//! A value is an instance of a type.

mod array_value;
#[deny(missing_docs)]
mod basic_value_use;
#[deny(missing_docs)]
mod call_site_value;
mod enums;
mod float_value;
mod fn_value;
mod generic_value;
mod global_value;
mod instruction_value;
mod int_value;
mod metadata_value;
mod phi_value;
mod ptr_value;
mod struct_value;
mod traits;
mod vec_value;

pub use crate::values::array_value::ArrayValue;
pub use crate::values::basic_value_use::BasicValueUse;
pub use crate::values::call_site_value::CallSiteValue;
pub use crate::values::enums::{AnyValueEnum, AggregateValueEnum, BasicValueEnum, BasicMetadataValueEnum};
pub use crate::values::float_value::FloatValue;
pub use crate::values::fn_value::FunctionValue;
pub use crate::values::generic_value::GenericValue;
pub use crate::values::global_value::GlobalValue;
#[llvm_versions(7.0..=latest)]
pub use crate::values::global_value::UnnamedAddress;
pub use crate::values::instruction_value::{InstructionValue, InstructionOpcode};
pub use crate::values::int_value::IntValue;
pub use crate::values::metadata_value::{MetadataValue, FIRST_CUSTOM_METADATA_KIND_ID};
pub use crate::values::phi_value::PhiValue;
pub use crate::values::ptr_value::PointerValue;
pub use crate::values::struct_value::StructValue;
pub use crate::values::traits::{AnyValue, AggregateValue, BasicValue, IntMathValue, FloatMathValue, PointerMathValue};
pub use crate::values::vec_value::VectorValue;
pub(crate) use crate::values::traits::AsValueRef;

use llvm_sys::core::{LLVMIsConstant, LLVMIsNull, LLVMIsUndef, LLVMPrintTypeToString, LLVMPrintValueToString, LLVMTypeOf, LLVMDumpValue, LLVMIsAInstruction, LLVMGetMetadata, LLVMHasMetadata, LLVMSetMetadata, LLVMReplaceAllUsesWith, LLVMGetFirstUse};
use llvm_sys::prelude::{LLVMValueRef, LLVMTypeRef};

use std::ffi::CStr;
use std::fmt;

use crate::support::LLVMString;

#[derive(PartialEq, Eq, Clone, Copy, Hash)]
struct Value {
    value: LLVMValueRef,
}

impl Value {
    pub(crate) fn new(value: LLVMValueRef) -> Value {
        debug_assert!(!value.is_null(), "This should never happen since containing struct should check null ptrs");

        Value {
            value: value
        }
    }

    fn is_instruction(&self) -> bool {
        unsafe {
            !LLVMIsAInstruction(self.value).is_null()
        }
    }

    fn as_instruction(&self) -> Option<InstructionValue> {
        if !self.is_instruction() {
            return None;
        }

        Some(InstructionValue::new(self.value))
    }

    fn is_null(&self) -> bool {
        unsafe {
            LLVMIsNull(self.value) == 1
        }
    }

    fn is_const(&self) -> bool {
        unsafe {
            LLVMIsConstant(self.value) == 1
        }
    }

    // TODOC: According to https://stackoverflow.com/questions/21593752/llvm-how-to-pass-a-name-to-constantint
    // you can't use set_name name on a constant(by can't, I mean it wont do anything), unless it's also a global.
    // So, you can set names on variables (ie a function parameter)
    // REVIEW: It'd be great if we could encode this into the type system somehow. For example,
    // add a ParamValue wrapper type that always have it but conditional types (IntValue<Variable>)
    // that also have it. This isn't a huge deal though, since it hasn't proven to be UB so far
    fn set_name(&self, name: &str) {
        #[cfg(any(feature = "llvm3-6", feature = "llvm3-7", feature = "llvm3-8", feature = "llvm3-9",
                  feature = "llvm4-0", feature = "llvm5-0", feature = "llvm6-0"))]
        {
            use llvm_sys::core::LLVMSetValueName;
            use std::ffi::CString;

            let c_string = CString::new(name).expect("Conversion to CString failed unexpectedly");

            unsafe {
                LLVMSetValueName(self.value, c_string.as_ptr());
            }
        }
        #[cfg(not(any(feature = "llvm3-6", feature = "llvm3-7", feature = "llvm3-8", feature = "llvm3-9",
                      feature = "llvm4-0", feature = "llvm5-0", feature = "llvm6-0")))]
        {
            use llvm_sys::core::LLVMSetValueName2;

            unsafe {
                LLVMSetValueName2(self.value, name.as_ptr() as *const i8, name.len())
            }
        }
    }

