/*
 * The MIT License (MIT)
 * Copyright (C) 2024 Huawei Device Co., Ltd.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 */

use std::mem;
use std::ptr;

use crate::bindgen_runtime::TypeName;
use crate::bindgen_runtime::ValidateNapiValue;
use crate::ValueType;
use crate::{check_status, sys, Result, Value};

pub use latin1::JsStringLatin1;
pub use utf16::JsStringUtf16;
pub use utf8::JsStringUtf8;

mod latin1;
mod utf16;
mod utf8;

#[derive(Clone, Copy)]
pub struct JsString(pub(crate) Value);

impl TypeName for JsString {
  fn type_name() -> &'static str {
    "String"
  }

  fn value_type() -> crate::ValueType {
    ValueType::String
  }
}

impl ValidateNapiValue for JsString {}

impl JsString {
  pub fn utf8_len(&self) -> Result<usize> {
    let mut length = 0;
    check_status!(unsafe {
      sys::napi_get_value_string_utf8(self.0.env, self.0.value, ptr::null_mut(), 0, &mut length)
    })?;
    Ok(length)
  }

  pub fn utf16_len(&self) -> Result<usize> {
    let mut length = 0;
    check_status!(unsafe {
      sys::napi_get_value_string_utf16(self.0.env, self.0.value, ptr::null_mut(), 0, &mut length)
    })?;
    Ok(length)
  }

  pub fn latin1_len(&self) -> Result<usize> {
    let mut length = 0;
    check_status!(unsafe {
      sys::napi_get_value_string_latin1(self.0.env, self.0.value, ptr::null_mut(), 0, &mut length)
    })?;
    Ok(length)
  }

  pub fn into_utf8(self) -> Result<JsStringUtf8> {
    let mut written_char_count = 0;
    let len = self.utf8_len()? + 1;
    let mut result = Vec::with_capacity(len);
    let buf_ptr = result.as_mut_ptr();
    check_status!(unsafe {
      sys::napi_get_value_string_utf8(
        self.0.env,
        self.0.value,
        buf_ptr,
        len,
        &mut written_char_count,
      )
    })?;

    // respect '\0' with js string, for example: `let hello = [a,'\0',b,'\0',c].join('')`
    let mut result = mem::ManuallyDrop::new(result);
    let buf_ptr = result.as_mut_ptr();
    let bytes = unsafe { Vec::from_raw_parts(buf_ptr as *mut u8, written_char_count, len) };
    Ok(JsStringUtf8 {
      inner: self,
      buf: bytes,
    })
  }

  pub fn into_utf16(self) -> Result<JsStringUtf16> {
    let mut written_char_count = 0usize;
    let len = self.utf16_len()? + 1;
    let mut result = vec![0; len];
    let buf_ptr = result.as_mut_ptr();
    check_status!(unsafe {
      sys::napi_get_value_string_utf16(
        self.0.env,
        self.0.value,
        buf_ptr,
        len,
        &mut written_char_count,
      )
    })?;

    Ok(JsStringUtf16 {
      inner: self,
      buf: result,
    })
  }

  pub fn into_latin1(self) -> Result<JsStringLatin1> {
    let mut written_char_count = 0usize;
    let len = self.latin1_len()? + 1;
    let mut result = Vec::with_capacity(len);
    let buf_ptr = result.as_mut_ptr();
    check_status!(unsafe {
      sys::napi_get_value_string_latin1(
        self.0.env,
        self.0.value,
        buf_ptr,
        len,
        &mut written_char_count,
      )
    })?;

    mem::forget(result);

    Ok(JsStringLatin1 {
      inner: self,
      buf: mem::ManuallyDrop::new(unsafe {
        Vec::from_raw_parts(buf_ptr as *mut _, written_char_count, written_char_count)
      }),
    })
  }
}