use std::fs::File;
use std::io::Write;
use crate::common::{DisplayBuffer, IMG_HEIGHT, IMG_WIDTH};

pub struct View<'a> {
    pub display_buffer: &'a DisplayBuffer,
    pub viewer: fn(&DisplayBuffer) -> Result<String, std::io::Error>,
}

impl<'a> View<'a> {
    pub fn display(&self) {
        let result = (self.viewer)(self.display_buffer);
        match result {
            Ok(success_msg) => {
                println!("{}", success_msg);
            },
            Err(error_msg) => {
                eprintln!("{}", error_msg);
            }
        }
    }
}

pub mod render_viewer {
    use image::ImageFormat;
    use crate::common::Pixel;
    use super::*;

    pub fn ppm_exporter(data: &DisplayBuffer) -> Result<String, std::io::Error> {
        let file_name = "output.ppm";
        let mut file = File::create(file_name)?;
        // header
        let mut txt_data = String::from("P3\n");
        txt_data.push_str(format!("{} {}\n255\n", IMG_WIDTH, IMG_HEIGHT).as_str());
        // data point
        data.iter().for_each(|row| {
            row.iter().for_each(|&pixel| {
                txt_data.push_str(&format!("{} {} {}\n", pixel.r, pixel.g, pixel.b));
            })
        });
        file.write_all(txt_data.as_bytes())?;
        Ok(format!("Output rendered to file {}", file_name))
    }

    fn common_img_format_exporter(data: &DisplayBuffer, img_format: ImageFormat) -> Result<String, std::io::Error> {
        let ext = match img_format {
            ImageFormat::Png => { "png" }
            ImageFormat::Jpeg => { "jpeg" }
            ImageFormat::Bmp => { "bmp" }
            _ => {
                return Err(std::io::Error::new(std::io::ErrorKind::Other, "Not supported"));
            }
        };
        let file_name = format!("output.{}", ext);
        let mut imgbuf = image::ImageBuffer::new(IMG_WIDTH as u32, IMG_HEIGHT as u32);
        for (x, y, pixel) in imgbuf.enumerate_pixels_mut() {
            let Pixel{r, g, b} = data[y as usize][x as usize];
            *pixel = image::Rgb([r, g, b]);
        }
        imgbuf.save(file_name.clone()).unwrap();
        Ok(format!("Output rendered to file {}", file_name))
    }

    pub fn png_exporter(data: &DisplayBuffer) -> Result<String, std::io::Error> {
        common_img_format_exporter(data, ImageFormat::Png)
    }

    pub fn jpeg_exporter(data: &DisplayBuffer) -> Result<String, std::io::Error> {
        common_img_format_exporter(data, ImageFormat::Jpeg)
    }

    pub fn bmp_exporter(data: &DisplayBuffer) -> Result<String, std::io::Error> {
        common_img_format_exporter(data, ImageFormat::Bmp)
    }
}