graphile_worker_queries 0.1.1

use chrono::{DateTime, Utc};
use graphile_worker_database::{DbExecutorArg, DbParams, DbValue, Schema};
use indoc::formatdoc;

use crate::errors::Result;
use graphile_worker_job::Job;

use super::job_query_helpers::{
    get_flag_clause, get_now_clause, get_queue_clause, get_update_queue_clause,
};
use super::task_identifiers::TaskDetails;

pub async fn get_job(
    mut executor: impl DbExecutorArg,
    task_details: &TaskDetails,
    schema: impl Into<Schema>,
    worker_id: &str,
    flags_to_skip: &[String],
    now: Option<DateTime<Utc>>,
) -> Result<Option<Job>> {
    let schema = schema.into();
    let has_flags = !flags_to_skip.is_empty();
    let has_now = now.is_some();

    let mut next_param: u8 = 3;
    let flag_param = if has_flags {
        let p = next_param;
        next_param += 1;
        Some(p)
    } else {
        None
    };
    let now_param = if has_now { Some(next_param) } else { None };

    let flag_clause = flag_param
        .map(|p| get_flag_clause(flags_to_skip, p))
        .unwrap_or_default();
    let jobs = schema.private_table("jobs");
    let queue_clause = get_queue_clause(&schema);
    let update_queue_clause = get_update_queue_clause(&schema, 1, now_param);
    let now_clause = get_now_clause(now_param);

    let sql = formatdoc!(
        r#"
            with j as (
                select jobs.job_queue_id, jobs.priority, jobs.run_at, jobs.id
                    from {jobs} as jobs
                    where jobs.is_available = true
                    and run_at <= {now_clause}
                    and task_id = any($2::int[])
                    {queue_clause}
                    {flag_clause}
                    order by priority asc, run_at asc
                    limit 1
                    for update
                    skip locked
                ) {update_queue_clause}
                    update {jobs} as jobs
                        set
                            attempts = jobs.attempts + 1,
                            locked_by = $1::text,
                            locked_at = {now_clause}
                        from j
                        where jobs.id = j.id
                        returning *
        "#
    );

    let mut params = vec![
        DbValue::Text(worker_id.to_string()),
        DbValue::I32Array(task_details.task_ids().to_vec()),
    ];
    if has_flags {
        params.push(DbValue::TextArray(flags_to_skip.to_vec()));
    }
    if let Some(ts) = now {
        params.push(DbValue::TimestampTz(ts));
    }

    let job = executor
        .fetch_optional(&sql, DbParams::from(params))
        .await?
        .map(|row| super::rows::db_job_from_row(&row))
        .transpose()?;
    Ok(job.map(|job| {
        let task_identifier = task_details.get_or_empty(job.id(), job.task_id());
        Job::from_db_job(job, task_identifier)
    }))
}