#!/usr/bin/env bash
#
# Regenerates the gRPC C# files from sitestream.proto.
#
# Background: protoc (linux/arm64) segfaults inside our Docker build container
# (Grpc.Tools 2.71.0). As a workaround the generated Sitestream.cs +
# SitestreamGrpc.cs are checked into src/ScadaLink.Communication/SiteStreamGrpc/
# and the Protobuf ItemGroup in the .csproj is commented out — Docker just
# compiles the checked-in C# files.
#
# Run this script ON YOUR DEV MACHINE whenever Protos/sitestream.proto changes:
#
#   1. Temporarily uncomments the Protobuf ItemGroup so Grpc.Tools runs.
#   2. dotnet build (regen writes fresh files to obj/).
#   3. Copies the regenerated files back into SiteStreamGrpc/.
#   4. Re-comments the Protobuf ItemGroup so Docker builds stay safe.
#
# Once we move to a Dockerfile base image that ships a working linux/arm64
# protoc, this script can be retired and Docker can regen the proto on every
# build like every other normal .NET project.

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
COMM_DIR="$REPO_ROOT/src/ScadaLink.Communication"
CSPROJ="$COMM_DIR/ScadaLink.Communication.csproj"
GEN_DIR="$COMM_DIR/SiteStreamGrpc"

echo "=== Regenerating gRPC files from sitestream.proto ==="

if [[ ! -f "$CSPROJ" ]]; then
  echo "ERROR: csproj not found at $CSPROJ" >&2
  exit 1
fi

# Backup so we can always restore the comment state on failure.
BACKUP="$(mktemp)"
cp "$CSPROJ" "$BACKUP"
trap 'cp "$BACKUP" "$CSPROJ"; rm -f "$BACKUP"; echo "Restored csproj from backup."' ERR

# 1. Uncomment the Protobuf ItemGroup (strip the surrounding <!-- ... --> wrapper).
python3 - <<PY
import re, pathlib
p = pathlib.Path("$CSPROJ")
src = p.read_text()
# Find the commented Protobuf block and unwrap it.
new = re.sub(
    r"<!--\s*\n(\s*<ItemGroup>\s*\n\s*<Protobuf [^>]*/>\s*\n\s*</ItemGroup>)\s*\n\s*-->",
    r"\1",
    src,
    count=1,
)
if new == src:
    raise SystemExit("Couldn't find commented Protobuf ItemGroup to enable.")
p.write_text(new)
PY

# 2. Delete the stale files so any failure to regen is obvious.
rm -f "$GEN_DIR/Sitestream.cs" "$GEN_DIR/SitestreamGrpc.cs"

# 3. Regenerate by building.
echo "Building Communication project (regen)..."
dotnet build "$CSPROJ" --nologo -v minimal | tail -5

# 4. Copy generated files back into the source tree.
mkdir -p "$GEN_DIR"
cp "$COMM_DIR/obj/Debug/net10.0/Protos/Sitestream.cs" "$GEN_DIR/Sitestream.cs"
cp "$COMM_DIR/obj/Debug/net10.0/Protos/SitestreamGrpc.cs" "$GEN_DIR/SitestreamGrpc.cs"
echo "Copied regenerated files to $GEN_DIR/"

# 5. Re-comment the Protobuf ItemGroup so Docker builds keep working.
python3 - <<PY
import re, pathlib
p = pathlib.Path("$CSPROJ")
src = p.read_text()
new = re.sub(
    r"(\s*<ItemGroup>\s*\n\s*<Protobuf [^>]*/>\s*\n\s*</ItemGroup>)",
    r"\n  <!--\1\n  -->",
    src,
    count=1,
)
p.write_text(new)
PY

rm -f "$BACKUP"
trap - ERR

echo ""
echo "Done. Review and commit:"
echo "  git diff src/ScadaLink.Communication/Protos/sitestream.proto"
echo "  git diff src/ScadaLink.Communication/SiteStreamGrpc/"