PATH_TO_IOS_REPO is environment variable (#52)

* PATH_TO_IOS_REPO is environment variable

* [#37] Cleanup

* [#37] Code formatting

scripts/ios/create_ios_universal.sh

@@ -1,19 +1,29 @@
 #!/bin/bash
 
-# Requirements: 
+# Requirements:
 # 1. https://github.com/getditto/rust-bitcode
 # 2. libtool
 # See https://github.com/Co-Epi/app-backend-rust/wiki/Building-library-for-iOS
 
+if test -z "$PATH_TO_IOS_REPO"; then
+    echo "Environment variable PATH_TO_IOS_REPO not set. Please set the variable using: 'export PATH_TO_IOS_REPO=<your_path_here>'"
+    exit 1
+else
+    echo "\$PATH_TO_IOS_REPO is $PATH_TO_IOS_REPO"
+    if [ -d "$PATH_TO_IOS_REPO" ]; then
+        echo "Will copy files to ${PATH_TO_IOS_REPO}..."
+    else
+        echo "Error: ${PATH_TO_IOS_REPO} not found. Make sure that you have checked out the iOS project and that the path specified in PATH_TO_IOS_REPO environment variable is correct"
+        exit 1
+    fi
+fi
+
 RUSTFLAGS="-Z embed-bitcode" cargo +ios-arm64 build --target aarch64-apple-ios --release --lib
 cargo build --target=x86_64-apple-ios --release
 
 libtool -static -o ./target/CoEpiCore ./target/aarch64-apple-ios/release/libcoepi_core.a ./target/x86_64-apple-ios/release/libcoepi_core.a
 
 # Overwrite library in iOS app (downloaded with Carthage) with local build.
-
-PATH_TO_IOS_REPO="<insert path>"
-
 PATH_TO_CARTHAGE_FRAMEWORK=$PATH_TO_IOS_REPO/Carthage/Build/iOS/CoEpiCore.framework
 cp ./target/CoEpiCore $PATH_TO_CARTHAGE_FRAMEWORK/Versions/A/
 cp ./src/ios/c_headers/coepicore.h $PATH_TO_CARTHAGE_FRAMEWORK/Versions/A/Headers/