//! Defines regex replacement rules to filter text with.
//!
//! This module defines the FilterRule type, which represents
//! a regex replacement rule, as well as several functions
//! that return lists of predefined filter rules.
//!
//! Creating a `FilterRule` compiles a [regular expression](https://docs.rs/regex/1/regex/struct.Regex.html),
//! which means it is potentially expensive to call these predefined
//! filter rule functions in a loop.

use std::borrow::Cow;
use std::error::Error;

use regex::Regex;

/// Represents a regex replacement rule with a pattern and replacement text.
#[derive(Debug, Clone)]
pub struct FilterRule(Regex, &'static str);

impl FilterRule {
    /// Create a new filter rule with a pattern and a replacement text.
    /// The pattern follows the syntax from the [`regex`](https://docs.rs/regex/1) crate.
    /// Returns an error if the regex could not be compiled.
    pub fn new(pattern: &str, replacement: &'static str) -> Result<Self, Box<dyn Error>> {
        Ok(Self(
            Regex::new(&pattern)?,
            replacement
        ))
    }

    /// Apply the filter rule. Returns Cow::Owned if a replacement was done,
    /// or Cow::Borrowed (referencing the original text) if nothing was changed.
    pub fn apply<'t>(&self, text: &'t str) -> Cow<'t, str> {
        self.0.replace(text, self.1)
    }
}

macro_rules! filter_rules {
    ($(#[$meta:meta])* $name:ident, $rules:expr) => {
        $(#[$meta])*
        pub fn $name() -> Vec<FilterRule> {
            $rules
                .iter()
                .map(|rule| FilterRule(Regex::new(rule.0).unwrap(), rule.1))
                .collect()
        }
    };
}

filter_rules!(
    /// Filter rules to remove YouTube suffixes and prefixes from a text.
    youtube_track_filter_rules,
    [
        // Trim whitespaces
        (r"^\s+", ""),
        (r"\s+$", ""),
        // **NEW**
        (r"\*+\s?\S+\s?\*+$", ""),
        // [whatever]
        (r"\[[^\]]+\]", ""),
        // (whatever version)
        (r"(?i)\([^)]*version\)$", ""),
        // video extensions
        (r"(?i)\.(avi|wmv|mpg|mpeg|flv)$", ""),
        // (LYRICs VIDEO)
        (r"(?i)\(.*lyrics?\s*(video)?\)", ""),
        // (Official Track Stream)
        (r"(?i)\((of+icial\s*)?(track\s*)?stream\)", ""),
        // (official)? (music)? video
        (r"(?i)\((of+icial\s*)?(music\s*)?video\)", ""),
        // (official)? (music)? audio
        (r"(?i)\((of+icial\s*)?(music\s*)?audio\)", ""),
        // (ALBUM TRACK)
        (r"(?i)(album track\s*)", ""),
        // (Cover Art)
        (r"(?i)(cover art\s*)", ""),
        // (official)
        (r"(?i)\(\s*of+icial\s*\)", ""),
        // (1999)
        (r"(?i)\(\s*[0-9]{4}\s*\)", ""),
        // HD (HQ)
        (r"(HD|HQ)\s*$", ""),
        // video clip officiel or video clip official
        ("(?i)(vid[\u{00E9}e]o)?\\s?clip\\sof+ici[ae]l", ""),
        // offizielles
        (r"(?i)of+iziel+es\s*video", ""),
        // video clip
        ("(?i)vid[\u{00E9}e]o\\s?clip", ""),
        // clip
        (r"(?i)\sclip", ""),
        // Full Album
        (r"(?i)full\s*album", ""),
        // (live)
        (r"(?i)\(live.*?\)$", ""),
        // | something
        (r"(?i)\|.*$", ""),
        // Artist - The new "Track title" featuring someone
        (r#"^(|.*\s)"(.{5,})"(\s.*|)$"#, "$2"),
        // 'Track title'
        (r"^(|.*\s)'(.{5,})'(\s.*|)$", "$2"),
        // (*01/01/1999*)
        (r"(?i)\(.*[0-9]{1,2}/[0-9]{1,2}/[0-9]{2,4}.*\)", ""),
        // Sub Español
        (r"(?i)sub\s*español", ""),
        // (Letra/Lyrics)
        (r"(?i)\s\(Letra/Lyrics\)", ""),
        // (Letra)
        (r"(?i)\s\(Letra\)", ""),
        // (En vivo)
        (r"(?i)\s\(En\svivo\)", ""),
    ]
);

