use std::io::{BufWriter, Write, Result};

use crate::types_defined::Color;

pub struct PPMWriter<W: Write> {
    writter: BufWriter<W>
}

impl<W: Write> PPMWriter<W> {
    /// 创建新的 PPM 写入器
    /// 
    /// 参数:
    ///   writer: 实现 Write 的目标
    ///   width: 图像宽度
    ///   height: 图像高度
    pub fn new(mut inner: W, width: i32, height: i32) -> Result<Self> {
        // 写入 PPM 头 (P6 二进制格式)
        let header = format!("P6\n{} {}\n255\n", width, height);
        inner.write_all(header.as_bytes())?;
        
        Ok(PPMWriter { writter: BufWriter::new(inner) })
    }

    /// 写入单个像素 (高性能实现)
    #[inline]
    pub fn write(&mut self, color: Color) -> Result<()> {
        // 直接写入字节数组避免额外内存分配
        let bytes = [color.x as u8, color.y as u8, color.z as u8];
        self.writter.write_all(&bytes)
    }

    /// 完成写入并刷新缓冲区
    pub fn finish(mut self) -> Result<()> {
        self.writter.flush()
    }
}