lofty 0.25.4

use crate::config::WriteOptions;
use crate::id3::v2::error::FrameParseError;
use crate::id3::v2::frame::content::verify_encoding;
use crate::id3::v2::frame::error::FrameEncodingError;
use crate::id3::v2::header::Id3v2Version;
use crate::id3::v2::{FrameFlags, FrameHeader, FrameId};
use crate::util::text::{
	TextDecodeOptions, TextDecodingError, TextEncoding, decode_text, utf16_decode_bytes,
};

use std::borrow::Cow;
use std::hash::{Hash, Hasher};
use std::io::Read;

use byteorder::ReadBytesExt;

const FRAME_ID: FrameId<'static> = FrameId::Valid(Cow::Borrowed("TXXX"));

/// An extended `ID3v2` text frame
///
/// This is used in the `TXXX` frame, where the frames
/// are told apart by descriptions, rather than their [`FrameID`](crate::id3::v2::FrameId)s.
/// This means for each `ExtendedTextFrame` in the tag, the description
/// must be unique.
#[derive(Clone, Debug, Eq)]
pub struct ExtendedTextFrame<'a> {
	pub(crate) header: FrameHeader<'a>,
	/// The encoding of the description and comment text
	pub encoding: TextEncoding,
	/// Unique content description
	pub description: Cow<'a, str>,
	/// The actual frame content
	pub content: Cow<'a, str>,
}

impl PartialEq for ExtendedTextFrame<'_> {
	fn eq(&self, other: &Self) -> bool {
		self.description == other.description
	}
}

impl Hash for ExtendedTextFrame<'_> {
	fn hash<H: Hasher>(&self, state: &mut H) {
		self.description.hash(state);
	}
}

impl<'a> ExtendedTextFrame<'a> {
	/// Create a new [`ExtendedTextFrame`]
	pub fn new(
		encoding: TextEncoding,
		description: impl Into<Cow<'a, str>>,
		content: impl Into<Cow<'a, str>>,
	) -> Self {
		let header = FrameHeader::new(FRAME_ID, FrameFlags::default());
		Self {
			header,
			encoding,
			description: description.into(),
			content: content.into(),
		}
	}

	/// Get the ID for the frame
	pub fn id(&self) -> FrameId<'_> {
		FRAME_ID
	}

	/// Get the flags for the frame
	pub fn flags(&self) -> FrameFlags {
		self.header.flags
	}

	/// Set the flags for the frame
	pub fn set_flags(&mut self, flags: FrameFlags) {
		self.header.flags = flags;
	}

	/// Read an [`ExtendedTextFrame`] from a slice
	///
	/// NOTE: This expects the frame header to have already been skipped
	///
	/// # Errors
	///
	/// * Unable to decode the text
	///
	/// ID3v2.2:
	///
	/// * The encoding is not [`TextEncoding::Latin1`] or [`TextEncoding::UTF16`]
	pub fn parse<R>(
		reader: &mut R,
		frame_flags: FrameFlags,
		version: Id3v2Version,
	) -> Result<Option<Self>, FrameParseError>
	where
		R: Read,
	{
		fn parse_inner<'a, R>(
			reader: &mut R,
			frame_flags: FrameFlags,
			version: Id3v2Version,
		) -> Result<Option<ExtendedTextFrame<'a>>, FrameParseError>
		where
			R: Read,
		{
			let Ok(encoding_byte) = reader.read_u8() else {
				return Ok(None);
			};

			let encoding = verify_encoding(encoding_byte, version)?;
			let description = decode_text(
				reader,
				TextDecodeOptions::new().encoding(encoding).terminated(true),
			)?;

			let frame_content;
			if encoding != TextEncoding::UTF16 {
				frame_content =
					decode_text(reader, TextDecodeOptions::new().encoding(encoding))?.content;

				let header = FrameHeader::new(FRAME_ID, frame_flags);
				return Ok(Some(ExtendedTextFrame {
					header,
					encoding,
					description: Cow::Owned(description.content),
					content: Cow::Owned(frame_content),
				}));
			}

			// It's possible for the description to be the only string with a BOM
			'utf16: {
				let mut raw_text = Vec::new();
				reader.read_to_end(&mut raw_text)?;

				if raw_text.is_empty() {
					// Nothing left to do
					frame_content = String::new();
					break 'utf16;
				}

				// Reuse the BOM from the description as a fallback if the text
				// doesn't specify one.
				let mut bom = description.bom;
				if raw_text.starts_with(&[0xFF, 0xFE]) || raw_text.starts_with(&[0xFE, 0xFF]) {
					// The text specifies a BOM
					bom = [raw_text[0], raw_text[1]];
				}

				let endianness = match bom {
					[0x00, 0x00] if raw_text.is_empty() => {
						debug_assert!(description.content.is_empty());
						// Empty string
						frame_content = String::new();
						break 'utf16;
					},
					[0x00, 0x00] => {
						debug_assert!(description.content.is_empty());
						return Err(TextDecodingError::utf16_missing_bom().into());
					},
					[0xFF, 0xFE] => u16::from_le_bytes,
					[0xFE, 0xFF] => u16::from_be_bytes,
					// Handled in description decoding
					_ => unreachable!(),
				};

				frame_content = utf16_decode_bytes(&raw_text, endianness)?;
			}

			let header = FrameHeader::new(FRAME_ID, frame_flags);
			Ok(Some(ExtendedTextFrame {
				header,
				encoding,
				description: Cow::Owned(description.content),
				content: Cow::Owned(frame_content),
			}))
		}

		parse_inner(reader, frame_flags, version).map_err(|mut e| {
			e.set_id(FRAME_ID);
			e
		})
	}

	/// Convert an [`ExtendedTextFrame`] to a byte vec
	///
	/// # Errors
	///
	/// * [`WriteOptions::lossy_text_encoding()`] is disabled and the content cannot be encoded in the specified [`TextEncoding`].
	pub fn as_bytes(&self, write_options: WriteOptions) -> Result<Vec<u8>, FrameEncodingError> {
		let mut encoding = self.encoding;
		if write_options.use_id3v23 {
			encoding = encoding.to_id3v23();
		}

		let mut bytes = vec![encoding as u8];

		bytes.extend(
			encoding
				.encode(&self.description, true, write_options.lossy_text_encoding)?
				.iter(),
		);
		bytes.extend(encoding.encode(&self.content, false, write_options.lossy_text_encoding)?);

		Ok(bytes)
	}
}

impl ExtendedTextFrame<'_> {
	pub(crate) fn borrow(&self) -> ExtendedTextFrame<'_> {
		ExtendedTextFrame {
			header: self.header.borrow(),
			encoding: self.encoding,
			description: Cow::Borrowed(&self.description),
			content: Cow::Borrowed(&self.content),
		}
	}
}