filter_rules!(
    /// Filter rules to remove leftovers after filtering text using
    /// [`youtube_track_filter_rules`](fn.youtube_track_filter_rules.html).
    trim_symbols_filter_rules,
    [
        // Leftovers after e.g. (official video)
        (r"\(+\s*\)+", ""),
        // trim starting white chars and dash
        (r#"^[/,:;~\-\s"]+"#, ""),
        // trim trailing white chars and dash
        (r#"[/,:;~\-\s"]+$"#, ""),
    ]
);

filter_rules!(
    /// Filter rules to remove "Remastered..."-like strings from a text.
    remastered_filter_rules,
    [
        // Here Comes The Sun - Remastered
        (r"-\sRemastered$", ""),
        // Hey Jude - Remastered 2015
        (r"-\sRemastered\s\d+$", ""),
        // Let It Be (Remastered 2009)
        // Red Rain (Remaster 2012)
        (r"\(Remaster(ed)?\s\d+\)$", ""),
        // Pigs On The Wing (Part One) [2011 - Remaster]
        (r"\[\d+\s-\sRemaster\]$", ""),
        // Comfortably Numb (2011 - Remaster)
        // Dancing Days (2012 Remaster)
        (r"\(\d+(\s-)?\sRemaster\)$", ""),
        // Outside The Wall - 2011 - Remaster
        // China Grove - 2006 Remaster
        (r"-\s\d+(\s-)?\sRemaster$", ""),
        // Learning To Fly - 2001 Digital Remaster
        (r"-\s\d+\s.+?\sRemaster$", ""),
        // Your Possible Pasts - 2011 Remastered Version
        (r"-\s\d+\sRemastered Version$", ""),
        // Roll Over Beethoven (Live / Remastered)
        (r"\(Live\s/\sRemastered\)$", ""),
        // Ticket To Ride - Live / Remastered
        (r"-\sLive\s/\sRemastered$", ""),
        // Mothership (Remastered)
        // How The West Was Won [Remastered]
        (r"[(\[]Remastered[)\]]$", ""),
        // A Well Respected Man (2014 Remastered Version)
        // A Well Respected Man [2014 Remastered Version]
        (r"[(\[]\d{4} Re[Mm]astered Version[)\]]$", ""),
        // She Was Hot (2009 Re-Mastered Digital Version)
        // She Was Hot (2009 Remastered Digital Version)
        (r"[(\[]\d{4} Re-?[Mm]astered Digital Version[)\]]$", ""),
        // In The Court Of The Crimson King (Expanded & Remastered Original Album Mix)
        (r"\([^(]*Remaster[^)]*\)$", ""),
    ]
);

filter_rules!(
    /// Filter rules to remove "Live..."-like strings from a text.
    live_filter_rules,
    [
        // Track - Live
        (r"-\sLive?$", ""),
        // Track - Live at
        (r"-\sLive\s.+?$", ""),
        // (Live) or [Live]
        (r"(?i)[(\[]Live[)\]]", ""),
    ]
);

filter_rules!(
    /// Filter rules to remove "Explicit" and "Clean" from a text.
    clean_explicit_filter_rules,
    [
        // (Explicit) or [Explicit]
        (r"(?i)\s[(\[]Explicit[)\]]", ""),
        // (Clean) or [Clean]
        (r"(?i)\s[(\[]Clean[)\]]", ""),
    ]
);

filter_rules!(
    /// Filter rules to remove feature information from a text.
    feature_filter_rules,
    [
        // [Feat. Artist] or (Feat. Artist)
        (r"(?i)\s[(\[]feat. .+[)\]]", ""),
    ]
);

filter_rules!(
    /// Filter rules to normalize feature information to "Feat. Artist".
    normalize_feature_filter_rules,
    [
        // [Feat. Artist] or (Feat. Artist) -> Feat. Artist
        (r"(?i)\s[(\[](feat. .+)[)\]]", " $1"),
    ]
);

filter_rules!(
    /// Filter rules to remove version information (eg. "Album Version" or "Deluxe Edition")
    /// from a text.
    version_filter_rules,
    [
        // Love Will Come To You (Album Version)
        (r"[(\[]Album Version[)\]]$", ""),
        // I Melt With You (Rerecorded)
        // When I Need You [Re-Recorded]
        (r"[(\[]Re-?[Rr]ecorded[)\]]$", ""),
        // Your Cheatin' Heart (Single Version)
        (r"[(\[]Single Version[)\]]$", ""),
        // All Over Now (Edit)
        (r"[(\[]Edit[)\]]$", ""),
        // (I Can't Get No) Satisfaction - Mono Version
        (r"-\sMono Version$", ""),
        // Ruby Tuesday - Stereo Version
        (r"-\sStereo Version$", ""),
        // Pure McCartney (Deluxe Edition)
        (r"\(Deluxe Edition\)$", ""),
        // 6 Foot 7 Foot (Explicit Version)
        (r"(?i)[(\[]Explicit Version[)\]]", ""),
    ]
);

