#!/usr/bin/env bash

# file      : brep/handler/upload/upload-bindist.in
# license   : MIT; see accompanying LICENSE file

# Binary distribution packages upload handler which places the uploaded
# packages under the following filesystem hierarchy:
#
# <root>/[<tenant>/]<instance>/<os-release-name-id><os-release-version-id>/<project>/<package>/<version>/<package-config>
#
# The overall idea behind this handler is to create a uniquely named package
# configuration directory for each upload and maintain the package
# configuration symlink at the above path to refer to the directory of the
# latest upload.
#
# The root directory is passed as an argument (via upload-handler-argument).
# All the remaining directory components are retrieved from the respective
# manifest values of request.manifest created by brep and
# bindist-result.manifest contained in the uploaded archive.
#
# Note that the leaf component of the package configuration symlink path is
# sanitized, having the "bindist", <instance>, <os-release-name-id>, and
# <os-release-name-id><os-release-version-id> dash-separated sub-components
# removed. If the component becomes empty as a result of the sanitization,
# then the target CPU is assumed, if the package is not architecture-
# independent, and "noarch" otherwise. If the sanitized component is not
# empty, the package is not architecture-independent, and the resulting
# component doesn't containt the target CPU, then prepend it with the <cpu>-
# prefix. For example, the following symlink paths:
#
# .../archive/windows10/foo/libfoo/1.0.0/bindist-archive-windows10-release
# .../archive/windows10/foo/libfoo/1.0.0/bindist-archive-windows10
#
# are reduced to:
#
# .../archive/windows10/foo/libfoo/1.0.0/x86_64-release
# .../archive/windows10/foo/libfoo/1.0.0/x86_64
#
# To achieve this the handler performs the following steps (<dir> is passed as
# last argument by brep and is a subdirectory of upload-data):
#
# - Parse <dir>/request.manifest to retrieve the upload archive path,
#   timestamp, and the values which are required to compose the package
#   configuration symlink path.
#
# - Extract files from the upload archive.
#
# - Parse <dir>/<instance>/bindist-result.manifest to retrieve the values
#   required to compose the package configuration symlink path and the package
#   file paths.
#
# - Compose the package configuration symlink path.
#
# - Compose the package configuration directory path by appending the
#   -<timestamp>[-<number>] suffix to the package configuration symlink path.
#
# - Create the package configuration directory.
#
# - Copy the uploaded package files into the package configuration directory.
#
# - Generate the packages.sha256 file in the package configuration directory,
#   which lists the SHA256 checksums of the files contained in this directory.
#
# - Switch the package configuration symlink to refer to the newly created
#   package configuration directory.
#
# - If the --keep-previous option is not specified, then remove the previous
#   target of the package configuration symlink, if exists.
#
# Notes:
#
# - There could be a race both with upload-bindist-clean and other
#   upload-bindist instances while creating the package version/configuration
#   directories, querying the package configuration symlink target, switching
#   the symlink, and removing the symlink's previous target. To avoid it, the
#   root directory needs to be locked for the duration of these operations.
#   This, however, needs to be done granularly to perform the time consuming
#   operations (files copying, etc) while not holding the lock.
#
# - The brep module doesn't acquire the root directory lock. Thus, the package
#   configuration symlink during its lifetime should always refer to a
#   valid/complete package configuration directory.
#
# - Filesystem entries that exist or are created in the data directory:
#
#   <archive>           saved by brep
#   request.manifest    created by brep
#   <instance>/*        extracted by the handler (bindist-result.manifest, etc)
#   result.manifest     saved by brep
#
# Options:
#
# --keep-previous
#
#   Don't remove the previous target of the package configuration symlink.
#
usage="usage: $0 [<options>] <root> <dir>"

# Diagnostics.
#
verbose= #true

# The root directory lock timeout (in seconds).
#
lock_timeout=60

# If the package configuration directory already exists (may happen due to the
# low timestamp resolution), then re-try creating the configuration directory
# by adding the -<number> suffix and incrementing it until the creation
# succeeds or the retries limit is reached.
#
create_dir_retries=99

trap "{ exit 1; }" ERR
set -o errtrace     # Trap in functions and subshells.
set -o pipefail     # Fail if any pipeline command fails.
shopt -s lastpipe   # Execute last pipeline command in the current shell.
shopt -s nullglob   # Expand no-match globs to nothing rather than themselves.

