#[cfg(feature = "dtype-categorical")]
use polars_utils::sync::SyncPtr;

#[cfg(feature = "object")]
use crate::chunked_array::object::extension::polars_extension::PolarsExtension;
use crate::prelude::*;

#[inline]
#[allow(unused_variables)]
pub(crate) unsafe fn arr_to_any_value<'a>(
    arr: &'a dyn Array,
    idx: usize,
    dtype: &'a DataType,
) -> AnyValue<'a> {
    debug_assert!(idx < arr.len());
    if arr.is_null(idx) {
        return AnyValue::Null;
    }

    macro_rules! downcast_and_pack {
        ($casttype:ident, $variant:ident) => {{
            let arr = &*(arr as *const dyn Array as *const $casttype);
            let v = arr.value_unchecked(idx);
            AnyValue::$variant(v)
        }};
    }
    macro_rules! downcast {
        ($casttype:ident) => {{
            let arr = &*(arr as *const dyn Array as *const $casttype);
            arr.value_unchecked(idx)
        }};
    }
    match dtype {
        DataType::Utf8 => downcast_and_pack!(LargeStringArray, Utf8),
        DataType::Binary => downcast_and_pack!(LargeBinaryArray, Binary),
        DataType::Boolean => downcast_and_pack!(BooleanArray, Boolean),
        DataType::UInt8 => downcast_and_pack!(UInt8Array, UInt8),
        DataType::UInt16 => downcast_and_pack!(UInt16Array, UInt16),
        DataType::UInt32 => downcast_and_pack!(UInt32Array, UInt32),
        DataType::UInt64 => downcast_and_pack!(UInt64Array, UInt64),
        DataType::Int8 => downcast_and_pack!(Int8Array, Int8),
        DataType::Int16 => downcast_and_pack!(Int16Array, Int16),
        DataType::Int32 => downcast_and_pack!(Int32Array, Int32),
        DataType::Int64 => downcast_and_pack!(Int64Array, Int64),
        DataType::Float32 => downcast_and_pack!(Float32Array, Float32),
        DataType::Float64 => downcast_and_pack!(Float64Array, Float64),
        DataType::List(dt) => {
            let v: ArrayRef = downcast!(LargeListArray);
            if dt.is_primitive() {
                let s = Series::from_chunks_and_dtype_unchecked("", vec![v], dt);
                AnyValue::List(s)
            } else {
                let s = Series::from_chunks_and_dtype_unchecked("", vec![v], &dt.to_physical())
                    .cast_unchecked(dt)
                    .unwrap();
                AnyValue::List(s)
            }
        }
        #[cfg(feature = "dtype-array")]
        DataType::Array(dt, width) => {
            let v: ArrayRef = downcast!(FixedSizeListArray);
            if dt.is_primitive() {
                let s = Series::from_chunks_and_dtype_unchecked("", vec![v], dt);
                AnyValue::Array(s, *width)
            } else {
                let s = Series::from_chunks_and_dtype_unchecked("", vec![v], &dt.to_physical())
                    .cast_unchecked(dt)
                    .unwrap();
                AnyValue::Array(s, *width)
            }
        }
        #[cfg(feature = "dtype-categorical")]
        DataType::Categorical(rev_map) => {
            let arr = &*(arr as *const dyn Array as *const UInt32Array);
            let v = arr.value_unchecked(idx);
            AnyValue::Categorical(v, rev_map.as_ref().unwrap().as_ref(), SyncPtr::new_null())
        }
        #[cfg(feature = "dtype-struct")]
        DataType::Struct(flds) => {
            let arr = &*(arr as *const dyn Array as *const StructArray);
            AnyValue::Struct(idx, arr, flds)
        }
        #[cfg(feature = "dtype-datetime")]
        DataType::Datetime(tu, tz) => {
            let arr = &*(arr as *const dyn Array as *const Int64Array);
            let v = arr.value_unchecked(idx);
            AnyValue::Datetime(v, *tu, tz)
        }
        #[cfg(feature = "dtype-date")]
        DataType::Date => {
            let arr = &*(arr as *const dyn Array as *const Int32Array);
            let v = arr.value_unchecked(idx);
            AnyValue::Date(v)
        }
        #[cfg(feature = "dtype-duration")]
        DataType::Duration(tu) => {
            let arr = &*(arr as *const dyn Array as *const Int64Array);
            let v = arr.value_unchecked(idx);
            AnyValue::Duration(v, *tu)
        }
        #[cfg(feature = "dtype-time")]
        DataType::Time => {
            let arr = &*(arr as *const dyn Array as *const Int64Array);
            let v = arr.value_unchecked(idx);
            AnyValue::Time(v)
        }
        #[cfg(feature = "dtype-decimal")]
        DataType::Decimal(precision, scale) => {
            let arr = &*(arr as *const dyn Array as *const Int128Array);
            let v = arr.value_unchecked(idx);
            AnyValue::Decimal(v, scale.unwrap_or_else(|| unreachable!()))
        }
        #[cfg(feature = "object")]
        DataType::Object(_) => {
            // We should almost never hit this. The only known exception is when we put objects in
            // structs. Any other hit should be considered a bug.
            let arr = &*(arr as *const dyn Array as *const FixedSizeBinaryArray);
            PolarsExtension::arr_to_av(arr, idx)
        }
        DataType::Null => AnyValue::Null,
        dt => panic!("not implemented for {dt:?}"),
    }
}

