/* Dependency graph analysis.
   Copyright (C) 2025 Free Software Foundation, Inc.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "elna/boot/dependency.h"

#include <fstream>
#include <sstream>
#include <string.h>

#include "elna/boot/driver.h"
#include "elna/boot/semantic.h"
#include "parser.hh"

namespace elna::boot
{
    source_path_error::source_path_error(const std::string& message, const char *path)
        : error(path, { 0, 0 }), message(message)
    {
    }

    std::string source_path_error::what() const
    {
        std::stringstream output;
        output << "Cannot open filename ";
        output << this->path;
        output << ": ";
        output << this->message;

        return output.str();
    }

    dependency::dependency()
    {
    }

    dependency::dependency(error_list&& errors)
        : m_errors(std::move(errors))
    {
    }

    bool dependency::has_errors() const
    {
        return !errors().empty();
    }

    const error_list& dependency::errors() const
    {
        return m_errors;
    }

    dependency parse_source(std::istream& entry_point, const char *entry_path)
    {
        driver parse_driver{ entry_path };
        lexer tokenizer(entry_point);
        yy::parser parser(tokenizer, parse_driver);

        if (parser())
        {
            return dependency(std::move(parse_driver.errors()));
        }
        else
        {
            dependency outcome;
            std::swap(outcome.tree, parse_driver.tree);

            return outcome;
        }
    }

    dependency read_sources(const char *entry_path, std::shared_ptr<symbol_table> info_table,
            std::shared_ptr<symbol_table> imports)
    {
        std::ifstream entry_point{ entry_path, std::ios::in };

        if (!entry_point)
        {
            error_list errors;
            errors.push_back(std::make_unique<source_path_error>(strerror(errno), entry_path));

            return dependency(std::move(errors));
        }
        auto outcome = parse_source(entry_point, entry_path);

        declaration_visitor declaration_visitor(entry_path);
        outcome.tree->accept(&declaration_visitor);

        if (!declaration_visitor.errors().empty())
        {
            return dependency(std::move(declaration_visitor.errors()));
        }
        outcome.unresolved = declaration_visitor.unresolved;
        outcome.bag = symbol_bag{ std::move(declaration_visitor.unresolved), info_table };

        if (imports != nullptr)
        {
            outcome.bag.add_import(imports);
        }
        elna::boot::name_analysis_visitor name_analysis_visitor(entry_path, outcome.bag);
        outcome.tree->accept(&name_analysis_visitor);

        if (!name_analysis_visitor.errors().empty())
        {
            return dependency(std::move(declaration_visitor.errors()));
        }
        return outcome;
    }
}