#!/usr/bin/env sh

set -eu

SCRIPT_DIR="$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)"
UPSTREAM_DIR="$SCRIPT_DIR/upstream"
OUT_DIR="$SCRIPT_DIR/../../pb"
MODULE_IMPORT="git.maze.io/go/ham/protocol/meshtastic/pb"

if ! command -v protoc >/dev/null 2>&1; then
	echo "error: protoc not found in PATH" >&2
	exit 1
fi

GOBIN_DIR="$(go env GOPATH 2>/dev/null)/bin"
if [ -n "$GOBIN_DIR" ] && [ -d "$GOBIN_DIR" ]; then
	PATH="$GOBIN_DIR:$PATH"
	export PATH
fi

if ! command -v protoc-gen-go >/dev/null 2>&1; then
	echo "error: protoc-gen-go not found in PATH" >&2
	exit 1
fi

if [ ! -d "$UPSTREAM_DIR/meshtastic" ]; then
	echo "error: upstream proto directory not found: $UPSTREAM_DIR/meshtastic" >&2
	exit 1
fi

PROTO_FILES=$(find "$UPSTREAM_DIR" -type f -name '*.proto' | LC_ALL=C sort)

if [ -z "$PROTO_FILES" ]; then
	echo "error: no proto files found in $UPSTREAM_DIR" >&2
	exit 1
fi

M_OPTS=""
for file in $PROTO_FILES; do
	rel="${file#$UPSTREAM_DIR/}"
	M_OPTS="$M_OPTS --go_opt=M$rel=$MODULE_IMPORT"
done

rm -rf "$OUT_DIR"/*.pb.go
mkdir -p "$OUT_DIR"

# shellcheck disable=SC2086
protoc \
	-I "$UPSTREAM_DIR" \
	--go_out="$OUT_DIR" \
	--go_opt=paths=source_relative \
	$M_OPTS \
	$(printf '%s ' $PROTO_FILES)

# Flatten meshtastic/ subdirectory into pb/ root
if [ -d "$OUT_DIR/meshtastic" ]; then
	mv "$OUT_DIR/meshtastic"/*.pb.go "$OUT_DIR/"
	rmdir "$OUT_DIR/meshtastic"
fi

# Fix package name from 'generated' to 'pb'
for pbfile in "$OUT_DIR"/*.pb.go; do
	if [ -f "$pbfile" ]; then
		sed -i.bak 's/^package generated$/package pb/' "$pbfile"
		rm -f "$pbfile.bak"
	fi
done

# Convert JSON tags from snake_case to camelCase
# This converts json:"field_name,omitempty" to json:"fieldName,omitempty"
for pbfile in "$OUT_DIR"/*.pb.go; do
	if [ -f "$pbfile" ]; then
		perl -i -pe 's/json:"([a-z0-9_]+)((?:,[^"]*)?)"/my ($f, $r) = ($1, $2); $f =~ s#_([a-z0-9])#uc($1)#ge; "json:\"$f$r\""/gex' "$pbfile"
	fi
done