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use binread::BinRead;
use crc32fast::Hasher;
use crate::{HashToIndex, DirInfo, StreamEntry, QuickDir};

/// A hash consisting of a crc32 and a 8-bit length. Used within Smash Ultimate as a unique
/// identifier for various strings.
#[repr(transparent)]
#[derive(BinRead, Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash)]
pub struct Hash40(pub u64);

impl Hash40 {
    pub fn as_u64(&self) -> u64 {
        self.0
    }

    pub fn len(&self) -> u8 {
        (self.0 >> 32) as u8
    }

    pub fn crc32(&self) -> u32 {
        self.0 as u32
    }
}

impl From<&Hash40> for Hash40 {
    fn from(hash: &Hash40) -> Self {
        *hash
    }
}

impl From<u64> for Hash40 {
    fn from(hash: u64) -> Self {
        Hash40(hash)
    }
}

impl From<&str> for Hash40 {
    fn from(string: &str) -> Self {
        hash40(string)
    }
}

impl From<&HashToIndex> for Hash40 {
    fn from(hash_index: &HashToIndex) -> Self {
        hash_index.hash40()
    }
}

impl From<HashToIndex> for Hash40 {
    fn from(hash_index: HashToIndex) -> Self {
        hash_index.hash40()
    }
}

impl From<&StreamEntry> for Hash40 {
    fn from(hash_index: &StreamEntry) -> Self {
        hash_index.hash40()
    }
}

impl From<StreamEntry> for Hash40 {
    fn from(hash_index: StreamEntry) -> Self {
        hash_index.hash40()
    }
}

impl HashToIndex {
    pub fn hash40(&self) -> Hash40 {
        Hash40((self.hash() as u64) + ((self.length() as u64) << 32))
    }
}

impl StreamEntry {
    pub fn hash40(&self) -> Hash40 {
        Hash40((self.hash() as u64) + ((self.name_length() as u64) <<  32))
    }
}

impl DirInfo {
    pub fn path_hash40(&self) -> Hash40 {
        Hash40((self.path_hash as u64) + ((self.dir_offset_index as u64) & 0xFF) << 32)
    }
}

impl QuickDir {
    pub fn hash40(&self) -> Hash40 {
        Hash40((self.hash() as u64) + ((self.name_length() as u64) <<  32))
    }
}


/// Find the [`Hash40`] of a given string
pub fn hash40(string: &str) -> Hash40 {
    let bytes = string.as_bytes();

    Hash40(((bytes.len() as u64) << 32) + crc32(bytes) as u64)
}

fn crc32(bytes: &[u8]) -> u32 {
    let mut hasher = Hasher::new();
    hasher.update(bytes);
    hasher.finalize()
}