FindMy: Refactors and improvements

- state handled reparately, decoupled from app
- better apple/samsung/unknown parsing and handling
- improve error handling
- add url to manifest + up stack size just in case

applications/system/findmy/findmy_state.c

@@ -0,0 +1,61 @@
+#include "findmy_state.h"
+
+#include <string.h>
+#include <stddef.h>
+#include <furi_hal_bt.h>
+
+bool findmy_state_load(FindMyState* out_state) {
+    FindMyState state;
+
+    // Set default values
+    state.beacon_active = false;
+    state.broadcast_interval = 5;
+    state.transmit_power = 6;
+    state.config.min_adv_interval_ms = state.broadcast_interval * 1000; // Converting s to ms
+    state.config.max_adv_interval_ms = (state.broadcast_interval * 1000) + 150;
+    state.config.adv_channel_map = GapAdvChannelMapAll;
+    state.config.adv_power_level = GapAdvPowerLevel_0dBm + state.transmit_power;
+    state.config.address_type = GapAddressTypePublic;
+
+    // Set default mac
+    uint8_t default_mac[EXTRA_BEACON_MAC_ADDR_SIZE] = {0x66, 0x55, 0x44, 0x33, 0x22, 0x11};
+    memcpy(state.mac, default_mac, sizeof(state.mac));
+    memcpy(state.config.address, default_mac, sizeof(state.config.address));
+
+    // Set default empty AirTag data
+    uint8_t* data = state.data;
+    *data++ = 0x1E; // Length
+    *data++ = 0xFF; // Manufacturer Specific Data
+    *data++ = 0x4C; // Company ID (Apple, Inc.)
+    *data++ = 0x00; // ...
+    *data++ = 0x12; // Type (FindMy)
+    *data++ = 0x19; // Length
+    *data++ = 0x00; // Status
+    // Placeholder Empty Public Key without the MAC address
+    for(size_t i = 0; i < 22; ++i) {
+        *data++ = 0x00;
+    }
+    *data++ = 0x00; // First 2 bits are the version, the rest is the battery level
+    *data++ = 0x00; // Hint (0x00)
+
+    // Copy to caller state before popping stack
+    memcpy(out_state, &state, sizeof(state));
+
+    // Return if active, can be used to start after loading in an if statement
+    return state.beacon_active;
+}
+
+void findmy_state_apply(FindMyState* state) {
+    // Stop any running beacon
+    if(furi_hal_bt_extra_beacon_is_active()) {
+        furi_check(furi_hal_bt_extra_beacon_stop());
+    }
+
+    furi_check(furi_hal_bt_extra_beacon_set_config(&state->config));
+
+    furi_check(furi_hal_bt_extra_beacon_set_data(state->data, sizeof(state->data)));
+
+    if(state->beacon_active) {
+        furi_check(furi_hal_bt_extra_beacon_start());
+    }
+}