#include <stdlib.h>
#include <stdint.h>

#include "encoding.h"
#include "platform.h"
#include "prci_driver.h"

#include "eos.h"
#include "i2s.h"
#include "i2c.h"

int eos_i2c_init(uint8_t wakeup_cause) {
    eos_i2c_speed(EOS_I2C_SPEED);
    eos_i2c_enable();

    return EOS_OK;
}

void eos_i2c_enable(void) {
    I2C0_REGB(I2C_CONTROL)  |=  I2C_CONTROL_EN;

    GPIO_REG(GPIO_IOF_SEL)  &= ~IOF0_I2C0_MASK;
    GPIO_REG(GPIO_IOF_EN)   |=  IOF0_I2C0_MASK;
}

void eos_i2c_disable(void) {
    GPIO_REG(GPIO_IOF_EN)   &= ~IOF0_I2C0_MASK;

    I2C0_REGB(I2C_CONTROL)  &= ~I2C_CONTROL_EN;
}

int eos_i2c_enabled(void) {
    return !!(GPIO_REG(GPIO_IOF_EN) & IOF0_I2C0_MASK);
}

void eos_i2c_speed(uint32_t baud_rate) {
    unsigned long clock_rate = PRCI_get_cpu_freq();
    uint16_t prescaler = (clock_rate / (baud_rate * 5)) - 1;

    I2C0_REGB(I2C_PRESCALE_LOW) = prescaler & 0xFF;
    I2C0_REGB(I2C_PRESCALE_HIGH) = (prescaler >> 8) & 0xFF;
}


static int i2c_read(uint8_t cmd) {
    I2C0_REGB(I2C_COMMAND) = I2C_CMD_READ | cmd;
    while (I2C0_REGB(I2C_STATUS) & I2C_STATUS_TIP);

    return I2C0_REGB(I2C_RECEIVE);
}

static int i2c_write(uint8_t cmd, uint8_t b) {
    I2C0_REGB(I2C_TRANSMIT) = b;
    I2C0_REGB(I2C_COMMAND) = I2C_CMD_WRITE | cmd;
    while (I2C0_REGB(I2C_STATUS) & I2C_STATUS_TIP);

    if (I2C0_REGB(I2C_STATUS) & I2C_STATUS_RXACK) return EOS_ERR;
    return EOS_OK;
}

static int i2c_addr(uint8_t addr, uint8_t rw_flag) {
    return i2c_write(I2C_CMD_START, ((addr & 0x7F) << 1) | (rw_flag & 0x1));
}

int eos_i2c_read8(uint8_t addr, uint8_t reg, uint8_t *buffer, uint16_t len) {
    int rv;
    int i;

    rv = i2c_addr(addr, I2C_WRITE);
    if (rv) return rv;

    rv = i2c_write(0, reg);
    if (rv) return rv;

    rv = i2c_addr(addr, I2C_READ);
    if (rv) return rv;

    for (i=0; i<len; i++) {
        rv = i2c_read(i == (len - 1) ? (I2C_CMD_ACK | I2C_CMD_STOP) : 0);  /* Set NACK to end read, and generate STOP condition */
        if (rv < 0) return rv;

        buffer[i] = (uint8_t)rv;
    }

    return EOS_OK;
}

int eos_i2c_read16(uint8_t addr, uint16_t reg, uint8_t *buffer, uint16_t len) {
    int rv;
    int i;

    rv = i2c_addr(addr, I2C_WRITE);
    if (rv) return rv;

    rv = i2c_write(0, reg >> 8);
    if (rv) return rv;

    rv = i2c_write(0, reg & 0xff);
    if (rv) return rv;

    rv = i2c_addr(addr, I2C_READ);
    if (rv) return rv;

    for (i=0; i<len; i++) {
        rv = i2c_read(i == (len - 1) ? (I2C_CMD_ACK | I2C_CMD_STOP) : 0);  /* Set NACK to end read, and generate STOP condition */
        if (rv < 0) return rv;

        buffer[i] = (uint8_t)rv;
    }

    return EOS_OK;
}

int eos_i2c_write8(uint8_t addr, uint8_t reg, uint8_t *buffer, uint16_t len) {
    int rv;
    int i;

    rv = i2c_addr(addr, I2C_WRITE);
    if (rv) return rv;

    rv = i2c_write(0, reg);
    if (rv) return rv;

    for (i=0; i<len; i++) {
        rv = i2c_write(i == (len - 1) ? I2C_CMD_STOP : 0, buffer[i]);
        if (rv) return rv;
    }

    return EOS_OK;
}

int eos_i2c_write16(uint8_t addr, uint16_t reg, uint8_t *buffer, uint16_t len) {
    int rv;
    int i;

    rv = i2c_addr(addr, I2C_WRITE);
    if (rv) return rv;

    rv = i2c_write(0, reg >> 8);
    if (rv) return rv;

    rv = i2c_write(0, reg & 0xff);
    if (rv) return rv;

    for (i=0; i<len; i++) {
        rv = i2c_write(i == (len - 1) ? I2C_CMD_STOP : 0, buffer[i]);
        if (rv) return rv;
    }

    return EOS_OK;
}