use {
    crate::{
        error::Error, extended::Extended, gitrev::GitRev, prerelease::PreRelease, rapid::Rapid,
        simple::Simple, MAX_U12,
    },
    serde::{Deserialize, Serialize},
    std::{cmp::Ordering, fmt, str::FromStr},
};

#[derive(Clone, Copy, Debug, Deserialize, Serialize)]
pub struct SemVer {
    pub major: u16,
    pub minor: u16,
    pub patch: u16,
    pub pre: PreRelease,
}

impl fmt::Display for SemVer {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "{}.{}.{}", self.major, self.minor, self.patch)?;
        match self.pre {
            PreRelease::None => Ok(()),
            p => write!(f, "_{p}"),
        }
    }
}

impl FromStr for SemVer {
    type Err = Error;

    fn from_str(s: &str) -> Result<Self, Self::Err> {
        let (s, pre) = match s.split_once('_') {
            Some((a, b)) => (a, b.parse::<PreRelease>()?),
            None => (s, PreRelease::None),
        };
        let split = s.split('.').collect::<Vec<_>>();
        match split.len() {
            3 => {
                let major = split.first().unwrap().parse::<u16>()?;
                let minor = split.get(1).unwrap().parse::<u16>()?;
                let patch = split.get(2).unwrap().parse::<u16>()?;
                if major > MAX_U12 || minor > MAX_U12 || patch > MAX_U12 {
                    return Err(Error::Range);
                }
                Ok(Self {
                    major,
                    minor,
                    patch,
                    pre,
                })
            }
            _ => Err(Error::ParseSemver),
        }
    }
}

impl From<SemVer> for u64 {
    fn from(value: SemVer) -> Self {
        let major = u64::from(value.major) << 52;
        let minor = u64::from(value.minor) << 40;
        let patch = u64::from(value.patch) << 28;
        let pre = u64::from(u16::from(value.pre));
        major | minor | patch | pre
    }
}

impl TryFrom<u64> for SemVer {
    type Error = Error;

    fn try_from(value: u64) -> Result<Self, Self::Error> {
        let mut mask: u64 = 0o7777 << 52;
        let major = (value & mask) >> 52;
        mask = 0o7777 << 40;
        let minor = (value & mask) >> 40;
        mask = 0o7777 << 28;
        let patch = (value & mask) >> 28;
        mask = 0o37777;
        let p = u16::try_from(value & mask)?;
        let pre: PreRelease = p.try_into()?;
        Ok(Self {
            major: major.try_into()?,
            minor: minor.try_into()?,
            patch: patch.try_into()?,
            pre,
        })
    }
}

impl PartialEq for SemVer {
    fn eq(&self, other: &Self) -> bool {
        self.major == other.major
            && self.minor == other.minor
            && self.patch == other.patch
            && self.pre == other.pre
    }
}

impl Eq for SemVer {}

impl Ord for SemVer {
    fn cmp(&self, other: &Self) -> Ordering {
        let a = u64::from(*self);
        let b = u64::from(*other);
        a.cmp(&b)
    }
}

impl PartialOrd for SemVer {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

impl PartialEq<Extended> for SemVer {
    fn eq(&self, other: &Extended) -> bool {
        self.major == other.major
            && self.minor == other.minor
            && self.patch == other.patch
            && other.build == 0
            && self.pre == other.pre
    }
}

impl PartialEq<Rapid> for SemVer {
    fn eq(&self, other: &Rapid) -> bool {
        self.major == other.major
            && self.minor == other.minor
            && self.patch == 0
            && self.pre == other.pre
    }
}

impl PartialEq<Simple> for SemVer {
    fn eq(&self, other: &Simple) -> bool {
        self.major == other.major && self.minor == 0 && self.patch == 0 && self.pre == other.pre
    }
}

impl PartialEq<GitRev> for SemVer {
    fn eq(&self, _other: &GitRev) -> bool {
        false
    }
}

impl PartialOrd<Extended> for SemVer {
    fn partial_cmp(&self, other: &Extended) -> Option<Ordering> {
        let a = u64::from(*self);
        let b = u64::from(*other);
        Some(a.cmp(&b))
    }
}

impl PartialOrd<Rapid> for SemVer {
    fn partial_cmp(&self, other: &Rapid) -> Option<Ordering> {
        let a = u64::from(*self);
        let b = u64::from(*other);
        Some(a.cmp(&b))
    }
}

impl PartialOrd<Simple> for SemVer {
    fn partial_cmp(&self, other: &Simple) -> Option<Ordering> {
        let a = u64::from(*self);
        let b = u64::from(*other);
        Some(a.cmp(&b))
    }
}

impl PartialOrd<GitRev> for SemVer {
    fn partial_cmp(&self, _other: &GitRev) -> Option<Ordering> {
        None
    }
}

#[cfg(test)]
mod tests {
    use std::num::NonZeroU16;

    use super::*;

    #[test]
    fn from_str() {
        let mut s: SemVer = "1.2.3".parse().unwrap();
        assert_eq!(
            s,
            SemVer {
                major: 1,
                minor: 2,
                patch: 3,
                pre: PreRelease::None,
            }
        );
        s = "0.3.0_alpha4".parse().unwrap();
        assert_eq!(
            s,
            SemVer {
                major: 0,
                minor: 3,
                patch: 0,
                pre: PreRelease::Alpha(Some(NonZeroU16::new(4).unwrap())),
            }
        )
    }

    #[test]
    fn to_string() {
        let mut s = SemVer {
            major: 1,
            minor: 0,
            patch: 2,
            pre: PreRelease::None,
        };
        assert_eq!(s.to_string(), "1.0.2");
        s = SemVer {
            major: 2,
            minor: 1,
            patch: 14,
            pre: PreRelease::Beta(Some(NonZeroU16::new(2).unwrap())),
        };
        assert_eq!(s.to_string(), "2.1.14_beta2");
    }

    #[test]
    fn to_from_u64() {
        let sem = SemVer {
            major: 1,
            minor: 0,
            patch: 11,
            pre: PreRelease::Beta(Some(NonZeroU16::new(2).unwrap())),
        };
        assert_eq!(SemVer::try_from(u64::from(sem)).unwrap(), sem);
    }

    #[test]
    fn eq() {
        assert_eq!(
            "1.0.0_alpha".parse::<SemVer>().unwrap(),
            "1.0.0_alpha1".parse::<SemVer>().unwrap(),
        );
        assert_eq!(
            "2.1.3_beta".parse::<SemVer>().unwrap(),
            "2.1.3_beta1".parse::<SemVer>().unwrap(),
        );
        assert_eq!(
            "1.11.0_rc".parse::<SemVer>().unwrap(),
            "1.11.0_rc1".parse::<SemVer>().unwrap(),
        );
    }

    #[test]
    fn ord() {
        let a: SemVer = "1.0.2".parse().unwrap();
        let b: SemVer = "1.0.3".parse().unwrap();
        let c: SemVer = "1.0.2_alpha1".parse().unwrap();
        let d: SemVer = "1.0.2_alpha2".parse().unwrap();
        assert!(a < b);
        assert!(c < a);
        assert!(d > c);
    }
}