#!/bin/sh
# SPDX-License-Identifier: BSD-3-Clause
me=$0
scriptversion="1.0.1"

version="$me $scriptversion

Copyright (C) 2025 GCK.
This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law."

usage="\
Usage: $me [OPTION]...
Generate template headers

Options:

   --help     print this help and exit
   --version  output version information"

while test $# -gt 0; do
  case $1 in
    --help) echo "$usage"; exit 0;;
    --version) echo "$version"; exit 0;;
    -*)
     echo "$0: Unknown option '$1'." >&2
     echo "$0: Try '--help' for more information." >&2
     exit 1;;
  esac
  shift
done

x_files=$(find . -maxdepth 1 -name "*.x" -type f | sort)

if test -z "$x_files"; then
  echo "$0: No .x files found in current directory." >&2
  exit 1
fi

output_file="../build/include/template.h"
mkdir -p ../build/include/

first_template=true

{
  echo "/* DO NOT MODIFY THIS FILE! It was generated by t $scriptversion. */"
  echo "#ifndef TEMPLATE_H"
  echo "#define TEMPLATE_H"
  
  for input_file in $x_files; do
    base_name=$(basename "$input_file" .x)
    template_name=$(echo "$base_name" | tr '[:lower:]' '[:upper:]')

    tmp_format=$(mktemp)
    tmp_template=$(mktemp)
    tmp_params=$(mktemp)

    format_index=$(head -n 1 "$input_file")
    if ! echo "$format_index" | grep -q "^Format_Index:"; then
      echo "$0: '$input_file': Missing Format_Index line." >&2
      rm -f "$tmp_format" "$tmp_template" "$tmp_params"
      continue
    fi
    
    if test "$first_template" = false; then
      echo ""
    fi
    first_template=false

    tmp_specs=$(mktemp)

    echo "$format_index" | sed 's/Format_Index://' | tr ',' '\n' | sed 's/^[[:space:]]*//;s/[[:space:]]*$//' > "$tmp_params"

    tail -n +2 "$input_file" | sed '/^$/d' > "$tmp_template"

    param_names=""
    while IFS= read -r param; do
      param_names="$param_names $param"
    done < "$tmp_params"

    while IFS= read -r line; do
      echo "$line" | grep -o '%[sdifgxXoucpeEaAn]' >> "$tmp_specs"
    done < "$tmp_template"

    echo "/*"
    
    param_idx=1
    for param in $param_names; do
      format_type=""
      spec=$(sed -n "${param_idx}p" "$tmp_specs")
      case "$spec" in
        %s|%S) format_type="(s)" ;;
        %d|%i|%u|%x|%X|%o) format_type="(d)" ;;
        %f|%g|%e|%E|%a|%A) format_type="(f)" ;;
        %c) format_type="(c)" ;;
        %p) format_type="(p)" ;;
        %n) format_type="(n)" ;;
        *) format_type="(?)" ;;
      esac
      
      case "$param" in
        a) param="author" ;;
        y) param="year" ;;
        l) param="license" ;;
        d) param="description" ;;
        p) param="package" ;;
      esac
      
      printf " * %-13s%s\n" "$param" "$format_type"
      param_idx=$((param_idx + 1))
    done
    
    echo " */"
    echo "const char templ_${template_name}[] = \"\\"
    
    line_count=0
    total_lines=$(wc -l < "$tmp_template")
    while IFS= read -r line; do
      line_count=$((line_count + 1))
      escaped_line=$(echo "$line" | sed \
        -e 's/\\\\/__BSLASH__/g' \
        -e 's/\\"/__BQUOTE__/g' \
        -e 's/\\n/__NEWLINE__/g' \
        -e 's/\\t/__TAB__/g' \
        -e 's/\\r/__RETURN__/g' \
        -e 's/\\a/__ALERT__/g' \
        -e 's/\\b/__BACKSPACE__/g' \
        -e 's/\\f/__FORMFEED__/g' \
        -e 's/\\v/__VTAB__/g' \
        -e 's/\\0/__NULL__/g' \
        -e 's/\\/\\\\/g' \
        -e 's/"/\\"/g' \
        -e 's/__BSLASH__/\\\\/g' \
        -e 's/__BQUOTE__/\\"/g' \
        -e 's/__NEWLINE__/\\n/g' \
        -e 's/__TAB__/\\t/g' \
        -e 's/__RETURN__/\\r/g' \
        -e 's/__ALERT__/\\a/g' \
        -e 's/__BACKSPACE__/\\b/g' \
        -e 's/__FORMFEED__/\\f/g' \
        -e 's/__VTAB__/\\v/g' \
        -e 's/__NULL__/\\0/g')
      if test $line_count -lt $total_lines; then
        printf '%s\\n\\\n' "$escaped_line"
      else
        printf '%s";\n' "$escaped_line"
      fi
    done < "$tmp_template"
    
    rm -f "$tmp_format" "$tmp_template" "$tmp_params" "$tmp_specs"
  done
  
  echo "#endif"
} > "$output_file"