    // get_name should *not* return a LLVMString, because it is not an owned value AFAICT
    fn get_name(&self) -> &CStr {
        #[cfg(any(feature = "llvm3-6", feature = "llvm3-7", feature = "llvm3-8", feature = "llvm3-9",
                  feature = "llvm4-0", feature = "llvm5-0", feature = "llvm6-0"))]
        let ptr = unsafe {
            use llvm_sys::core::LLVMGetValueName;

            LLVMGetValueName(self.value)
        };
        #[cfg(not(any(feature = "llvm3-6", feature = "llvm3-7", feature = "llvm3-8", feature = "llvm3-9",
                      feature = "llvm4-0", feature = "llvm5-0", feature = "llvm6-0")))]
        let ptr = unsafe {
            use llvm_sys::core::LLVMGetValueName2;
            let mut len = 0;

            LLVMGetValueName2(self.value, &mut len)
        };

        unsafe {
            CStr::from_ptr(ptr)
        }
    }

    fn is_undef(&self) -> bool {
        unsafe {
            LLVMIsUndef(self.value) == 1
        }
    }

    fn get_type(&self) -> LLVMTypeRef {
        unsafe {
            LLVMTypeOf(self.value)
        }
    }

    fn print_to_string(&self) -> LLVMString {
        let c_string = unsafe {
            LLVMPrintValueToString(self.value)
        };

        LLVMString::new(c_string)
    }

    fn print_to_stderr(&self) {
        unsafe {
            LLVMDumpValue(self.value)
        }
    }

    fn has_metadata(&self) -> bool {
        unsafe {
            LLVMHasMetadata(self.value) == 1
        }
    }

    // SubTypes: -> Option<MetadataValue<Node>>
    // TODOC: This always returns a metadata node, which can be used to get its node values
    fn get_metadata(&self, kind_id: u32) -> Option<MetadataValue> {
        let metadata_value = unsafe {
            LLVMGetMetadata(self.value, kind_id)
        };

        if metadata_value.is_null() {
            return None;
        }

        Some(MetadataValue::new(metadata_value))
    }

    fn set_metadata(&self, metadata: MetadataValue, kind_id: u32) {
        unsafe {
            LLVMSetMetadata(self.value, kind_id, metadata.as_value_ref())
        }
    }

    // REVIEW: I think this is memory safe, though it may result in an IR error
    // if used incorrectly, which is OK.
    fn replace_all_uses_with(&self, other: LLVMValueRef) {
        unsafe {
            LLVMReplaceAllUsesWith(self.value, other)
        }
    }

    pub fn get_first_use(&self) -> Option<BasicValueUse> {
        let use_ = unsafe {
            LLVMGetFirstUse(self.value)
        };

        if use_.is_null() {
            return None;
        }

        Some(BasicValueUse::new(use_))
    }
}

impl fmt::Debug for Value {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        let llvm_value = self.print_to_string();
        let llvm_type = unsafe {
            CStr::from_ptr(LLVMPrintTypeToString(LLVMTypeOf(self.value)))
        };
        let name = self.get_name();
        let is_const = self.is_const();
        let is_null = self.is_null();
        let is_undef = self.is_undef();

        f.debug_struct("Value")
            .field("name", &name)
            .field("address", &self.value)
            .field("is_const", &is_const)
            .field("is_null", &is_null)
            .field("is_undef", &is_undef)
            .field("llvm_value", &llvm_value)
            .field("llvm_type", &llvm_type)
            .finish()
    }
}