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

# Usage:
#   ./build.sh [--debug] <dll_path> <output_path>
#
# Examples:
#   ./build.sh /path/to/agent.dll /tmp/output
#   ./build.sh --debug /path/to/agent.dll /tmp/output

MODE="release"
DLL_PATH=""
OUTPUT_PATH=""

readonly LINKER="./dist/link"
readonly SPEC_FILE="spec/loader.spec"
readonly STUB_HEADER="stub/pic.h"

readonly RELEASE_BIN_FILENAME="out.x64.bin"
readonly DEBUG_BIN_FILENAME="out.x64.debug.bin"
readonly RULES_FILENAME="rules.yar"
readonly STUB_FILENAME="stub.exe"

usage() {
    cat <<'EOF'
        Usage:
        ./build.sh [--debug] <dll_path> <output_path>

        Arguments:
        dll_path               Path to the DLL to link
        output_path            Directory where output files will be written

        Options:
        --debug                Build the debug version instead of the release version
        -h, --help             Show this help message
EOF
}

log() {
    printf '[*] %s\n' "$*"
}

error() {
    printf '[!] %s\n' "$*" >&2
}

require_command() {
    local cmd="$1"

    if ! command -v "$cmd" >/dev/null 2>&1; then
        error "Command not found: $cmd"
        exit 1
    fi
}

require_file() {
    local file_path="$1"

    if [[ ! -f "$file_path" ]]; then
        error "File not found: $file_path"
        exit 1
    fi
}

ensure_directory() {
    local dir_path="$1"
    mkdir -p "$dir_path"
}

parse_args() {
    while [[ $# -gt 0 ]]; do
        case "$1" in
            --debug)
                MODE="debug"
                shift
                ;;
            -h|--help)
                usage
                exit 0
                ;;
            --)
                shift
                break
                ;;
            -*)
                error "Unknown option: $1"
                usage
                exit 1
                ;;
            *)
                if [[ -z "$DLL_PATH" ]]; then
                    DLL_PATH="$1"
                elif [[ -z "$OUTPUT_PATH" ]]; then
                    OUTPUT_PATH="$1"
                else
                    error "Unexpected argument: $1"
                    usage
                    exit 1
                fi
                shift
                ;;
        esac
    done

    if [[ -z "$DLL_PATH" || -z "$OUTPUT_PATH" ]]; then
        usage
        exit 1
    fi
}

build_release() {
    local release_bin_output
    local rules_output
    local stub_output

    release_bin_output="$OUTPUT_PATH/$RELEASE_BIN_FILENAME"
    rules_output="$OUTPUT_PATH/$RULES_FILENAME"

    log "Building release version"

    ensure_directory "$OUTPUT_PATH"

    make -s clean
    make -s release

    "$LINKER" "$SPEC_FILE" "$DLL_PATH" "$release_bin_output" -g "$rules_output" -r %root=./ %MODE=release

    xxd -i -n crystal_loader "$release_bin_output" > "$STUB_HEADER"

    make -s stub "STUB_OUTPUT=$OUTPUT_PATH/$STUB_FILENAME"

    log "Release build completed successfully"
}

build_debug() {
    local debug_bin_output

    debug_bin_output="$OUTPUT_PATH/$DEBUG_BIN_FILENAME"

    log "Building debug version"

    ensure_directory "$OUTPUT_PATH"

    make -s clean
    make -s debug

    "$LINKER" "$SPEC_FILE" "$DLL_PATH" "$debug_bin_output" -r %root=./ %MODE=debug

    log "Debug build completed successfully"
}

main() {
    parse_args "$@"

    require_command make
    require_command xxd

    require_file "$DLL_PATH"
    require_file "$LINKER"
    require_file "$SPEC_FILE"

    case "$MODE" in
        release)
            build_release
            ;;
        debug)
            build_debug
            ;;
        *)
            error "Invalid mode: $MODE"
            exit 1
            ;;
    esac
}

main "$@"