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use crate::bytes::Bytes32;
use crate::chia_error;
use crate::streamable::Streamable;
use crate::streamable_struct;
use chia_streamable_macro::Streamable;
use sha2::{Digest, Sha256};
use std::convert::TryInto;

#[cfg(feature = "py-bindings")]
use crate::from_json_dict::FromJsonDict;
#[cfg(feature = "py-bindings")]
use crate::to_json_dict::ToJsonDict;
#[cfg(feature = "py-bindings")]
use chia_py_streamable_macro::PyStreamable;
#[cfg(feature = "py-bindings")]
use pyo3::prelude::*;
#[cfg(feature = "py-bindings")]
use pyo3::types::PyBytes;

streamable_struct!(Coin {
    parent_coin_info: Bytes32,
    puzzle_hash: Bytes32,
    amount: u64,
});

impl Coin {
    pub fn coin_id(&self) -> [u8; 32] {
        let mut hasher = Sha256::new();
        hasher.update(self.parent_coin_info);
        hasher.update(self.puzzle_hash);

        let amount_bytes = self.amount.to_be_bytes();
        if self.amount >= 0x8000000000000000_u64 {
            hasher.update([0_u8]);
            hasher.update(amount_bytes);
        } else {
            let start = match self.amount {
                n if n >= 0x80000000000000_u64 => 0,
                n if n >= 0x800000000000_u64 => 1,
                n if n >= 0x8000000000_u64 => 2,
                n if n >= 0x80000000_u64 => 3,
                n if n >= 0x800000_u64 => 4,
                n if n >= 0x8000_u64 => 5,
                n if n >= 0x80_u64 => 6,
                n if n > 0 => 7,
                _ => 8,
            };
            hasher.update(&amount_bytes[start..]);
        }

        hasher.finalize().as_slice().try_into().unwrap()
    }
}

#[cfg(feature = "py-bindings")]
#[cfg_attr(feature = "py-bindings", pymethods)]
impl Coin {
    fn name<'p>(&self, py: Python<'p>) -> PyResult<&'p PyBytes> {
        Ok(PyBytes::new(py, &self.coin_id()))
    }
}