[] = "foobar";
    crc = chunk_crc32(data2, 6);
    TEST_ASSERT(crc == 0x9EF61F95UL, "'foobar' CRC = 0x9EF61F95");
    
    /* Test 4: Incremental update */
    uint32_t crc1 = chunk_crc32((uint8_t*)"foo", 3);
    uint32_t crc2 = chunk_crc32_update(crc1, (uint8_t*)"bar", 3);
    uint32_t crc3 = chunk_crc32(data2, 6);
    TEST_ASSERT(crc2 == crc3, "Incremental update matches single call");
}

/* Test chunk size calculations */
static void test_chunk_calculations(void) {
    printf("\n--- Chunk Calculation Tests ---\n");
    
    /* Test 1: Exact multiple */
    uint16_t chunks = chunk_calc_total_chunks(4096, 1024);
    TEST_ASSERT(chunks == 4, "4096/1024 = 4 chunks");
    
    /* Test 2: Not exact multiple */
    chunks = chunk_calc_total_chunks(4097, 1024);
    TEST_ASSERT(chunks == 5, "4097/1024 = 5 chunks");
    
    /* Test 3: Last chunk payload size */
    uint16_t payload = chunk_calc_payload_size(4097, 4, 1024);
    TEST_ASSERT(payload == 1, "Last chunk of 4097 bytes = 1 byte");
    
    /* Test 4: Middle chunk payload size */
    payload = chunk_calc_payload_size(4097, 2, 1024);
    TEST_ASSERT(payload == 1024, "Middle chunk = 1024 bytes");
}

/* Test CRC32 table initialization */
static void test_crc32_table(void) {
    printf("\n--- CRC32 Table Tests ---\n");
    
    /* Call multiple times to verify idempotent initialization */
    chunk_crc32((uint8_t*)"test", 4);
    chunk_crc32((uint8_t*)"test", 4);
    chunk_crc32((uint8_t*)"test", 4);
    
    TEST_ASSERT(1, "Multiple initializations OK");
}

int main(void) {
    printf("========================================\n");
    printf(" CRC32 Test Suite\n");
    printf("========================================\n");
    
    test_crc32_basic();
    test_chunk_calculations();
    test_crc32_table();
    
    printf("\n========================================\n");
    printf(" Results: %d passed, %d failed\n", passed, failed);
    printf("========================================\n");
    
    return failed == 0 ? 0 : 1;
}