#include "byte_stream.hh"

#include <algorithm>
// Dummy implementation of a flow-controlled in-memory byte stream.

// For Lab 0, please replace with a real implementation that passes the
// automated checks run by `make check_lab0`.

// You will need to add private members to the class declaration in `byte_stream.hh`

template <typename... Targs>
void DUMMY_CODE(Targs &&.../* unused */) {}

using namespace std;

ByteStream::ByteStream(const size_t capacity) { _capacity = capacity; }

size_t ByteStream::write(const string &data) {
    size_t remain = this->_capacity - this->_buffer.size();
    size_t written = std::min(remain, data.size());
    for (size_t i = 0; i < written; ++i) {
        _buffer.push_back(data[i]);
    }
    this->_written_count += written;
    return written;
}

//! \param[in] len bytes will be copied from the output side of the buffer
string ByteStream::peek_output(const size_t len) const {
    string output;
    size_t avail = std::min(len, _buffer.size());
    for (size_t i = 0; i < avail; ++i) {
        output += this->_buffer[i];
    }
    return output;
}

//! \param[in] len bytes will be removed from the output side of the buffer
void ByteStream::pop_output(const size_t len) {
    size_t avail = std::min(len, _buffer.size());
    for (size_t i = 0; i < avail; ++i) {
        this->_buffer.pop_front();
    }
    this->_read_count += avail;
    // the test case is more or less stupid here
    //  it expects read count be updated on return of `pop_output`
    //  rather than `read`
}

//! Read (i.e., copy and then pop) the next "len" bytes of the stream
//! \param[in] len bytes will be popped and returned
//! \returns a string
std::string ByteStream::read(const size_t len) {
    std::string data_read = peek_output(len);
    pop_output(len);
    return data_read;
}

void ByteStream::end_input() { this->_ended = true; }

bool ByteStream::input_ended() const { return this->_ended; }

size_t ByteStream::buffer_size() const { return this->_buffer.size(); }

bool ByteStream::buffer_empty() const { return this->_buffer.empty(); }

bool ByteStream::eof() const { return (this->_ended && buffer_empty()); }

size_t ByteStream::bytes_written() const { return this->_written_count; }

size_t ByteStream::bytes_read() const { return this->_read_count; }

size_t ByteStream::remaining_capacity() const { return this->_capacity - this->_buffer.size(); }