#pragma once

#include <cstddef>
#include <cstdint>
#include <functional>

// A PNG of the screen, written a row at a time with almost no memory (issue #67, Q209): 8-bit
// indexed colour with the 256 colours of RGB332 as its palette, and the pixels stored, not
// compressed (a "stored" deflate block), so there is nothing to compress with and nothing to buffer.
// One block holds at most 65,535 bytes: enough for the 240 x 135 screen (32,535 with its row bytes).
namespace roro::png {

uint32_t crc32(uint32_t crc, const uint8_t* data, size_t len);      // running; start from 0
uint32_t adler32(uint32_t adler, const uint8_t* data, size_t len);  // running; start from 1

class Rgb332Writer {
   public:
    using Sink = std::function<bool(const uint8_t* data, size_t len)>;  // false: writing failed

    Rgb332Writer(int width, int height, Sink sink) : w_(width), h_(height), sink_(std::move(sink)) {}

    // The file's size, known before a byte is written.
    static size_t fileSize(int width, int height);

    bool begin();                      // false: too big for one block, or the sink refused
    bool row(const uint8_t* pixels);   // `width` bytes, RRRGGGBB each
    bool end();

   private:
    bool put(const uint8_t* data, size_t len, bool inIdat);
    bool put32(uint32_t value, bool inIdat);

    int w_, h_, rows_ = 0;
    Sink sink_;
    uint32_t crc_ = 0, adler_ = 1;
};

}  // namespace roro::png