#![allow(unreachable_patterns)]
#![allow(non_snake_case)]

use std::io;

mod decode;
mod encode;
pub mod error;

use crate::error::{OBIError, OBIResult};

#[non_exhaustive]
#[derive(Copy, Clone, Debug, PartialEq)]
pub enum OBIVersion {
    One,
}

impl OBIVersion {
    pub fn header_size(&self) -> u32 {
        match self {
            OBIVersion::One => 26,
        }
    }
}

#[non_exhaustive]
pub struct FileHeader {
    pub file_size: u32,
    pub data_offset: u32,
    pub version: u16,
}

impl FileHeader {
    pub fn new(version: OBIVersion, data_size: u32) -> Self {
        let header_size = version.header_size();
        Self {
            version: match version {
                OBIVersion::One => 1u16,
                _ => unreachable!("New version has been added!"),
            },
            file_size: header_size + data_size,
            data_offset: header_size,
        }
    }
}

#[non_exhaustive]
pub struct ImageInfoHeader {
    pub width: u32,
    pub height: u32,
    pub compression_type: u32,
    pub post_compression_size: u32,
}

impl ImageInfoHeader {
    pub fn new(width: u32, height: u32) -> Self {
        Self {
            width,
            height,
            compression_type: 0u32,
            post_compression_size: 0u32,
        }
    }
}

#[non_exhaustive]
#[derive(Copy, Clone, Debug, PartialEq)]
pub enum CompressionType {
    RLE,
    Kosinki,
    None,
}

impl CompressionType {
    pub fn from_u32(kind: u32) -> Self {
        match kind {
            0 => CompressionType::None,
            1 => CompressionType::RLE,
            10 => CompressionType::Kosinki,
            _ => panic!("Invalid compression algorithm"),
        }
    }
}

pub struct Image {
    pub file_header: FileHeader,
    pub image_info_header: ImageInfoHeader,
    pub data: Vec<bool>,
}

impl Image {
    pub fn new(width: u32, height: u32) -> Self {
        // round to the nearest multiple of 8
        // convert to number of bytes by dividing by 8
        let mut data_size = width * height + 7;
        data_size = data_size - (data_size % 8);
        let data = vec![false; data_size as usize];

        Self {
            file_header: FileHeader::new(OBIVersion::One, data_size / 8),
            image_info_header: ImageInfoHeader::new(width, height),
            data,
        }
    }

    pub fn width(&self) -> u32 {
        self.image_info_header.width
    }

    pub fn height(&self) -> u32 {
        self.image_info_header.height
    }

    fn to_index(&self, x: u32, y: u32) -> usize {
        (y * self.width() + x) as usize
    }

    pub fn set_pixel(&mut self, x: u32, y: u32, val: bool) -> OBIResult<()> {
        if x >= self.width() || y > self.height() {
            Err(OBIError::Image)
        } else {
            let index = self.to_index(x, y);
            self.data[index] = val;
            Ok(())
        }
    }

    pub fn encode(&self) -> OBIResult<Vec<u8>> {
        encode::encode_image(self)
    }

    pub fn decode(data: &mut io::Cursor<Vec<u8>>) -> OBIResult<Image> {
        decode::decode_image(data)
    }
}