#include "comdel_lexer.h"
#include "comdel_parser.h"
#include "parser_util.h"

#include <iostream>
#include <fstream>
#include <string>
#include <QDir>

std::optional<LibraryNode> load_library_from_file(ParseContext *parseContext,
                                                  const char *name,
                                                  std::ostream &stream) {
    std::ifstream in(name, std::ios::in | std::ios::binary);
    if (!in) {
        stream << "ERROR: cannot open file '" << name
               << "' (file does not exist or is unreadable)" << std::endl;
        return std::nullopt;
    }

    std::string source((std::istreambuf_iterator<char>(in)),
                       std::istreambuf_iterator<char>());
    ComdelLexer lexer(name, source, parseContext);
    LexerResult lexerResult = lexer.tokenize();

    if (!lexerResult.errors.empty()) {
        for (auto &error: lexerResult.errors) {
            parseContext->formatError(error, stream, "ERROR: ");
        }
        return std::nullopt;  // if lexer has found errors => don't parseLibrary
    }

    ComdelParser parser(lexerResult.tokens);
    auto unit = parser.parseLibrary();
    if (!unit) {
        for (auto &error: parser.getErrors()) {
            parseContext->formatError(error, stream, "ERROR: ");
        }
        return std::nullopt;
    }

    return *unit;
}


std::optional<SchemaNode> load_schema_from_file(ParseContext *parseContext,
                                                const char *name,
                                                std::ostream &stream) {
    std::ifstream in(name, std::ios::in | std::ios::binary);
    if (!in) {
        stream << "ERROR: cannot open file '" << name
               << "' (file does not exist or is unreadable)" << std::endl;
        return std::nullopt;
    }

    std::string source((std::istreambuf_iterator<char>(in)),
                       std::istreambuf_iterator<char>());
    ComdelLexer lexer(name, source, parseContext);
    LexerResult lexerResult = lexer.tokenize();

    if (!lexerResult.errors.empty()) {
        for (auto &error: lexerResult.errors) {
            parseContext->formatError(error, stream, "ERROR: ");
        }
        return std::nullopt;  // if lexer has found errors => don't parseLibrary
    }

    ComdelParser parser(lexerResult.tokens);
    auto unit = parser.parseSchema();
    if (!unit) {
        for (auto &error: parser.getErrors()) {
            parseContext->formatError(error, stream, "ERROR: ");
        }
        return std::nullopt;
    }

    if (unit->source) {
        QFileInfo info(name);
        auto filepath = info.absolutePath();
        QDir::setCurrent(filepath);

        QDir dir;
        auto libraryPath = dir.absoluteFilePath(QString::fromStdString(unit->source->asString()));

        unit->library = load_library_from_file(parseContext, libraryPath.toUtf8().data(), stream);
        if (unit->library == std::nullopt) {
            return std::nullopt;
        }
    }


    return *unit;
}