no_proto 0.9.60

use alloc::string::String;
use alloc::vec::Vec;

use crate::error::NP_Error;

pub static SEED: u32 = 2181155409;

#[derive(Debug)]
pub struct NP_HashMap {
    data: Vec<Vec<(String, usize)>>
}

const HASH_SIZE: usize = 2048;

impl NP_HashMap {

    pub fn empty() -> Self {
        Self { data: Vec::with_capacity(1) }
    }

    pub fn new() -> Self {
        let mut vector = Vec::with_capacity(HASH_SIZE);
        vector.extend((0..HASH_SIZE).map(|_| Vec::new()));
        Self { data: vector }
    }

    pub fn insert(&mut self, key: &str, value: usize) -> Result<(), NP_Error> {

        let hash = murmurhash3_x86_32(key.as_bytes(), SEED);
    
        let bucket = hash as usize % HASH_SIZE;

        if self.data[bucket].len() == 0 {
            self.data[bucket].push((String::from(key), value));
        } else {
            for (k, v) in self.data[bucket].iter_mut() {
                if k == key {
                    *v = value;
                    return Ok(())
                }
            }
            self.data[bucket].push((String::from(key), value));
        }

        Ok(())
    }

    pub fn get(&self, key: &str) -> Option<&usize> {
        let hash = murmurhash3_x86_32(key.as_bytes(), SEED);
        let bucket = hash as usize % HASH_SIZE;

        match self.data.get(bucket) {
            Some(x) => {
                let len = x.len();
                if len == 0 {
                    return None;
                }
                if len == 1 {
                    return Some(&x[0].1);
                }
                for (k, v) in x.iter() {
                    if k == key {
                        return Some(v)
                    }
                }
                None
            },
            None => None
        }
    }

    pub fn delete(&mut self, key: &str) {
        let hash = murmurhash3_x86_32(key.as_bytes(), SEED);
        let bucket = hash as usize % HASH_SIZE;
        match self.data.get_mut(bucket) {
            Some(bucket) => {
                bucket.retain(|(k, _v)| *k != key);
            },
            _ => { }
        }
    }
}

// https://github.com/mhallin/murmurhash3-rs
// 
// The MIT License (MIT)
// 
// Copyright (c) 2015 Magnus Hallin
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

#[inline(always)]
fn fmix32(mut h: u32) -> u32 {
    h ^= h >> 16;
    h = h.wrapping_mul(0x85ebca6b);
    h ^= h >> 13;
    h = h.wrapping_mul(0xc2b2ae35);
    h ^= h >> 16;

    return h;
}

#[inline(always)]
fn get_32_block(bytes: &[u8], index: usize) -> u32 {
    let real_index = index.wrapping_mul(4);
    let u32_bytes = &bytes[real_index..(real_index + 4)];

    return unsafe {
        let bytes = *(u32_bytes as *const [u8] as *const [u8; 4]);
        core::mem::transmute(bytes)
    }
}

#[inline(always)]
pub fn murmurhash3_x86_32(bytes: &[u8], seed: u32) -> u32 {
    let c1 = 0xcc9e2d51u32;
    let c2 = 0x1b873593u32;
    let read_size = 4;
    let len = bytes.len() as u32;
    let block_count = len / read_size;

    let mut h1 = seed;

    for i in 0..block_count as usize {
        let mut k1 = get_32_block(bytes, i);

        k1 = k1.wrapping_mul(c1);
        k1 = k1.rotate_left(15);
        k1 = k1.wrapping_mul(c2);

        h1 ^= k1;
        h1 = h1.rotate_left(13);
        h1 = h1.wrapping_mul(5);
        h1 = h1.wrapping_add(0xe6546b64)
    }
    let mut k1 = 0u32;

    if len & 3 == 3 { k1 ^= (bytes[(block_count * read_size) as usize + 2] as u32) << 16; }
    if len & 3 >= 2 { k1 ^= (bytes[(block_count * read_size) as usize + 1] as u32) << 8; }
    if len & 3 >= 1 { k1 ^=  bytes[(block_count * read_size) as usize + 0] as u32;
        k1 = k1.wrapping_mul(c1);
        k1 = k1.rotate_left(15);
        k1 = k1.wrapping_mul(c2);
        h1 ^= k1;
    }

    h1 ^= bytes.len() as u32;
    h1 = fmix32(h1);

    return h1;
}