ens-normalize-rs 0.2.0

use crate::{
    constants, static_data::spec_json, utils, CodePoint, CodePointsSpecs, CollapsedEnsNameToken,
    CurrableError, DisallowedSequence, EnsNameToken, ParsedGroup, ProcessError, TokenizedLabel,
    TokenizedName,
};
use itertools::Itertools;
use std::collections::HashSet;
pub type LabelType = spec_json::GroupName;

/// Represents a validated ENS label as result of the `validate_label` function.
/// Contains the original tokenized label and the type of the label.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ValidatedLabel {
    pub tokens: Vec<EnsNameToken>,
    pub label_type: LabelType,
}

pub fn validate_name(
    name: &TokenizedName,
    specs: &CodePointsSpecs,
) -> Result<Vec<ValidatedLabel>, ProcessError> {
    if name.is_empty() {
        return Ok(vec![]);
    }
    let labels = name
        .iter_labels()
        .map(|label| validate_label(label, specs))
        .collect::<Result<Vec<_>, _>>()?;
    Ok(labels)
}

/// Validates a tokenized ENS label according to the ENSIP 15 specification
/// https://docs.ens.domains/ensip/15#validate
pub fn validate_label(
    label: TokenizedLabel<'_>,
    specs: &CodePointsSpecs,
) -> Result<ValidatedLabel, ProcessError> {
    non_empty(&label)?;
    check_token_types(&label)?;
    if label.is_fully_emoji() {
        return Ok(ValidatedLabel {
            tokens: label.tokens.to_owned(),
            label_type: LabelType::Emoji,
        });
    };
    underscore_only_at_beginning(&label)?;
    if label.is_fully_ascii() {
        no_hyphen_at_second_and_third(&label)?;
        return Ok(ValidatedLabel {
            tokens: label.tokens.to_owned(),
            label_type: LabelType::Ascii,
        });
    }
    check_fenced(&label, specs)?;
    check_cm_leading_emoji(&label, specs)?;
    let group = check_and_get_group(&label, specs)?;
    Ok(ValidatedLabel {
        tokens: label.tokens.to_owned(),
        label_type: group.name,
    })
}

fn non_empty(label: &TokenizedLabel) -> Result<(), ProcessError> {
    let non_ignored_token_exists = label.tokens.iter().any(|token| !token.is_ignored());
    if !non_ignored_token_exists {
        return Err(ProcessError::DisallowedSequence(
            DisallowedSequence::EmptyLabel,
        ));
    }
    Ok(())
}

fn check_token_types(label: &TokenizedLabel) -> Result<(), ProcessError> {
    if let Some(token) = label
        .tokens
        .iter()
        .find(|token| token.is_disallowed() || token.is_stop())
    {
        let cps = token.cps();
        let maybe_invisible_cp = cps.iter().find(|cp| {
            *cp == &constants::CP_ZERO_WIDTH_JOINER || *cp == &constants::CP_ZERO_WIDTH_NON_JOINER
        });
        if let Some(invisible_cp) = maybe_invisible_cp {
            return Err(ProcessError::DisallowedSequence(
                DisallowedSequence::InvisibleCharacter(*invisible_cp),
            ));
        } else {
            return Err(ProcessError::DisallowedSequence(
                DisallowedSequence::Invalid(utils::cps2str(&cps)),
            ));
        }
    }
    Ok(())
}

fn underscore_only_at_beginning(label: &TokenizedLabel) -> Result<(), ProcessError> {
    let leading_underscores = label
        .iter_cps()
        .take_while(|cp| *cp == constants::CP_UNDERSCORE)
        .count();
    let underscore_in_middle = label
        .iter_cps()
        .enumerate()
        .skip(leading_underscores)
        .find(|(_, cp)| *cp == constants::CP_UNDERSCORE);
    if let Some((index, _)) = underscore_in_middle {
        return Err(ProcessError::CurrableError {
            inner: CurrableError::UnderscoreInMiddle,
            index,
            sequence: utils::cps2str(&[constants::CP_UNDERSCORE]),
            maybe_suggest: Some("".to_string()),
        });
    }
    Ok(())
}

