#!/usr/bin/env bash

set -Eeuo pipefail

revision=""
force=false
skip_build=false

while (($# > 0)); do
    case "$1" in
        --revision)
            if (($# < 2)); then
                echo "--revision requires a full Git commit SHA." >&2
                exit 2
            fi
            revision="$2"
            shift 2
            ;;
        --force)
            force=true
            shift
            ;;
        --skip-build)
            skip_build=true
            shift
            ;;
        *)
            echo "Unknown argument: $1" >&2
            exit 2
            ;;
    esac
done

command -v git >/dev/null 2>&1 || {
    echo "Git was not found on PATH." >&2
    exit 1
}

script_directory="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd -P)"
root_directory="$(cd -- "$script_directory/.." && pwd -P)"
module_relative_path="cmvr-iot-api/cmvr-iot-edge/cmvr-iot-grpc-lib"
module_directory="$root_directory/$module_relative_path"
pom_path="$module_directory/pom.xml"
proto_relative_path="$module_relative_path/src/main/proto/cmvr"
proto_directory="$root_directory/$proto_relative_path"
checkout_directory="$module_directory/target/cmvr-es"

read_pom_property() {
    local name="$1"
    local escaped_name="${name//./\\.}"
    local value
    value="$(sed -n "s:.*<$escaped_name>\([^<]*\)</$escaped_name>.*:\1:p" "$pom_path" | head -n 1)"
    if [[ -z "$value" ]]; then
        echo "Cannot find Maven property '$name'." >&2
        exit 1
    fi
    printf '%s' "$value"
}

repository="$(read_pom_property 'cmvr.es.repository')"
branch="$(read_pom_property 'cmvr.es.proto.branch')"

local_proto_changes="$(git -C "$root_directory" status --porcelain -- "$proto_relative_path")"
if [[ -n "$local_proto_changes" && "$force" != true ]]; then
    echo "Local proto files have uncommitted changes:" >&2
    echo "$local_proto_changes" >&2
    echo "Commit/stash them first, or rerun with --force." >&2
    exit 1
fi

if [[ -z "$revision" ]]; then
    echo "Looking up the latest '$branch' revision..."
    remote_line="$(git ls-remote "$repository" "refs/heads/$branch")"
    if [[ -z "$remote_line" || "$remote_line" == *$'\n'* ]]; then
        echo "Upstream branch '$branch' was not found or was ambiguous." >&2
        exit 1
    fi
    revision="${remote_line%%[[:space:]]*}"
fi

revision="${revision,,}"
if [[ ! "$revision" =~ ^[0-9a-f]{40}$ ]]; then
    echo "Revision must be a full 40-character Git commit SHA: $revision" >&2
    exit 1
fi

mkdir -p -- "$(dirname -- "$checkout_directory")"
if [[ -d "$checkout_directory/.git" ]]; then
    echo "Refreshing the existing upstream checkout..."
    git -C "$checkout_directory" remote set-url origin "$repository"
    git -C "$checkout_directory" fetch --filter=blob:none origin "$branch"
else
    if [[ -e "$checkout_directory" ]]; then
        checkout_parent="$(cd -- "$(dirname -- "$checkout_directory")" && pwd -P)"
        expected_parent="$(cd -- "$module_directory/target" && pwd -P)"
        if [[ "$checkout_parent" != "$expected_parent" || "$(basename -- "$checkout_directory")" != "cmvr-es" ]]; then
            echo "Refusing to replace unexpected checkout path: $checkout_directory" >&2
            exit 1
        fi
        rm -rf -- "$checkout_directory"
    fi

    echo "Cloning the upstream proto repository..."
    git clone --filter=blob:none --sparse --single-branch \
        --branch "$branch" "$repository" "$checkout_directory"
fi

git -C "$checkout_directory" sparse-checkout set \
    protos/cmvr/api protos/cmvr/msgs protos/cmvr/common
git -C "$checkout_directory" checkout --detach "$revision"

actual_revision="$(git -C "$checkout_directory" rev-parse HEAD)"
if [[ "$actual_revision" != "$revision" ]]; then
    echo "Expected revision $revision, but checked out $actual_revision." >&2
    exit 1
fi

echo "Syncing proto files from revision $revision..."
for group in api msgs common; do
    source_directory="$checkout_directory/protos/cmvr/$group"
    destination_directory="$proto_directory/$group"
    if [[ ! -d "$source_directory" ]]; then
        echo "Upstream proto directory does not exist: $source_directory" >&2
        exit 1
    fi

    mkdir -p -- "$destination_directory"
    find "$destination_directory" -type f -name '*.proto' -delete
    while IFS= read -r -d '' source_file; do
        relative_path="${source_file#"$source_directory/"}"
        destination_file="$destination_directory/$relative_path"
        mkdir -p -- "$(dirname -- "$destination_file")"
        cp -- "$source_file" "$destination_file"
    done < <(find "$source_directory" -type f -name '*.proto' -print0)
done

sed -i \
    "s#<cmvr\.es\.proto\.revision>[^<]*</cmvr\.es\.proto\.revision>#<cmvr.es.proto.revision>$revision</cmvr.es.proto.revision>#" \
    "$pom_path"

updated_revision="$(read_pom_property 'cmvr.es.proto.revision')"
if [[ "$updated_revision" != "$revision" ]]; then
    echo "Unable to update cmvr.es.proto.revision in pom.xml." >&2
    exit 1
fi

echo
echo "Updated files:"
git -C "$root_directory" status --short -- \
    "$proto_relative_path" "$module_relative_path/pom.xml"

if [[ "$skip_build" != true ]]; then
    command -v mvn >/dev/null 2>&1 || {
        echo "Maven was not found on PATH. Proto files were updated, but the verification build was not run." >&2
        exit 1
    }

    echo
    echo "Running the gRPC verification build..."
    (
        cd -- "$root_directory"
        mvn -pl cmvr-iot-api/cmvr-iot-edge/cmvr-iot-grpc-client \
            -am clean package -DskipTests
    )
fi

echo
echo "CMVR-ES proto update completed: $revision"
echo "Review and commit the proto files and pom.xml together."