/* 
 * (c) danielinux 2019
 * GPLv.2
 *
 * See LICENSE for details
 */
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "system.h"
#include "button.h"
#include "systick.h"
#include "unicore-mx/stm32/gpio.h"
#include "unicore-mx/stm32/exti.h"
#include "unicore-mx/stm32/rcc.h"
#include "unicore-mx/stm32/f4/rcc.h"
#include "unicore-mx/stm32/adc.h"
#include "unicore-mx/stm32/f4/adc.h"
#include "unicore-mx/stm32/f4/nvic.h"

// Uncomment to enable debug
//#define BUTTON_DEBUG

enum button_state {
    IDLE = 0,
    PRESSING,
    PRESSED,
    HOLD,
    RELEASING,
};



#ifdef BUTTON_DEBUG
#   define DBG printf
#else
#   define DBG(...) do {} while (0)
#endif

#define BUTTON_DEBOUNCE_TIME 50
#define BUTTON_HOLD_TIME 200



static volatile int button_press_pending = 0;
#define BUTTON_PLUS '+'
#define BUTTON_MINUS '-'

static void input_run(uint32_t ev, void *arg);
static void input_init(void);

const char button_task_name[] = "Input";

// PA8 + PA9 // ROTARY encoder
// PC0 // BUTTON
//
// TODO:
// C4 + C5 rotary
// B0 + B1 + C3 Buttons (- + RotSW)
//

void pin_exti_init(void)
{
}

void pin_exti_start_read(void)
{
    exti_set_trigger(GPIO0|GPIO1|GPIO3|GPIO4|GPIO5, EXTI_TRIGGER_BOTH);
    exti_enable_request(GPIO0);
    exti_enable_request(GPIO1);
    exti_enable_request(GPIO3);
    exti_enable_request(GPIO4);
    exti_enable_request(GPIO5);
}


static void button_setup(void)
{
    rcc_periph_clock_enable(RCC_SYSCFG);
    rcc_periph_clock_enable(RCC_GPIOB);
    rcc_periph_clock_enable(RCC_GPIOC);
    gpio_mode_setup(GPIOC, GPIO_MODE_INPUT, GPIO_PUPD_PULLDOWN, GPIO3 | GPIO4 | GPIO5);
    gpio_mode_setup(GPIOB, GPIO_MODE_INPUT, GPIO_PUPD_PULLDOWN, GPIO0 | GPIO1);
    nvic_enable_irq(NVIC_EXTI9_5_IRQ);
    nvic_enable_irq(NVIC_EXTI0_IRQ);
    nvic_enable_irq(NVIC_EXTI1_IRQ);
    nvic_enable_irq(NVIC_EXTI3_IRQ);
    nvic_enable_irq(NVIC_EXTI4_IRQ);
    nvic_set_priority(NVIC_EXTI9_5_IRQ, 1);
    nvic_set_priority(NVIC_EXTI0_IRQ, 1);
    nvic_set_priority(NVIC_EXTI1_IRQ, 1);
    nvic_set_priority(NVIC_EXTI3_IRQ, 1);
    nvic_set_priority(NVIC_EXTI4_IRQ, 1);
    exti_select_source(GPIO0, GPIOB);
    exti_select_source(GPIO1, GPIOB);
    exti_select_source(GPIO3, GPIOC);
    exti_select_source(GPIO4, GPIOC);
    exti_select_source(GPIO5, GPIOC);
}

static volatile uint32_t rot_up = 0;
static volatile uint32_t rot_down = 0;

static void button_start_read(void)
{
    exti_set_trigger(GPIO0|GPIO1|GPIO3, EXTI_TRIGGER_RISING);
    exti_set_trigger(GPIO4, EXTI_TRIGGER_FALLING);
    exti_enable_request(GPIO0);
    exti_enable_request(GPIO1);
    exti_enable_request(GPIO3);
    exti_enable_request(GPIO4);
}


static volatile uint32_t last_rot_ev = 0;
void isr_exti_rot0(void)
{
    uint32_t rot_val = gpio_get(GPIOC, GPIO4 | GPIO5);
    if ((jiffies - last_rot_ev) > 100) {
        if ((rot_val & GPIO4) == 0) {

            if ((rot_val & GPIO5) == 0)
                rot_down++;
            else
                rot_up++;
        }
    }
    exti_reset_request(GPIO4);
    exti_reset_request(GPIO5);
}

void isr_exti_button(void)
{
    uint32_t pending;

    pending = (gpio_get(GPIOB, GPIO0|GPIO1));
    if ((pending & GPIO0) != 0)  {
        button_press_pending = '-';
    }
    if ((pending & GPIO1) != 0) {
        button_press_pending = '+';
    }
    if (!pending) {
        pending = (gpio_get(GPIOC, GPIO3));
        if ((pending & GPIO3) != 0) {
            button_press_pending = '*';
        }
    }
    exti_reset_request(GPIO0);
    exti_reset_request(GPIO1);
    exti_reset_request(GPIO3);
}

static uint32_t t0s, t0us;
static uint32_t t1s, t1us;

static uint32_t time_diff_ms(uint32_t s_a, uint32_t us_a, uint32_t s_b, uint32_t us_b)
{
    uint32_t res = 0;
    res = (s_a - s_b) * 1000;
    if (us_b > us_a) {
        us_a += 1000000;
        res -= 1000;
    }
    res += (us_a - us_b) / 1000;
    return res;
}


/* Button interface */
struct user_button 
{
    enum button_state state;
    uint32_t transition_start_timestamp;
};

static struct user_button Buttons[N_BUTTONS];

int button_poll(void (*callback)(uint8_t press, int hold))
{
    int b = 0;
    int st;
    static uint32_t last_event = 0;
    static uint32_t pressed_start = 0;
    while(rot_down > 0) {
        callback('D',0);
        rot_down--;
    }
    while(rot_up > 0) {
        callback('U',0);
        rot_up--;
    }

    if (jiffies - last_event < BUTTON_DEBOUNCE_TIME)
        return;
    last_event = jiffies;
    st = !!(gpio_get(GPIOB, GPIO0 | GPIO1) | gpio_get(GPIOC, GPIO3)); 
    if (!st) {
        pressed_start = 0;
    }

    if ((button_press_pending) && st) {
        if ((pressed_start == 0) || ((jiffies - pressed_start) > BUTTON_HOLD_TIME)) {
            pressed_start = jiffies;
            callback(button_press_pending, 0);
            return 1;
        }
    }
    button_press_pending = 0;
    return 0;
}

void button_init(void)
{
    memset(Buttons, 0, sizeof(struct user_button) * N_BUTTONS);
    button_setup();
    button_start_read();
}