#!/bin/bash

# Script for building and distributing release artifacts.
# Used by the build-distribute.yml workflow.

set -e

COMMAND="${1}"
shift

case "${COMMAND}" in

  ###############################################################################
  # Generate a version string from the current commit SHA.
  # Outputs:
  #   commit_sha: First 8 characters of GITHUB_SHA.
  #   version: VERSION_PREFIX-commit_sha.
  ###############################################################################
  generate-version)
    # GITHUB_SHA, VERSION_PREFIX, and GITHUB_OUTPUT are set by the GitHub Actions runner.
    # shellcheck disable=SC2154
    COMMIT_SHA="${GITHUB_SHA:0:8}"
    # shellcheck disable=SC2154
    VERSION="${VERSION_PREFIX}-${COMMIT_SHA}"
    # shellcheck disable=SC2154
    echo "commit_sha=${COMMIT_SHA}" >> "${GITHUB_OUTPUT}"
    echo "version=${VERSION}" >> "${GITHUB_OUTPUT}"
    echo "Generated version: ${VERSION} (commit: ${COMMIT_SHA})"
    ;;

  ###############################################################################
  # Create the distribution directory for a given architecture and copy action
  # files into it.
  # Arguments:
  #   1: Architecture name (e.g., X64, ARM64, ARM, X86).
  ###############################################################################
  create-distribute-directory)
    ARCH="${1}"
    DIST_DIR="distribute/${ARCH}"
    mkdir -p "${DIST_DIR}"
    echo "Created distribution directory: ${DIST_DIR}"

    # Copy shell scripts and action definition.
    cp ./*.sh "${DIST_DIR}/"
    cp action.yml "${DIST_DIR}/"
    echo "Copied action files to ${DIST_DIR}"
    ;;

  ###############################################################################
  # Clone the apt-fast repository for bundling with the distribution.
  ###############################################################################
  clone-apt-fast)
    echo "Cloning apt-fast repository..."
    git clone --depth=1 https://github.com/ilikenwf/apt-fast.git apt-fast-repo
    echo "Cloned apt-fast repository to apt-fast-repo/"
    ;;

  ###############################################################################
  # Build the apt_query binary for a target architecture.
  # Arguments:
  #   1: GOOS (e.g., linux).
  #   2: GOARCH (e.g., amd64, arm64, arm, 386).
  #   3: GOARCH variant (e.g., "6" for armv6; empty string if not applicable).
  #   4: Architecture name (e.g., X64, ARM64, ARM, X86).
  ###############################################################################
  build-binary)
    GOOS="${1}"
    GOARCH="${2}"
    GOARCH_VARIANT="${3}"
    ARCH="${4}"

    ARCH_LOWER="$(echo "${ARCH}" | tr '[:upper:]' '[:lower:]')"
    DIST_DIR="distribute/${ARCH}"
    BINARY_NAME="apt_query-${ARCH_LOWER}"
    OUTPUT="${DIST_DIR}/${BINARY_NAME}"

    echo "Building ${BINARY_NAME} for ${GOOS}/${GOARCH} (variant: ${GOARCH_VARIANT:-none})..."
    GOOS="${GOOS}" GOARCH="${GOARCH}" GOARM="${GOARCH_VARIANT}" CGO_ENABLED=0 \
      go build -o "${OUTPUT}" ./src/cmd/apt_query
    chmod +x "${OUTPUT}"
    echo "Binary built: ${OUTPUT} ($(du -h "${OUTPUT}" | cut -f1))"

    # Copy the apt-fast install script if available.
    if [[ -f "apt-fast-repo/apt-fast" ]]; then
      cp apt-fast-repo/apt-fast "${DIST_DIR}/"
      echo "Bundled apt-fast script in ${DIST_DIR}"
    fi
    ;;

