ext/ext-backend-imgui/inc/cimgui/generator/generator.lua
--------------------------------------------------------------------------
--script for auto_funcs.h and auto_funcs.cpp generation
--expects LuaJIT
--------------------------------------------------------------------------
assert(_VERSION=='Lua 5.1',"Must use LuaJIT")
assert(bit,"Must use LuaJIT")
local script_args = {...}
local COMPILER = script_args[1]
local INTERNAL_GENERATION = script_args[2]:match("internal") and true or false
local FREETYPE_GENERATION = true --script_args[2]:match("freetype") and true or false
local COMMENTS_GENERATION = script_args[2]:match("comments") and true or false
local CONSTRUCTORS_GENERATION = script_args[2]:match("constructors") and true or false
local NOCHAR = script_args[2]:match("nochar") and true or false
local NOIMSTRV = script_args[2]:match("noimstrv") and true or false
local IMGUI_PATH = os.getenv"IMGUI_PATH" or "../imgui"
local CONFIG_GENERATOR_PATH = os.getenv"CONFIG_GENERATOR_PATH" or "./config_generator.lua"
local CFLAGS = ""
local CPRE,CTEST
--get implementations
local implementations = {}
for i=3,#script_args do
    if script_args[i]:match(COMPILER == "cl" and "^/" or "^%-") then
		if script_args[i]:match("IMGUI_USE_WCHAR32") then
			script_args[i] = "" --dont use this define
		end
        local key, value = script_args[i]:match("^(.+)=(.+)$")
        if key and value then
            CFLAGS = CFLAGS .. " " .. key .. "=\"" .. value:gsub("\"", "\\\"") .. "\"";
        else
            CFLAGS = CFLAGS .. " " .. script_args[i]
        end
    else
        table.insert(implementations,script_args[i])
    end
end

if FREETYPE_GENERATION then
	CFLAGS = CFLAGS .. " -DIMGUI_ENABLE_FREETYPE -DIMGUI_ENABLE_STB_TRUETYPE" --both builders
end

if COMPILER == "gcc" or COMPILER == "clang" or COMPILER == "zig cc" then
    CPRE = COMPILER..[[ -E -DIMGUI_DISABLE_OBSOLETE_FUNCTIONS -DIMGUI_API="" -DIMGUI_IMPL_API=""  ]] .. CFLAGS
    CTEST = COMPILER.." --version"
elseif COMPILER == "cl" then
    CPRE = COMPILER..[[ /E /DIMGUI_DISABLE_OBSOLETE_FUNCTIONS /DIMGUI_DEBUG_PARANOID /DIMGUI_API="" /DIMGUI_IMPL_API="" ]] .. CFLAGS
    CTEST = COMPILER
else
    print("Working without compiler ")
	error("cant work with "..COMPILER.." compiler")
end
--test compiler present
local HAVE_COMPILER = false

local pipe,err = io.popen(CTEST,"r")
if pipe then
    local str = pipe:read"*a"
    print(str)
    pipe:close()
    if str=="" then
        HAVE_COMPILER = false
    else
        HAVE_COMPILER = true
    end
else
    HAVE_COMPILER = false
    print(err)
end
assert(HAVE_COMPILER,"gcc, clang or cl needed to run script")


print("HAVE_COMPILER",HAVE_COMPILER)
print("INTERNAL_GENERATION",INTERNAL_GENERATION)
print("FREETYPE_GENERATION",FREETYPE_GENERATION)
print("COMMENTS_GENERATION",COMMENTS_GENERATION)
print("CONSTRUCTORS_GENERATION",CONSTRUCTORS_GENERATION)
print("CPRE",CPRE)
--------------------------------------------------------------------------
--this table has the functions to be skipped in generation
--------------------------------------------------------------------------
local cimgui_manuals = {
   -- igLogText = true,
    ImGuiTextBuffer_appendf = true,
    --igColorConvertRGBtoHSV = true,
    --igColorConvertHSVtoRGB = true
}
local cimgui_skipped = {
	 --igShowDemoWindow = true
}
--------------------------------------------------------------------------
--this table is a dictionary to force a naming of function overloading (instead of algorythmic generated)
--first level is cimguiname without postfix, second level is the signature of the function, value is the
--desired name
---------------------------------------------------------------------------
local cimgui_overloads = {
	-- igGetIO = {
		-- ["()"] = "igGetIO",
		-- ["(ImGuiContext*)"] = "igGetIOEx",
	-- },
    --igPushID = {
        --["(const char*)"] =           "igPushIDStr",
        --["(const char*,const char*)"] = "igPushIDRange",
        --["(const void*)"] =           "igPushIDPtr",
        --["(int)"] =                   "igPushIDInt"
    --},
}

