#!/bin/sh

# receive one package to be built from the build-list whose dependencies
# are already satisfied or which breaks a dependency cycle

# exit code shows state of success:
#  0: ok, I gave you an assignment
#  1: come back (shortly) later - I was running already
#  2: come back later - there are still packages to be built,
#     but currently none has all its dependencies ready
#  3: come back after the next run of get-package-updates - currently
#     there are no pending packages
#  4: come back, when you've done your work - you hit the limit on
#     maximum allowed parallel jobs per ip

# TODO:

#  if all loops are locked, broken packages are not handed out as long
#   as the script believes there is a looped package before the broken
#   one on the build-list - clean up that mess!

# shellcheck source=conf/default.conf
. "${0%/*}/../conf/default.conf"

mkdir -p "${work_dir}/package-states"

hand_out_assignment() {

  # locked and blocked packages won't be handed out
  if package_locked_or_blocked "$1" "$2" "$3" "$4"; then
    return 0
  fi

  # we don't care anymore if an older version of this package was
  # "locked" or "broken" (we keep only marker for older "done" packages)
  find "${work_dir}/package-states" -maxdepth 1 | \
    grep "/$(str_to_regex "${1}")\(\.[^.]\+\)\{3\}\.\(locked\|broken\)\$" | \
    grep -v "/$(str_to_regex "$1.$2.$3.$4.")[^.]\+\$" | \
    xargs -rn1 rm -f

  echo "$1 $2 $3 $4"
  # shellcheck disable=SC2154
  echo "${slave}" > "${work_dir}/package-states/$1.$2.$3.$4.locked"

  # lock every loop this package breaks
  grep -lxF "${1}" "${work_dir}/build-list.loops/"loop_* | \
    tee -a "${work_dir}/package-states/$1.$2.$3.$4.locked" | \
    sed 's|$|.locked|' | \
    xargs -rn1 touch

  exit 0

}

if [ -s "${work_dir}/build-master-sanity" ]; then
  >&2 echo 'Build master is not sane.'
  exit 1
fi

# Create a lock file and a trap.

exec 9> "${build_list_lock_file}"
if ! flock -n 9; then
  >&2 echo 'come back (shortly) later - I cannot lock build list.'
  exit 1
fi

clean_up() {
  rm -f "${build_list_lock_file}"
}

trap clean_up EXIT

# Check if there are any pending packages at all and if the requester
# has already hit its max_parallel_build_per_client limit.

num_jobs=0
pending_packages=false

while read -r package git_revision mod_git_revision repository; do

  if [ -z "${git_revision}${mod_git_revision}${repository}" ] && \
    [ "${package}" = 'break_loops' ]; then
    continue
  fi

  generate_package_metadata "${package}.${git_revision}.${mod_git_revision}.${repository}"

  if [ -f "${work_dir}/package-states/${package}.${git_revision}.${mod_git_revision}.${repository}.blocked" ]; then
    continue
  fi

  if [ -f "${work_dir}/package-states/${package}.${git_revision}.${mod_git_revision}.${repository}.locked" ];
  then
    if [ "${slave}" = "$(head -n1 "${work_dir}/package-states/${package}.${git_revision}.${mod_git_revision}.${repository}.locked")" ]; then
      num_jobs=$((num_jobs+1));
    fi
  else
    pending_packages=true
  fi

done < "${work_dir}/build-list"

if ! ${pending_packages}; then
  >&2 echo 'come back after the next run of get-package-updates - currently there are no pending packages'
  exit 3
fi

if [ ${num_jobs} -ge ${max_parallel_build_per_client} ]; then
  >&2 echo "come back, when you've done your work - you hit the limit on maximum allowed parallel jobs per ip"
  exit 4
fi

# Find first package of build-list whose dependencies are all met

for hand_out_broken in false true; do

  # shellcheck disable=SC2094
  while read -r package git_revision mod_git_revision repository; do

    if [ -z "${git_revision}${mod_git_revision}${repository}" ] && \
      [ "${package}" = 'break_loops' ]; then
      if ${hand_out_broken}; then
        first=true
        while read -r s; do
          if [ "${s}" = 'break_loops' ] && \
            ${first}; then
            first=false
            continue
          fi
          printf '%s\n' "${s}"
        done < \
          "${work_dir}/build-list" | \
          sponge "${work_dir}/build-list"
        insert_break_loops_orders "${work_dir}/build-list"
        break
      else
        continue
      fi
    fi

    if package_locked_or_blocked "${package}" "${git_revision}" "${mod_git_revision}" "${repository}"; then
      continue
    fi

    if ! ${hand_out_broken} && \
      [ -f "${work_dir}/package-states/${package}.${git_revision}.${mod_git_revision}.${repository}.broken" ]; then
      continue
    fi

    if [ -n "$(find_dependencies_on_build_list "${package}" "${git_revision}" "${mod_git_revision}" "${repository}")" ]; then
      continue
    fi

    hand_out_assignment "${package}" "${git_revision}" "${mod_git_revision}" "${repository}"

  done < \
    "${work_dir}/build-list"

done

# Find package (of all packages which are not locked and have been broken the least times)
# which breaks the most unlocked loops

locked_packages=$(
  find "${work_dir}/package-states/" -maxdepth 1 -printf '%f\n' | \
    grep '\(\.[0-9a-f]\{40\}\)\{2\}\.[^\.\]\+\.locked$' | \
    sed 's|\(\.[0-9a-f]\{40\}\)\{2\}\.[^\.\]\+\.locked$||'
)

grep -vxF 'break_loops' "${work_dir}/build-list" | \
  sort -k1,1 > \
  "${work_dir}/build-list.sorted-by-package"

for package in $(
  # shellcheck disable=SC2030
  find "${work_dir}/build-list.loops/" -maxdepth 1 | \
    grep '/loop_[0-9]\+$' | \
    while read -r loop; do
      if [ -z "$(
        (
          cat "${loop}"
          echo "${locked_packages}"
        ) | \
          sort | \
          uniq -d
        )" ]; then
        cat "${loop}"
      fi
    done | \
    sort | \
    uniq -c | \
    join -1 2 -2 1 -o 1.1,2.1,2.2,2.3,2.4 \
      - \
      "${work_dir}/build-list.sorted-by-package" | \
    while read -r count package git_revision git_mod_revision repository; do
      if [ -f "${work_dir}/package-states/${package}.${git_revision}.${git_mod_revision}.${repository}.broken" ]; then
        trials=$(
          wc -l < \
            "${work_dir}/package-states/${package}.${git_revision}.${git_mod_revision}.${repository}.broken"
        )
      else
        trials='0'
      fi
      printf '%s %s %s.%s.%s.%s\n' \
        "${trials}" \
        "${count}" \
        "${package}" \
        "${git_revision}" \
        "${git_mod_revision}" \
        "${repository}"
    done | \
    sort -k1n,1 -k2nr,2 | \
    cut -d' ' -f3
); do
  # shellcheck disable=SC2046,SC2031
  hand_out_assignment $(
    echo "${package}" | \
      sed 's|\.\([^.]\+\)\.\([^.]\+\)\.\([^.]\+\)$| \1 \2 \3|'
  )
done

# Remove the lock file

>&2 echo 'come back later - there are still packages to be built, but currently none has all its dependencies ready'
exit 2