TicketManagement/BTreeMap/Task/src/lib.rs

// TODO: Replace `todo!()`s with the correct implementation.
//  Implement `IntoIterator` for `&TicketStore`. The iterator should yield immutable
//  references to the tickets, ordered by their `TicketId`.
//  Implement additional traits on `TicketId` if needed.

use std::collections::BTreeMap;
use std::ops::{Index, IndexMut};
use ticket_fields::{TicketDescription, TicketTitle};

#[derive(Clone)]
pub struct TicketStore {
    tickets: BTreeMap<TicketId, Ticket>,
    counter: u64,
}

#[derive(Clone, Copy, Debug, PartialEq, Ord, PartialOrd, Eq)]
pub struct TicketId(u64);

#[derive(Clone, Debug, PartialEq)]
pub struct Ticket {
    pub id: TicketId,
    pub title: TicketTitle,
    pub description: TicketDescription,
    pub status: Status,
}

#[derive(Clone, Debug, PartialEq, Eq)]
pub struct TicketDraft {
    pub title: TicketTitle,
    pub description: TicketDescription,
}

#[derive(Clone, Debug, Copy, PartialEq, Eq)]
pub enum Status {
    ToDo,
    InProgress,
    Done,
}

impl TicketStore {
    pub fn new() -> Self {
        Self {
            tickets: BTreeMap::new(),
            counter: 0,
        }
    }

    pub fn add_ticket(&mut self, ticket: TicketDraft) -> TicketId {
        let id = TicketId(self.counter);
        self.counter += 1;
        let ticket = Ticket {
            id,
            title: ticket.title,
            description: ticket.description,
            status: Status::ToDo,
        };
        self.tickets.insert(id, ticket);
        id
    }

    pub fn get(&self, id: TicketId) -> Option<&Ticket> {
        self.tickets.get(&id)
    }

    pub fn get_mut(&mut self, id: TicketId) -> Option<&mut Ticket> {
        self.tickets.get_mut(&id)
    }
}

impl Index<TicketId> for TicketStore {
    type Output = Ticket;

    fn index(&self, index: TicketId) -> &Self::Output {
        self.get(index).unwrap()
    }
}

impl Index<&TicketId> for TicketStore {
    type Output = Ticket;

    fn index(&self, index: &TicketId) -> &Self::Output {
        &self[*index]
    }
}

impl IndexMut<TicketId> for TicketStore {
    fn index_mut(&mut self, index: TicketId) -> &mut Self::Output {
        self.get_mut(index).unwrap()
    }
}

impl IndexMut<&TicketId> for TicketStore {
    fn index_mut(&mut self, index: &TicketId) -> &mut Self::Output {
        &mut self[*index]
    }
}

impl<'a> IntoIterator for &'a TicketStore {
    type Item = &'a Ticket;
    type IntoIter = std::collections::btree_map::Values<'a, TicketId, Ticket>;

    fn into_iter(self) -> Self::IntoIter {
        self.tickets.values()
    }
}