--------------------------header definitions
local cimgui_header = 
[[//This file is automatically generated by generator.lua from https://github.com/cimgui/cimgui
//based on imgui.h file version XXX from Dear ImGui https://github.com/ocornut/imgui
]]
local gdefines = {} --for FLT_MAX and others
--------------------------------------------------------------------------
--helper functions
--------------------------------functions for C generation
--load parser module
local cpp2ffi = require"cpp2ffi"
local read_data = cpp2ffi.read_data
local save_data = cpp2ffi.save_data
local copyfile = cpp2ffi.copyfile
local serializeTableF = cpp2ffi.serializeTableF

local function func_header_impl_generate(FP)

    local outtab = {}
    
    for _,t in ipairs(FP.funcdefs) do
        if t.cimguiname then
            local cimf = FP.defsT[t.cimguiname]
            local def = cimf[t.signature]
			local addcoment = def.comment or ""
			local empty = def.args:match("^%(%)") --no args
			if def.constructor then
				-- only vulkan is manually created
				assert(def.ov_cimguiname=="ImGui_ImplVulkanH_Window_ImGui_ImplVulkanH_Window" or
				def.ov_cimguiname=="ImGui_ImplVulkanH_Window_Construct", "not cpp for "..def.ov_cimguiname)
			    assert(def.stname ~= "","constructor without struct")
                table.insert(outtab,"CIMGUI_API "..def.stname.."* "..def.ov_cimguiname ..(empty and "(void)" or def.args)..";"..addcoment.."\n")
            elseif def.destructor then
                --table.insert(outtab,"CIMGUI_API void "..def.ov_cimguiname..def.args..";"..addcoment.."\n")
			else
                
                if def.stname == "" then --ImGui namespace or top level
                    table.insert(outtab,"CIMGUI_API".." "..def.ret.." "..def.ov_cimguiname..(empty and "(void)" or def.args)..";"..addcoment.."\n")
                else
					cpp2ffi.prtable(def)
                    error("class function in implementations")
                end
            end
        else --not cimguiname
            table.insert(outtab,t.comment:gsub("%%","%%%%").."\n")-- %% substitution for gsub
        end
    end
    local cfuncsstr = table.concat(outtab)
    cfuncsstr = cfuncsstr:gsub("\n+","\n") --several empty lines to one empty line
    return cfuncsstr
end

local func_header_generate = cpp2ffi.func_header_generate
local func_implementation = cpp2ffi.func_implementation

-------------------functions for getting and setting defines
local function get_defines(t)
    local compiler_cmd = COMPILER == "cl"
                         and COMPILER..[[ /TP /nologo /c /Fo"NUL" /DIMGUI_DISABLE_OBSOLETE_FUNCTIONS ]]..CFLAGS..[[ /I"]]..IMGUI_PATH..[[" print_defines.cpp]]
                         or COMPILER..[[ -E -dM -DIMGUI_DISABLE_OBSOLETE_FUNCTIONS -DIMGUI_API="" -DIMGUI_IMPL_API="" ]]..IMGUI_PATH..[[/imgui.h]]..CFLAGS
    print(compiler_cmd)
    local pipe,err = io.popen(compiler_cmd,"r")
    local defines = {}
    local compiler_output = {"There were fails in compilation."}
    while true do
        local line = pipe:read"*l"
        if not line then break end
        local key,value = line:match([[^#define%s+(%S+)%s*(.*)]])
        if not key then --or not value then 
			table.insert(compiler_output, line)
            --print(line)
        else
            defines[key]=value or ""
        end
    end
    pipe:close()
    --require"anima.utils"
    --prtable(defines)
	assert(next(defines), table.concat(compiler_output, "\n"))
    local ret = {}
    for i,v in ipairs(t) do
        local aa = defines[v]
        while true do
            local tmp = defines[aa]
            if not tmp then
                break
            else
                aa = tmp
            end
        end
        ret[v] = aa
    end
    return ret
end
  --subtitution of FLT_MAX value for FLT_MAX or FLT_MIN
local function set_defines(fdefs)
	local FLT_MINpat = gdefines.FLT_MIN:gsub("([%.%-])","%%%1")
    for k,defT in pairs(fdefs) do
        for i,def in ipairs(defT) do
            for name,default in pairs(def.defaults) do
                if default == gdefines.FLT_MAX then
                    def.defaults[name] = "FLT_MAX"
                elseif default:match(FLT_MINpat) then
                    def.defaults[name] = default:gsub(FLT_MINpat,"FLT_MIN")
                end
            end
        end
    end
end 
--this creates defsBystruct in case you need to list by struct container
local function DefsByStruct(FP)
    local structs = {}
    for fun,defs in pairs(FP.defsT) do
        local stname = defs[1].stname
        structs[stname] = structs[stname] or {}
        table.insert(structs[stname],defs)--fun)
    end
    FP.defsBystruct = structs
end  

