/*
 * Ricochet - A minimalist CLI web browser for fast, distraction-free navigation.
 * Copyright (C) 2026  Richard Qin
 *
 * This program 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 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include "ricochet/parser/tree_builder.hh"
#include "ricochet/parser/dom_tree.hh"
#include <utility>
#include <vector>

namespace ricochet::parser {

namespace {
struct TokenVisitor {
    std::vector<DomNode>* stack;

    void operator()(const TextToken& token) const {
        stack->back().children.emplace_back(
            DomNode{
                .tag_name = "",
                .text_content = token.content, 
                .children = {}
            }
        );
    }

    void operator()(const TagOpenToken& token) const {
        DomNode new_node{
            .tag_name = token.name, 
            .text_content = "", 
            .children = {}
        };

        if (token.name == "meta" || token.name == "link" || token.name == "img" || 
            token.name == "br" || token.name == "hr" || token.name == "input" || 
            token.name == "base" || token.name == "col") {
            
            stack->back().children.push_back(std::move(new_node));
        } else {
            stack->push_back(std::move(new_node));
        }
    }

    void operator()(const TagCloseToken& /*token*/) const {
        if (stack->size() > 1) {
            DomNode completed_node = std::move(stack->back());
            stack->pop_back();
            stack->back().children.push_back(std::move(completed_node));
        }
    }
};
} // namespace

DomNode TreeBuilder::build(const std::vector<HtmlToken>& tokens) const // NOLINT(readability-convert-member-functions-to-static)
{
    std::vector<DomNode> stack;
    stack.emplace_back(DomNode{
        .tag_name = "Document",
        .text_content = "",
        .children = {}
    });

    TokenVisitor visitor{&stack};
    for (const auto& token : tokens) {
        std::visit(visitor, token);
    }

    while (stack.size() > 1) {
        DomNode completed_node = std::move(stack.back());
        stack.pop_back();
        stack.back().children.push_back(std::move(completed_node));
    }

    return std::move(stack.front());
}

} // namespace ricochet::parser