#!/bin/bash

# https://stackoverflow.com/a/13062682
uncomment() {
  [ $# -eq 2 ] && arg="$1" || arg=""
  eval file="\$$#"
  sed 's/a/aA/g; s/__/aB/g; s/#/aC/g' "$file" | \
    gcc -P -E $arg - | \
    sed 's/aC/#/g; s/aB/__/g; s/aA/a/g'
}

# this is the magic that turns multiline statements into
# single line statements
# LITERALLY DOES NOT WORK WITH PREPROCESSOR
onelineize() {
  grep -v '^#' | sed -e ':r;$!{N;br};s/\([^{;]\)\n\s*/\1 /g'
}

discard_preprocessors() {
  grep -v '#\(include\|if\|endif\)'
}

# sed regex for extracting data from function signature
# if this isn't regex, idk what is
# LUA_API (return type as \2) (function name as \3) (args as \4)
sym_regex='^LUA\(LIB\)\?_API\s\+\([^(]\+\)\s*(\([^)]\+\))\s\+(\([^)]\+\))'

# get funcptr declarations
ptrize() {
  grep '^LUA' | sed -e "s/$sym_regex/static \2(*\3) (\4)/"
}

export_sym() {
  # don't even bother reading this again
  grep '^LUA' | sed -e "s/$sym_regex/\tIMPORT_SYMBOL(\3, \2, \4)/"
}

decl() {
  header="$(uncomment $1 | discard_preprocessors)"
  header1="$(onelineize <<< "$header")"

  # typedef
  grep -v '^\(LUA\|#\|extern\)' <<< "$header1"
  # funcptrs
  ptrize <<< "$header1"
  # defines
  grep '^#' <<< "$header"
}

decl_export() {
  uncomment $1 | onelineize | export_sym
}

LUA_PATH="$1"

cat << EOF
/**
The lite_xl plugin API is quite simple. Any shared library can be a plugin file, so long
as it has an entrypoint that looks like the following, where xxxxx is the plugin name:
#include "lite_xl_plugin_api.h"
int lua_open_lite_xl_xxxxx(lua_State* L, void* XL) {
  lite_xl_plugin_init(XL);
  ...
  return 1;
}
In linux, to compile this file, you'd do: 'gcc -o xxxxx.so -shared xxxxx.c'. Simple!
Due to the way the API is structured, you *should not* link or include lua libraries.
This file was automatically generated by the below code. Do NOT MODIFY DIRECTLY.


EOF

cat "$0"

cat << EOF
**/


#ifndef LITE_XL_PLUGIN_API
#define LITE_XL_PLUGIN_API
EOF

decl "$LUA_PATH/lua.h"
decl "$LUA_PATH/lauxlib.h"

echo "#define IMPORT_SYMBOL(name, ret, ...) name = (ret (*) (__VA_ARGS__)) symbol(#name)"
echo "static void lite_xl_plugin_init(void *XL) {"
echo -e "\tvoid* (*symbol)(const char *) = (void* (*) (const char *)) XL;"

decl_export "$LUA_PATH/lua.h"
decl_export "$LUA_PATH/lauxlib.h"

echo "}"
echo "#endif"