local function colapse_defines(str, define)
	local num = 1
	while num > 0 do
		str,num = str:gsub("(#ifdef "..define..".+)".."(#endif\n+#ifdef "..define.."\n)", "%1")
	end
	return str
end
local wchardefine =
[[

#ifdef IMGUI_USE_WCHAR32            
typedef ImWchar32 ImWchar;
#else
typedef ImWchar16 ImWchar;
#endif
#ifdef IMGUI_USE_WCHAR32
#define IM_UNICODE_CODEPOINT_MAX     0x10FFFF   
#else
#define IM_UNICODE_CODEPOINT_MAX     0xFFFF  
#endif
	]]

--generate cimgui.cpp cimgui.h 
local function cimgui_generation(parser)

--[[
	-- clean ImVector:contains() for not applicable types
	local clean_f = {}
	for k,v in pairs(parser.defsT) do
		if k:match"ImVector" and k:match"contains" then
			--cpp2ffi.prtable(k,v)
			local stname = v[1].stname
			if not(stname:match"float" or stname:match"int" or stname:match"char") then
				parser.defsT[k] = nil
				--delete also from funcdefs
				for i,t in ipairs(parser.funcdefs) do
					if t.cimguiname == k then
						table.remove(parser.funcdefs, i)
						break
					end
				end
			end
		end
	end
--]]
	--------------------------------------------------
    local hstrfile = read_data"./cimgui_template.h"

	local outpre,outpost = parser.structs_and_enums[1],parser.structs_and_enums[2]
	cpp2ffi.prtable(parser.templates)
	cpp2ffi.prtable(parser.typenames)
	

	local  tdt = parser:generate_templates()
	local cstructsstr = outpre..tdt..outpost 
    
	if gdefines.IMGUI_HAS_DOCK then
		cstructsstr = cstructsstr.."\n#define IMGUI_HAS_DOCK       1\n"
	end
	if gdefines.ImDrawCallback_ResetRenderState then
		cstructsstr = cstructsstr.."\n#define ImDrawCallback_ResetRenderState       "..gdefines.ImDrawCallback_ResetRenderState.."\n"
	end
	if gdefines.IMGUI_HAS_IMSTR then
		if not (NOCHAR or NOIMSTRV) then
		cstructsstr = cstructsstr.."\n#define IMGUI_HAS_IMSTR       1\n"
		end
	end
	
	cstructsstr = colapse_defines(cstructsstr, "IMGUI_ENABLE_FREETYPE")
	
    hstrfile = hstrfile:gsub([[#include "imgui_structs%.h"]],cstructsstr)
    local cfuncsstr = func_header_generate(parser)
	cfuncsstr = colapse_defines(cfuncsstr, "IMGUI_ENABLE_FREETYPE")
    hstrfile = hstrfile:gsub([[#include "auto_funcs%.h"]],cfuncsstr)
	--patch hstrfile for ImWchar
	local num
	hstrfile, num = hstrfile:gsub("typedef ImWchar16 ImWchar;", wchardefine)
	assert(num == 1)
	hstrfile, num = hstrfile:gsub("kPagesMap%[%(0xFFFF", "kPagesMap[(IM_UNICODE_CODEPOINT_MAX")
	assert(num == 1, "kPagesMap[(IM_UNICODE_CODEPOINT_MAX not found or found more than once")
    save_data("./output/cimgui.h",cimgui_header,hstrfile)
    
