led-sync-studio/firmware/src/protocol.cpp

#include "protocol.h"
#include <ArduinoJson.h>

// ---------------------------------------------------------------------------
// parseCommand — deserialize raw JSON bytes into a LedCommand struct
//
// Protocol spec (D-05 through D-08):
//   - Every command must include {"v":1, ...} version field
//   - zone field is mandatory ("schrank", "wand", "all") — except STATUS
//   - Either "animation" field or "cmd" field must be present
//   - Unknown extra fields are silently ignored (ArduinoJson default)
//   - Errors: logged to Serial, return false, no UDP response sent
// ---------------------------------------------------------------------------
bool parseCommand(const uint8_t* data, size_t len, LedCommand& out) {
    JsonDocument doc;
    DeserializationError err = deserializeJson(doc, data, len);

    if (err) {
        Serial.print("JSON parse error: ");
        Serial.println(err.c_str());
        return false;
    }

    // Check protocol version (D-08)
    if ((doc["v"] | 0) != 1) {
        Serial.println("Unknown protocol version — expected v:1");
        return false;
    }

    // Determine zone (mandatory for all commands except STATUS)
    const char* zoneStr = doc["zone"] | "";
    if (strcmp(zoneStr, "schrank") == 0) {
        out.zone = Zone::SCHRANK;
    } else if (strcmp(zoneStr, "wand") == 0) {
        out.zone = Zone::WAND;
    } else if (strcmp(zoneStr, "all") == 0) {
        out.zone = Zone::ALL;
    } else {
        // Zone may be absent for STATUS commands — handle below
        out.zone = Zone::UNKNOWN;
    }

    // Determine command type from "cmd" field or "animation" field (D-06)
    const char* cmdStr = doc["cmd"] | "";

    if (strcmp(cmdStr, "stop") == 0) {
        // STOP command — zone required
        if (out.zone == Zone::UNKNOWN) {
            Serial.println("STOP command missing valid zone field");
            return false;
        }
        out.type = CmdType::STOP;
        return true;
    }

    if (strcmp(cmdStr, "brightness") == 0) {
        // BRIGHTNESS command — zone required, value 0-60 (D-09)
        if (out.zone == Zone::UNKNOWN) {
            Serial.println("BRIGHTNESS command missing valid zone field");
            return false;
        }
        out.type = CmdType::BRIGHTNESS;
        uint8_t val = doc["value"] | 40;
        // Clamp to firmware-enforced max (D-09: max 60)
        out.brightness = (val > 60) ? 60 : val;
        return true;
    }

    if (strcmp(cmdStr, "status") == 0) {
        // STATUS command — zone not required, sender IP/port already set by caller
        out.type = CmdType::STATUS;
        out.zone = Zone::ALL; // Status responds for all zones
        return true;
    }

    // Check for ANIMATION command (presence of "animation" field)
    const char* animStr = doc["animation"] | "";
    if (strlen(animStr) > 0) {
        // Animation command — zone required (D-05)
        if (out.zone == Zone::UNKNOWN) {
            Serial.println("ANIMATION command missing valid zone field");
            return false;
        }

        out.type = CmdType::ANIMATION;

        // Copy animation name (max 31 chars + null terminator)
        strncpy(out.animName, animStr, 31);
        out.animName[31] = '\0';

        // Parse params object (D-01, D-04)
        JsonObject params = doc["params"];

        // Speed, intensity, direction with sensible defaults
        out.params.speed     = params["speed"]     | 0.5f;
        out.params.intensity = params["intensity"]  | 1.0f;
        out.params.direction = params["direction"]  | (uint8_t)0;

        // Parse colors array — each element is [R, G, B, W]
        JsonArray colorsArr = params["colors"];
        out.params.colorCount = 0;

        if (colorsArr) {
            for (JsonArray color : colorsArr) {
                if (out.params.colorCount >= 8) break;
                uint8_t i = out.params.colorCount;
                out.params.colors[i][0] = color[0] | (uint8_t)0; // R
                out.params.colors[i][1] = color[1] | (uint8_t)0; // G
                out.params.colors[i][2] = color[2] | (uint8_t)0; // B
                out.params.colors[i][3] = color[3] | (uint8_t)0; // W
                out.params.colorCount++;
            }
        }

        // Default to single warm white if no colors provided
        if (out.params.colorCount == 0) {
            out.params.colors[0][0] = 255; // R
            out.params.colors[0][1] = 255; // G
            out.params.colors[0][2] = 255; // B
            out.params.colors[0][3] = 255; // W
            out.params.colorCount   = 1;
        }

        return true;
    }

    // Neither a known "cmd" nor an "animation" field
    Serial.println("No cmd or animation field in command — dropping packet");
    return false;
}

// ---------------------------------------------------------------------------
// buildStatusResponse — serialize current state as JSON for STATUS reply
//
// Returns: {"v":1,"status":"ok","wand":"chase","schrank":"breathe","brightness":40}
// ---------------------------------------------------------------------------
String buildStatusResponse(const char* wandAnim, const char* schrankAnim, uint8_t brightness) {
    JsonDocument doc;
    doc["v"]          = 1;
    doc["status"]     = "ok";
    doc["wand"]       = wandAnim;
    doc["schrank"]    = schrankAnim;
    doc["brightness"] = brightness;

    String out;
    serializeJson(doc, out);
    return out;
}