#[cfg(feature = "dtype-struct")]
impl<'a> AnyValue<'a> {
    pub fn _iter_struct_av(&self) -> impl Iterator<Item = AnyValue> {
        match self {
            AnyValue::Struct(idx, arr, flds) => {
                let idx = *idx;
                unsafe {
                    arr.values().iter().zip(*flds).map(move |(arr, fld)| {
                        // The dictionary arrays categories don't have to map to the rev-map in the dtype
                        // so we set the array pointer with values of the dictionary array.
                        #[cfg(feature = "dtype-categorical")]
                        {
                            use polars_arrow::is_valid::{IsValid as _};
                            if let Some(arr) = arr.as_any().downcast_ref::<DictionaryArray<u32>>() {
                                let keys = arr.keys();
                                let values = arr.values();
                                let values =
                                    values.as_any().downcast_ref::<Utf8Array<i64>>().unwrap();
                                let arr = &*(keys as *const dyn Array as *const UInt32Array);

                                if arr.is_valid_unchecked(idx) {
                                    let v = arr.value_unchecked(idx);
                                    let DataType::Categorical(Some(rev_map)) = fld.data_type() else {
                                        unimplemented!()
                                    };
                                    AnyValue::Categorical(v, rev_map, SyncPtr::from_const(values))
                                } else {
                                    AnyValue::Null
                                }

                            } else {
                                arr_to_any_value(&**arr, idx, fld.data_type())
                            }
                        }

                        #[cfg(not(feature = "dtype-categorical"))]
                        {
                            arr_to_any_value(&**arr, idx, fld.data_type())
                        }
                    })
                }
            }
            _ => unreachable!(),
        }
    }

    pub fn _materialize_struct_av(&'a self, buf: &mut Vec<AnyValue<'a>>) {
        let iter = self._iter_struct_av();
        buf.extend(iter)
    }
}

macro_rules! get_any_value_unchecked {
    ($self:ident, $index:expr) => {{
        let (chunk_idx, idx) = $self.index_to_chunked_index($index);
        debug_assert!(chunk_idx < $self.chunks.len());
        let arr = &**$self.chunks.get_unchecked(chunk_idx);
        debug_assert!(idx < arr.len());
        arr_to_any_value(arr, idx, $self.dtype())
    }};
}

macro_rules! get_any_value {
    ($self:ident, $index:expr) => {{
        let (chunk_idx, idx) = $self.index_to_chunked_index($index);
        let arr = &*$self.chunks[chunk_idx];
        polars_ensure!(idx < arr.len(), oob = idx, arr.len());
        // SAFETY
        // bounds are checked
        Ok(unsafe { arr_to_any_value(arr, idx, $self.dtype()) })
    }};
}

impl<T> ChunkAnyValue for ChunkedArray<T>
where
    T: PolarsNumericType,
{
    #[inline]
    unsafe fn get_any_value_unchecked(&self, index: usize) -> AnyValue {
        get_any_value_unchecked!(self, index)
    }

    fn get_any_value(&self, index: usize) -> PolarsResult<AnyValue> {
        get_any_value!(self, index)
    }
}

impl ChunkAnyValue for BooleanChunked {
    #[inline]
    unsafe fn get_any_value_unchecked(&self, index: usize) -> AnyValue {
        get_any_value_unchecked!(self, index)
    }

    fn get_any_value(&self, index: usize) -> PolarsResult<AnyValue> {
        get_any_value!(self, index)
    }
}

impl ChunkAnyValue for Utf8Chunked {
    #[inline]
    unsafe fn get_any_value_unchecked(&self, index: usize) -> AnyValue {
        get_any_value_unchecked!(self, index)
    }

    fn get_any_value(&self, index: usize) -> PolarsResult<AnyValue> {
        get_any_value!(self, index)
    }
}

impl ChunkAnyValue for BinaryChunked {
    #[inline]
    unsafe fn get_any_value_unchecked(&self, index: usize) -> AnyValue {
        get_any_value_unchecked!(self, index)
    }

    fn get_any_value(&self, index: usize) -> PolarsResult<AnyValue> {
        get_any_value!(self, index)
    }
}

impl ChunkAnyValue for ListChunked {
    #[inline]
    unsafe fn get_any_value_unchecked(&self, index: usize) -> AnyValue {
        get_any_value_unchecked!(self, index)
    }

    fn get_any_value(&self, index: usize) -> PolarsResult<AnyValue> {
        get_any_value!(self, index)
    }
}

#[cfg(feature = "dtype-array")]
impl ChunkAnyValue for ArrayChunked {
    #[inline]
    unsafe fn get_any_value_unchecked(&self, index: usize) -> AnyValue {
        get_any_value_unchecked!(self, index)
    }

    fn get_any_value(&self, index: usize) -> PolarsResult<AnyValue> {
        get_any_value!(self, index)
    }
}

#[cfg(feature = "object")]
impl<T: PolarsObject> ChunkAnyValue for ObjectChunked<T> {
    #[inline]
    unsafe fn get_any_value_unchecked(&self, index: usize) -> AnyValue {
        match self.get_object_unchecked(index) {
            None => AnyValue::Null,
            Some(v) => AnyValue::Object(v),
        }
    }

    fn get_any_value(&self, index: usize) -> PolarsResult<AnyValue> {
        match self.get_object(index) {
            None => Err(polars_err!(ComputeError: "index is out of bounds")),
            Some(v) => Ok(AnyValue::Object(v)),
        }
    }
}