/* A2 验收主项：能在假总线上挂一个器件并读回预置值。
   顺带把「器件失联 / 偶发 NAK」这两种后面 A15 要用的故障注入也测掉。 */
#include <string.h>

#include "sim_hal.h"
#include "unity.h"

#define INA226_CH1 0x40 /* 设计文档 §8.2 的地址表；A3 才会真的写驱动 */
#define PCA9555    0x20

void setUp(void) { sim_hal_reset(); }
void tearDown(void) {}

static void init_bus(void)
{
    TEST_ASSERT_EQUAL_INT(HAL_OK, hal_i2c_init(NULL));
}

static void test_use_before_init_is_state_error(void)
{
    sim_i2c_add(INA226_CH1, 2);
    uint8_t rd[2];
    TEST_ASSERT_EQUAL_INT(HAL_ERR_STATE, hal_i2c_read(INA226_CH1, rd, sizeof(rd)));
}

/* ⭐ A2 的验收判据本身 */
static void test_read_back_preset_register(void)
{
    init_bus();
    sim_i2c_add(INA226_CH1, 2);
    sim_i2c_set_reg(INA226_CH1, 0x02, 0x1234); /* INA226 的 Bus Voltage 寄存器 */

    const uint8_t ptr = 0x02;
    uint8_t rd[2] = { 0, 0 };
    TEST_ASSERT_EQUAL_INT(HAL_OK, hal_i2c_write_read(INA226_CH1, &ptr, 1, rd, sizeof(rd)));
    TEST_ASSERT_EQUAL_HEX8(0x12, rd[0]); /* 大端 */
    TEST_ASSERT_EQUAL_HEX8(0x34, rd[1]);
    TEST_ASSERT_EQUAL_UINT32(1, sim_i2c_dev(INA226_CH1)->n_read);
}

static void test_write_stores_big_endian_and_logs_bytes(void)
{
    init_bus();
    sim_i2c_add(INA226_CH1, 2);

    const uint8_t wr[3] = { 0x05, 0x12, 0x34 };
    TEST_ASSERT_EQUAL_INT(HAL_OK, hal_i2c_write(INA226_CH1, wr, sizeof(wr)));
    TEST_ASSERT_EQUAL_HEX16(0x1234, sim_i2c_get_reg(INA226_CH1, 0x05));

    const sim_i2c_dev_t *d = sim_i2c_dev(INA226_CH1);
    TEST_ASSERT_EQUAL_UINT8(3, d->last_write_len);
    TEST_ASSERT_EQUAL_HEX8_ARRAY(wr, d->last_write, 3);
}

/* 寄存器指针自增：一次事务连读两个寄存器，真器件就是这个行为。 */
static void test_pointer_auto_increments(void)
{
    init_bus();
    sim_i2c_add(INA226_CH1, 2);
    sim_i2c_set_reg(INA226_CH1, 0x01, 0xAAAA);
    sim_i2c_set_reg(INA226_CH1, 0x02, 0xBBBB);

    const uint8_t ptr = 0x01;
    uint8_t rd[4];
    TEST_ASSERT_EQUAL_INT(HAL_OK, hal_i2c_write_read(INA226_CH1, &ptr, 1, rd, sizeof(rd)));
    TEST_ASSERT_EQUAL_HEX8(0xAA, rd[0]);
    TEST_ASSERT_EQUAL_HEX8(0xBB, rd[2]);
}

/* PCA9555 是 8 位寄存器；同一套 HAL 要能同时伺候两种宽度。 */
static void test_byte_wide_device(void)
{
    init_bus();
    sim_i2c_add(PCA9555, 1);
    const uint8_t wr[3] = { 0x06, 0xFF, 0x0F }; /* 配置寄存器 Port0/Port1 */
    TEST_ASSERT_EQUAL_INT(HAL_OK, hal_i2c_write(PCA9555, wr, sizeof(wr)));
    TEST_ASSERT_EQUAL_HEX16(0x00FF, sim_i2c_get_reg(PCA9555, 0x06));
    TEST_ASSERT_EQUAL_HEX16(0x000F, sim_i2c_get_reg(PCA9555, 0x07));
}

static void test_absent_device_naks(void)
{
    init_bus();
    TEST_ASSERT_EQUAL_INT(HAL_ERR_NAK, hal_i2c_probe(0x77)); /* 总线上没这个地址 */

    sim_i2c_add(INA226_CH1, 2);
    TEST_ASSERT_EQUAL_INT(HAL_OK, hal_i2c_probe(INA226_CH1));
    sim_i2c_set_present(INA226_CH1, false); /* 器件失联（A15 降级矩阵） */
    TEST_ASSERT_EQUAL_INT(HAL_ERR_NAK, hal_i2c_probe(INA226_CH1));
}

static void test_transient_nak_then_recovers(void)
{
    init_bus();
    sim_i2c_add(INA226_CH1, 2);
    sim_i2c_inject_nak(INA226_CH1, 2); /* 接下来两次事务失败 */

    uint8_t rd[2];
    TEST_ASSERT_EQUAL_INT(HAL_ERR_NAK, hal_i2c_read(INA226_CH1, rd, sizeof(rd)));
    TEST_ASSERT_EQUAL_INT(HAL_ERR_NAK, hal_i2c_read(INA226_CH1, rd, sizeof(rd)));
    TEST_ASSERT_EQUAL_INT(HAL_OK, hal_i2c_read(INA226_CH1, rd, sizeof(rd)));
    /* NAK 掉的事务不该被算成一次成功访问 */
    TEST_ASSERT_EQUAL_UINT32(1, sim_i2c_dev(INA226_CH1)->n_read);
}

/* 半个寄存器的长度：真器件上是未定义行为，这里必须当场报错而不是悄悄凑合。 */
static void test_partial_register_length_rejected(void)
{
    init_bus();
    sim_i2c_add(INA226_CH1, 2);
    uint8_t rd[1];
    TEST_ASSERT_EQUAL_INT(HAL_ERR_ARG, hal_i2c_read(INA226_CH1, rd, 1));
    const uint8_t wr[2] = { 0x05, 0x12 };
    TEST_ASSERT_EQUAL_INT(HAL_ERR_ARG, hal_i2c_write(INA226_CH1, wr, sizeof(wr)));
}

static void test_address_out_of_range(void)
{
    init_bus();
    TEST_ASSERT_EQUAL_INT(HAL_ERR_ARG, hal_i2c_probe(0x80));
}

int main(void)
{
    UNITY_BEGIN();
    RUN_TEST(test_use_before_init_is_state_error);
    RUN_TEST(test_read_back_preset_register);
    RUN_TEST(test_write_stores_big_endian_and_logs_bytes);
    RUN_TEST(test_pointer_auto_increments);
    RUN_TEST(test_byte_wide_device);
    RUN_TEST(test_absent_device_naks);
    RUN_TEST(test_transient_nak_then_recovers);
    RUN_TEST(test_partial_register_length_rejected);
    RUN_TEST(test_address_out_of_range);
    return UNITY_END();
}