#include <assert.h>
#include <string.h>

#include "api.h"
#include "../any_log.h"

static lua_CFunction lua_log_stringformat = NULL;

static int lua_log_format(lua_State *state, any_log_level_t level) {

    // Use string.format to print safely
    //
    int n_args = lua_gettop(state);
    lua_pushcfunction(state, lua_log_stringformat);

    for (int i = 1; i <= n_args; ++i)
        lua_pushvalue(state, i);

    lua_call(state, n_args, 1);
    const char *message = lua_tostring(state, -1);

    lua_getglobal(state, "debug");
    lua_getfield(state, -1, "getinfo");

    // Ignore the first frame (lua_log_format itself)
    lua_pushnumber(state, 2);
    // S: source, l: currentline, n: name
    lua_pushstring(state, "Sln");

    const char *source = "?", *func = "?";
    char buffer[4096];

    if (lua_pcall(state, 2, 1, 0) == LUA_OK) {

        lua_getfield(state, -1, "short_src");
        const char *shortsrc = lua_tostring(state, -1);

        lua_getfield(state, -2, "currentline");
        int line = lua_tointeger(state, -1);

        if (!strncmp(shortsrc, "[string ", 8)) {
            int length = strlen(shortsrc);
            snprintf(buffer, sizeof(buffer), "lua %.*s", length - 9, shortsrc + 8);
        } else {
            snprintf(buffer, sizeof(buffer), "lua %s:%d", shortsrc, line);
        }

        lua_getfield(state, -3, "name");
        const char *name = lua_tostring(state, -1);

        source = buffer;
        func = name ? name :  "...";
    }

    lua_pop(state, 3);
    any_log_format(level, source, func, "%s", message);
    return 0;
}

static int lua_log_log(lua_State *state) {
    const char *level = luaL_checkstring(state, 1);
    lua_pop(state, 1);
    any_log_level_t l = any_log_level_from_string(level);
    assert(l > ANY_LOG_ALL);
    return lua_log_format(state, l);
}

static int lua_log_panic(lua_State *state) {
    return lua_log_format(state, ANY_LOG_PANIC);
}

static int lua_log_error(lua_State *state) {
    return lua_log_format(state, ANY_LOG_ERROR);
}

static int lua_log_warn(lua_State *state) {
    return lua_log_format(state, ANY_LOG_WARN);
}

static int lua_log_info(lua_State *state) {
    return lua_log_format(state, ANY_LOG_INFO);
}

static int lua_log_debug(lua_State *state) {
    return lua_log_format(state, ANY_LOG_DEBUG);
}

static int lua_log_trace(lua_State *state) {
    return lua_log_format(state, ANY_LOG_TRACE);
}

int lua_log_library(lua_State *state)
{
    static const luaL_Reg library[] = {
        { "log",   lua_log_log },
        { "panic", lua_log_panic },
        { "error", lua_log_error },
        { "warn",  lua_log_warn },
        { "info",  lua_log_info },
        { "debug", lua_log_debug },
        { "trace", lua_log_trace },
        { NULL, NULL },
    };

    lua_getglobal(state, "string");
    lua_getfield(state, -1, "format");
    lua_log_stringformat = lua_tocfunction(state, -1);
    lua_pop(state, 2);

    luaL_newlib(state, library);
    return 1;
}