#!@stdenv_shell@ -e
set -euo pipefail
shopt -s extglob

export NIXPKGS_DF_ENV="@env@"

### BEGIN: Default DF options
declare -A _NIXPKGS_DF_OPTS
_NIXPKGS_DF_OPTS[fmod]=0    # Don't use fmod by default.
_NIXPKGS_DF_OPTS[debug]=0   # No debugging output by default.
### END: Default DF options

# Read NIXPKGS_DF_OPTS.
if [[ ! -v NIXPKGS_DF_OPTS ]]; then
  NIXPKGS_DF_OPTS=''
fi
IFS=',' read -ra options <<< "$NIXPKGS_DF_OPTS"
for option in ${options[@]+"${options[@]}"}; do
  key="${option%=*}"
  value="${option##*=}"
  if [ -n "$key" ]; then
    if [ -z "$value" ] || [ "$key" == "$value" ]; then
      value=1
    fi
    _NIXPKGS_DF_OPTS["$key"]="$value"
  fi
done

# Rebuild the canonical option string from the read options.
NIXPKGS_DF_OPTS=''
for key in "${!_NIXPKGS_DF_OPTS[@]}"; do
  value="${_NIXPKGS_DF_OPTS["${key}"]}"
  NIXPKGS_DF_OPTS="$NIXPKGS_DF_OPTS$key=$value,"
done
NIXPKGS_DF_OPTS="${NIXPKGS_DF_OPTS%,}"

# Echoes a log.
# $@: log messages
log() {
  for msg in "$@"; do
    echo "[nixpkgs] $msg" >&2
  done
}

# Echoes a log if NIXPKGS_DF_OPTS includes debug.
# $@: log messages
debug() {
  if [ "${_NIXPKGS_DF_OPTS[debug]}" -ne 0 ]; then
    log "$@"
  fi
}

# Updates a path in $NIXPKGS_DF_HOME from $NIXPKGS_DF_ENV.
# $1: The environment path.
update_path() {
  local path="$1"
  local orig="$NIXPKGS_DF_ENV/$path"
  local final="$NIXPKGS_DF_HOME/$path"

  # If user has replaced these data directories, let them stay.
  @mkdir@ -p "$(dirname -- "$final")"
  if [ ! -e "$final" ] || [ -L "$final" ]; then
    debug "Linking: $final -> $orig"
    @rm@ -f "$final"
    @ln@ -s "$orig" "$final"
  else
    debug "Not updating: $final"
  fi
}

# Cleans up a path in $NIXPKGS_DF_HOME that may or may not be in $NIXPKGS_DF_ENV.
# $1: The environment path.
cleanup_path() {
  local path="$1"
  local final="$NIXPKGS_DF_HOME/$path"

  # Let them stay if not a link.
  if [ ! -e "$final" ] || [ -L "$final" ]; then
    debug "Cleaning up: $final"
    @rm@ -f "$final"
  else
    debug "Not cleaning: $final"
  fi
}

# Force copies a path in $NIXPKGS_DF_HOME that may or may not be in $NIXPKGS_DF_ENV.
# $1: The environment path.
forcecopy_path() {
  local path="$1"

  if [ -z "$NIXPKGS_DF_ENV" ] || [ -z "$path" ]; then
    # Avoid producing "/" for any `rm -rf`
    return
  fi

  local orig="$NIXPKGS_DF_ENV/$path"
  local final="$NIXPKGS_DF_HOME/$path"

  if [ -e "$orig" ]; then
    debug "Force copying: $orig -> $final"
    @mkdir@ -p "$(dirname -- "$final")"
    @rm@ -rf "$final"
    @cp@ -rL --no-preserve=all "$orig" "$final"
  else
    debug "Removing: $final"
    @rm@ -rf "$final"
  fi
}