  ###############################################################################
  # Generate SHA256 checksums for all files in the distribution directory.
  # Arguments:
  #   1: Architecture name (e.g., X64, ARM64, ARM, X86).
  ###############################################################################
  generate-checksums)
    ARCH="${1}"
    DIST_DIR="distribute/${ARCH}"
    CHECKSUM_FILE="${DIST_DIR}/checksums.txt"

    echo "Generating checksums for ${DIST_DIR}..."
    # Generate checksums for all files except the checksums file itself.
    (cd "${DIST_DIR}" && find . -maxdepth 1 -type f ! -name "checksums.txt" \
      -exec sha256sum {} + | sed 's|\./||' | sort > checksums.txt)
    echo "Checksums written to ${CHECKSUM_FILE}"
    cat "${CHECKSUM_FILE}"
    ;;

  ###############################################################################
  # Verify the build output for a given architecture.
  # Arguments:
  #   1: Architecture name (e.g., X64, ARM64, ARM, X86).
  ###############################################################################
  verify-build)
    ARCH="${1}"
    ARCH_LOWER="$(echo "${ARCH}" | tr '[:upper:]' '[:lower:]')"
    DIST_DIR="distribute/${ARCH}"
    BINARY_NAME="apt_query-${ARCH_LOWER}"
    OUTPUT="${DIST_DIR}/${BINARY_NAME}"

    if [[ ! -f "${OUTPUT}" ]]; then
      echo "Error: Binary not found: ${OUTPUT}" >&2
      exit 1
    fi

    echo "Verifying build: ${OUTPUT}"
    file "${OUTPUT}"

    # Verify it's an ELF executable.
    if ! file "${OUTPUT}" | grep -q "ELF"; then
      echo "Error: ${OUTPUT} is not a valid ELF executable" >&2
      exit 1
    fi

    echo "Build verified successfully: ${OUTPUT}"
    ;;

  ###############################################################################
  # Reorganize downloaded artifacts from distribute-artifacts/ into the
  # distribute/<arch>/ layout expected by the release step.
  # Artifact directories are named cache-apt-pkgs-<ARCH>-<commit_sha> and
  # are mapped to distribute/<arch_lowercase>/.
  ###############################################################################
  reorganize-artifacts)
    echo "Reorganizing artifacts..."
    # Use nullglob so the loop does not run if no directories match.
    shopt -s nullglob
    for artifact_dir in distribute-artifacts/cache-apt-pkgs-*/; do
      dir_name="$(basename "${artifact_dir}")"
      # Extract arch from the format "cache-apt-pkgs-<ARCH>-<8-char-commit-sha>".
      # The commit SHA is exactly 8 hex characters at the end.
      arch_upper="$(echo "${dir_name}" | sed 's/^cache-apt-pkgs-//; s/-[0-9a-f]\{8\}$//')"
      if [[ -z "${arch_upper}" ]]; then
        echo "Warning: Could not extract architecture from ${dir_name}, skipping" >&2
        continue
      fi
      arch_lower="$(echo "${arch_upper}" | tr '[:upper:]' '[:lower:]')"
      dest_dir="distribute/${arch_lower}"

      mkdir -p "${dest_dir}"
      cp -r "${artifact_dir}"* "${dest_dir}/"
      echo "Reorganized ${artifact_dir} -> ${dest_dir}"
    done
    shopt -u nullglob
    echo "Artifact reorganization complete"
    ;;

  *)
    echo "Error: Unknown command: ${COMMAND}" >&2
    echo "Usage: distribute.sh <command> [args...]" >&2
    echo "Commands:" >&2
    echo "  generate-version" >&2
    echo "  create-distribute-directory <arch>" >&2
    echo "  clone-apt-fast" >&2
    echo "  build-binary <goos> <goarch> <goarch_variant> <arch>" >&2
    echo "  generate-checksums <arch>" >&2
    echo "  verify-build <arch>" >&2
    echo "  reorganize-artifacts" >&2
    exit 1
    ;;

esac