use crate::bitmap::{BitmapData, BitmapDataMut};
use crate::formats::{self, PixelFormatSpec, NUM_PIXEL_FORMATS};
use crate::op::{self, BinaryOpSpec, UnaryOpSpec};

pub type UnaryFunc<Params> = for<'l> fn(&'l mut dyn BitmapDataMut, &'l Params);
pub type BinaryFunc<Params> = for<'l> fn(&'l mut dyn BitmapDataMut, &'l dyn BitmapData, &'l Params);

pub trait GenericUnary<Params> {
    fn perform<'l, Format: PixelFormatSpec>(
        write_data: &'l mut dyn BitmapDataMut,
        params: &'l Params,
    );
}

pub trait GenericBinary<Params> {
    fn perform<'l, Format: PixelFormatSpec, ReadFormat: PixelFormatSpec>(
        write_data: &'l mut dyn BitmapDataMut,
        read_data: &'l dyn BitmapData,
        params: &'l Params,
    );
}

pub struct UnaryDispatch<Params> {
    op_array: [UnaryFunc<Params>; NUM_PIXEL_FORMATS],
    changed: [bool; NUM_PIXEL_FORMATS],
}

impl<Params> UnaryDispatch<Params> {
    pub fn with<Format: PixelFormatSpec>(mut self, specific_imp: UnaryFunc<Params>) -> Self {
        self.op_array[Format::FORMAT_ENUM as usize] = specific_imp;
        self.changed[Format::FORMAT_ENUM as usize] = true;
        self
    }
    pub fn with_avx<Format: PixelFormatSpec>(mut self, avx_imp: UnaryFunc<Params>) -> Self {
        if is_x86_feature_detected!("avx") {
            self.op_array[Format::FORMAT_ENUM as usize] = avx_imp;
            self.changed[Format::FORMAT_ENUM as usize] = true;
            self
        } else {
            self
        }
    }

    pub fn select<Format: PixelFormatSpec>(&self) -> UnaryFunc<Params> {
        self.op_array[Format::FORMAT_ENUM as usize]
    }

    pub fn is_generic<Format: PixelFormatSpec>(&self) -> bool {
        !self.changed[Format::FORMAT_ENUM as usize]
    }
}

pub struct BinaryDispatch<Params> {
    op_array: [[BinaryFunc<Params>; NUM_PIXEL_FORMATS]; NUM_PIXEL_FORMATS],
    changed: [[bool; NUM_PIXEL_FORMATS]; NUM_PIXEL_FORMATS],
}

impl<Params> BinaryDispatch<Params> {
    pub fn with<WriteFormat: PixelFormatSpec, ReadFormat: PixelFormatSpec>(
        mut self,
        imp: BinaryFunc<Params>,
    ) -> Self {
        self.op_array[WriteFormat::FORMAT_ENUM as usize][ReadFormat::FORMAT_ENUM as usize] = imp;
        self.changed[WriteFormat::FORMAT_ENUM as usize][ReadFormat::FORMAT_ENUM as usize] = true;
        self
    }
    pub fn with_avx<WriteFormat: PixelFormatSpec, ReadFormat: PixelFormatSpec>(
        mut self,
        avx_imp: BinaryFunc<Params>,
    ) -> Self {
        if is_x86_feature_detected!("avx") {
            self.op_array[WriteFormat::FORMAT_ENUM as usize][ReadFormat::FORMAT_ENUM as usize] =
                avx_imp;
            self.changed[WriteFormat::FORMAT_ENUM as usize][ReadFormat::FORMAT_ENUM as usize] = true;
            self
        } else {
            self
        }
    }

    pub fn select<WriteFormat: PixelFormatSpec, ReadFormat: PixelFormatSpec>(
        &self,
    ) -> BinaryFunc<Params> {
        self.op_array[WriteFormat::FORMAT_ENUM as usize][ReadFormat::FORMAT_ENUM as usize]
    }

    pub fn is_generic<WriteFormat: PixelFormatSpec, ReadFormat: PixelFormatSpec>(&self) -> bool {
        !self.changed[WriteFormat::FORMAT_ENUM as usize][ReadFormat::FORMAT_ENUM as usize]
    }
}

macro_rules! dispatch_entry {
    (unary, $sn:ident, $opn:ident) => {
        UnaryDispatch < <op::$sn::$opn as UnaryOpSpec>::Params<'l>>
    };