@import brep/handler/handler@
@import brep/handler/upload/upload@

# Parse the command line options.
#
keep_previous=

while [[ "$#" -gt 0 ]]; do
  case $1 in
    --keep-previous)
      shift
      keep_previous=true
      ;;
    *)
      break
      ;;
  esac
done

if [[ "$#" -ne 2 ]]; then
  error "$usage"
fi

# Destination root directory.
#
root_dir="${1%/}"
shift

if [[ -z "$root_dir" ]]; then
  error "$usage"
fi

if [[ ! -d "$root_dir" ]]; then
  error "'$root_dir' does not exist or is not a directory"
fi

# Upload data directory.
#
data_dir="${1%/}"
shift

if [[ -z "$data_dir" ]]; then
  error "$usage"
fi

if [[ ! -d "$data_dir" ]]; then
  error "'$data_dir' does not exist or is not a directory"
fi

reference="$(basename "$data_dir")" # Upload request reference.

# Parse the upload request manifest.
#
manifest_parser_start "$data_dir/request.manifest"

archive=
instance=
timestamp=
name=
version=
project=
package_config=
target=
tenant=

while IFS=: read -ru "$manifest_parser_ofd" -d '' n v; do
  case "$n" in
    archive)        archive="$v"        ;;
    instance)       instance="$v"       ;;
    timestamp)      timestamp="$v"      ;;
    name)           name="$v"           ;;
    version)        version="$v"        ;;
    project)        project="$v"        ;;
    package-config) package_config="$v" ;;
    target)         target="$v"         ;;
    tenant)         tenant="$v"         ;;
  esac
done

manifest_parser_finish

if [[ -z "$archive" ]]; then
  error "archive manifest value expected"
fi

if [[ -z "$instance" ]]; then
  error "instance manifest value expected"
fi

if [[ -z "$timestamp" ]]; then
  error "timestamp manifest value expected"
fi

if [[ -z "$name" ]]; then
  error "name manifest value expected"
fi

if [[ -z "$version" ]]; then
  error "version manifest value expected"
fi

if [[ -z "$project" ]]; then
  error "project manifest value expected"
fi

if [[ -z "$package_config" ]]; then
  error "package-config manifest value expected"
fi

if [[ -z "$target" ]]; then
  error "target manifest value expected"
fi

# Let's disallow the leading dot in the package-config manifest value since
# the latter serves as the package configuration symlink name and brep skips
# symlinks with the leading dots assuming them as hidden (see
# mod/mod-package-version-details.cxx for details).
#
if [[ "$package_config" == "."* ]]; then
  exit_with_manifest 400 "package-config manifest value may not start with dot"
fi

# Extract the CPU component from the target triplet and deduce the binary
# distribution-specific CPU representation which is normally used in the
# package file names.
#
cpu="$(sed -n -re 's/^([^-]+)-.+/\1/p' <<<"$target")"

if [[ -z "$cpu" ]]; then
  error "CPU expected in target triplet '$target'"
fi

# Use CPU extracted from the target triplet as a distribution-specific
# representation, unless this is Debian or Fedora (see bpkg's
# system-package-manager-{fedora,debian}.cxx for details).
#
cpu_dist="$cpu"

case $instance in
  debian)
    case $cpu in
      x86_64)                    cpu_dist="amd64" ;;
      aarch64)                   cpu_dist="arm64" ;;
      i386 | i486 | i586 | i686) cpu_dist="i386"  ;;
    esac
    ;;
  fedora)
    case $cpu in
      i386 | i486 | i586 | i686) cpu_dist="i686"  ;;
    esac
    ;;
esac

# Unpack the archive.
#
run tar -xf "$data_dir/$archive" -C "$data_dir"

# Parse the bindist result manifest list.
#
f="$data_dir/$instance/bindist-result.manifest"

if [[ ! -f "$f" ]]; then
  exit_with_manifest 400 "$instance/bindist-result.manifest not found"
fi

manifest_parser_start "$f"

