/**
 * @file evdev.c
 *
 */

/*********************
 *      INCLUDES
 *********************/
#include "evdev.h"
#if USE_EVDEV != 0 || USE_BSD_EVDEV

#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#if USE_BSD_EVDEV
#include <dev/evdev/input.h>
#else
#include <linux/input.h>
#endif

#if USE_XKB
#include "xkb.h"
#endif /* USE_XKB */

/**********************
 *  STATIC VARIABLES
 **********************/

evdev_device_t global_dsc;

/**********************
 *  STATIC FUNCTIONS
 **********************/

static int _evdev_process_key(uint16_t code, bool pressed)
{
#if USE_XKB
    return xkb_process_key(code, pressed);
#else
    LV_UNUSED(pressed);
    switch(code) {
        case KEY_UP:
            return LV_KEY_UP;
        case KEY_DOWN:
            return LV_KEY_DOWN;
        case KEY_RIGHT:
            return LV_KEY_RIGHT;
        case KEY_LEFT:
            return LV_KEY_LEFT;
        case KEY_ESC:
            return LV_KEY_ESC;
        case KEY_DELETE:
            return LV_KEY_DEL;
        case KEY_BACKSPACE:
            return LV_KEY_BACKSPACE;
        case KEY_ENTER:
            return LV_KEY_ENTER;
        case KEY_NEXT:
        case KEY_TAB:
            return LV_KEY_NEXT;
        case KEY_PREVIOUS:
            return LV_KEY_PREV;
        case KEY_HOME:
            return LV_KEY_HOME;
        case KEY_END:
            return LV_KEY_END;
        default:
            return 0;
    }
#endif /*USE_XKB*/
}

static int _evdev_calibrate(int v, int in_min, int in_max, int out_min, int out_max)
{
    if(in_min != in_max) v = (v - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
    return LV_CLAMP(out_min, v, out_max);
}

static lv_point_t _evdev_process_pointer(lv_indev_drv_t * drv, int x, int y)
{
    evdev_device_t * dsc = drv->user_data ? drv->user_data : &global_dsc;

    int swapped_x = dsc->swap_axes ? y : x;
    int swapped_y = dsc->swap_axes ? x : y;

    int offset_x = 0; /*Not lv_disp_get_offset_x(drv->disp) for bc*/
    int offset_y = 0; /*Not lv_disp_get_offset_y(drv->disp) for bc*/
    int width = lv_disp_get_hor_res(drv->disp);
    int height = lv_disp_get_ver_res(drv->disp);

    lv_point_t p;
    p.x = _evdev_calibrate(swapped_x, dsc->hor_min, dsc->hor_max, offset_x, offset_x + width - 1);
    p.y = _evdev_calibrate(swapped_y, dsc->ver_min, dsc->ver_max, offset_y, offset_y + height - 1);
    return p;
}

/**********************
 *   GLOBAL FUNCTIONS
 **********************/

void evdev_init()
{
    evdev_device_init(&global_dsc);
#ifdef EVDEV_SWAP_AXES
    evdev_device_set_swap_axes(&global_dsc, EVDEV_SWAP_AXES);
#endif
#if EVDEV_CALIBRATE
    evdev_device_set_calibration(&global_dsc, EVDEV_HOR_MIN, EVDEV_VER_MIN, EVDEV_HOR_MAX, EVDEV_VER_MAX);
#endif
    evdev_device_set_file(&global_dsc, EVDEV_NAME);
}

void evdev_device_init(evdev_device_t * dsc)
{
    lv_memset(dsc, 0, sizeof(evdev_device_t));
    dsc->fd = -1;

#if USE_XKB
    xkb_init();
#endif
}

bool evdev_set_file(const char * dev_path)
{
    return evdev_device_set_file(&global_dsc, dev_path);
}

bool evdev_device_set_file(evdev_device_t * dsc, const char * dev_path)
{
    /*Reset state*/
    dsc->root_x = 0;
    dsc->root_y = 0;
    dsc->key = 0;
    dsc->state = LV_INDEV_STATE_RELEASED;

    /*Close previous*/
    if(dsc->fd >= 0) {
        close(dsc->fd);
        dsc->fd = -1;
    }
    if(!dev_path) return false;

    /*Open new*/
    dsc->fd = open(dev_path, O_RDONLY | O_NOCTTY | O_CLOEXEC);
    if(dsc->fd < 0) {
        LV_LOG_ERROR("open failed: %s", strerror(errno));
        return false;
    }
    if(fcntl(dsc->fd, F_SETFL, O_NONBLOCK) < 0) {
        LV_LOG_ERROR("fcntl failed: %s", strerror(errno));
        close(dsc->fd);
        dsc->fd = -1;
        return false;
    }

    return true;
}

void evdev_device_set_swap_axes(evdev_device_t * dsc, bool swap_axes)
{
    dsc->swap_axes = swap_axes;
}

void evdev_device_set_calibration(evdev_device_t * dsc, int ver_min, int hor_min, int ver_max, int hor_max)
{
    dsc->ver_min = ver_min;
    dsc->hor_min = hor_min;
    dsc->ver_max = ver_max;
    dsc->hor_max = hor_max;
}

void evdev_read(lv_indev_drv_t * drv, lv_indev_data_t * data)
{
    evdev_device_t * dsc = drv->user_data ? drv->user_data : &global_dsc;
    if(dsc->fd < 0) return;

    /*Update dsc with buffered events*/
    struct input_event in = { 0 };
    while(read(dsc->fd, &in, sizeof(in)) > 0) {
        if(in.type == EV_REL) {
            if(in.code == REL_X) dsc->root_x += in.value;
            else if(in.code == REL_Y) dsc->root_y += in.value;
        }
        else if(in.type == EV_ABS) {
            if(in.code == ABS_X || in.code == ABS_MT_POSITION_X) dsc->root_x = in.value;
            else if(in.code == ABS_Y || in.code == ABS_MT_POSITION_Y) dsc->root_y = in.value;
            else if(in.code == ABS_MT_TRACKING_ID) {
                if(in.value == -1) dsc->state = LV_INDEV_STATE_RELEASED;
                else if(in.value == 0) dsc->state = LV_INDEV_STATE_PRESSED;
            }
        }
        else if(in.type == EV_KEY) {
            if(in.code == BTN_MOUSE || in.code == BTN_TOUCH) {
                if(in.value == 0) dsc->state = LV_INDEV_STATE_RELEASED;
                else if(in.value == 1) dsc->state = LV_INDEV_STATE_PRESSED;
            }
            else {
                dsc->key = _evdev_process_key(in.code, in.value != 0);
                if(dsc->key) {
                    dsc->state = in.value ? LV_INDEV_STATE_PRESSED : LV_INDEV_STATE_RELEASED;
                    data->continue_reading = true; /*Keep following events in buffer for now*/
                    break;
                }
            }
        }
    }

    /*Process and store in data*/
    switch(drv->type) {
        case LV_INDEV_TYPE_KEYPAD:
            data->state = dsc->state;
            data->key = dsc->key;
            break;
        case LV_INDEV_TYPE_POINTER:
            data->state = dsc->state;
            data->point = _evdev_process_pointer(drv, dsc->root_x, dsc->root_y);
            break;
        default:
            break;
    }
}

#endif /*USE_EVDEV*/