// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.

mod blob;
mod compression;
mod message_port;
mod timers;

use deno_core::error::range_error;
use deno_core::error::type_error;
use deno_core::error::AnyError;
use deno_core::include_js_files;
use deno_core::op;
use deno_core::serde_v8;
use deno_core::url::Url;
use deno_core::v8;
use deno_core::ByteString;
use deno_core::CancelHandle;
use deno_core::Extension;
use deno_core::OpState;
use deno_core::Resource;
use deno_core::ResourceId;
use deno_core::U16String;
use deno_core::ZeroCopyBuf;

use encoding_rs::CoderResult;
use encoding_rs::Decoder;
use encoding_rs::DecoderResult;
use encoding_rs::Encoding;
use std::borrow::Cow;
use std::cell::RefCell;
use std::fmt;
use std::path::PathBuf;
use std::usize;

use crate::blob::op_blob_create_object_url;
use crate::blob::op_blob_create_part;
use crate::blob::op_blob_from_object_url;
use crate::blob::op_blob_read_part;
use crate::blob::op_blob_remove_part;
use crate::blob::op_blob_revoke_object_url;
use crate::blob::op_blob_slice_part;
pub use crate::blob::Blob;
pub use crate::blob::BlobPart;
pub use crate::blob::BlobStore;
pub use crate::blob::InMemoryBlobPart;

pub use crate::message_port::create_entangled_message_port;
use crate::message_port::op_message_port_create_entangled;
use crate::message_port::op_message_port_post_message;
use crate::message_port::op_message_port_recv_message;
pub use crate::message_port::JsMessageData;
pub use crate::message_port::MessagePort;

use crate::timers::op_now;
use crate::timers::op_sleep;
use crate::timers::op_timer_handle;
use crate::timers::StartTime;
pub use crate::timers::TimersPermission;

/// Load and execute the javascript code.
pub fn init<P: TimersPermission + 'static>(
  blob_store: BlobStore,
  maybe_location: Option<Url>,
) -> Extension {
  Extension::builder()
    .js(include_js_files!(
      prefix "deno:ext/web",
      "00_infra.js",
      "01_dom_exception.js",
      "01_mimesniff.js",
      "02_event.js",
      "02_structured_clone.js",
      "02_timers.js",
      "03_abort_signal.js",
      "04_global_interfaces.js",
      "05_base64.js",
      "06_streams.js",
      "08_text_encoding.js",
      "09_file.js",
      "10_filereader.js",
      "11_blob_url.js",
      "12_location.js",
      "13_message_port.js",
      "14_compression.js",
      "15_performance.js",
    ))
    .ops(vec![
      op_base64_decode::decl(),
      op_base64_encode::decl(),
      op_base64_atob::decl(),
      op_base64_btoa::decl(),
      op_encoding_normalize_label::decl(),
      op_encoding_decode_single::decl(),
      op_encoding_decode_utf8::decl(),
      op_encoding_new_decoder::decl(),
      op_encoding_decode::decl(),
      op_encoding_encode_into::decl(),
      op_encode_binary_string::decl(),
      op_blob_create_part::decl(),
      op_blob_slice_part::decl(),
      op_blob_read_part::decl(),
      op_blob_remove_part::decl(),
      op_blob_create_object_url::decl(),
      op_blob_revoke_object_url::decl(),
      op_blob_from_object_url::decl(),
      op_message_port_create_entangled::decl(),
      op_message_port_post_message::decl(),
      op_message_port_recv_message::decl(),
      compression::op_compression_new::decl(),
      compression::op_compression_write::decl(),
      compression::op_compression_finish::decl(),
      op_now::decl::<P>(),
      op_timer_handle::decl(),
      op_cancel_handle::decl(),
      op_sleep::decl(),
      op_transfer_arraybuffer::decl(),
    ])
    .state(move |state| {
      state.put(blob_store.clone());
      if let Some(location) = maybe_location.clone() {
        state.put(Location(location));
      }
      state.put(StartTime::now());
      Ok(())
    })
    .build()
}

#[op]
fn op_base64_decode(input: String) -> Result<ZeroCopyBuf, AnyError> {
  let mut s = input.into_bytes();
  let decoded_len = forgiving_base64_decode(&mut s)?;
  s.truncate(decoded_len);
  Ok(s.into())
}

#[op]
fn op_base64_atob(mut s: ByteString) -> Result<ByteString, AnyError> {
  let decoded_len = forgiving_base64_decode(&mut s)?;
  s.truncate(decoded_len);
  Ok(s)
}

/// See <https://infra.spec.whatwg.org/#forgiving-base64>
#[inline]
fn forgiving_base64_decode(input: &mut [u8]) -> Result<usize, AnyError> {
  let error: _ =
    || DomExceptionInvalidCharacterError::new("Failed to decode base64");
  let decoded = base64_simd::Base64::forgiving_decode_inplace(input)
    .map_err(|_| error())?;
  Ok(decoded.len())
}