    --merge it in cimgui_template.cpp to cimgui.cpp
    local cimplem = func_implementation(parser)
	cimplem = colapse_defines(cimplem, "IMGUI_ENABLE_FREETYPE")
    local hstrfile = read_data"./cimgui_template.cpp"

    hstrfile = hstrfile:gsub([[#include "auto_funcs%.cpp"]],cimplem)
	local ftdef = "" --FREETYPE_GENERATION and "#define IMGUI_ENABLE_FREETYPE\n" or ""
    save_data("./output/cimgui.cpp",cimgui_header, ftdef, hstrfile)

end
--------------------------------------------------------
-----------------------------do it----------------------
--------------------------------------------------------
--get imgui.h version and IMGUI_HAS_DOCK--------------------------
--defines for the cl compiler must be present in the print_defines.cpp file
gdefines = get_defines{"IMGUI_VERSION","IMGUI_VERSION_NUM","FLT_MAX","FLT_MIN","IMGUI_HAS_DOCK","IMGUI_HAS_IMSTR","ImDrawCallback_ResetRenderState","IMGUI_HAS_TEXTURES"}
cpp2ffi.prtable(gdefines)
if gdefines.IMGUI_HAS_DOCK then gdefines.IMGUI_HAS_DOCK = true end
if gdefines.IMGUI_HAS_IMSTR then gdefines.IMGUI_HAS_IMSTR = true end

cimgui_header = cimgui_header:gsub("XXX",gdefines.IMGUI_VERSION .. " "..(gdefines.IMGUI_VERSION_NUM or ""))
if INTERNAL_GENERATION then
	cimgui_header = cimgui_header..[[//with imgui_internal.h api
]]
end
if FREETYPE_GENERATION then
	cimgui_header = cimgui_header..[[//with imgui_freetype.h api
]]
end
if gdefines.IMGUI_HAS_DOCK then
	cimgui_header = cimgui_header..[[//docking branch
]]
	
end
assert(not NOCHAR or not NOIMSTRV,"nochar and noimstrv cant be set at the same time")
print("IMGUI_HAS_IMSTR",gdefines.IMGUI_HAS_IMSTR)
print("IMGUI_HAS_TEXTURES",gdefines.IMGUI_HAS_TEXTURES and true)
print("NOCHAR",NOCHAR)
print("NOIMSTRV",NOIMSTRV)
print("IMGUI_HAS_DOCK",gdefines.IMGUI_HAS_DOCK)
print("IMGUI_VERSION",gdefines.IMGUI_VERSION)

local function custom_function_post(self, outtab, def)
	assert(def.location)
	if def.location:match("imgui_freetype") then 
		outtab[#outtab] = "#ifdef IMGUI_ENABLE_FREETYPE\n"..outtab[#outtab].."\n#endif\n"
	end
end
local function header_text_insert(self, outtab, txt, it)
	assert(it.locat)
	if it.locat:match("imgui_freetype") then 
		table.insert(outtab, "\n#ifdef IMGUI_ENABLE_FREETYPE"..txt.."\n#endif")
	else
		table.insert(outtab, txt)
	end
end

--funtion for parsing imgui headers
local function parseImGuiHeader(header,names)
	--prepare parser
	local parser = cpp2ffi.Parser()
	
	parser.getCname = function(stname,funcname,namespace)
		local pre = (stname == "") and (namespace and (namespace=="ImGui" and "ig" or namespace.."_") or "ig") or stname.."_"
		return pre..funcname
	end
	parser.cname_overloads = cimgui_overloads
	--parser.manuals = cimgui_manuals
	parser:set_manuals(cimgui_manuals, "cimgui")
	parser.skipped = cimgui_skipped
	parser.UDTs = {"ImVec2","ImVec4","ImColor","ImRect"}
	--parser.gen_template_typedef = gen_template_typedef --use auto
	parser.COMMENTS_GENERATION = COMMENTS_GENERATION
	parser.CONSTRUCTORS_GENERATION = CONSTRUCTORS_GENERATION
	parser.NOCHAR = NOCHAR
	parser.NOIMSTRV = NOIMSTRV
	parser.IMGUI_HAS_TEXTURES = gdefines.IMGUI_HAS_TEXTURES
	parser.custom_function_post = custom_function_post
	parser.header_text_insert = header_text_insert
	local defines = parser:take_lines(CPRE..header,names,COMPILER)
	
