// This file is part of ICU4X. For terms of use, please see the file

// called LICENSE at the top level of the ICU4X source tree

// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).

//! This module exposes tooling for running the [unicode bidi algorithm](https://unicode.org/reports/tr9/) using ICU4X data.

//!

//! `BidiClassAdapter` enables ICU4X to provide data to [`unicode-bidi`], an external crate implementing UAX #9.

//!

//! ✨ *Enabled with the `bidi` Cargo feature.*

//!

//! # Examples

//!

//!```

//! use icu::properties::bidi::BidiClassAdapter;

//! use icu::properties::maps;

//! use unicode_bidi::BidiInfo;

//! // This example text is defined using `concat!` because some browsers

//! // and text editors have trouble displaying bidi strings.

//! let text =  concat!["א", // RTL#1

//!                     "ב", // RTL#2

//!                     "ג", // RTL#3

//!                     "a", // LTR#1

//!                     "b", // LTR#2

//!                     "c", // LTR#3

//!                     ]; //

//!

//!

//! let adapter = BidiClassAdapter::new(maps::bidi_class());

//! // Resolve embedding levels within the text.  Pass `None` to detect the

//! // paragraph level automatically.

//!

//! let bidi_info = BidiInfo::new_with_data_source(&adapter, text, None);

//!

//! // This paragraph has embedding level 1 because its first strong character is RTL.

//! assert_eq!(bidi_info.paragraphs.len(), 1);

//! let para = &bidi_info.paragraphs[0];

//! assert_eq!(para.level.number(), 1);

//! assert!(para.level.is_rtl());

//!

//! // Re-ordering is done after wrapping each paragraph into a sequence of

//! // lines. For this example, I'll just use a single line that spans the

//! // entire paragraph.

//! let line = para.range.clone();

//!

//! let display = bidi_info.reorder_line(para, line);

//! assert_eq!(display, concat!["a", // LTR#1

//!                             "b", // LTR#2

//!                             "c", // LTR#3

//!                             "ג", // RTL#3

//!                             "ב", // RTL#2

//!                             "א", // RTL#1

//!                             ]);

//! ```

use crate::maps::CodePointMapDataBorrowed;

use crate::props::BidiClass;

use unicode_bidi::data_source::BidiDataSource;

use unicode_bidi::BidiClass as DataSourceBidiClass;

/// An adapter to convert from icu4x `BidiClass` to `unicode_bidi::BidiClass`.

///

/// ✨ *Enabled with the `bidi` Cargo feature.*

///

/// # Example

///

/// ```

/// use icu::collections::codepointtrie::CodePointTrie;

/// use icu::properties::bidi::BidiClassAdapter;

/// use icu::properties::{maps, BidiClass};

/// use unicode_bidi::BidiClass as DataSourceBidiClass;

/// use unicode_bidi::BidiDataSource;

///

/// let adapter = BidiClassAdapter::new(maps::bidi_class());

/// assert_eq!(adapter.bidi_class('a'), DataSourceBidiClass::L);

/// assert_eq!(adapter.bidi_class('ع'), DataSourceBidiClass::AL);

/// ```

#[derive(Debug)]

pub struct BidiClassAdapter<'a> {

    data: CodePointMapDataBorrowed<'a, BidiClass>,

}

impl<'a> BidiClassAdapter<'a> {

    /// Creates new instance of `BidiClassAdapter`.

    pub const fn new(data: CodePointMapDataBorrowed<'a, BidiClass>) -> BidiClassAdapter<'a> {

        BidiClassAdapter { data }

    }

}

impl<'a> BidiDataSource for BidiClassAdapter<'a> {

    /// Returns a [`DataSourceBidiClass`] given a unicode character.

    ///

    /// # Example

    ///

    /// ```

    /// use icu::collections::codepointtrie::CodePointTrie;

    /// use icu::properties::bidi::BidiClassAdapter;

    /// use icu::properties::{maps, BidiClass};

    /// use unicode_bidi::BidiClass as DataSourceBidiClass;

    /// use unicode_bidi::BidiDataSource;

    ///

    /// let adapter = BidiClassAdapter::new(maps::bidi_class());

    /// assert_eq!(adapter.bidi_class('a'), DataSourceBidiClass::L);

    /// ```

    ///

    /// [`CodePointTrie`]: icu::collections::codepointtrie::CodePointTrie

    fn bidi_class(&self, c: char) -> DataSourceBidiClass {

        let bidi_class = self.data.get(c);

        match bidi_class {

            BidiClass::LeftToRight => DataSourceBidiClass::L,

            BidiClass::RightToLeft => DataSourceBidiClass::R,

            BidiClass::EuropeanNumber => DataSourceBidiClass::EN,

            BidiClass::EuropeanSeparator => DataSourceBidiClass::ES,

            BidiClass::EuropeanTerminator => DataSourceBidiClass::ET,

            BidiClass::ArabicNumber => DataSourceBidiClass::AN,

            BidiClass::CommonSeparator => DataSourceBidiClass::CS,

            BidiClass::ParagraphSeparator => DataSourceBidiClass::B,

            BidiClass::SegmentSeparator => DataSourceBidiClass::S,

            BidiClass::WhiteSpace => DataSourceBidiClass::WS,

            BidiClass::OtherNeutral => DataSourceBidiClass::ON,

            BidiClass::LeftToRightEmbedding => DataSourceBidiClass::LRE,

            BidiClass::LeftToRightOverride => DataSourceBidiClass::LRO,

            BidiClass::ArabicLetter => DataSourceBidiClass::AL,

            BidiClass::RightToLeftEmbedding => DataSourceBidiClass::RLE,

            BidiClass::RightToLeftOverride => DataSourceBidiClass::RLO,

            BidiClass::PopDirectionalFormat => DataSourceBidiClass::PDF,

            BidiClass::NonspacingMark => DataSourceBidiClass::NSM,

            BidiClass::BoundaryNeutral => DataSourceBidiClass::BN,

            BidiClass::FirstStrongIsolate => DataSourceBidiClass::FSI,

            BidiClass::LeftToRightIsolate => DataSourceBidiClass::LRI,

            BidiClass::RightToLeftIsolate => DataSourceBidiClass::RLI,

            BidiClass::PopDirectionalIsolate => DataSourceBidiClass::PDI,

            _ =>

            // This must not happen.

            {

                DataSourceBidiClass::ON

            }

        }

    }

}