#[op]
fn op_base64_encode(s: &[u8]) -> String {
  forgiving_base64_encode(s)
}

#[op]
fn op_base64_btoa(s: ByteString) -> String {
  forgiving_base64_encode(s.as_ref())
}

/// See <https://infra.spec.whatwg.org/#forgiving-base64>
#[inline]
fn forgiving_base64_encode(s: &[u8]) -> String {
  const BASE64_STANDARD: base64_simd::Base64 = base64_simd::Base64::STANDARD;
  BASE64_STANDARD.encode_to_boxed_str(s).into_string()
}

#[op]
fn op_encoding_normalize_label(label: String) -> Result<String, AnyError> {
  let encoding = Encoding::for_label_no_replacement(label.as_bytes())
    .ok_or_else(|| {
      range_error(format!(
        "The encoding label provided ('{}') is invalid.",
        label
      ))
    })?;
  Ok(encoding.name().to_lowercase())
}

#[op(v8)]
fn op_encoding_decode_utf8<'a>(
  scope: &mut v8::HandleScope<'a>,
  zero_copy: &[u8],
  ignore_bom: bool,
) -> Result<serde_v8::Value<'a>, AnyError> {
  let buf = &zero_copy;

  let buf = if !ignore_bom
    && buf.len() >= 3
    && buf[0] == 0xef
    && buf[1] == 0xbb
    && buf[2] == 0xbf
  {
    &buf[3..]
  } else {
    buf
  };

  // If `String::new_from_utf8()` returns `None`, this means that the
  // length of the decoded string would be longer than what V8 can
  // handle. In this case we return `RangeError`.
  //
  // For more details see:
  // - https://encoding.spec.whatwg.org/#dom-textdecoder-decode
  // - https://github.com/denoland/deno/issues/6649
  // - https://github.com/v8/v8/blob/d68fb4733e39525f9ff0a9222107c02c28096e2a/include/v8.h#L3277-L3278
  match v8::String::new_from_utf8(scope, buf, v8::NewStringType::Normal) {
    Some(text) => Ok(serde_v8::from_v8(scope, text.into())?),
    None => Err(type_error("buffer exceeds maximum length")),
  }
}

#[op]
fn op_encoding_decode_single(
  data: &[u8],
  label: String,
  fatal: bool,
  ignore_bom: bool,
) -> Result<U16String, AnyError> {
  let encoding = Encoding::for_label(label.as_bytes()).ok_or_else(|| {
    range_error(format!(
      "The encoding label provided ('{}') is invalid.",
      label
    ))
  })?;

  let mut decoder = if ignore_bom {
    encoding.new_decoder_without_bom_handling()
  } else {
    encoding.new_decoder_with_bom_removal()
  };

  let max_buffer_length = decoder
    .max_utf16_buffer_length(data.len())
    .ok_or_else(|| range_error("Value too large to decode."))?;

  let mut output = vec![0; max_buffer_length];

  if fatal {
    let (result, _, written) =
      decoder.decode_to_utf16_without_replacement(data, &mut output, true);
    match result {
      DecoderResult::InputEmpty => {
        output.truncate(written);
        Ok(output.into())
      }
      DecoderResult::OutputFull => {
        Err(range_error("Provided buffer too small."))
      }
      DecoderResult::Malformed(_, _) => {
        Err(type_error("The encoded data is not valid."))
      }
    }
  } else {
    let (result, _, written, _) =
      decoder.decode_to_utf16(data, &mut output, true);
    match result {
      CoderResult::InputEmpty => {
        output.truncate(written);
        Ok(output.into())
      }
      CoderResult::OutputFull => Err(range_error("Provided buffer too small.")),
    }
  }
}

#[op]
fn op_encoding_new_decoder(
  state: &mut OpState,
  label: &str,
  fatal: bool,
  ignore_bom: bool,
) -> Result<ResourceId, AnyError> {
  let encoding = Encoding::for_label(label.as_bytes()).ok_or_else(|| {
    range_error(format!(
      "The encoding label provided ('{}') is invalid.",
      label
    ))
  })?;

  let decoder = if ignore_bom {
    encoding.new_decoder_without_bom_handling()
  } else {
    encoding.new_decoder_with_bom_removal()
  };

  let rid = state.resource_table.add(TextDecoderResource {
    decoder: RefCell::new(decoder),
    fatal,
  });

