/* Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

#include "misc/InterpreterDataReader.h"

#include "Vocabulary.h"
#include "atn/ATN.h"
#include "atn/ATNDeserializer.h"

using namespace antlr4::dfa;
using namespace antlr4::atn;
using namespace antlr4::misc;

InterpreterData::InterpreterData(
    std::vector<std::string> const& literalNames, std::vector<std::string> const& symbolicNames)
    : vocabulary(literalNames, symbolicNames) {}

InterpreterData InterpreterDataReader::parseFile(std::string const& fileName) {
    // The structure of the data file is very simple. Everything is line based with empty lines
    // separating the different parts. For lexers the layout is:
    // token literal names:
    // ...
    //
    // token symbolic names:
    // ...
    //
    // rule names:
    // ...
    //
    // channel names:
    // ...
    //
    // mode names:
    // ...
    //
    // atn:
    // <a single line with comma separated int values> enclosed in a pair of squared brackets.
    //
    // Data for a parser does not contain channel and mode names.

    std::ifstream input(fileName);
    if (!input.good())
        return {};

    std::vector<std::string> literalNames;
    std::vector<std::string> symbolicNames;

    std::string line;

    std::getline(input, line, '\n');
    assert(line == "token literal names:");
    while (true) {
        std::getline(input, line, '\n');
        if (line.empty())
            break;

        literalNames.push_back(line == "null" ? "" : line);
    };

    std::getline(input, line, '\n');
    assert(line == "token symbolic names:");
    while (true) {
        std::getline(input, line, '\n');
        if (line.empty())
            break;

        symbolicNames.push_back(line == "null" ? "" : line);
    };
    InterpreterData result(literalNames, symbolicNames);

    std::getline(input, line, '\n');
    assert(line == "rule names:");
    while (true) {
        std::getline(input, line, '\n');
        if (line.empty())
            break;

        result.ruleNames.push_back(line);
    };

    std::getline(input, line, '\n');
    if (line == "channel names:") {
        while (true) {
            std::getline(input, line, '\n');
            if (line.empty())
                break;

            result.channels.push_back(line);
        };

        std::getline(input, line, '\n');
        assert(line == "mode names:");
        while (true) {
            std::getline(input, line, '\n');
            if (line.empty())
                break;

            result.modes.push_back(line);
        };
    }

    std::vector<uint16_t> serializedATN;

    std::getline(input, line, '\n');
    assert(line == "atn:");
    std::getline(input, line, '\n');
    std::stringstream tokenizer(line);
    std::string value;
    while (tokenizer.good()) {
        std::getline(tokenizer, value, ',');
        unsigned long number;
        if (value[0] == '[')
            number = std::strtoul(&value[1], nullptr, 10);
        else
            number = std::strtoul(value.c_str(), nullptr, 10);
        serializedATN.push_back(static_cast<uint16_t>(number));
    }

    ATNDeserializer deserializer;
    result.atn = deserializer.deserialize(serializedATN);
    return result;
}