	return parser
end
--generation
print("------------------generation with "..COMPILER.."------------------------")
local parser1
local headers = [[#include "]]..IMGUI_PATH..[[/imgui.h" 
]]
local headersT = {[[imgui]]}
if INTERNAL_GENERATION then
	headers = headers .. [[#include "]]..IMGUI_PATH..[[/imgui_internal.h"
	]]
	headersT[#headersT + 1] = [[imgui_internal]]
	headersT[#headersT + 1] = [[imstb_textedit]]
end
if FREETYPE_GENERATION then
	headers = headers .. [[
	#include "]]..IMGUI_PATH..[[/misc/freetype/imgui_freetype.h"
	]]
	headersT[#headersT + 1] = [[imgui_freetype]]
end
save_data("headers.h",headers)
local include_cmd = COMPILER=="cl" and [[ /I ]] or [[ -I ]]
local extra_includes = include_cmd.." " ..IMGUI_PATH.." "
local parser1 = parseImGuiHeader(extra_includes .. [[headers.h]],headersT)
os.remove("headers.h")
parser1:do_parse()

--to debug items parsing
--save_data("./itemsarr2.txt",cpp2ffi.ToStr(parser1.itemsarr))
save_data("./output/overloads.txt",parser1.overloadstxt)
cimgui_generation(parser1)

----------save struct and enums lua table in structs_and_enums.lua for using in bindings

local structs_and_enums_table = parser1.structs_and_enums_table
structs_and_enums_table.templated_structs = parser1.templated_structs
structs_and_enums_table.typenames = parser1.typenames
structs_and_enums_table.templates_done = parser1.templates_done

save_data("./output/structs_and_enums.lua",serializeTableF(structs_and_enums_table))
save_data("./output/typedefs_dict.lua",serializeTableF(parser1.typedefs_dict))

----------save fundefs in definitions.lua for using in bindings
--DefsByStruct(pFP)
set_defines(parser1.defsT) 
save_data("./output/definitions.lua",serializeTableF(parser1.defsT))

--check every function has ov_cimguiname
-- for k,v in pairs(parser1.defsT) do
	-- for _,def in ipairs(v) do
		-- assert(def.ov_cimguiname)
	-- end
-- end

--=================================Now implementations
local backends_folder 
local ff,err = io.open (IMGUI_PATH .. "/examples/imgui_impl_glfw.h" ,"r")
if ff then
	backends_folder = IMGUI_PATH .. "/examples/"
	ff:close()
else
	backends_folder = IMGUI_PATH .. "/backends/"
end
 
local parser2

if #implementations > 0 then
	print("------------------implementations generation with "..COMPILER.."------------------------")
	--parser2 for function defs
	--parser3 for separated structs and enums in cimgui_impl.h
    parser2 = cpp2ffi.Parser()
	
	local config = dofile(CONFIG_GENERATOR_PATH) --"./config_generator.lua"
    local impl_str = "#ifndef CIMGUI_IMPL_DEFINED\n#define CIMGUI_IMPL_DEFINED\n"
	local impl_str_cpp = {}
    for i,impl in ipairs(implementations) do
		print("------------implementation:",impl)
		table.insert(impl_str_cpp, "\n#ifdef CIMGUI_USE_" .. string.upper(impl))
		table.insert(impl_str_cpp, [[#include "imgui_impl_]]..impl..[[.h"]])
		table.insert(impl_str_cpp, "#endif")

        local source = backends_folder .. [[imgui_impl_]].. impl .. ".h "
        local locati = [[imgui_impl_]].. impl

