#!/usr/bin/env bash
set -euo pipefail

cd "$(dirname "$0")"

cache_dir=${CNC_SIM_PREFLIGHT_CACHE_DIR:-}
check_args=("$@")
if [[ "${1:-}" == "--cache-dir" ]]; then
    if [[ "$#" -lt 2 ]]; then
        echo "missing --cache-dir value" >&2
        exit 1
    fi
    cache_dir=$2
    shift 2
    check_args=("$@")
fi

linuxcnc_root=${LINUXCNC_ROOT:-../linuxcnc}
manifest=${1:-linuxcnc-kinematics-source-files.txt}

if [[ -z "$cache_dir" ]]; then
    LINUXCNC_ROOT="$linuxcnc_root" ./check-linuxcnc-switchkins-remap-table.sh "${check_args[@]}"
    exit 0
fi
if [[ "$cache_dir" =~ [[:space:]] ]]; then
    echo "CNC_SIM_PREFLIGHT_CACHE_DIR must not contain whitespace: $cache_dir" >&2
    exit 1
fi

mkdir -p "$cache_dir"
cache_dir=$(cd "$cache_dir" && pwd)
if [[ "$cache_dir" == "/" ]]; then
    echo "CNC_SIM_PREFLIGHT_CACHE_DIR must not be the filesystem root" >&2
    exit 1
fi
exec 8>"$cache_dir/check-linuxcnc-switchkins-remap-table.lock"
flock 8

if [[ ! -d "$linuxcnc_root" || ! -f "$manifest" ]]; then
    LINUXCNC_ROOT="$linuxcnc_root" ./check-linuxcnc-switchkins-remap-table.sh "${check_args[@]}"
    exit 0
fi
linuxcnc_root=$(cd "$linuxcnc_root" && pwd)
manifest_path=$(cd "$(dirname "$manifest")" && pwd)/$(basename "$manifest")
manifest_key=$(printf '%s' "$manifest_path" | sha256sum | awk '{ print $1 }')
args_key=$(
    {
        printf 'ARGS='
        printf ' %q' "${check_args[@]}"
        printf '\n'
    } | sha256sum | awk '{ print $1 }'
)
cache_file="$cache_dir/check-linuxcnc-switchkins-remap-table.${manifest_key}.${args_key}.signature"
next_signature=$(mktemp "$cache_file.next.XXXXXX")

write_manifest_source_stats() {
    local source_path
    while IFS=: read -r group path note extra; do
        case "$group" in
            ""|\#*)
                continue
                ;;
        esac
        [[ -z "${path:-}" ]] && continue
        source_path="$linuxcnc_root/$path"
        if [[ ! -f "$source_path" ]]; then
            return 1
        fi
        stat -c 'SOURCE=%n:%s:%y' "$source_path"
    done < "$manifest_path"
}

write_project_output_hashes() {
    local project_output
    for project_output in \
        core/src/linuxcnc_switchkins_remap_table.inc \
        core/tests/linuxcnc_switchkins_remap_config_cases.inc \
        web/public/linuxcnc_switchkins_remap_config_cases.json; do
        [[ -f "$project_output" ]] || return 1
        sha256sum "$project_output"
    done
}

if ! {
    printf 'CHECK_SCRIPT='
    sha256sum check-linuxcnc-switchkins-remap-table.sh
    printf 'GENERATOR_SCRIPT='
    sha256sum generate-linuxcnc-switchkins-remap-table.sh
    printf 'LINUXCNC_ROOT=%s\n' "$linuxcnc_root"
    printf 'ARGS='
    printf ' %q' "${check_args[@]}"
    printf '\n'
    printf 'MANIFEST_PATH=%s\n' "$manifest_path"
    printf 'MANIFEST='
    sha256sum "$manifest_path"
    write_manifest_source_stats
    printf 'PROJECT_OUTPUTS:\n'
    write_project_output_hashes
} > "$next_signature"; then
    rm -f "$next_signature"
    LINUXCNC_ROOT="$linuxcnc_root" ./check-linuxcnc-switchkins-remap-table.sh "${check_args[@]}"
    exit 0
fi

if [[ -f "$cache_file" ]] && cmp -s "$cache_file" "$next_signature"; then
    rm -f "$next_signature"
    exit 0
fi

LINUXCNC_ROOT="$linuxcnc_root" ./check-linuxcnc-switchkins-remap-table.sh "${check_args[@]}"
mv "$next_signature" "$cache_file"