#include "text_buffer.h"

#include <algorithm>

namespace roro::gemini {

void TextBuffer::append(const char* data, size_t len) {
    bytes_ += len;
    for (size_t i = 0; i < len; i++) {
        if (data[i] == '\n') endLine();
        else partial_ += data[i];
    }
}

void TextBuffer::finish() {
    if (!partial_.empty()) endLine();
}

void TextBuffer::endLine() {
    if (!partial_.empty() && partial_.back() == '\r') partial_.pop_back();
    size_t len = std::min<size_t>(partial_.size(), 0xFFFF);
    // A line never spans two chunks: a new chunk when it doesn't fit (bigger if the line is).
    if (chunks_.empty() || chunks_.back().size() + len > chunks_.back().capacity()) {
        chunks_.emplace_back();
        chunks_.back().reserve(std::max(kChunk, len));
    }
    std::string& chunk = chunks_.back();
    lines_.push_back({static_cast<uint16_t>(chunks_.size() - 1), static_cast<uint16_t>(chunk.size()),
                      static_cast<uint16_t>(len)});
    chunk.append(partial_, 0, len);
    partial_.clear();
}

std::string TextBuffer::line(size_t i) const {
    if (i >= lines_.size()) return "";
    const Ref& r = lines_[i];
    return chunks_[r.chunk].substr(r.offset, r.length);
}

void TextBuffer::clear() {
    chunks_.clear();
    lines_.clear();
    partial_.clear();
    bytes_ = 0;
}

}  // namespace roro::gemini