  Ok(rid)
}

#[op]
fn op_encoding_decode(
  state: &mut OpState,
  data: &[u8],
  rid: ResourceId,
  stream: bool,
) -> Result<U16String, AnyError> {
  let resource = state.resource_table.get::<TextDecoderResource>(rid)?;

  let mut decoder = resource.decoder.borrow_mut();
  let fatal = resource.fatal;

  let max_buffer_length = decoder
    .max_utf16_buffer_length(data.len())
    .ok_or_else(|| range_error("Value too large to decode."))?;

  let mut output = vec![0; max_buffer_length];

  if fatal {
    let (result, _, written) =
      decoder.decode_to_utf16_without_replacement(data, &mut output, !stream);
    match result {
      DecoderResult::InputEmpty => {
        output.truncate(written);
        Ok(output.into())
      }
      DecoderResult::OutputFull => {
        Err(range_error("Provided buffer too small."))
      }
      DecoderResult::Malformed(_, _) => {
        Err(type_error("The encoded data is not valid."))
      }
    }
  } else {
    let (result, _, written, _) =
      decoder.decode_to_utf16(data, &mut output, !stream);
    match result {
      CoderResult::InputEmpty => {
        output.truncate(written);
        Ok(output.into())
      }
      CoderResult::OutputFull => Err(range_error("Provided buffer too small.")),
    }
  }
}

struct TextDecoderResource {
  decoder: RefCell<Decoder>,
  fatal: bool,
}

impl Resource for TextDecoderResource {
  fn name(&self) -> Cow<str> {
    "textDecoder".into()
  }
}

#[op]
fn op_encoding_encode_into(
  input: Cow<'_, str>,
  buffer: &mut [u8],
  out_buf: &mut [u32],
) {
  // Since `input` is already UTF-8, we can simply find the last UTF-8 code
  // point boundary from input that fits in `buffer`, and copy the bytes up to
  // that point.
  let boundary = if buffer.len() >= input.len() {
    input.len()
  } else {
    let mut boundary = buffer.len();

    // The maximum length of a UTF-8 code point is 4 bytes.
    for _ in 0..4 {
      if input.is_char_boundary(boundary) {
        break;
      }
      debug_assert!(boundary > 0);
      boundary -= 1;
    }

    debug_assert!(input.is_char_boundary(boundary));
    boundary
  };

  buffer[..boundary].copy_from_slice(input[..boundary].as_bytes());

  // The `read` output parameter is measured in UTF-16 code units.
  out_buf[0] = match input {
    // Borrowed Cow strings are zero-copy views into the V8 heap.
    // Thus, they are guarantee to be SeqOneByteString.
    Cow::Borrowed(v) => v[..boundary].len() as u32,
    Cow::Owned(v) => v[..boundary].encode_utf16().count() as u32,
  };
  out_buf[1] = boundary as u32;
}

#[op(v8)]
fn op_transfer_arraybuffer<'a>(
  scope: &mut v8::HandleScope<'a>,
  input: serde_v8::Value<'a>,
) -> Result<serde_v8::Value<'a>, AnyError> {
  let ab = v8::Local::<v8::ArrayBuffer>::try_from(input.v8_value)?;
  if !ab.is_detachable() {
    return Err(type_error("ArrayBuffer is not detachable"));
  }
  let bs = ab.get_backing_store();
  ab.detach(None);
  let ab = v8::ArrayBuffer::with_backing_store(scope, &bs);
  Ok(serde_v8::Value {
    v8_value: ab.into(),
  })
}

#[op]
fn op_encode_binary_string(s: &[u8]) -> ByteString {
  ByteString::from(s)
}

/// Creates a [`CancelHandle`] resource that can be used to cancel invocations of certain ops.
#[op(fast)]
pub fn op_cancel_handle(state: &mut OpState) -> u32 {
  state.resource_table.add(CancelHandle::new())
}

pub fn get_declaration() -> PathBuf {
  PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("lib.deno_web.d.ts")
}

#[derive(Debug)]
pub struct DomExceptionQuotaExceededError {
  pub msg: String,
}

impl DomExceptionQuotaExceededError {
  pub fn new(msg: &str) -> Self {
    DomExceptionQuotaExceededError {
      msg: msg.to_string(),
    }
  }
}

#[derive(Debug)]
pub struct DomExceptionInvalidCharacterError {
  pub msg: String,
}

impl DomExceptionInvalidCharacterError {
  pub fn new(msg: &str) -> Self {
    DomExceptionInvalidCharacterError {
      msg: msg.to_string(),
    }
  }
}

impl fmt::Display for DomExceptionQuotaExceededError {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    f.pad(&self.msg)
  }
}
impl fmt::Display for DomExceptionInvalidCharacterError {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    f.pad(&self.msg)
  }
}

impl std::error::Error for DomExceptionQuotaExceededError {}

impl std::error::Error for DomExceptionInvalidCharacterError {}

pub fn get_error_class_name(e: &AnyError) -> Option<&'static str> {
  e.downcast_ref::<DomExceptionQuotaExceededError>()
    .map(|_| "DOMExceptionQuotaExceededError")
    .or_else(|| {
      e.downcast_ref::<DomExceptionInvalidCharacterError>()
        .map(|_| "DOMExceptionInvalidCharacterError")
    })
}
pub struct Location(pub Url);