filter_rules!(
    /// Filter rules to normalize "- suffix" to "(suffix)" in a text.
    suffix_filter_rules,
    [
        // "- X Remix" -> "(X Remix)" and similar
        (
            r"(?i)-\s(.+?)\s((Re)?mix|edit|dub|mix|vip|version)$",
            "($1 $2)"
        ),
        (r"(?i)-\s(Remix|VIP)$", "($1)"),
    ]
);

filter_rules!(
    /// Filter rules to remove leading and trailing whitespace from a text.
    trim_whitespace_filter_rules,
    [(r"^\s+", ""), (r"\s+$", ""),]
);

#[cfg(test)]
mod tests {
    use super::*;

    fn apply_rules(text: &str, rules: &[FilterRule]) -> String {
        rules.iter().fold(text.to_string(), |mut result, rule| {
            let filtered = rule.apply(&result);
            if let Cow::Owned(filtered) = filtered {
                result.clear();
                result.push_str(&filtered);
            }
            result
        })
    }

    fn test_rules(values: &[(&str, &str)], rules: &[FilterRule]) {
        for value in values {
            let filtered = apply_rules(value.0, rules);
            println!("value: {:?}\nexpected: {:?}\nactual: {:?}\n-----", value.0, value.1, filtered);
            assert_eq!(filtered, value.1);
        }
    }

    #[test]
    fn test_youtube_track_filter_rules() {
        let titles = [
            ("   whitespace prefix", "whitespace prefix"),
            ("whitespace suffix   ", "whitespace suffix"),
            ("Artist - Song Title **NEW**", "Artist - Song Title "),
            ("Artist - Song Title [something]", "Artist - Song Title "),
            ("Artist - Song Title (xyz version)", "Artist - Song Title "),
            ("Artist - Song Title.avi", "Artist - Song Title"),
            ("Artist - Song Title (lyric video)", "Artist - Song Title "),
            ("Artist - Song Title (official track stream)", "Artist - Song Title "),
            ("Artist - Song Title (official music video)", "Artist - Song Title "),
            ("Artist - Song Title (official audio)", "Artist - Song Title "),
            ("Artist - Song Title (Album Track)", "Artist - Song Title ()"),
            ("Artist - Song Title (Cover Art)", "Artist - Song Title ()"),
            ("Artist - Song Title (official)", "Artist - Song Title "),
            ("Artist - Song Title (1999)", "Artist - Song Title "),
            ("Artist - Song Title HD", "Artist - Song Title "),
            ("Artist - Song Title (vidéo clip official)", "Artist - Song Title ()"),
            ("Artist - Song Title offizielles video", "Artist - Song Title "),
            ("Artist - Song Title video clip", "Artist - Song Title "),
            ("Artist - Song Title clip", "Artist - Song Title"),
            ("Artist - Album Title Full Album", "Artist - Album Title "),
            ("Artist - Song Title (live)", "Artist - Song Title "),
            ("Artist - Song Title | something", "Artist - Song Title "),
            ("Artist - Song Title (01/01/1999)", "Artist - Song Title "),
            ("Artist - Song Title (sub español)", "Artist - Song Title ()"),
            ("Artist - Song Title (Letra/Lyrics)", "Artist - Song Title "),
            ("Artist - Song Title (Letra)", "Artist - Song Title"),
            ("Artist - Song Title (En vivo)", "Artist - Song Title"),
        ];

        test_rules(&titles, &youtube_track_filter_rules());
    }

    #[test]
    fn test_trim_symbols_filter_rules() {
        let titles = [
            ("Artist - Song Title ()", "Artist - Song Title"),
            ("Artist - Song Title - ", "Artist - Song Title"),
            (" - Artist - Song Title", "Artist - Song Title"),
        ];