// The 3rd and 4th characters must not both be 2D (-) HYPHEN-MINUS.
// Must not match /^..--/
// Examples: "ab-c" and "---a"are valid, "xn--" and ---- are invalid.
fn no_hyphen_at_second_and_third(label: &TokenizedLabel) -> Result<(), ProcessError> {
    if label.iter_cps().nth(2) == Some(constants::CP_HYPHEN)
        && label.iter_cps().nth(3) == Some(constants::CP_HYPHEN)
    {
        return Err(ProcessError::CurrableError {
            inner: CurrableError::HyphenAtSecondAndThird,
            index: 2,
            sequence: utils::cps2str(&[constants::CP_HYPHEN, constants::CP_HYPHEN]),
            maybe_suggest: Some("".to_string()),
        });
    }
    Ok(())
}

fn check_fenced(label: &TokenizedLabel, specs: &CodePointsSpecs) -> Result<(), ProcessError> {
    if let Some(first_cp) = label.iter_cps().next() {
        if specs.is_fenced(first_cp) {
            return Err(ProcessError::CurrableError {
                inner: CurrableError::FencedLeading,
                index: 0,
                sequence: utils::cps2str(&[first_cp]),
                maybe_suggest: Some("".to_string()),
            });
        }
    }
    if let Some(last_cp) = label.iter_cps().last() {
        if specs.is_fenced(last_cp) {
            return Err(ProcessError::CurrableError {
                inner: CurrableError::FencedTrailing,
                index: label.iter_cps().count() - 1,
                sequence: utils::cps2str(&[last_cp]),
                maybe_suggest: Some("".to_string()),
            });
        }
    }

    for (i, window) in label.iter_cps().tuple_windows().enumerate() {
        let (one, two) = window;
        if specs.is_fenced(one) && specs.is_fenced(two) {
            return Err(ProcessError::CurrableError {
                inner: CurrableError::FencedConsecutive,
                index: i,
                sequence: utils::cps2str(&[one, two]),
                maybe_suggest: Some(utils::cp2str(one)),
            });
        }
    }
    Ok(())
}

fn check_cm_leading_emoji(
    label: &TokenizedLabel,
    specs: &CodePointsSpecs,
) -> Result<(), ProcessError> {
    let mut index = 0;
    let collapsed = label.collapse_into_text_or_emoji();
    for (i, token) in collapsed.iter().enumerate() {
        if let CollapsedEnsNameToken::Text(token) = token {
            if let Some(cp) = token.cps.first() {
                if specs.is_cm(*cp) {
                    if i == 0 {
                        return Err(ProcessError::CurrableError {
                            inner: CurrableError::CmStart,
                            index,
                            sequence: utils::cps2str(&[*cp]),
                            maybe_suggest: Some("".to_string()),
                        });
                    } else {
                        return Err(ProcessError::CurrableError {
                            inner: CurrableError::CmAfterEmoji,
                            index,
                            sequence: utils::cps2str(&[*cp]),
                            maybe_suggest: Some("".to_string()),
                        });
                    }
                }
            }
        }
        index += token.input_size();
    }

    Ok(())
}

fn check_and_get_group(
    label: &TokenizedLabel,
    specs: &CodePointsSpecs,
) -> Result<ParsedGroup, ProcessError> {
    let cps = label.get_cps_of_not_ignored_text();
    let unique_cps = cps
        .clone()
        .into_iter()
        .collect::<HashSet<_>>()
        .into_iter()
        .collect::<Vec<_>>();
    let group = determine_group(&unique_cps, specs).cloned()?;
    check_group(&group, &cps, specs)?;
    check_whole(&group, &unique_cps, specs)?;
    Ok(group)
}

fn check_group(
    group: &ParsedGroup,
    cps: &[CodePoint],
    specs: &CodePointsSpecs,
) -> Result<(), ProcessError> {
    for cp in cps.iter() {
        if !group.contains_cp(*cp) {
            return Err(ProcessError::Confused(format!(
                "symbol {} not present in group {}",
                utils::cp2str(*cp),
                group.name
            )));
        }
    }
    if group.cm_absent {
        let decomposed = utils::nfd_cps(cps, specs);
        let mut i = 1;
        let e = decomposed.len();
        while i < e {
            if specs.is_nsm(decomposed[i]) {
                let mut j = i + 1;
                while j < e && specs.is_nsm(decomposed[j]) {
                    if j - i + 1 > specs.nsm_max() as usize {
                        return Err(ProcessError::DisallowedSequence(
                            DisallowedSequence::NsmTooMany,
                        ));
                    }
                    for k in i..j {
                        if decomposed[k] == decomposed[j] {
                            return Err(ProcessError::DisallowedSequence(
                                DisallowedSequence::NsmRepeated,
                            ));
                        }
                    }
                    j += 1;
                }
                i = j;
            }
            i += 1;
        }
    }
    Ok(())
}

fn check_whole(
    group: &ParsedGroup,
    unique_cps: &[CodePoint],
    specs: &CodePointsSpecs,
) -> Result<(), ProcessError> {
    let mut shared = Vec::new();
    let mut universe = Vec::new();
    let mut universe_len = 0usize;