# Runs the final executable. Expects NIXPKGS_DF_HOME and NIXPKGS_DF_EXE to be set.
go() {
  cd "$NIXPKGS_DF_HOME"
  debug "Executing: $NIXPKGS_DF_HOME/$NIXPKGS_DF_EXE"

  # If we make it past here, we want to log.
  # shellcheck disable=SC2093
  exec -a "$NIXPKGS_DF_EXE" "$NIXPKGS_DF_HOME/$NIXPKGS_DF_EXE"
  log "Execution of $NIXPKGS_DF_HOME/$NIXPKGS_DF_EXE failed!"
  exit 1
}

os_name="$(@uname@)"
os_rev="$(@uname@ -r)"

if [ "$os_name" == Linux ]; then
  df_dir="df_linux"
elif [ "$os_name" == Darwin ]; then
  df_dir="df_osx"
else
  log "Unknown platform: $os_name"
  exit 1
fi

if [[ -v DF_DIR ]] && [ -n "$DF_DIR" ] && { [[ ! -v NIXPKGS_DF_HOME ]] || [ -z "$NIXPKGS_DF_HOME" ]; }; then
  # Compatibility for users that were using DF_DIR, since the dfhack script clobbers this variable.
  export NIXPKGS_DF_HOME="$DF_DIR"
fi

if [[ ! -v NIXPKGS_DF_HOME ]] || [ -z "$NIXPKGS_DF_HOME" ]; then
  export NIXPKGS_DF_HOME="${XDG_DATA_HOME:-$HOME/.local/share}/$df_dir"
fi

# Compatibility.
export DF_DIR="$NIXPKGS_DF_HOME"

@mkdir@ -p "$NIXPKGS_DF_HOME"

@cat@ <<EOF >&2
/------------------------------------------------------------------------------\\
| Hello from the nixpkgs Dwarf Fortress wrapper!                               |
|                                                                              |
| Using the following Dwarf Fortress overlay directory as NIXPKGS_DF_HOME:     |
| $(@printf@ '% -76s' "$NIXPKGS_DF_HOME") |
|                                                                              |
| If you make any changes in it, don't forget to clean it when updating the    |
| game version! We detect changes if data directories are symbolic links.      |
|                                                                              |
| Even though we do our best on our own, this script may miss some. Submit a   |
| pull request if there are any that become a problem.                         |
|                                                                              |
| We started with the following nixpkgs launch options as NIXPKGS_DF_OPTS:     |
| $(@printf@ '% -76s' "$NIXPKGS_DF_OPTS") |
|                                                                              |
| If you want to try fmod over SDL_mixer, set NIXPKGS_DF_OPTS=fmod.            |
\\------------------------------------------------------------------------------/
EOF

cd "$NIXPKGS_DF_ENV"

# All potential important files in DF 50 and below.
for path in dwarfort dwarfort.exe df *.so libs raw data/init/* data/!(init|index|announcement); do
  force_delete=0
  if [[ "$path" == libfmod*.so* ]] && [ "${_NIXPKGS_DF_OPTS[fmod]}" -eq 0 ]; then
    force_delete=1
  fi

  if [ -e "$path" ] && [ "$force_delete" -eq 0 ]; then
    update_path "$path"
  else
    cleanup_path "$path"
  fi
done

# These need to be copied due to read only flags on older versions of DF.
for path in index announcement help dipscript; do
  forcecopy_path "data/$path"
done

# Handle library paths on Darwin.
if [ "$os_name" == Darwin ]; then
  if [ "${os_rev%%.*}" -ge 11 ]; then
    export DYLD_LIBRARY_PATH="$NIXPKGS_DF_ENV/libs"
    export DYLD_FRAMEWORK_PATH="$NIXPKGS_DF_ENV/libs"
  else
    export DYLD_FALLBACK_LIBRARY_PATH="$NIXPKGS_DF_ENV/libs"
    export DYLD_FALLBACK_FRAMEWORK_PATH="$NIXPKGS_DF_ENV/libs"
  fi
fi