#!/bin/sh
# Copyright (C) 2023 Carlos Maniero
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

AS="as"
LD="ld"
SCRIPT_DIR=$(dirname "$0")
PIPAC_PATH="$SCRIPT_DIR/pipac"
SILENT=0

ERROR_PREFIX="[ERROR]"
WELCOME_MESSAGE="Welcome to Pipa Compiler"
PIPA_LOGO=""
COMPILING_MESSAGE="Compiling:"
BUILT_MESSAGE="Built:"
COMPILATION_ERROR_MESSAGE="Compilation error:"

if [ -t 1 ] && [ "$(tput colors)" -ge 8 ]; then
  ERROR_PREFIX="\033[31m$ERROR_PREFIX\033[0m"
  PIPA_LOGO="🪁"
  WELCOME_MESSAGE="\033[1m$PIPA_LOGO $WELCOME_MESSAGE\033[0m"
  COMPILING_MESSAGE="\033[1m$PIPA_LOGO $COMPILING_MESSAGE\033[0m"
  BUILT_MESSAGE="\033[1m✅ $BUILT_MESSAGE\033[0m"
fi

check_deps() {
  if [ ! -e "$PIPAC_PATH" ]; then
    printf "$ERROR_PREFIX pipac not found at $PIPAC_PATH. Consider running make command.\n"
    exit 1
  fi
  if [ ! -e "$AS" ] && ! which "$AS" >/dev/null; then
    printf "$ERROR_PREFIX $AS not found.\n\n"
    printf "Install it or provide the path with --as <as-path>\n"
    exit 1
  fi
  if [ ! -e "$LD" ] && ! which "$LD" >/dev/null; then
    printf "$ERROR_PREFIX $LD not found.\n\n"
    printf "Install it or provide the path with --ld <ld-path>\n"
    exit 1
  fi
}

print_help() {
  printf "$WELCOME_MESSAGE\n"
  printf "Usage:\n"
  printf "$0 [options] <filename.pipa>  Compile filename.pipa\n\n"
  printf "Options:\n"
  printf -- "--as     The path of gas compiler.    Default: as\n"
  printf -- "--help   Prints this prompt.\n"
  printf -- "--ld     The path of linker compiler. Default: ld\n"
  printf -- "--out    The executable name.         Default: filename without extension.\n"
  printf -- "--silent Hide logs. Errors are sill displayed.\n"
  exit 0
}

# FIXME: Allow the filename to came before the options
while [ $# -gt 0 ]; do
  case "$1" in
    --silent)
      SILENT=1
      shift 1
      ;;
    --as)
      if [ ! -n "$2" ]; then
        printf "$ERROR_PREFIX no argument passed for --as\n" >&2
        exit 1
      fi
      AS="$2"
      shift 2
      ;;
    --ld)
      if [ ! -n "$2" ]; then
        printf "$ERROR_PREFIX no argument passed for --ld\n" >&2
        exit 1
      fi
      LD="$2"
      shift 2
      ;;
    --out)
      if [ ! -n "$2" ]; then
        printf "$ERROR_PREFIX no argument passed for --out\n" >&2
        exit 1
      fi
      OUT="$2"
      shift 2
      ;;
    --help)
      print_help
      ;;
    *)
      break
      ;;
  esac
done

check_deps

FILE_NAME="$1"

log() {
  if [ "$SILENT" -eq 0 ]; then
    printf "$1\n"
  fi
}

cleanup() {
  rm -f "$OUT.s"
  rm -f "$OUT.o"
}

if [ ! -n "$FILE_NAME" ]; then
  printf "$ERROR_PREFIX no input file.\n" >&2
  exit 1
fi

if [ ! -e "$FILE_NAME" ]; then
  printf "$ERROR_PREFIX filename not found.\n" >&2
  exit 1
fi

log "$COMPILING_MESSAGE $FILE_NAME"

if ! [ -n "${OUT+x}" ]; then
  OUT="${FILE_NAME%.*}"
fi


if ! $PIPAC_PATH "$FILE_NAME" > "$OUT.s"; then
  printf "$ERROR_PREFIX $COMPILATION_ERROR_MESSAGE unable to generate assembly.\n"
  cleanup
  exit 1
fi

if ! $AS -o "$OUT.o" "$OUT.s" --64; then
  printf "$ERROR_PREFIX $COMPILATION_ERROR_MESSAGE unable to compile gas.\n"
  cleanup
  exit 1
fi

if ! $LD -o "$OUT" "$OUT.o"; then
  printf "$ERROR_PREFIX $COMPILATION_ERROR_MESSAGE unable to link the application.\n"
  cleanup
  exit 1
fi

cleanup

log "$BUILT_MESSAGE $OUT"