//! Scheduled ingest — the production-substrate piece that turns the
//! lakehouse from "manual API toolkit" into a system that runs itself.
//!
//! A `ScheduleDef` declares "what to ingest" + "when to fire." A
//! background `Scheduler` task wakes periodically, asks each enabled
//! schedule whether it's due, and runs the matching ingest path. Outcomes
//! land back on the schedule so operators can see what happened without
//! `journalctl` archaeology.
//!
//! Storage shape: one JSON file per schedule at
//! `primary://_schedules/{id}.json`. Serializable via serde, rebuilt on
//! startup. Same write-once shape as the rest of the catalog — no DB.
//!
//! Concurrency model: single-flight per schedule_id. The scheduler holds
//! a `HashSet<String>` of currently-running ids; a tick that finds a
//! schedule already in flight skips it (no queueing — a slow ingest
//! shouldn't pile up runs). Different schedules run concurrently.
//!
//! What's deliberately not in scope here:
//! - Sub-minute cron precision. 5-field Unix cron is supported; seconds
//!   are pinned to 0. Intervals cover sub-minute cases; cron is
//!   easy to bolt on later.
//! - Backoff / retry policies. A failed run records the failure and
//!   schedules `next_run_at` as if it succeeded — no exponential backoff.
//! - Distributed coordination. Single-machine scheduler; no leader
//!   election. If you run two gateway instances they'll both fire.

use chrono::{DateTime, Duration, Utc};
use object_store::ObjectStore;
use serde::{Deserialize, Serialize};
use std::collections::{HashMap, HashSet};
use std::sync::Arc;
use tokio::sync::RwLock;

use storaged::ops;

const PREFIX: &str = "_schedules";

// =================== Public types ===================

/// What kind of ingest the schedule fires.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum ScheduleKind {
    /// Pull a MySQL/MariaDB table via the my_stream path.
    Mysql {
        /// `mysql://user:pass@host:port/db` — DSN with full credentials.
        /// Stored encrypted-at-rest is a future concern; for now it lives
        /// in plain JSON in the catalog. Don't put production root creds
        /// here without disk-level encryption.
        dsn: String,
        table: String,
        #[serde(default)]
        dataset_name: Option<String>,
        #[serde(default)]
        batch_size: Option<usize>,
        #[serde(default)]
        order_by: Option<String>,
    },
    /// Pull a Postgres table via the pg_stream path.
    Postgres {
        dsn: String,
        table: String,
        #[serde(default)]
        dataset_name: Option<String>,
        #[serde(default)]
        batch_size: Option<usize>,
        #[serde(default)]
        order_by: Option<String>,
    },
}

impl ScheduleKind {
    pub fn label(&self) -> String {
        match self {
            ScheduleKind::Mysql { table, .. } => format!("mysql:{table}"),
            ScheduleKind::Postgres { table, .. } => format!("postgres:{table}"),
        }
    }
}

/// When the schedule fires.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(tag = "type", rename_all = "snake_case")]
pub enum ScheduleTrigger {
    /// Run every N seconds. Time anchor = compute_next_run_at decision.
    Interval { secs: u64 },
    /// 5-field Unix cron expression: "min hour dom month dow".
    /// Seconds are implicitly 0 (minute-granularity scheduling).
    /// Examples: "15 14 * * *" = 14:15 UTC daily, "0 */6 * * *" = every
    /// 6 hours on the hour, "0 9 * * 1-5" = 09:00 UTC weekdays.
    /// Timezone: UTC always — the scheduler's clock is UTC and we don't
    /// carry a per-schedule timezone field.
    Cron { expr: String },
}

/// Outcome of a single run, kept on the schedule for observability.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct RunOutcome {
    pub at: DateTime<Utc>,
    pub success: bool,
    pub message: String,
    pub rows: Option<usize>,
    pub duration_secs: f32,
}

/// One scheduled ingest definition.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ScheduleDef {
    pub id: String,
    pub kind: ScheduleKind,
    pub trigger: ScheduleTrigger,
    pub enabled: bool,
    pub created_at: DateTime<Utc>,
    #[serde(default)]
    pub created_by: String,
    /// When the next run is due. Recomputed after each completion via
    /// `compute_next_run_at`. On creation: set to "now" so the schedule
    /// fires on the next scheduler tick.
    pub next_run_at: DateTime<Utc>,
    #[serde(default)]
    pub last_run_at: Option<DateTime<Utc>>,
    #[serde(default)]
    pub last_outcome: Option<RunOutcome>,
    /// Total successful runs and total failures since creation. Useful
    /// for at-a-glance "is this schedule healthy?" checks.
    #[serde(default)]
    pub run_count: u64,
    #[serde(default)]
    pub failure_count: u64,
}

impl ScheduleDef {
    /// True if this schedule should fire at `now`. Honors `enabled`.
    pub fn is_due(&self, now: DateTime<Utc>) -> bool {
        self.enabled && now >= self.next_run_at
    }
}

