#!/bin/sh
# genfont - generate font converted to code from pure font data
# author Neil Franklin, last modification 2009.01.22


### ------ configuration for this site

# first CONF_*  various site or user dependant user config variables
# then  DEBUG_* various debugging settings
# last  SYS_*   various system internal values

# input file, ASCII drawings of characters pixel maps
CONF_INFILE=vga_text_font.fon

# output file, AVR code for including
CONF_OUTFILE=vga_text_font.inc


### ------ actual implementation from here on
# no user settings any more below this point

set -e


# --- get ready to work

# sanitise this place, else some commands may fail
PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin
export PATH

# stuff that goes wrong, not expected by user, not in data output, use >&2
#   so also with $0 in case this script was called by an other script
# something within the system that user does not expect, give up
CMD_FATAL="echo $0: FATAL:"
# something from users input, user will correct this and continue
CMD_ERROR="echo $0: ERROR:"
# something we can continue with, but may be wrong, and user may not suspect it
CMD_WARNING="echo $0: WARNING:"
# something most likely not wrong, but tell user for the odd case it is wrong
CMD_NOTE="echo $0: NOTE:"

# normal stuff users expect, so to stdout as normal output, no $0, no marking
CMD_INFO="echo"
# stuff users asked for, so add to stdout as normal output, no $0, but mark it
CMD_DEBUG="echo DEBUG:"


# --- convert graphical symbols to segment index values names

symbol_to_name () {

  SYMB="$1"

  if   [ "${SYMB}" = "................" ] ; then
    NAME="SEGM0000"
  elif [ "${SYMB}" = "............@@@@" ] ; then
    NAME="SEGM0001"
  elif [ "${SYMB}" = "........@@@@...." ] ; then
    NAME="SEGM0010"
  elif [ "${SYMB}" = "........@@@@@@@@" ] ; then
    NAME="SEGM0011"
  elif [ "${SYMB}" = "....@@@@........" ] ; then
    NAME="SEGM0100"
  elif [ "${SYMB}" = "....@@@@....@@@@" ] ; then
    NAME="SEGM0101"
  elif [ "${SYMB}" = "....@@@@@@@@...." ] ; then
    NAME="SEGM0110"
  elif [ "${SYMB}" = "....@@@@@@@@@@@@" ] ; then
    NAME="SEGM0111"
  elif [ "${SYMB}" = "@@@@............" ] ; then
    NAME="SEGM1000"
  elif [ "${SYMB}" = "@@@@........@@@@" ] ; then
    NAME="SEGM1001"
  elif [ "${SYMB}" = "@@@@....@@@@...." ] ; then
    NAME="SEGM1010"
  elif [ "${SYMB}" = "@@@@....@@@@@@@@" ] ; then
    NAME="SEGM1011"
  elif [ "${SYMB}" = "@@@@@@@@........" ] ; then
    NAME="SEGM1100"
  elif [ "${SYMB}" = "@@@@@@@@....@@@@" ] ; then
    NAME="SEGM1101"
  elif [ "${SYMB}" = "@@@@@@@@@@@@...." ] ; then
    NAME="SEGM1110"
  elif [ "${SYMB}" = "@@@@@@@@@@@@@@@@" ] ; then
    NAME="SEGM1111"
  elif [ "${SYMB}" = "....FFFFXXXXBBBB" ] ; then
    NAME="SEGM0FXB"
  elif [ "${SYMB}" = "....FFFFXXXX1111" ] ; then
    NAME="SEGM0FX1"
  elif [ "${SYMB}" = "....FFFFXXXX2222" ] ; then
    NAME="SEGM0FX2"
  elif [ "${SYMB}" = "....BBBBXXXX3333" ] ; then
    NAME="SEGM0BX3"
  else
    # unknown symbol, so we can not process it
    ${CMD_ERROR} "unknown symbol \"${SYMB}\", aborting ..." >&2
    exit 1
  fi

  return 0

}


# --- check input

if [ ! -f "${CONF_INFILE}" ] ; then
  # input file nonexistant, so we can not work on it
  ${CMD_ERROR} "no input file ${CONF_INFILE} to process" >&2
  exit 1
fi
${CMD_INFO} "generating include ${CONF_OUTFILE} from font ${CONF_INFILE}" >&2