    (binary, $sn:ident, $opn:ident) => {
        BinaryDispatch < <op::$sn::$opn as BinaryOpSpec>::Params<'l>>
    };
}

pub struct KahloDispatch<'l> {
    pub composite: dispatch_entry!(binary, composite, CompositeOp),
    pub copy_from: dispatch_entry!(binary, copy_from, CopyFromOp),
    pub fill: dispatch_entry!(unary, fill, FillOp),
    pub fill_region: dispatch_entry!(unary, fill_region, FillRegionOp),
    pub fill_region_masked: dispatch_entry!(unary, fill_region_masked, FillRegionMaskedOp),
    pub rectangle: dispatch_entry!(unary, rectangle, RectangleOp),
}

impl<'l> Default for KahloDispatch<'l> {
    fn default() -> Self {
        Self {
            composite: op::composite::CompositeOp::build(),
            copy_from: op::copy_from::CopyFromOp::build(),
            fill: op::fill::FillOp::build(),
            fill_region: op::fill_region::FillRegionOp::build(),
            fill_region_masked: op::fill_region_masked::FillRegionMaskedOp::build(),
            rectangle: op::rectangle::RectangleOp::build(),
        }
    }
}

impl<'l> KahloDispatch<'l> {
    pub fn use_lifetime(&self) -> &KahloDispatch<'_> {
        unsafe { std::mem::transmute(self) }
    }
}

lazy_static::lazy_static! {
    pub static ref DISPATCH: KahloDispatch<'static> = KahloDispatch::default();
}

// long but simple implementations

impl<Params> UnaryDispatch<Params> {
    pub(crate) fn from_generic<G: GenericUnary<Params>>() -> Self {
        Self {
            op_array: [
                G::perform::<formats::A8>,
                G::perform::<formats::Abgr32>,
                G::perform::<formats::Bgr24>,
                G::perform::<formats::Bgr32>,
                G::perform::<formats::Rgb24>,
                G::perform::<formats::Rgb32>,
                G::perform::<formats::Rgba32>,
            ],
            changed: Default::default(),
        }
    }
}

impl<Params> BinaryDispatch<Params> {
    pub(crate) fn from_generic<G: GenericBinary<Params>>() -> Self {
        Self {
            op_array: [
                [
                    G::perform::<formats::A8, formats::A8>,
                    G::perform::<formats::A8, formats::Abgr32>,
                    G::perform::<formats::A8, formats::Bgr24>,
                    G::perform::<formats::A8, formats::Bgr32>,
                    G::perform::<formats::A8, formats::Rgb24>,
                    G::perform::<formats::A8, formats::Rgb32>,
                    G::perform::<formats::A8, formats::Rgba32>,
                ],
                [
                    G::perform::<formats::Abgr32, formats::A8>,
                    G::perform::<formats::Abgr32, formats::Abgr32>,
                    G::perform::<formats::Abgr32, formats::Bgr24>,
                    G::perform::<formats::Abgr32, formats::Bgr32>,
                    G::perform::<formats::Abgr32, formats::Rgb24>,
                    G::perform::<formats::Abgr32, formats::Rgb32>,
                    G::perform::<formats::Abgr32, formats::Rgba32>,
                ],
                [
                    G::perform::<formats::Bgr24, formats::A8>,
                    G::perform::<formats::Bgr24, formats::Abgr32>,
                    G::perform::<formats::Bgr24, formats::Bgr24>,
                    G::perform::<formats::Bgr24, formats::Bgr32>,
                    G::perform::<formats::Bgr24, formats::Rgb24>,
                    G::perform::<formats::Bgr24, formats::Rgb32>,
                    G::perform::<formats::Bgr24, formats::Rgba32>,
                ],
                [
                    G::perform::<formats::Bgr32, formats::A8>,
                    G::perform::<formats::Bgr32, formats::Abgr32>,
                    G::perform::<formats::Bgr32, formats::Bgr24>,
                    G::perform::<formats::Bgr32, formats::Bgr32>,
                    G::perform::<formats::Bgr32, formats::Rgb24>,
                    G::perform::<formats::Bgr32, formats::Rgb32>,
                    G::perform::<formats::Bgr32, formats::Rgba32>,
                ],
                [
                    G::perform::<formats::Rgb24, formats::A8>,
                    G::perform::<formats::Rgb24, formats::Abgr32>,
                    G::perform::<formats::Rgb24, formats::Bgr24>,
                    G::perform::<formats::Rgb24, formats::Bgr32>,
                    G::perform::<formats::Rgb24, formats::Rgb24>,
                    G::perform::<formats::Rgb24, formats::Rgb32>,
                    G::perform::<formats::Rgb24, formats::Rgba32>,
                ],
                [
                    G::perform::<formats::Rgb32, formats::A8>,
                    G::perform::<formats::Rgb32, formats::Abgr32>,
                    G::perform::<formats::Rgb32, formats::Bgr24>,
                    G::perform::<formats::Rgb32, formats::Bgr32>,
                    G::perform::<formats::Rgb32, formats::Rgb24>,
                    G::perform::<formats::Rgb32, formats::Rgb32>,
                    G::perform::<formats::Rgb32, formats::Rgba32>,
                ],
                [
                    G::perform::<formats::Rgba32, formats::A8>,
                    G::perform::<formats::Rgba32, formats::Abgr32>,
                    G::perform::<formats::Rgba32, formats::Bgr24>,
                    G::perform::<formats::Rgba32, formats::Bgr32>,
                    G::perform::<formats::Rgba32, formats::Rgb24>,
                    G::perform::<formats::Rgba32, formats::Rgb32>,
                    G::perform::<formats::Rgba32, formats::Rgba32>,
                ],
            ],
            changed: Default::default(),
        }
    }
}