#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/io.h>
#include <time.h>
#include <errno.h>
#include "led_ctl.h"

#define EC_CMD_PORT 0x66
#define EC_DATA_PORT 0x62

#define EC_OBF 0x01 // Output Buffer Full
#define EC_IBF 0x02 // Input Buffer Full

#define CMD_READ_RAM 0x97
#define CMD_WRITE_RAM 0x98

#define OFFSET_COLOR_CTL 0x01
#define OFFSET_BLINK_TIME 0x02
#define OFFSET_BLINK_CTL 0x03

#define BIT0 (1 << 0)
#define TIMEOUT_LOOPS 100000

static int wait_ibf(void)
{
    int i = 0;
    while (inb(EC_CMD_PORT) & EC_IBF)
    {
        if (++i > TIMEOUT_LOOPS)
        {
            fprintf(stderr, "Error: EC IBF Timeout!\n");
            return -1;
        }
        usleep(1);
    }
    return 0;
}

static int wait_obf(void)
{
    int i = 0;
    while (!(inb(EC_CMD_PORT) & EC_OBF))
    {
        if (++i > TIMEOUT_LOOPS)
        {
            fprintf(stderr, "Error: EC OBF Timeout!\n");
            return -1;
        }
        usleep(1);
    }
    return 0;
}

static int ec_read_ram(uint8_t offset, uint8_t *data)
{
    if (wait_ibf() < 0)
        return -1;
    outb(CMD_READ_RAM, EC_CMD_PORT);

    if (wait_ibf() < 0)
        return -1;
    outb(offset, EC_DATA_PORT);

    if (wait_obf() < 0)
        return -1;
    *data = inb(EC_DATA_PORT);

    return 0;
}

static int ec_write_ram(uint8_t offset, uint8_t data)
{
    if (wait_ibf() < 0)
        return -1;
    outb(CMD_WRITE_RAM, EC_CMD_PORT);

    if (wait_ibf() < 0)
        return -1;
    outb(offset, EC_DATA_PORT);

    if (wait_ibf() < 0)
        return -1;
    outb(data, EC_DATA_PORT);

    return 0;
}

// ---------API functions---------
int led_driver_init(void)
{
    if (ioperm(EC_DATA_PORT, 1, 1))
    {
        perror("Failed to get permission for 0x62");
        return -1;
    }
    if (ioperm(EC_CMD_PORT, 1, 1))
    {
        perror("Failed to get permission for 0x66");
        return -1;
    }
    return 0;
}

int led_set_color(led_color_t color)
{
    uint8_t val;
    if (ec_read_ram(OFFSET_COLOR_CTL, &val) < 0)
        return -1;

    if (color == LED_RED)
        val |= BIT0;
    else
        val &= ~BIT0;

    return ec_write_ram(OFFSET_COLOR_CTL, val);
}

int led_set_blink(int enable, uint8_t interval_unit)
{
    uint8_t ctl;

    if (enable)
    {
        if (ec_write_ram(OFFSET_BLINK_TIME, interval_unit) < 0)
            return -1;
    }

    if (ec_read_ram(OFFSET_BLINK_CTL, &ctl) < 0)
        return -1;

    if (enable)
        ctl |= BIT0;
    else
        ctl &= ~BIT0;

    return ec_write_ram(OFFSET_BLINK_CTL, ctl);
}

int led_print_status(void)
{
    uint8_t color_reg, blink_time, blink_ctl;

    if (ec_read_ram(OFFSET_COLOR_CTL, &color_reg) < 0)
        return -1;
    if (ec_read_ram(OFFSET_BLINK_TIME, &blink_time) < 0)
        return -1;
    if (ec_read_ram(OFFSET_BLINK_CTL, &blink_ctl) < 0)
        return -1;

    printf(" Color     : %s\n", (color_reg & BIT0) ? "RED" : "GREEN");
    printf(" Blink     : %s\n", (blink_ctl & BIT0) ? "ON" : "OFF");
    if (blink_ctl & BIT0)
    {
        printf(" Interval  : %d ms (%d units)\n", blink_time * 100, blink_time);
    }

    return 0;
}