potion_party_leds/main/parse.c

#include "shared.h"
#include "leds.h"
#include <string.h>
#include <esp_http_server.h>

// parse a URL query as described in api-doc.txt into a valid Gradient struct.
// If the gradient is invalid, the is_ok flag on the return value will be set, and error will be set to a message describing the problem.
Result parse_leds_query(char* query_string, size_t query_size) {
    char query_value[16];
    char query_key[3];
    Gradient* gradient = malloc(sizeof(Gradient));

    // Fetch the &l length parameter.
    // Interpret as a positive integer number of points on the gradient.
    if(httpd_query_key_value(query_string, "l", query_value, sizeof(query_value)) == ESP_OK) {
        gradient->points_len = max(0, atoi(query_value));
    } else {
        free(gradient);
        return PARSE_ERR("ERROR: Failed to find length parameter &l");
    }

    // Get the &d 'duration' parameter from the query.
    // Interpreted as a floating point number of seconds before returning to default state.
    if(httpd_query_key_value(query_string, "d", query_value, sizeof(query_value)) == ESP_OK) {
        gradient->duration = atof(query_string);
    } else {
        gradient->duration = 0;
    }

    LOGLN("Reading %zu points of gradient query:", gradient->points_len);
    LOGLN("duration: %f", gradient->duration);

    // Get the gradient point components for every point that was promised by the &l parameter
    for(int point = 0; point < gradient->points_len; ++point) {
        // Get the r, g, and b components as 8 bit integers
        sprintf(query_key, "r%d", point);
        if(httpd_query_key_value(query_string, query_key, query_value, sizeof(query_size)) == ESP_OK) {
            gradient->points[point].led.components.red = atoi(query_value);
        } else {
            free(gradient);
            return PARSE_ERR("ERROR: Point missing red component &r.");
        }
        sprintf(query_key, "g%d", point);
        if(httpd_query_key_value(query_string, query_key, query_value, sizeof(query_size)) == ESP_OK) {
            gradient->points[point].led.components.green = atoi(query_value);
        } else {
            free(gradient);
            return PARSE_ERR("ERROR: Point missing green component &g.");
        }
        sprintf(query_key, "b%d", point);
        if(httpd_query_key_value(query_string, query_key, query_value, sizeof(query_value)) == ESP_OK) {
            gradient->points[point].led.components.blue = atoi(query_value);
        } else {
            free(gradient);
            return PARSE_ERR("ERROR: Point missing blue component &b.");
        }
        // Get the global variable, passed as alpha. Limited to 0-32 (a 5bit unsigned int)
        // Make sure the most significant 3 bits are all ones
        sprintf(query_key, "a%d", point);
        if(httpd_query_key_value(query_string, query_key, query_value, sizeof(query_value)) == ESP_OK) {
            gradient->points[point].led.components.global = GLOBAL((uint8_t)atoi(query_value));
        } else {
            free(gradient);
            return PARSE_ERR("ERROR: Point missing alpha component &a.");
        }
        // Get the time of the gradient as a number ranging from 0 - 120.
        // Interpreted as an integer offset from the first led to the last
        sprintf(query_key, "t%d", point);
        if(httpd_query_key_value(query_string, query_key, query_value, sizeof(query_value)) == ESP_OK) {
            gradient->points[point].offset = clamp(0, 120, atoi(query_value));
        } else {
            free(gradient);
            return PARSE_ERR("ERROR: Point missing time component &t.");
        }
        // Get the movement variable &m.
        // Interpreted as an integer number from -1 to +1
        sprintf(query_key, "m%d", point);
        if(gradient->duration > 0 && httpd_query_key_value(query_string, query_key, query_value, sizeof(query_value)) == ESP_OK) {
            gradient->points[point].movement = clamp(-1, +1, atoi(query_value));
        } else {
            gradient->points[point].movement = 0;
        }

        // Log fetched fields
        LOGLN("led[%d]:", point);
        LOGLN("    r %d", gradient->points[point].led.components.red);
        LOGLN("    g %d", gradient->points[point].led.components.green);
        LOGLN("    b %d", gradient->points[point].led.components.blue);
        LOGLN("    global %d", gradient->points[point].led.components.global >> 3);
        // may show up as a compile error on modern computers,
        // x86_64 size_t is usually an unsigned long int, on the ESP8266 it is an unsigned int
        LOGLN("    t %u", gradient->points[point].offset);
    }

    return PARSE_OK(gradient);
}