vesys-bank-server/src/account.rs

use std::hash::{Hash, Hasher};

use thiserror::Error;
use anyhow::{bail, Result};
use uuid::Uuid;
use crate::account::AccountError::{Inactive, InvalidAmount, Overdraw};

#[derive(Error, Debug)]
pub enum AccountError {
    #[error("can not overdraw account")]
    Overdraw(),
    #[error("account is inactive")]
    Inactive(),
    #[error("amount must be > 0")]
    InvalidAmount(),
}

#[derive(Debug, Clone)]
pub struct Account {
    pub number: String,
    pub owner: String,
    pub balance: f64,
    pub is_active: bool,
}

impl Default for Account {
    fn default() -> Self {
        Account {
            number: Uuid::new_v4().to_string(),
            owner: "".into(),
            balance: 0_f64,
            is_active: true,
        }
    }
}

impl PartialEq for Account {
    fn eq(&self, other: &Self) -> bool {
        self.number == other.number
    }
}

impl Eq for Account {}

impl Hash for Account {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.number.hash(state);
    }
}

impl Account {
    #[cfg(test)]
    pub fn new() -> Self {
        Self { ..Default::default() }
    }

    pub fn deposit(&mut self, amount: f64) -> Result<()> {
        self.check_account(amount)?;
        self.balance += amount;
        Ok(())
    }

    pub fn withdraw(&mut self, amount: f64) -> Result<()> {
        self.check_account(amount)?;

        if self.balance - amount < 0 as f64 {
            bail!(Overdraw());
        }
        self.balance -= amount;

        Ok(())
    }

    fn check_account(&self, amount: f64) -> Result<()> {
        if !self.is_active {
            bail!(Inactive());
        }

        if amount < 0 as f64 {
            bail!(InvalidAmount());
        }

        Ok(())
    }

    pub fn passivate(&mut self) -> bool {
        let is_passivated = self.balance <= 0 as f64 && self.is_active;

        if is_passivated {
            self.is_active = false;
        }

        is_passivated
    }
}

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

    #[test]
    fn deposits() {
        let mut acc = Account::new();

        let ok_result = acc.deposit(10.56);
        assert!(ok_result.is_ok());

        let err_result = acc.deposit(-5.89);
        assert!(err_result.is_err());
    }

    #[test]
    fn withdrawals() {
        let mut acc = Account::new();

        let ok_result1 = acc.deposit(10_f64);
        assert!(ok_result1.is_ok());

        let ok_result2 = acc.withdraw(5_f64);
        assert!(ok_result2.is_ok());

        let err_result1 = acc.withdraw(10_f64);
        assert!(err_result1.is_err());

        let err_result2 = acc.withdraw(-10_f64);
        assert!(err_result2.is_err());
    }

    #[test]
    fn passivation() {
        let mut acc = Account::new();
        let deposit_amount = 100_f64;

        acc.deposit(deposit_amount).unwrap();

        assert!(!acc.passivate());
        acc.withdraw(deposit_amount).unwrap();

        assert!(acc.passivate());
        assert!(!acc.passivate());
    }
}