    for &cp in unique_cps {
        if let Some(whole) = specs.whole_for_confusable(cp) {
            let complements = whole
                .complements
                .get(&cp)
                .expect("confusable codepoint must have complements");

            if universe_len == 0 {
                universe_len = complements.len();
                universe = complements.to_vec();
            } else {
                let mut next = 0;
                for i in 0..universe_len {
                    if complements.binary_search(&universe[i]).is_ok() {
                        universe[next] = universe[i];
                        next += 1;
                    }
                }
                universe_len = next;
                universe.truncate(universe_len);
            }

            if universe_len == 0 {
                return Ok(());
            }
        } else if specs.is_unique_non_confusable(cp) {
            return Ok(());
        } else {
            shared.push(cp);
        }
    }

    if universe_len > 0 {
        for &group_idx in &universe[..universe_len] {
            let other = specs.group_at(group_idx);
            if other.contains_all_cps(&shared) {
                return Err(ProcessError::ConfusedGroups {
                    group1: group.name.to_string(),
                    group2: other.name.to_string(),
                });
            }
        }
    }

    Ok(())
}

fn determine_group<'a>(
    unique_cps: &'a [CodePoint],
    specs: &'a CodePointsSpecs,
) -> Result<&'a ParsedGroup, ProcessError> {
    specs
        .groups_for_cps(unique_cps)
        .next()
        .ok_or(ProcessError::Confused(format!(
            "no group found for {:?}",
            unique_cps
        )))
}

#[cfg(test)]
mod tests {
    use crate::TokenizedName;

    use super::*;
    use pretty_assertions::assert_eq;
    use rstest::{fixture, rstest};

    #[fixture]
    #[once]
    fn specs() -> CodePointsSpecs {
        CodePointsSpecs::default()
    }

    #[rstest]
    // success
    #[case::hello("hello", Ok(LabelType::Ascii))]
    #[case::latin("E︎̃", Ok(LabelType::Other("Latin".to_string())))]
    #[case::cyrillic("всем-привет", Ok(LabelType::Other("Cyrillic".to_string())))]
    #[case::with_fenced_in_middle("a・a’s", Ok(LabelType::Other("Han".to_string())))]
    #[case::ascii_with_hyphen("ab-c", Ok(LabelType::Ascii))]
    // errors
    #[case::hyphen_at_second_and_third("ab--", Err(ProcessError::CurrableError {
        inner: CurrableError::HyphenAtSecondAndThird,
        index: 2,
        sequence: "--".to_string(),
        maybe_suggest: Some("".to_string())
    }))]
    #[case::fenced_leading("’85", Err(ProcessError::CurrableError {
        inner: CurrableError::FencedLeading,
        index: 0,
        sequence: "’".to_string(),
        maybe_suggest: Some("".to_string())
    }))]
    #[case::fenced_contiguous("a・・a", Err(ProcessError::CurrableError {
        inner: CurrableError::FencedConsecutive,
        index: 1,
        sequence: "・・".to_string(),
        maybe_suggest: Some("・".to_string())
    }))]
    #[case::cm_after_emoji("😎😎😎😎😎😎😎😎\u{300}hello", Err(ProcessError::CurrableError {
        inner: CurrableError::CmAfterEmoji,
        index: 8,
        sequence: "\u{300}".to_string(),
        maybe_suggest: Some("".to_string())
    }))]
    #[case::cm_leading("\u{300}hello", Err(ProcessError::CurrableError {
        inner: CurrableError::CmStart,
        index: 0,
        sequence: "\u{300}".to_string(),
        maybe_suggest: Some("".to_string())
    }))]
    fn test_validate_and_get_type(
        #[case] input: &str,
        #[case] expected: Result<LabelType, ProcessError>,
        specs: &CodePointsSpecs,
    ) {
        let name = TokenizedName::from_input(input, specs, true).unwrap();
        let label = name.iter_labels().next().unwrap();
        let result = validate_label(label, specs);
        assert_eq!(
            result.clone().map(|v| v.label_type),
            expected,
            "{:?}",
            result
        );
    }

    #[rstest]
    #[case::emoji("\"Emoji\"", LabelType::Emoji)]
    #[case::ascii("\"ASCII\"", LabelType::Ascii)]
    #[case::greek("\"Greek\"", LabelType::Greek)]
    #[case::other("\"FooBar\"", LabelType::Other("FooBar".to_string()))]
    fn test_deserialize_label_type(#[case] input: &str, #[case] expected: LabelType) {
        let result: LabelType = serde_json::from_str(input).unwrap();
        assert_eq!(result, expected);
    }
}