// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.

use crate::dlfcn::DynamicLibraryResource;
use crate::symbol::NativeType;
use crate::MAX_SAFE_INTEGER;
use crate::MIN_SAFE_INTEGER;
use deno_core::error::type_error;
use deno_core::error::AnyError;
use deno_core::op;
use deno_core::serde_v8;
use deno_core::v8;
use deno_core::ResourceId;
use std::ffi::c_void;
use std::ptr;

#[op(v8)]
pub fn op_ffi_get_static<'scope>(
  scope: &mut v8::HandleScope<'scope>,
  state: &mut deno_core::OpState,
  rid: ResourceId,
  name: String,
  static_type: NativeType,
  optional: bool,
) -> Result<serde_v8::Value<'scope>, AnyError> {
  let resource = state.resource_table.get::<DynamicLibraryResource>(rid)?;

  let data_ptr = match resource.get_static(name) {
    Ok(data_ptr) => Ok(data_ptr),
    Err(err) => {
      if optional {
        let null: v8::Local<v8::Value> = v8::null(scope).into();
        return Ok(null.into());
      } else {
        Err(err)
      }
    }
  }?;

  Ok(match static_type {
    NativeType::Void => {
      return Err(type_error("Invalid FFI static type 'void'"));
    }
    NativeType::Bool => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const bool) };
      let boolean: v8::Local<v8::Value> =
        v8::Boolean::new(scope, result).into();
      boolean.into()
    }
    NativeType::U8 => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const u8) };
      let number: v8::Local<v8::Value> =
        v8::Integer::new_from_unsigned(scope, result as u32).into();
      number.into()
    }
    NativeType::I8 => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const i8) };
      let number: v8::Local<v8::Value> =
        v8::Integer::new(scope, result as i32).into();
      number.into()
    }
    NativeType::U16 => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const u16) };
      let number: v8::Local<v8::Value> =
        v8::Integer::new_from_unsigned(scope, result as u32).into();
      number.into()
    }
    NativeType::I16 => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const i16) };
      let number: v8::Local<v8::Value> =
        v8::Integer::new(scope, result as i32).into();
      number.into()
    }
    NativeType::U32 => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const u32) };
      let number: v8::Local<v8::Value> =
        v8::Integer::new_from_unsigned(scope, result).into();
      number.into()
    }
    NativeType::I32 => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const i32) };
      let number: v8::Local<v8::Value> = v8::Integer::new(scope, result).into();
      number.into()
    }
    NativeType::U64 => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const u64) };
      let integer: v8::Local<v8::Value> = if result > MAX_SAFE_INTEGER as u64 {
        v8::BigInt::new_from_u64(scope, result).into()
      } else {
        v8::Number::new(scope, result as f64).into()
      };
      integer.into()
    }
    NativeType::I64 => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const i64) };
      let integer: v8::Local<v8::Value> = if result > MAX_SAFE_INTEGER as i64
        || result < MIN_SAFE_INTEGER as i64
      {
        v8::BigInt::new_from_i64(scope, result).into()
      } else {
        v8::Number::new(scope, result as f64).into()
      };
      integer.into()
    }
    NativeType::USize => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const usize) };
      let integer: v8::Local<v8::Value> = if result > MAX_SAFE_INTEGER as usize
      {
        v8::BigInt::new_from_u64(scope, result as u64).into()
      } else {
        v8::Number::new(scope, result as f64).into()
      };
      integer.into()
    }
    NativeType::ISize => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const isize) };
      let integer: v8::Local<v8::Value> =
        if !(MIN_SAFE_INTEGER..=MAX_SAFE_INTEGER).contains(&result) {
          v8::BigInt::new_from_i64(scope, result as i64).into()
        } else {
          v8::Number::new(scope, result as f64).into()
        };
      integer.into()
    }
    NativeType::F32 => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const f32) };
      let number: v8::Local<v8::Value> =
        v8::Number::new(scope, result as f64).into();
      number.into()
    }
    NativeType::F64 => {
      // SAFETY: ptr is user provided
      let result = unsafe { ptr::read_unaligned(data_ptr as *const f64) };
      let number: v8::Local<v8::Value> = v8::Number::new(scope, result).into();
      number.into()
    }
    NativeType::Pointer | NativeType::Function | NativeType::Buffer => {
      let external: v8::Local<v8::Value> =
        v8::External::new(scope, data_ptr as *mut c_void).into();
      external.into()
    }
    NativeType::Struct(_) => {
      return Err(type_error("Invalid FFI static type 'struct'"));
    }
  })
}