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


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

LuaConsole::LuaConsole() {
    lua_state_ = lua_open();
    clear();
}

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

void LuaConsole::clear() {
    raw_input_ = "";
    lines_ = 0;
    lua_expression_ = "";
    words_.clear();
    syntax_ = "";
    action_ = DO_NOTHING;
}

void LuaConsole::split_words() {
    words_.clear();
    std::string acc;
    for (char c : raw_input_) {
        if ((c == ' ')||(c == '\n')) {
            if (!acc.empty()) {
                words_.push_back(acc);
                acc = "";
            }
        } else {
            acc += c;
        }
    }
    if (!acc.empty()) {
        words_.push_back(acc);
    }
}

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

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

    // 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>'";
        size_t lmsg;
        const char *msg = lua_tolstring(lua_state_, -1, &lmsg);
        const char *tp = msg + lmsg - (sizeof(eof) - 1);
        if (strstr(msg, eof) == tp) {
            action_ = DO_NOTHING;
        } else {
            action_ = DO_SYNTAX;
            syntax_ = msg;
        }
    } else {
        action_ = DO_LUA;
        lua_expression_ = partial;
    }
    lua_settop(lua_state_, top);
}

void LuaConsole::add_stdin() {
    if (action_ != DO_NOTHING) {
        clear();
    }
    const int MAXINPUT = 1000;
    char buf[MAXINPUT];
    fputs(raw_input_.empty() ? "> " : ">> ", stdout);
    fflush(stdout);
    if (fgets(buf, MAXINPUT, stdin)) {
        size_t len = strlen(buf);
        if (len > 0 && buf[len - 1] == '\n')
            buf[len - 1] = '\0';
        add(buf);
    }
}