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//! `ReplaySubject` example
//!
//! This example demonstrates the usage of the `ReplaySubject` in the `rxr` library.
//!
//! The `ReplaySubject` is a type of subject in reactive programming that replays a
//! specified number of previously emitted items to new subscribers. It keeps a
//! buffer of past emissions and immediately provides these buffered items to any new
//! subscriber upon subscription. The number of items replayed is determined by the
//! specified buffer size.
//!
//! If no buffer size is specified, the `ReplaySubject` will replay all previously
//! emitted items to new subscribers.
//!
//! To run this example, execute `cargo run --example replay_subject`.

use rxr::{
    subjects::{BufSize, ReplaySubject},
    subscribe::Subscriber,
};
use rxr::{ObservableExt, Observer, Subscribeable};

pub fn create_subscriber(subscriber_id: i32) -> Subscriber<i32> {
    Subscriber::new(
        move |v| println!("Subscriber #{} emitted: {}", subscriber_id, v),
        |_| eprintln!("Error"),
        move || println!("Completed {}", subscriber_id),
    )
}

pub fn main() {
    // Initialize a `ReplaySubject` with an unbounded buffer size and obtain
    // its emitter and receiver.
    let (mut emitter, mut receiver) = ReplaySubject::emitter_receiver(BufSize::Unbounded);

    // Registers `Subscriber` 1.
    receiver.subscribe(create_subscriber(1));

    emitter.next(101); // Stores 101 and emits it to registered `Subscriber` 1.
    emitter.next(102); // Stores 102 and emits it to registered `Subscriber` 1.

    // All Observable operators can be applied to the receiver.
    // Registers mapped `Subscriber` 2 and emits buffered values (101, 102) to it.
    receiver
        .clone() // Shallow clone: clones only the pointer to the `ReplaySubject` object.
        .map(|v| format!("mapped {}", v))
        .subscribe(Subscriber::new(
            move |v| println!("Subscriber #2 emitted: {}", v),
            |_| eprintln!("Error"),
            || println!("Completed 2"),
        ));

    // Registers `Subscriber` 3 and emits buffered values (101, 102) to it.
    receiver.subscribe(create_subscriber(3));

    emitter.next(103); // Stores 103 and emits it to registered `Subscriber`'s 1, 2 and 3.

    emitter.complete(); // Calls `complete` on registered `Subscriber`'s 1, 2 and 3.

    // Subscriber 4: post-completion subscribe, emits buffered values (101, 102, 103)
    // and completes.
    receiver.subscribe(create_subscriber(4));

    emitter.next(104); // Called post-completion, does not emit.
}