use std::fmt;
use std::str::FromStr;

use crate::types::{ProtocolVersion, RequiredVersion};
use crate::utils::tag;
use crate::Error;

/// # [4.3.1.2. EXT-X-VERSION]
/// The [ExtXVersion] tag indicates the compatibility version of the
/// Playlist file, its associated media, and its server.
///
/// The [ExtXVersion] tag applies to the entire Playlist file. Its
/// format is:
///
/// ```text
/// #EXT-X-VERSION:<n>
/// ```
/// where `n` is an integer indicating the protocol compatibility version
/// number.
///
/// [4.3.1.2. EXT-X-VERSION]: https://tools.ietf.org/html/rfc8216#section-4.3.1.2
#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
pub struct ExtXVersion(ProtocolVersion);

impl ExtXVersion {
    pub(crate) const PREFIX: &'static str = "#EXT-X-VERSION:";

    /// Makes a new [ExtXVersion] tag.
    ///
    /// # Example
    /// ```
    /// # use hls_m3u8::tags::ExtXVersion;
    /// use hls_m3u8::types::ProtocolVersion;
    ///
    /// let version_tag = ExtXVersion::new(ProtocolVersion::V2);
    /// ```
    pub const fn new(version: ProtocolVersion) -> Self {
        Self(version)
    }

    /// Returns the protocol compatibility version of the playlist, containing this tag.
    ///
    /// # Example
    /// ```
    /// # use hls_m3u8::tags::ExtXVersion;
    /// use hls_m3u8::types::ProtocolVersion;
    ///
    /// assert_eq!(
    ///     ExtXVersion::new(ProtocolVersion::V6).version(),
    ///     ProtocolVersion::V6
    /// );
    /// ```
    pub const fn version(self) -> ProtocolVersion {
        self.0
    }
}

impl RequiredVersion for ExtXVersion {
    fn required_version(&self) -> ProtocolVersion {
        ProtocolVersion::V1
    }
}

impl fmt::Display for ExtXVersion {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}{}", Self::PREFIX, self.0)
    }
}

impl Default for ExtXVersion {
    fn default() -> Self {
        Self(ProtocolVersion::V1)
    }
}

impl From<ProtocolVersion> for ExtXVersion {
    fn from(value: ProtocolVersion) -> Self {
        Self(value)
    }
}

impl FromStr for ExtXVersion {
    type Err = Error;

    fn from_str(input: &str) -> Result<Self, Self::Err> {
        let version = tag(input, Self::PREFIX)?.parse()?;
        Ok(ExtXVersion::new(version))
    }
}

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

    #[test]
    fn test_display() {
        assert_eq!(
            ExtXVersion::new(ProtocolVersion::V6).to_string(),
            "#EXT-X-VERSION:6"
        );
    }

    #[test]
    fn test_parser() {
        assert_eq!(
            "#EXT-X-VERSION:6".parse::<ExtXVersion>().unwrap(),
            ExtXVersion::new(ProtocolVersion::V6)
        );
    }

    #[test]
    fn test_required_version() {
        assert_eq!(
            ExtXVersion::new(ProtocolVersion::V6).required_version(),
            ProtocolVersion::V1
        );
    }
}