# Parse the distribution manifest.
#
# Note that we need to skip the first manifest version value and parse until
# the next one is encountered, which introduces the first package file
# manifest.
#
os_release_name_id=
os_release_version_id=

first=true
more=
while IFS=: read -ru "$manifest_parser_ofd" -d '' n v; do
  case "$n" in
    "") if [[ "$first" ]]; then # Start of the first (distribution) manifest?
          first=
        else                    # Start of the second (package file) manifest.
          more=true
          break
        fi
        ;;

    os-release-name-id)    os_release_name_id="$v"    ;;
    os-release-version-id) os_release_version_id="$v" ;;
  esac
done

if [[ -z "$os_release_name_id" ]]; then
  exit_with_manifest 400 "os-release-name-id bindist result manifest value expected"
fi

if [[ -z "$os_release_version_id" ]]; then
  exit_with_manifest 400 "os-release-version-id bindist result manifest value expected"
fi

if [[ ! "$more" ]]; then
  exit_with_manifest 400 "no package file manifests in bindist result manifest list"
fi

# Parse the package file manifest list and cache the file paths.
#
# While at it, detect if the package is architecture-specific or not by
# checking if any package file names contain the distribution-specific CPU
# representation (as a sub-string).
#
# Note that while we currently only need the package file paths, we can make
# use of their types and system names in the future. Thus, let's verify that
# all the required package file values are present and, while at it, cache
# them all in the parallel arrays.
#
package_file_paths=()
package_file_types=()
package_file_system_names=()

arch_specific=

# The outer loop iterates over package file manifests while the inner loop
# iterates over manifest values in each such manifest.
#
while [[ "$more" ]]; do
  more=
  type=
  path=
  system_name=

  while IFS=: read -ru "$manifest_parser_ofd" -d '' n v; do
    case "$n" in
      "") # Start of the next package file manifest.
        more=true
        break
        ;;

      package-file-path)        path="$v"        ;;
      package-file-type)        type="$v"        ;;
      package-file-system-name) system_name="$v" ;;
    esac
  done

  if [[ -z "$path" ]]; then
    exit_with_manifest 400 "package-file-path bindist result manifest value expected"
  fi

  if [[ -z "$type" ]]; then
    exit_with_manifest 400 "package-file-type bindist result manifest value expected"
  fi

  package_file_paths+=("$path")
  package_file_types+=("$type")
  package_file_system_names+=("$system_name") # Note: system name can be empty.

  if [[ "$path" == *"$cpu_dist"* ]]; then
    arch_specific=true
  fi
done

manifest_parser_finish

# Sanitize the package configuration name.
#
config=
for c in $(sed 's/-/ /g' <<<"$package_config"); do
  if [[ "$c" != "bindist"             &&
        "$c" != "$instance"           &&
        "$c" != "$os_release_name_id" &&
        "$c" != "$os_release_name_id$os_release_version_id" ]]; then
    if [[ -z "$config" ]]; then
      config="$c"
    else
      config="$config-$c"
    fi
  fi
done

# Reflect the architecture in the sanitized configuration name.
#
if [[ -z "$config" ]]; then
  if [[ "$arch_specific"  ]]; then
    config="$cpu"
  else
    config="noarch"
  fi
else
  if [[ "$arch_specific" && ("$config" != *"$cpu"*) ]]; then
    config="$cpu-$config"
  fi
fi

# Compose the package configuration symlink path.
#
config_link="$root_dir"

if [[ -n "$tenant" ]]; then
  config_link="$config_link/$tenant"
fi

config_link="$config_link/$instance/$os_release_name_id$os_release_version_id"
config_link="$config_link/$project/$name/$version/$config"

# Compose the package configuration directory path.
#
config_dir="$config_link-$timestamp"

# Create the package configuration directory.
#
# Note that it is highly unlikely that multiple uploads for the same package
# configuration/distribution occur at the same time (with the seconds
# resolution) making the directory name not unique. If that still happens,
# lets retry for some reasonable number of times to create the directory,
# while adding the -<number> suffix to its path on each iteration. If
# that also fails, then we assume that there is some issue with the handler
# setup and fail, printing the cached mkdir diagnostics to stderr.
#
# Note that we need to prevent removing of the potentially empty package
# version directory by the upload-bindist-clean script before we create
# configuration directory. To achieve that, we lock the root directory for the
# duration of the package version/configuration directories creation.
#
# Open the reading file descriptor and lock the root directory. Fail if
# unable to lock before timeout.
#
lock="$root_dir/upload.lock"
run touch "$lock"
trace "+ exec {lfd}<$lock"
exec {lfd}<"$lock"

if ! run flock -w "$lock_timeout" "$lfd"; then
  exit_with_manifest 503 "upload service is busy"
fi

