#include <string.h>
#include "luaconsole.hpp"
#include "util.hpp"
#include <iostream>

static bool is_single_letter(const std::string &s) {
    return ((s.size() == 1) && (s[0] >= 'a') && (s[0] <= 'z'));
}

LuaConsole::LuaConsole() {
    lua_state_ = luaL_newstate();
    clear_raw_input();
}

LuaConsole::~LuaConsole() {
    lua_close(lua_state_);
}

static LuaConsole::StringVec split_words(const std::string &raw) {
    LuaConsole::StringVec result;
    std::string acc;
    for (char c : raw) {
        if ((c == ' ')||(c == '\n')||(c == '\r')) {
            if (!acc.empty()) {
                result.push_back(acc);
                acc = "";
            }
        } else {
            acc += c;
        }
    }
    if (!acc.empty()) {
        result.push_back(acc);
    }
    return result;
}

LuaConsole::StringVec LuaConsole::get_command() {
    StringVec result = words_;
    words_.clear();
    return result;
}

void LuaConsole::clear_raw_input() {
    raw_input_ = "";
    lines_ = 0;
    prompt_ = "> ";
}

void LuaConsole::add(std::string line) {
    for (int i = 0; i < int(line.size()); i++) {
        if (line[i] == '\n') line[i] = ' ';
    }
    raw_input_ += line;
    raw_input_ += '\n';
    lines_ += 1;
    prompt_ = ">> ";

    // Try to interpret it as a special command.
    if (lines_ == 1) {
        StringVec words = split_words(raw_input_);
        if (words.size() >= 1) {
            if (is_single_letter(words[0]) || (util::validinteger(words[0]))) {
                words_ = words;
                clear_raw_input();
                return;
            }
        }
    }

    // Translate lua expression with leading '=' to 'return'
    std::string partial;
    if (raw_input_[0] == '=') {
        partial = std::string("return ") + raw_input_.substr(1);
    } else {
        partial = raw_input_;
    }

    // Try to parse the lua expression
    int top = lua_gettop(lua_state_);
    int status = luaL_loadbuffer(lua_state_, partial.c_str(), partial.size(), "=stdin");
    if (status == LUA_ERRSYNTAX)
    {
        const char *eof = "<eof>";
        int leof = strlen(eof);
        size_t lmsg;
        const char *msg = lua_tolstring(lua_state_, -1, &lmsg);
        const char *tp = msg + lmsg - leof;
        if (strstr(msg, eof) != tp) {
            words_.push_back("syntax");
            words_.push_back(msg);
            clear_raw_input();
        }
    } else {
        words_.push_back("lua");
        words_.push_back(partial);
        clear_raw_input();
    }
    lua_settop(lua_state_, top);
}