		local define_cmd = COMPILER=="cl" and [[ /E /D]] or [[ -E -D]]
		local extra_defines = ""
		if impl == "opengl3" then extra_defines = define_cmd .. "IMGUI_IMPL_OPENGL_LOADER_GL3W " end
		local include_cmd = COMPILER=="cl" and [[ /I ]] or [[ -I ]]
		local extra_includes = include_cmd.." ".. IMGUI_PATH .." "
		if config[impl] then
			for j,inc in ipairs(config[impl]) do
				extra_includes = extra_includes .. include_cmd .. inc .. " "
			end
		end
		parser2.cimgui_inherited =  dofile([[./output/structs_and_enums.lua]])
		local defines = parser2:take_lines(CPRE..extra_defines..extra_includes..source, {locati}, COMPILER)
		
		local parser3 = cpp2ffi.Parser()
		parser3.cimgui_inherited =  dofile([[./output/structs_and_enums.lua]])
		parser3:take_lines(CPRE..extra_defines..extra_includes..source, {locati}, COMPILER)
		parser3:do_parse()
		local cfuncsstr = func_header_impl_generate(parser3) 
		local cstructstr1,cstructstr2 = parser3.structs_and_enums[1], parser3.structs_and_enums[2]
		local cstru = cstructstr1 .. cstructstr2
		if cstru ~="" then
			cstru = "#ifdef CIMGUI_DEFINE_ENUMS_AND_STRUCTS\n"..cstru .."\n#endif //CIMGUI_DEFINE_ENUMS_AND_STRUCTS\n"
		end
		impl_str = impl_str .. "#ifdef CIMGUI_USE_".. string.upper(impl).."\n".. cstru
		local outtab = cpp2ffi.func_header_generate_structs(parser3)
		if #outtab > 0 then
			table.insert(outtab, 1, "#ifndef CIMGUI_DEFINE_ENUMS_AND_STRUCTS\n")
			table.insert(outtab,"#endif //CIMGUI_DEFINE_ENUMS_AND_STRUCTS\n")
		end
		impl_str = impl_str.. table.concat(outtab)..cfuncsstr .. "\n#endif\n"
    end
	impl_str = impl_str .. "#endif //CIMGUI_IMPL_DEFINED\n"
    parser2:do_parse()
	save_data("./output/cimgui_impl.h",impl_str)

    ----------save fundefs in impl_definitions.lua for using in bindings
    save_data("./output/impl_definitions.lua",serializeTableF(parser2.defsT))
	--impl cpp
	impl_str_cpp = table.concat(impl_str_cpp, "\n")
	local cppstr = read_data"./cimgui_impl_template.cpp"
	cppstr = cppstr:gsub("GENERATED_PLACEHOLDER", impl_str_cpp)
	save_data("./output/cimgui_impl.cpp",cppstr)
	
	copyfile("./output/cimgui_impl.h", "../cimgui_impl.h")
	copyfile("./output/cimgui_impl.cpp", "../cimgui_impl.cpp")
	os.remove("./output/cimgui_impl.h")
	os.remove("./output/cimgui_impl.cpp")

end -- #implementations > 0 then

-------------------------------json saving
--avoid mixed tables (with string and integer keys)
local function json_prepare(defs)
    --delete signatures in function
    for k,def in pairs(defs) do
        for k2,v in pairs(def) do
            if type(k2)=="string" then
                def[k2] = nil
            end
        end
    end
    return defs
end
---[[
local json = require"json"
save_data("./output/definitions.json",json.encode(json_prepare(parser1.defsT),{dict_on_empty={defaults=true}}))
--delete extra info for json
--structs_and_enums_table.templated_structs = nil
--structs_and_enums_table.typenames = nil
--structs_and_enums_table.templates_done = nil
save_data("./output/structs_and_enums.json",json.encode(structs_and_enums_table))
save_data("./output/typedefs_dict.json",json.encode(parser1.typedefs_dict))
if parser2 then
    save_data("./output/impl_definitions.json",json.encode(json_prepare(parser2.defsT),{dict_on_empty={defaults=true}}))
end
--]]
-------------------copy C files to repo root
copyfile("./output/cimgui.h", "../cimgui.h")
copyfile("./output/cimgui.cpp", "../cimgui.cpp")
os.remove("./output/cimgui.h")
os.remove("./output/cimgui.cpp")
print"all done!!"
