use crate::r#ref::{ref_to_val, WasmRefInner};
use crate::{from_valtype, into_valtype, wasm_ref_t, wasm_valkind_t, WASM_I32};
use std::mem::MaybeUninit;
use std::ptr;
use wasmtime::{Val, ValType};

#[repr(C)]
pub struct wasm_val_t {
    pub kind: wasm_valkind_t,
    pub of: wasm_val_union,
}

#[repr(C)]
#[derive(Copy, Clone)]
pub union wasm_val_union {
    pub i32: i32,
    pub i64: i64,
    pub u32: u32,
    pub u64: u64,
    pub f32: f32,
    pub f64: f64,
    pub ref_: *mut wasm_ref_t,
}

impl Drop for wasm_val_t {
    fn drop(&mut self) {
        match into_valtype(self.kind) {
            ValType::FuncRef | ValType::ExternRef => unsafe {
                if !self.of.ref_.is_null() {
                    drop(Box::from_raw(self.of.ref_));
                }
            },
            _ => {}
        }
    }
}

impl Clone for wasm_val_t {
    fn clone(&self) -> Self {
        let mut ret = wasm_val_t {
            kind: self.kind,
            of: self.of,
        };
        unsafe {
            match into_valtype(self.kind) {
                ValType::ExternRef | ValType::FuncRef if !self.of.ref_.is_null() => {
                    ret.of.ref_ = Box::into_raw(Box::new((*self.of.ref_).clone()));
                }
                _ => {}
            }
        }
        return ret;
    }
}

impl Default for wasm_val_t {
    fn default() -> Self {
        wasm_val_t {
            kind: WASM_I32,
            of: wasm_val_union { i32: 0 },
        }
    }
}

impl wasm_val_t {
    pub fn from_val(val: Val) -> wasm_val_t {
        match val {
            Val::I32(i) => wasm_val_t {
                kind: from_valtype(&ValType::I32),
                of: wasm_val_union { i32: i },
            },
            Val::I64(i) => wasm_val_t {
                kind: from_valtype(&ValType::I64),
                of: wasm_val_union { i64: i },
            },
            Val::F32(f) => wasm_val_t {
                kind: from_valtype(&ValType::F32),
                of: wasm_val_union { u32: f },
            },
            Val::F64(f) => wasm_val_t {
                kind: from_valtype(&ValType::F64),
                of: wasm_val_union { u64: f },
            },
            Val::ExternRef(None) => wasm_val_t {
                kind: from_valtype(&ValType::ExternRef),
                of: wasm_val_union {
                    ref_: ptr::null_mut(),
                },
            },
            Val::ExternRef(Some(r)) => wasm_val_t {
                kind: from_valtype(&ValType::ExternRef),
                of: wasm_val_union {
                    ref_: Box::into_raw(Box::new(wasm_ref_t {
                        r: WasmRefInner::ExternRef(r),
                    })),
                },
            },
            Val::FuncRef(None) => wasm_val_t {
                kind: from_valtype(&ValType::FuncRef),
                of: wasm_val_union {
                    ref_: ptr::null_mut(),
                },
            },
            Val::FuncRef(Some(f)) => wasm_val_t {
                kind: from_valtype(&ValType::FuncRef),
                of: wasm_val_union {
                    ref_: Box::into_raw(Box::new(wasm_ref_t {
                        r: WasmRefInner::FuncRef(f),
                    })),
                },
            },
            _ => unimplemented!("wasm_val_t::from_val {:?}", val),
        }
    }

    pub fn val(&self) -> Val {
        match into_valtype(self.kind) {
            ValType::I32 => Val::from(unsafe { self.of.i32 }),
            ValType::I64 => Val::from(unsafe { self.of.i64 }),
            ValType::F32 => Val::from(unsafe { self.of.f32 }),
            ValType::F64 => Val::from(unsafe { self.of.f64 }),
            ValType::ExternRef => unsafe {
                if self.of.ref_.is_null() {
                    Val::ExternRef(None)
                } else {
                    ref_to_val(&*self.of.ref_)
                }
            },
            ValType::FuncRef => unsafe {
                if self.of.ref_.is_null() {
                    Val::FuncRef(None)
                } else {
                    ref_to_val(&*self.of.ref_)
                }
            },
            _ => unimplemented!("wasm_val_t::val {:?}", self.kind),
        }
    }
}

#[no_mangle]
pub unsafe extern "C" fn wasm_val_copy(out: &mut MaybeUninit<wasm_val_t>, source: &wasm_val_t) {
    crate::initialize(out, source.clone());
}

#[no_mangle]
pub unsafe extern "C" fn wasm_val_delete(val: *mut wasm_val_t) {
    ptr::drop_in_place(val);
}