# Create parent (doesn't fail if directory exists).
#
config_parent_dir="$(dirname "$config_dir")"
run mkdir -p "$config_parent_dir"

created=

trace_cmd mkdir "$config_dir"
if ! e="$(mkdir "$config_dir" 2>&1)"; then # Note: fails if directory exists.
  for ((i=0; i != $create_dir_retries; ++i)); do
    d="$config_dir-$i"
    trace_cmd mkdir "$d"
    if e="$(mkdir "$d" 2>&1)"; then
      config_dir="$d"
      created=true
      break
    fi
  done
else
  created=true
fi

# Close the file descriptor and unlock the root directory.
#
trace "+ exec {lfd}<&-"
exec {lfd}<&-

if [[ ! "$created" ]]; then
  echo "$e" 1>&2
  error "unable to create package configuration directory"
fi

# On exit, remove the newly created package configuration directory, unless
# its removal is canceled (for example, the symlink is switched to refer to
# it). Also remove the new symlink, if already created.
#
# Make sure we don't fail if the entries are already removed, for example, by
# the upload-bindist-clean script.
#
config_link_new=
function exit_trap ()
{
  if [[ -n "$config_dir" && -d "$config_dir" ]]; then
    if [[ -n "$config_link_new" && -L "$config_link_new" ]]; then
      run rm -f "$config_link_new"
    fi
    run rm -rf "$config_dir"
  fi
}

trap exit_trap EXIT

# Copy all the extracted package files to the package configuration directory.
#
for ((i=0; i != "${#package_file_paths[@]}"; ++i)); do
  run cp "$data_dir/$instance/${package_file_paths[$i]}" "$config_dir"
done

# Generate the packages.sha256 file.
#
# Note that since we don't hold the root directory lock at this time, we
# temporary "hide" the resulting file from the upload-bindist-clean script
# (which uses it for the upload age calculation) by adding the leading dot to
# its name. Not doing so we may potentially end up with upload-bindist-clean
# removing the half-cooked directory and so breaking the upload handling.
#
trace "+ (cd $config_dir && exec sha256sum -b ${package_file_paths[@]} >.packages.sha256)"
(cd "$config_dir" && exec sha256sum -b "${package_file_paths[@]}" >".packages.sha256")

# Create the new package configuration "hidden" symlink. Construct its name by
# prepending the configuration directory name with a dot.
#
config_dir_name="$(basename "$config_dir")"
config_link_new="$config_parent_dir/.$config_dir_name"
run ln -s "$config_dir_name" "$config_link_new"

# Switch the package configuration symlink atomically. But first, cache the
# previous package configuration symlink target if the --keep-previous option
# is not specified and "unhide" the packages.sha256 file.
#
# Note that to avoid a race with upload-bindist-clean and other upload-bindist
# instances, we need to perform all the mentioned operations as well as
# removing the previous package configuration directory while holding the root
# directory lock.

# Lock the root directory.
#
trace "+ exec {lfd}<$lock"
exec {lfd}<"$lock"

if ! run flock -w "$lock_timeout" "$lfd"; then
  exit_with_manifest 503 "upload service is busy"
fi

# Note that while the realpath utility is not POSIX, it is present on both
# Linux and FreeBSD.
#
config_dir_prev=
if [[ ! "$keep_previous" && -L "$config_link" ]]; then
  config_dir_prev="$(realpath "$config_link")"
fi

# "Unhide" the packages.sha256 file.
#
run mv "$config_dir/.packages.sha256" "$config_dir/packages.sha256"

# Note that since brep doesn't acquire the root directory lock, we need to
# switch the symlink as the final step, when the package directory is fully
# prepared and can be exposed.
#
# @@ Also note that the -T option is Linux-specific. To add support for
#    FreeBSD we need to use -h option there (but maybe -T also works,
#    who knows).
#
run mv -T "$config_link_new" "$config_link"

# Now, when the package configuration symlink is switched, disable removal of
# the newly created package configuration directory.
#
# Note that we still can respond with an error status. However, the remaining
# operations are all cleanups and thus unlikely to fail.
#
config_dir=

# Remove the previous package configuration directory, if requested.
#
if [[ -n "$config_dir_prev" ]]; then
  run rm -r "$config_dir_prev"
fi

# Unlock the root directory.
#
trace "+ exec {lfd}<&-"
exec {lfd}<&-

# Remove the no longer needed upload data directory.
#
run rm -r "$data_dir"

trace "binary distribution packages are published"
exit_with_manifest 200 "binary distribution packages are published"