# --- start output file, header

# remove existing output file, as later all is >> additions

rm -f "${CONF_OUTFILE}"

# make output file header

echo "; ${CONF_OUTFILE} - font for generating VGA text - converted to code" \
  >> "${CONF_OUTFILE}"
echo "; generated from ${CONF_INFILE}, last generation `date "+%Y.%m.%d"`" \
  >> "${CONF_OUTFILE}"
echo \
  >> "${CONF_OUTFILE}"


# --- process input file

# get rid of comments (cut), then trailing spaces (may be chopped comment, sed)
#   and then empty lines (may be chopped comment, grep)
cut -f 1 -d '#' "${CONF_INFILE}" | sed -e 's/ *$//' | \
    grep -v '^ *$' | while read LINE ; do

  # extract command of this line
  CMD="`echo "${LINE}" | cut -f 1 -d ' '`"

  if   [ "${CMD}" = "SECTION" ] ; then
    # section begin definition: process the name into output file

    NAME="`echo "${LINE}" | cut -f 2 -d ' '`"
    echo "${NAME}:" \
      >> "${CONF_OUTFILE}"

    # output progress info, one [S]ection processed
    echo -n "S" >&2

  elif [ "${CMD}" = "NAME" ] ; then
    # character name definition: process the name and value into output file

    NAME="`echo "${LINE}" | cut -f 2 -d ' '`"
    VALUE="`echo "${LINE}" | cut -f 3 -d ' '`"
    echo "  .equ ${NAME} = ${VALUE}" \
      >> "${CONF_OUTFILE}"

    # output progress info, one [N]ame processed
    echo -n "N" >&2

  elif [ "${CMD}" = "CHAR" ] ; then
    # character definition: process that characters segments, next 8 file lines

    COMMENT="`echo "${LINE}" | cut -f 2- -d ' '`"
    echo "  ; ${COMMENT}" \
      >> "${CONF_OUTFILE}"

    # for each segment: read it in, convert it to .db data name
    read SYMB0
    symbol_to_name "${SYMB0}"
    NAME0=${NAME}

    read SYMB1
    symbol_to_name "${SYMB1}"
    NAME1=${NAME}

    read SYMB2
    symbol_to_name "${SYMB2}"
    NAME2=${NAME}

    read SYMB3
    symbol_to_name "${SYMB3}"
    NAME3=${NAME}

    read SYMB4
    symbol_to_name "${SYMB4}"
    NAME4=${NAME}

    read SYMB5
    symbol_to_name "${SYMB5}"
    NAME5=${NAME}

    read SYMB6
    symbol_to_name "${SYMB6}"
    NAME6=${NAME}

    read SYMB7
    symbol_to_name "${SYMB7}"
    NAME7=${NAME}

    # output this character to include file, as 8/4=2 lines
    #   must be n*2 bytes for each .db line, use 4 to save file length
    echo "  .db ${NAME0}, ${NAME1}, ${NAME2}, ${NAME3}" \
      >> "${CONF_OUTFILE}"
    #echo "  .db low(DR${NAME0}), low(DR${NAME1}), low(DR${NAME2}), low(DR${NAME3})" \
    #  >> "${CONF_OUTFILE}"
    echo "  .db ${NAME4}, ${NAME5}, ${NAME6}, ${NAME7}" \
      >> "${CONF_OUTFILE}"
    #echo "  .db low(DR${NAME4}), low(DR${NAME5}), low(DR${NAME6}), low(DR${NAME7})" \
    #  >> "${CONF_OUTFILE}"

    # output progress info, one [C]haracter processed
    echo -n "C" >&2

  else
    # any other random text: may be bug, not in font, warn user
    echo >&2
    ${CMD_WARNING} "unknown command ignored: \"${LINE}\"" >&2

  fi

done

# finish off progress info output dots with newline
echo >&2