#include "rs232_port_owner.h"

#include "freertos/FreeRTOS.h"
#include "freertos/semphr.h"

static SemaphoreHandle_t s_owner_mutex;
static rs232_port_owner_t s_owner = RS232_PORT_OWNER_NONE;

esp_err_t rs232_port_owner_init(void)
{
    if (s_owner_mutex != NULL) {
        return ESP_ERR_INVALID_STATE;
    }
    s_owner_mutex = xSemaphoreCreateMutex();
    return s_owner_mutex != NULL ? ESP_OK : ESP_ERR_NO_MEM;
}

esp_err_t rs232_port_claim(rs232_port_owner_t owner)
{
    if (s_owner_mutex == NULL || owner == RS232_PORT_OWNER_NONE || owner == RS232_PORT_OWNER_FAULT) {
        return ESP_ERR_INVALID_ARG;
    }

    xSemaphoreTake(s_owner_mutex, portMAX_DELAY);
    esp_err_t result = ESP_ERR_INVALID_STATE;
    if (s_owner == RS232_PORT_OWNER_NONE) {
        s_owner = owner;
        result = ESP_OK;
    }
    xSemaphoreGive(s_owner_mutex);
    return result;
}

esp_err_t rs232_port_release(rs232_port_owner_t owner)
{
    if (s_owner_mutex == NULL) {
        return ESP_ERR_INVALID_STATE;
    }

    xSemaphoreTake(s_owner_mutex, portMAX_DELAY);
    esp_err_t result = ESP_ERR_INVALID_STATE;
    if (s_owner == owner) {
        s_owner = RS232_PORT_OWNER_NONE;
        result = ESP_OK;
    }
    xSemaphoreGive(s_owner_mutex);
    return result;
}

void rs232_port_mark_fault(rs232_port_owner_t previous_owner)
{
    if (s_owner_mutex == NULL) {
        return;
    }

    xSemaphoreTake(s_owner_mutex, portMAX_DELAY);
    if (s_owner == previous_owner) {
        s_owner = RS232_PORT_OWNER_FAULT;
    }
    xSemaphoreGive(s_owner_mutex);
}

rs232_port_owner_t rs232_port_get_owner(void)
{
    if (s_owner_mutex == NULL) {
        return RS232_PORT_OWNER_FAULT;
    }

    xSemaphoreTake(s_owner_mutex, portMAX_DELAY);
    rs232_port_owner_t owner = s_owner;
    xSemaphoreGive(s_owner_mutex);
    return owner;
}

const char *rs232_port_owner_to_string(rs232_port_owner_t owner)
{
    switch (owner) {
    case RS232_PORT_OWNER_NONE:
        return "idle";
    case RS232_PORT_OWNER_PHASE0:
        return "Phase 0 diagnostics";
    case RS232_PORT_OWNER_SERVICE:
        return "serial service";
    case RS232_PORT_OWNER_FAULT:
        return "fault (reboot required)";
    default:
        return "unknown";
    }
}