#include "IPC_buffer.h"
#include <string.h>
#include "../debug.h"
#include <ctype.h>



static int syscalls_indexIPC_buffer(lua_State* L)
{
	struct IPC_buffer* r = luaL_checkudata(L, 1, syscalls_IPC_buffer_metatable_name);
	const char* index = luaL_checkstring(L, 2);

	if (strcmp(index, "used") == 0)
	{
		lua_pushinteger(L, r->used);
	}
	else if (strcmp(index, "lock") == 0)
	{
		lua_pushboolean(L, r->lock);
	}
	else if (strcmp(index, "size") == 0)
	{
		lua_pushnumber(L, r->size);
	}
	else
	{
		lua_pushnil(L);
	}

	return 1;
}

static int syscalls_newindexIPC_buffer(lua_State* L)
{
	struct IPC_buffer* r = luaL_checkudata(L, 1, syscalls_IPC_buffer_metatable_name);
	const char* index = luaL_checkstring(L, 2);
	int val = luaL_checkinteger(L, 3);

	if (strcmp(index, "used") == 0)
	{
		r->used = val;
	}
	else if (strcmp(index, "lock") == 0)
	{
		r->lock = val;
	}
	else
	{
		luaL_error(L, "wrong index: %s", index);
	}

	return 0;
}

static bool compare_ipc_buffer(ksys_ipc_buffer* a, ksys_ipc_buffer* b)
{	// блять че за высер...
	if (a == b)
		return true;

	if (a->used == b->used)
	{
		return memcmp(
			a + (2 * sizeof(unsigned)),
			b + (2 * sizeof(unsigned)),
			a->used
		);
	}
	else	// длина сообщений не совпадает, занчитт они зразу не могут быть равны
	{
		return false;
	}
}

static int syscalls_eqIPC_buffer(lua_State* L)
{
	lua_pushboolean(
		L,
		compare_ipc_buffer(
			luaL_checkudata(L, 1, syscalls_IPC_buffer_metatable_name),
			luaL_checkudata(L, 2, syscalls_IPC_buffer_metatable_name)
		)
	);

	return 1;
}

static int syscalls_IPC_buffer_lock(lua_State* L)
{
	ksys_ipc_buffer* buffer = luaL_checkudata(L, 1, syscalls_IPC_buffer_metatable_name);

	buffer->lock = 1;

	return 0;
}

static int syscalls_IPC_buffer_unlock(lua_State* L)
{
	ksys_ipc_buffer* buffer = luaL_checkudata(L, 1, syscalls_IPC_buffer_metatable_name);

	buffer->lock = 0;

	return 0;
}

/**
 * @brief Получить сообщение под номером
 * @param buffer
 * @param i
 * @return указатель на сообщение, если такого сообщения ещё нет, то возвращает
 */
static ksys_ipc_msg* IPC_buffer_get_message(struct IPC_buffer* buffer, int i)
{
	ksys_ipc_msg* j = (ksys_ipc_msg*)(buffer + 8);
	unsigned diff = 0;

	for (int k = 0; k < i; k++)
	{
		diff += j->datalen + 8; // прибавление длинны сообщения и заголовка 
		j += diff;

		if (diff >= buffer->used)
			return 0;
	}

	return j;
}

static ksys_ipc_msg* IPC_buffer_get_last_message(struct IPC_buffer* buffer)
{
	ksys_ipc_msg* j = (ksys_ipc_msg*)(buffer + 8);
	unsigned diff = 0;

	while (diff < buffer->used)
	{
		j += diff;
		diff += j->datalen + 8; // прибавление длинны сообщения и заголовка 
	}

	return j;
}

static int syscalls_IPC_buffer_get_message(lua_State* L)
{
	struct IPC_buffer* buffer = luaL_checkudata(L, 1, syscalls_IPC_buffer_metatable_name);
	unsigned i = luaL_checkinteger(L, 1);

	ksys_ipc_msg* msg = IPC_buffer_get_message(buffer, i);

	if (msg)
	{
		lua_pushlightuserdata(L, msg);
	}
	else
	{
		lua_pushnil(L);
	}

	return 1;
}

static int syscalls_IPC_buffer_get_last_message(lua_State* L)
{
	struct IPC_buffer* buffer = luaL_checkudata(L, 1, syscalls_IPC_buffer_metatable_name);

	lua_pushlightuserdata(L, IPC_buffer_get_last_message(buffer));

	return 1;
}

static int syscalls_IPC_buffer_reset(lua_State* L)
{
	struct IPC_buffer* buffer = luaL_checkudata(L, 1, syscalls_IPC_buffer_metatable_name);

	buffer->used = 0;
	memset(&buffer->data, 0, buffer->size);

	return 0;
}

static const luaL_Reg syscalls_IPC_buffer_m[] = {
	{"__index", syscalls_indexIPC_buffer},
	{"__newindex", syscalls_newindexIPC_buffer},
	{"__eq", syscalls_eqIPC_buffer},
	{"Lock", syscalls_IPC_buffer_lock},
	{"Unlock", syscalls_IPC_buffer_unlock},
	{"GetMessage", syscalls_IPC_buffer_get_message},
	{"GetLastMessage", syscalls_IPC_buffer_get_last_message},
	{"Reset", syscalls_IPC_buffer_reset},
	{NULL, NULL}
};

struct IPC_buffer* syscalls_pushIPC_buffer(lua_State* L, size_t size)
{
	DEBUG_LINE("push " syscalls_IPC_buffer_name " entry");

	struct IPC_buffer* buffer = lua_newuserdata(L, sizeof(struct IPC_buffer) + size);

	luaL_setmetatable(L, syscalls_IPC_buffer_metatable_name);

	buffer->used = 0;
	buffer->size = size;

	return buffer;
}

static int syscalls_newIPC_buffer(lua_State* L)
{
	size_t size = luaL_checkinteger(L, 1);
	struct IPC_buffer* buffer = syscalls_pushIPC_buffer(L, size);

	return 1;
}

static const luaL_Reg syscalls_IPC_buffer_lib[] = {
	{"new", syscalls_newIPC_buffer},
	{NULL, NULL}
};

void syscalls_register_IPC_buffer(lua_State* L)
{
	DEBUG_LINE("register " syscalls_IPC_buffer_name " entry");

	luaL_newlib(L, syscalls_IPC_buffer_lib);

	lua_setfield(L, -2, syscalls_IPC_buffer_name);


	luaL_newmetatable(L, syscalls_IPC_buffer_metatable_name);
	luaL_setfuncs(L, syscalls_IPC_buffer_m, 0);

	lua_pop(L, 1);
}