use llvm_sys::core::{LLVMConstVector, LLVMGetVectorSize, LLVMConstArray};
use llvm_sys::prelude::{LLVMTypeRef, LLVMValueRef};

use crate::AddressSpace;
use crate::context::ContextRef;
use crate::types::{ArrayType, BasicTypeEnum, Type, traits::AsTypeRef, FunctionType, PointerType};
use crate::values::{AsValueRef, ArrayValue, BasicValue, VectorValue, IntValue};

/// A `VectorType` is the type of a multiple value SIMD constant or variable.
#[derive(Debug, PartialEq, Eq, Clone, Copy)]
pub struct VectorType<'ctx> {
    vec_type: Type<'ctx>,
}

impl<'ctx> VectorType<'ctx> {
    pub unsafe fn new(vector_type: LLVMTypeRef) -> Self {
        assert!(!vector_type.is_null());

        VectorType {
            vec_type: Type::new(vector_type),
        }
    }

    // TODO: impl only for VectorType<!StructType<Opaque>>
    // REVIEW: What about Opaque struct hiding in deeper levels
    // like VectorType<ArrayType<StructType<Opaque>>>?
    /// Gets the size of this `VectorType`. Value may vary depending on the target architecture.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use inkwell::context::Context;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_vec_type = f32_type.vec_type(3);
    /// let f32_vec_type_size = f32_vec_type.size_of();
    /// ```
    pub fn size_of(self) -> Option<IntValue<'ctx>> {
        self.vec_type.size_of()
    }

    /// Gets the alignment of this `VectorType`. Value may vary depending on the target architecture.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use inkwell::context::Context;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_vec_type = f32_type.vec_type(7);
    /// let f32_type_alignment = f32_vec_type.get_alignment();
    /// ```
    pub fn get_alignment(self) -> IntValue<'ctx> {
        self.vec_type.get_alignment()
    }

    /// Gets the size of this `VectorType`.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use inkwell::context::Context;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_vector_type = f32_type.vec_type(3);
    ///
    /// assert_eq!(f32_vector_type.get_size(), 3);
    /// assert_eq!(f32_vector_type.get_element_type().into_float_type(), f32_type);
    /// ```
    pub fn get_size(self) -> u32 {
        unsafe {
            LLVMGetVectorSize(self.as_type_ref())
        }
    }

    // REVIEW:
    // TypeSafety v2 (GH Issue #8) could help here by constraining
    // sub-types to be the same across the board. For now, we could
    // have V just be the set of Int & Float and any others that
    // are valid for Vectors
    // REVIEW: Maybe we could make this use &self if the vector size
    // is stored as a const and the input values took a const size?
    // Something like: values: &[&V; self.size]. Doesn't sound possible though
    /// Creates a constant `VectorValue`.
    ///
    /// # Example
    /// ```no_run
    /// use inkwell::context::Context;
    /// use inkwell::types::VectorType;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_val = f32_type.const_float(0.);
    /// let f32_val2 = f32_type.const_float(2.);
    /// let f32_vec_val = VectorType::const_vector(&[f32_val, f32_val2]);
    ///
    /// assert!(f32_vec_val.is_constant_vector());
    /// ```
    pub fn const_vector<V: BasicValue<'ctx>>(values: &[V]) -> VectorValue<'ctx> {
        let mut values: Vec<LLVMValueRef> = values.iter()
                                                  .map(|val| val.as_value_ref())
                                                  .collect();
        unsafe {
            VectorValue::new(LLVMConstVector(values.as_mut_ptr(), values.len() as u32))
        }
    }

    /// Creates a constant zero value of this `VectorType`.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use inkwell::context::Context;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_vec_type = f32_type.vec_type(7);
    /// let f32_vec_zero = f32_vec_type.const_zero();
    /// ```
    pub fn const_zero(self) -> VectorValue<'ctx> {
        unsafe {
            VectorValue::new(self.vec_type.const_zero())
        }
    }

    // See Type::print_to_stderr note on 5.0+ status
    /// Prints the definition of an `IntType` to stderr. Not available in newer LLVM versions.
    #[llvm_versions(3.7..=4.0)]
    pub fn print_to_stderr(self) {
        self.vec_type.print_to_stderr()
    }

