#!/bin/bash

# Fail on any error.
set -e

# Debug mode for diagnosing issues.
# Setup first before other operations.
debug="${2}"
test "${debug}" = "true" && set -x

# Include library.
script_dir="$(dirname -- "$(realpath -- "${0}")")"
source "${script_dir}/lib.sh"

# Directory that holds the cached packages.
cache_dir="${1}"

# List of the packages to use.
input_packages="${@:3}"

# Trim commas, excess spaces, sort, and version syntax.
#
# NOTE: Unless specified, all APT package listings of name and version use
# colon delimited and not equals delimited syntax (i.e. <name>[:=]<ver>).
packages="$(get_normalized_package_list "${input_packages}")"

package_count=$(wc -w <<< "${packages}")
log "Clean installing and caching ${package_count} package(s)."

log_empty_line

manifest_main=""
log "Package list:"
for package in ${packages}; do
  read package_name package_ver < <(get_package_name_ver "${package}")
  manifest_main="${manifest_main}${package_name}:${package_ver},"  
  log "- ${package_name}:${package_ver}"
done
write_manifest "main" "${manifest_main}" "${cache_dir}/manifest_main.log"

log_empty_line

log "Installing apt-fast for optimized installs..."
# Install apt-fast for optimized installs.
/bin/bash -c "$(curl -sL https://git.io/vokNn)"
log "done"

log_empty_line

log "Updating APT package list..."
last_update_delta_s=$(($(date +%s) - $(date +%s -r /var/cache/apt/pkgcache.bin)))
if test $last_update_delta_s -gt 300; then
  sudo apt-fast update > /dev/null
  log "done"
else
  log "skipped (fresh by ${last_update_delta_s} seconds)"
fi

log_empty_line

# Strictly contains the requested packages.
manifest_main=""
# Contains all packages including dependencies.
manifest_all=""

install_log_filepath="${cache_dir}/install.log"

log "Clean installing ${package_count} packages..."
apt_syntax_packages="$(convert_action_to_apt_syntax_packages "${packages}")"
# Zero interaction while installing or upgrading the system via apt.
sudo DEBIAN_FRONTEND=noninteractive apt-fast --yes install ${apt_syntax_packages} > "${install_log_filepath}"
log "done"
log "Installation log written to ${install_log_filepath}"

log_empty_line

installed_packages=$(get_installed_packages "${install_log_filepath}")
log "Installed package list:"
for installed_package in ${installed_packages}; do
  log "- ${installed_package}"
done

log_empty_line

installed_packages_count=$(wc -w <<< "${installed_packages}")
log "Caching ${installed_packages_count} installed packages..."
for installed_package in ${installed_packages}; do
  cache_filepath="${cache_dir}/${installed_package}.tar"

  # Sanity test in case APT enumerates duplicates.
  if test ! -f "${cache_filepath}"; then
    read package_name package_ver < <(get_package_name_ver "${installed_package}")
    log "  * Caching ${package_name} to ${cache_filepath}..."

    # Pipe all package files (no folders) and installation control data to Tar.
    { dpkg -L "${package_name}" \
      & get_install_script_filepath "" "${package_name}" "preinst" \
      & get_install_script_filepath "" "${package_name}" "postinst"; } |
      while IFS= read -r f; do test -f "${f}" -o -L "${f}" && get_tar_relpath "${f}"; done |
      xargs -I {} echo \'{}\' | # Single quotes ensure literals like backslash get captured.
      sudo xargs tar -cf "${cache_filepath}" -C /

    log "    done (compressed size $(du -h "${cache_filepath}" | cut -f1))."
  fi

  # Comma delimited name:ver pairs in the all packages manifest.
  manifest_all="${manifest_all}${package_name}:${package_ver},"
done
log "done (total cache size $(du -h ${cache_dir} | tail -1 | awk '{print $1}'))"

log_empty_line

write_manifest "all" "${manifest_all}" "${cache_dir}/manifest_all.log"