        test_rules(&titles, &trim_symbols_filter_rules());
    }

    #[test]
    fn test_remastered_filter_rules() {
        let titles = [
            ("Here Comes The Sun - Remastered", "Here Comes The Sun "),
            ("Hey Jude - Remastered 2015", "Hey Jude "),
            ("Let It Be (Remastered 2009)", "Let It Be "),
            ("Red Rain (Remaster 2012)", "Red Rain "),
            (
                "Pigs On The Wing (Part One) [2011 - Remaster]",
                "Pigs On The Wing (Part One) ",
            ),
            ("Comfortably Numb (2011 - Remaster)", "Comfortably Numb "),
            ("Dancing Days (2012 Remaster)", "Dancing Days "),
            ("Outside The Wall - 2011 - Remaster", "Outside The Wall "),
            ("China Grove - 2006 Remaster", "China Grove "),
            (
                "Learning To Fly - 2001 Digital Remaster",
                "Learning To Fly ",
            ),
            (
                "Your Possible Pasts - 2011 Remastered Version",
                "Your Possible Pasts ",
            ),
            (
                "Roll Over Beethoven (Live / Remastered)",
                "Roll Over Beethoven ",
            ),
            ("Ticket To Ride - Live / Remastered", "Ticket To Ride "),
            ("Mothership (Remastered)", "Mothership "),
            ("How The West Was Won [Remastered]", "How The West Was Won "),
            (
                "A Well Respected Man (2014 Remastered Version)",
                "A Well Respected Man ",
            ),
            (
                "A Well Respected Man [2014 Remastered Version]",
                "A Well Respected Man ",
            ),
            (
                "She Was Hot (2009 Re-Mastered Digital Version)",
                "She Was Hot ",
            ),
            (
                "She Was Hot (2009 Remastered Digital Version)",
                "She Was Hot ",
            ),
            (
                "In The Court Of The Crimson King (Expanded & Remastered Original Album Mix)",
                "In The Court Of The Crimson King ",
            ),
        ];

        test_rules(&titles, &remastered_filter_rules());
    }

    #[test]
    fn test_live_filter_rules() {
        let titles = [
            ("Song Title - Live", "Song Title "),
            ("Song Title - Live at Location", "Song Title "),
            ("Song Title (Live)", "Song Title "),
            ("Song Title [Live]", "Song Title "),
        ];

        test_rules(&titles, &live_filter_rules());
    }

    #[test]
    fn test_clean_explicit_filter_rules() {
        let titles = [
            ("Song Title (Explicit)", "Song Title"),
            ("Song Title [Explicit]", "Song Title"),
            ("Song Title (Clean)", "Song Title"),
            ("Song Title [Clean]", "Song Title"),
        ];

        test_rules(&titles, &clean_explicit_filter_rules());
    }

    #[test]
    fn test_feature_filter_rules() {
        let titles = [
            ("Song Title (Feat. Other Artist)", "Song Title"),
            ("Song Title [Feat. Other Artist]", "Song Title"),
        ];

        test_rules(&titles, &feature_filter_rules());
    }

    #[test]
    fn test_normalize_feature_filter_rules() {
        let titles = [
            ("Song Title (Feat. Other Artist)", "Song Title Feat. Other Artist"),
            ("Song Title [Feat. Other Artist]", "Song Title Feat. Other Artist"),
        ];

        test_rules(&titles, &normalize_feature_filter_rules());
    }

    #[test]
    fn test_version_filter_rules() {
        let titles = [
            (
                "Love Will Come To You (Album Version)",
                "Love Will Come To You ",
            ),
            ("I Melt With You (Rerecorded)", "I Melt With You "),
            ("When I Need You [Re-Recorded]", "When I Need You "),
            (
                "Your Cheatin' Heart (Single Version)",
                "Your Cheatin' Heart ",
            ),
            ("All Over Now (Edit)", "All Over Now "),
            (
                "(I Can't Get No) Satisfaction - Mono Version",
                "(I Can't Get No) Satisfaction ",
            ),
            ("Ruby Tuesday - Stereo Version", "Ruby Tuesday "),
            ("Pure McCartney (Deluxe Edition)", "Pure McCartney "),
            ("6 Foot 7 Foot (Explicit Version)", "6 Foot 7 Foot "),
        ];

        test_rules(&titles, &version_filter_rules());
    }

    #[test]
    fn test_suffix_filter_rules() {
        let titles = [
            ("Song Title - X Remix", "Song Title (X Remix)"),
            ("Song Title - Y-Z Remix", "Song Title (Y-Z Remix)"),
            ("Song Title - Y-Z Abc Remix", "Song Title (Y-Z Abc Remix)"),
            ("Song Title - Abc Xyz Remix", "Song Title (Abc Xyz Remix)"),
            ("Song Title - Remix", "Song Title (Remix)"),
            ("Song Title - VIP", "Song Title (VIP)"),
        ];

        test_rules(&titles, &suffix_filter_rules());
    }

    #[test]
    fn test_trim_whitespace_filter_rules() {
        let titles = [
            ("   Text   ", "Text"),
            ("   Text", "Text"),
            ("Text   ", "Text"),
        ];

        test_rules(&titles, &trim_whitespace_filter_rules());
    }
}