    /// Creates an undefined instance of a `VectorType`.
    ///
    /// # Example
    /// ```no_run
    /// use inkwell::context::Context;
    /// use inkwell::AddressSpace;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_vec_type = f32_type.vec_type(3);
    /// let f32_vec_undef = f32_vec_type.get_undef();
    ///
    /// assert!(f32_vec_undef.is_undef());
    /// ```
    pub fn get_undef(self) -> VectorValue<'ctx> {
        unsafe {
            VectorValue::new(self.vec_type.get_undef())
        }
    }

    // SubType: VectorType<BT> -> BT?
    /// Gets the element type of this `VectorType`.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use inkwell::context::Context;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_vector_type = f32_type.vec_type(3);
    ///
    /// assert_eq!(f32_vector_type.get_size(), 3);
    /// assert_eq!(f32_vector_type.get_element_type().into_float_type(), f32_type);
    /// ```
    pub fn get_element_type(self) -> BasicTypeEnum<'ctx> {
        self.vec_type.get_element_type().to_basic_type_enum()

    }

    /// Creates a `PointerType` with this `VectorType` for its element type.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use inkwell::context::Context;
    /// use inkwell::AddressSpace;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_vec_type = f32_type.vec_type(3);
    /// let f32_vec_ptr_type = f32_vec_type.ptr_type(AddressSpace::Generic);
    ///
    /// assert_eq!(f32_vec_ptr_type.get_element_type().into_vector_type(), f32_vec_type);
    /// ```
    pub fn ptr_type(self, address_space: AddressSpace) -> PointerType<'ctx> {
        self.vec_type.ptr_type(address_space)
    }

    /// Creates a `FunctionType` with this `VectorType` for its return type.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use inkwell::context::Context;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_vec_type = f32_type.vec_type(3);
    /// let fn_type = f32_vec_type.fn_type(&[], false);
    /// ```
    pub fn fn_type(self, param_types: &[BasicTypeEnum<'ctx>], is_var_args: bool) -> FunctionType<'ctx> {
        self.vec_type.fn_type(param_types, is_var_args)
    }

    /// Creates an `ArrayType` with this `VectorType` for its element type.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use inkwell::context::Context;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_vec_type = f32_type.vec_type(3);
    /// let f32_vec_array_type = f32_vec_type.array_type(3);
    ///
    /// assert_eq!(f32_vec_array_type.len(), 3);
    /// assert_eq!(f32_vec_array_type.get_element_type().into_vector_type(), f32_vec_type);
    /// ```
    pub fn array_type(self, size: u32) -> ArrayType<'ctx> {
        self.vec_type.array_type(size)
    }

    /// Creates a constant `ArrayValue`.
    ///
    /// # Example
    /// ```no_run
    /// use inkwell::context::Context;
    /// use inkwell::types::VectorType;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_val = f32_type.const_float(0.);
    /// let f32_val2 = f32_type.const_float(2.);
    /// let f32_vec_type = f32_type.vec_type(2);
    /// let f32_vec_val = VectorType::const_vector(&[f32_val, f32_val2]);
    /// let f32_array = f32_vec_type.const_array(&[f32_vec_val, f32_vec_val]);
    ///
    /// assert!(f32_array.is_const());
    /// ```
    pub fn const_array(self, values: &[VectorValue<'ctx>]) -> ArrayValue<'ctx> {
        let mut values: Vec<LLVMValueRef> = values.iter()
                                                  .map(|val| val.as_value_ref())
                                                  .collect();

        unsafe {
            ArrayValue::new(LLVMConstArray(self.as_type_ref(), values.as_mut_ptr(), values.len() as u32))
        }
    }

    /// Gets a reference to the `Context` this `VectorType` was created in.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use inkwell::context::Context;
    ///
    /// let context = Context::create();
    /// let f32_type = context.f32_type();
    /// let f32_vec_type = f32_type.vec_type(7);
    ///
    /// assert_eq!(*f32_vec_type.get_context(), context);
    /// ```
    pub fn get_context(self) -> ContextRef<'ctx> {
        self.vec_type.get_context()
    }
}

impl AsTypeRef for VectorType<'_> {
    fn as_type_ref(&self) -> LLVMTypeRef {
        self.vec_type.ty
    }
}
