//! §11.6 D3 integration test: group-shared durable queue store.
//!
//! Proves the competing-consumer primitive: N messages enqueued into one
//! group-keyed store are claimed EXACTLY ONCE across concurrent claimers (the
//! `FOR UPDATE SKIP LOCKED` guarantee that makes per-descendant materialized
//! consumers safe). Also checks ack removes a row and nack re-defers it.
//!
//! Deterministic: drives `GroupQueueRepo` directly (no dispatcher). Skips when
//! `DATABASE_URL` is unset.

#![allow(clippy::too_many_lines, clippy::many_single_char_names)]

use std::collections::HashSet;

use picloud_manager_core::group_queue_repo::{
    GroupQueueRepo, NewGroupQueueMessage, PostgresGroupQueueRepo,
};
use picloud_shared::GroupId;
use sqlx::postgres::PgPoolOptions;
use sqlx::PgPool;
use uuid::Uuid;

async fn pool_or_skip() -> Option<PgPool> {
    let Ok(url) = std::env::var("DATABASE_URL") else {
        eprintln!("group_queue: DATABASE_URL unset — skipping");
        return None;
    };
    let pool = PgPoolOptions::new()
        .max_connections(6)
        .connect(&url)
        .await
        .expect("connect");
    sqlx::migrate!("./migrations")
        .run(&pool)
        .await
        .expect("migrate");
    Some(pool)
}

#[tokio::test(flavor = "multi_thread", worker_threads = 4)]
async fn competing_consumers_claim_each_message_exactly_once() {
    let Some(pool) = pool_or_skip().await else {
        return;
    };
    let sfx = Uuid::new_v4().simple().to_string();
    let g: (Uuid,) = sqlx::query_as("INSERT INTO groups (slug, name) VALUES ($1, $1) RETURNING id")
        .bind(format!("gq-g-{sfx}"))
        .fetch_one(&pool)
        .await
        .unwrap();
    let group = GroupId::from(g.0);
    let repo = PostgresGroupQueueRepo::new(pool.clone());

    // Enqueue 50 distinct messages into the shared `tasks` queue.
    let n_msgs: usize = 50;
    for i in 0..n_msgs {
        repo.enqueue(NewGroupQueueMessage {
            group_id: group,
            collection: "tasks".into(),
            payload: serde_json::json!({ "i": i }),
            deliver_after: None,
            max_attempts: 3,
            enqueued_by_principal: None,
        })
        .await
        .unwrap();
    }

    // Four concurrent "consumers" claim until the queue is drained, ack-ing each.
    // Every claimed payload id must be unique — no message delivered twice.
    let claim_loop = |repo: PostgresGroupQueueRepo, group: GroupId| async move {
        let mut got: Vec<i64> = Vec::new();
        while let Some(msg) = repo.claim(group, "tasks").await.unwrap() {
            got.push(msg.payload["i"].as_i64().unwrap());
            assert!(repo.ack(msg.id, msg.claim_token).await.unwrap(), "ack ok");
        }
        got
    };
    let (a, b, c, d) = tokio::join!(
        claim_loop(PostgresGroupQueueRepo::new(pool.clone()), group),
        claim_loop(PostgresGroupQueueRepo::new(pool.clone()), group),
        claim_loop(PostgresGroupQueueRepo::new(pool.clone()), group),
        claim_loop(PostgresGroupQueueRepo::new(pool.clone()), group),
    );

    let mut all: Vec<i64> = Vec::new();
    all.extend(a);
    all.extend(b);
    all.extend(c);
    all.extend(d);
    let unique: HashSet<i64> = all.iter().copied().collect();
    assert_eq!(
        all.len(),
        n_msgs,
        "every message delivered exactly once (no dupes)"
    );
    assert_eq!(unique.len(), n_msgs, "all distinct ids covered");
    assert_eq!(
        repo.depth(group, "tasks").await.unwrap(),
        0,
        "queue drained"
    );

    // nack re-defers a message (a later claim gets it back).
    let id = repo
        .enqueue(NewGroupQueueMessage {
            group_id: group,
            collection: "tasks".into(),
            payload: serde_json::json!({ "i": 999 }),
            deliver_after: None,
            max_attempts: 3,
            enqueued_by_principal: None,
        })
        .await
        .unwrap();
    let msg = repo.claim(group, "tasks").await.unwrap().expect("claimed");
    assert_eq!(msg.id, id);
    repo.nack(msg.id, msg.claim_token, chrono::Duration::milliseconds(0))
        .await
        .unwrap();
    // After nack (0ms delay) it is claimable again.
    let again = repo.claim(group, "tasks").await.unwrap().expect("re-claim");
    assert_eq!(again.id, id, "nacked message is re-delivered");
    assert_eq!(again.attempt, 2, "attempt incremented on re-claim");
    repo.ack(again.id, again.claim_token).await.unwrap();

    // Cleanup (messages cascade on group delete anyway).
    let _ = sqlx::query("DELETE FROM group_queue_messages WHERE group_id = $1")
        .bind(g.0)
        .execute(&pool)
        .await;
    let _ = sqlx::query("DELETE FROM groups WHERE id = $1")
        .bind(g.0)
        .execute(&pool)
        .await;
}