//! SQLite through `sqlx` (hub spec §3.1, §17.2): WAL, foreign keys on,
//! migrations embedded and applied at start. One module per table group.

pub mod accounts;
pub mod activity;
pub mod flow;
pub mod hooks;
pub mod issues;
pub mod notify;
pub mod projects;
pub mod proposals;
pub mod releases;
pub mod repos;
pub mod runners;

use sqlx::sqlite::{SqliteConnectOptions, SqliteJournalMode, SqlitePoolOptions, SqliteSynchronous};
use sqlx::SqlitePool;
use std::path::Path;

pub type Pool = SqlitePool;

/// Open (creating if needed) and migrate the database at `path`.
/// How long a statement waits for SQLite's write lock. Most writers are
/// background clients (runners appending logs, webhook deliveries), and a
/// commit can stall for seconds while a build saturates the host's disk, so
/// waiting beats failing.
const BUSY_TIMEOUT: std::time::Duration = std::time::Duration::from_secs(30);

pub async fn open(path: &Path) -> anyhow::Result<Pool> {
    let options = SqliteConnectOptions::new()
        .filename(path)
        .create_if_missing(true)
        .journal_mode(SqliteJournalMode::Wal)
        .synchronous(SqliteSynchronous::Normal)
        .foreign_keys(true)
        .busy_timeout(BUSY_TIMEOUT);
    migrate(options.clone()).await?;
    let pool = SqlitePoolOptions::new().max_connections(8).connect_with(options).await?;
    Ok(pool)
}

/// Apply the migrations on a connection of their own with foreign keys
/// off, as SQLite's way to change a table (rebuild it, drop the old one,
/// rename) needs: with them on, dropping a table its children reference
/// deletes the children too. Every reference must hold afterwards.
async fn migrate(options: SqliteConnectOptions) -> anyhow::Result<()> {
    use sqlx::Connection;
    let mut conn = sqlx::SqliteConnection::connect_with(&options.foreign_keys(false)).await?;
    sqlx::migrate!("./migrations").run(&mut conn).await?;
    let broken: Vec<(String,)> = sqlx::query_as("SELECT \"table\" FROM pragma_foreign_key_check").fetch_all(&mut conn).await?;
    if let Some((table,)) = broken.first() {
        anyhow::bail!("after the migrations, {} rows break a foreign key (the first in {table})", broken.len());
    }
    conn.close().await?;
    Ok(())
}

/// Milliseconds since the epoch, the hub's timestamp unit (as `oxy`'s).
pub fn now_ms() -> i64 {
    std::time::SystemTime::now().duration_since(std::time::UNIX_EPOCH).map(|d| d.as_millis() as i64).unwrap_or(0)
}

/// A write transaction that takes SQLite's write lock at `BEGIN`
/// (`BEGIN IMMEDIATE`). A deferred transaction that reads and then writes
/// fails at once with "database is locked" when another writer holds the
/// lock, whatever the busy timeout; an immediate one waits its turn.
pub async fn begin_write(pool: &Pool) -> sqlx::Result<sqlx::Transaction<'static, sqlx::Sqlite>> {
    pool.begin_with("BEGIN IMMEDIATE").await
}