/**
 * @file    bsp_cmd.c
 * @brief   JSON command parser - receives JSON, executes command, returns JSON via UART1
 */

#include "bsp_cmd.h"
#include "bsp_relay.h"
#include "bsp_uart.h"
#include "bsp_flash.h"
#include "cJSON.h"
#include <string.h>
#include <stdio.h>

/**
 * @brief  Send JSON response via UART1
 */
static void send_response(cJSON *root)
{
    char *json_str = cJSON_PrintUnformatted(root);
    if (json_str != NULL)
    {
        BSP_UART1_SendString(json_str);
        BSP_UART1_SendString("\r\n");
        cJSON_free(json_str);
    }
    cJSON_Delete(root);
}

/**
 * @brief  Make a simple {"status":"ok","msg":"xxx"} response
 */
static void respond_ok(const char *msg)
{
    cJSON *root = cJSON_CreateObject();
    cJSON_AddStringToObject(root, "status", "ok");
    cJSON_AddStringToObject(root, "msg", msg);
    send_response(root);
}

/**
 * @brief  Make a {"status":"error","msg":"xxx"} response
 */
static void respond_error(const char *msg)
{
    cJSON *root = cJSON_CreateObject();
    cJSON_AddStringToObject(root, "status", "error");
    cJSON_AddStringToObject(root, "msg", msg);
    send_response(root);
}

/**
 * @brief  Process JSON command
 *
 *  Supported commands:
 *    {"cmd":"status"}
 *    {"cmd":"fan_mode","value":"auto"}       or "manual"
 *    {"cmd":"fan_threshold","value":30.0}
 *    {"cmd":"fan","value":"on"}              or "off"
 *    {"cmd":"light","value":"on"}            or "off"
 *    {"cmd":"reset"}
 */
void BSP_Cmd_ProcessJSON(const uint8_t *buf, uint16_t len)
{
    cJSON *root = NULL;
    cJSON *cmd_item = NULL;
    cJSON *val_item = NULL;

    if (buf == NULL || len == 0)
    {
        respond_error("empty input");
        return;
    }

    /* Ensure null termination and strip non-JSON prefix/suffix */
    char tmp[256];
    if (len >= sizeof(tmp))
        len = sizeof(tmp) - 1;
    memcpy(tmp, buf, len);
    tmp[len] = '\0';

    /* Find the first '{' to skip any MQTT topic prefix */
    char *json_start = strchr(tmp, '{');
    if (json_start == NULL)
    {
        respond_error("no json found");
        return;
    }

    /* Find matching '}' to trim trailing garbage */
    char *json_end = json_start;
    int depth = 0;
    while (*json_end != '\0')
    {
        if (*json_end == '{') depth++;
        else if (*json_end == '}') depth--;
        if (depth == 0) { json_end++; break; }
        json_end++;
    }
    *json_end = '\0';

    /* Parse JSON */
    root = cJSON_Parse(json_start);
    if (root == NULL)
    {
        respond_error("invalid json");
        return;
    }

    /* Get "cmd" field */
    cmd_item = cJSON_GetObjectItemCaseSensitive(root, "cmd");
    if (cmd_item == NULL || !cJSON_IsString(cmd_item))
    {
        respond_error("missing cmd field");
        cJSON_Delete(root);
        return;
    }

    const char *cmd = cmd_item->valuestring;

    /* Get "value" field (optional) */
    val_item = cJSON_GetObjectItemCaseSensitive(root, "value");

    /* --- STATUS --- */
    if (strcasecmp(cmd, "status") == 0)
    {
        system_state_t state;
        BSP_System_GetState(&state);

        cJSON *resp = cJSON_CreateObject();
        cJSON_AddStringToObject(resp, "status", "ok");

        cJSON *data = cJSON_CreateObject();
        cJSON_AddStringToObject(data, "fan_mode", state.fan_mode == FAN_MODE_AUTO ? "auto" : "manual");
        cJSON_AddNumberToObject(data, "fan_threshold", state.fan_threshold);
        cJSON_AddStringToObject(data, "fan", state.fan_state ? "on" : "off");
        cJSON_AddStringToObject(data, "light", state.light_state ? "on" : "off");
        cJSON_AddItemToObject(resp, "data", data);

        send_response(resp);
    }
    /* --- FAN MODE --- */
    else if (strcasecmp(cmd, "fan_mode") == 0)
    {
        if (val_item == NULL || !cJSON_IsString(val_item))
        {
            respond_error("missing value");
        }
        else
        {
            const char *val = val_item->valuestring;
            if (strcasecmp(val, "auto") == 0)
            {
                BSP_FAN_SetMode(FAN_MODE_AUTO);
                respond_ok("fan mode set to auto");
            }
            else if (strcasecmp(val, "manual") == 0)
            {
                BSP_FAN_SetMode(FAN_MODE_MANUAL);
                respond_ok("fan mode set to manual");
            }
            else
            {
                respond_error("invalid fan_mode value");
            }
        }
    }
    /* --- FAN THRESHOLD --- */
    else if (strcasecmp(cmd, "fan_threshold") == 0)
    {
        if (val_item == NULL || !cJSON_IsNumber(val_item))
        {
            respond_error("missing or invalid value");
        }
        else
        {
            float thresh = (float)val_item->valuedouble;
            if (thresh > 0 && thresh < 100)
            {
                BSP_FAN_SetThreshold(thresh);
                respond_ok("fan threshold updated");
            }
            else
            {
                respond_error("threshold out of range");
            }
        }
    }
    /* --- FAN ON/OFF --- */
    else if (strcasecmp(cmd, "fan") == 0)
    {
        if (val_item == NULL || !cJSON_IsString(val_item))
        {
            respond_error("missing value");
        }
        else
        {
            const char *val = val_item->valuestring;
            if (strcasecmp(val, "on") == 0)
            {
                BSP_FAN_SetMode(FAN_MODE_MANUAL);
                BSP_FAN_On();
                respond_ok("fan on");
            }
            else if (strcasecmp(val, "off") == 0)
            {
                BSP_FAN_SetMode(FAN_MODE_MANUAL);
                BSP_FAN_Off();
                respond_ok("fan off");
            }
            else
            {
                respond_error("invalid fan value");
            }
        }
    }
    /* --- LIGHT ON/OFF --- */
    else if (strcasecmp(cmd, "light") == 0)
    {
        if (val_item == NULL || !cJSON_IsString(val_item))
        {
            respond_error("missing value");
        }
        else
        {
            const char *val = val_item->valuestring;
            if (strcasecmp(val, "on") == 0)
            {
                BSP_LIGHT_On();
                respond_ok("light on");
            }
            else if (strcasecmp(val, "off") == 0)
            {
                BSP_LIGHT_Off();
                respond_ok("light off");
            }
            else
            {
                respond_error("invalid light value");
            }
        }
    }
    /* --- RESET --- */
    else if (strcasecmp(cmd, "reset") == 0)
    {
        BSP_Flash_ResetSettings();
        respond_ok("settings reset to default");
    }
    /* --- UNKNOWN --- */
    else
    {
        respond_error("unknown command");
    }

    cJSON_Delete(root);
}