// =================== Trigger semantics ===================
//
// J: THIS IS YOURS TO IMPLEMENT
// =====================================================
//
// `compute_next_run_at` decides when a schedule fires next. The current
// state is the "since last completion" semantics — simple but has real
// trade-offs vs other strategies:
//
// 1. SINCE LAST COMPLETION (current default below):
//      next = completed_at + interval
//    Easy to reason about. A long-running ingest delays the next fire
//    by however long it took. Drift is bounded — the schedule never
//    "falls behind" trying to catch up.
//
// 2. ANCHORED INTERVAL:
//      next = previous_target + interval, regardless of when run finished
//    Keeps wall-clock alignment ("every 30min on the :00 and :30").
//    Risk: if ingest takes longer than the interval, the next run is
//    "due immediately" and you can fire back-to-back forever.
//
// 3. ANCHORED + SKIP:
//      Anchored, but skip a tick if the previous one is still running.
//    Best of both, slightly more code.
//
// 4. CRON:
//      Parse the expression, find the next match after `now`. Most
//    expressive but pulls in a cron parser dep.
//
pub fn compute_next_run_at(
    trigger: &ScheduleTrigger,
    completed_at: DateTime<Utc>,
    _previous_next: DateTime<Utc>,
) -> DateTime<Utc> {
    match trigger {
        ScheduleTrigger::Interval { secs } => {
            completed_at + Duration::seconds(*secs as i64)
        }
        ScheduleTrigger::Cron { expr } => {
            next_cron_fire(expr, completed_at)
                // Creation-time validation (see `validate_trigger`) rejects
                // unparseable expressions, so this fallback is only reached
                // if the schedule JSON was hand-edited on disk. One-hour
                // window keeps a bad expr from fire-looping the system.
                .unwrap_or(completed_at + Duration::hours(1))
        }
    }
}

/// Parse a Vixie/POSIX cron expression and return the next fire time
/// strictly after `after`. Accepts 5-field (`min hour dom month dow`) and
/// 6-field (with leading `sec`) forms natively — croner handles both.
/// Day-of-week follows Unix convention: 0=Sun, 1=Mon, …, 6=Sat (7=Sun as
/// synonym). Returns None if the expression fails to parse or produces no
/// upcoming match (which can happen for year-bounded patterns in the past).
fn next_cron_fire(expr: &str, after: DateTime<Utc>) -> Option<DateTime<Utc>> {
    use std::str::FromStr;
    let cron = croner::Cron::from_str(expr).ok()?;
    cron.find_next_occurrence(&after, false).ok()
}

/// Reject a ScheduleTrigger whose content can't be interpreted — used by
/// the HTTP handlers to fail fast at create/patch time rather than falling
/// back silently at fire time. Interval triggers get a sanity gate
/// (no zero secs); cron triggers get a full parse through croner.
pub fn validate_trigger(trigger: &ScheduleTrigger) -> Result<(), String> {
    match trigger {
        ScheduleTrigger::Interval { secs } => {
            if *secs == 0 {
                return Err("interval secs must be > 0".into());
            }
            Ok(())
        }
        ScheduleTrigger::Cron { expr } => {
            use std::str::FromStr;
            croner::Cron::from_str(expr)
                .map_err(|e| format!("invalid cron expression '{expr}': {e}"))?;
            Ok(())
        }
    }
}

// =================== Persistence ===================

/// Storage path for a schedule's JSON record.
fn schedule_key(id: &str) -> String {
    let safe: String = id
        .chars()
        .map(|c| if c.is_ascii_alphanumeric() || c == '_' || c == '-' { c } else { '_' })
        .collect();
    format!("{PREFIX}/{safe}.json")
}

/// In-memory + on-disk schedule registry. The Scheduler reads from here;
/// HTTP CRUD writes through here.
#[derive(Clone)]
pub struct ScheduleStore {
    /// Bucket where schedule JSON lives. Always primary today — a
    /// future enhancement could move to per-profile schedule buckets.
    store: Arc<dyn ObjectStore>,
    schedules: Arc<RwLock<HashMap<String, ScheduleDef>>>,
}

impl ScheduleStore {
    pub fn new(store: Arc<dyn ObjectStore>) -> Self {
        Self {
            store,
            schedules: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    /// Load every persisted schedule into memory. Call on startup.
    pub async fn rebuild(&self) -> Result<usize, String> {
        let keys = ops::list(&self.store, Some(&format!("{PREFIX}/")))
            .await
            .unwrap_or_default();
        let mut count = 0usize;
        for key in keys {
            if !key.ends_with(".json") { continue; }
            match ops::get(&self.store, &key).await {
                Ok(bytes) => match serde_json::from_slice::<ScheduleDef>(&bytes) {
                    Ok(def) => {
                        self.schedules.write().await.insert(def.id.clone(), def);
                        count += 1;
                    }
                    Err(e) => tracing::warn!("schedule {key}: malformed: {e}"),
                },
                Err(e) => tracing::warn!("schedule {key}: read failed: {e}"),
            }
        }
        Ok(count)
    }

    pub async fn list(&self) -> Vec<ScheduleDef> {
        let mut out: Vec<ScheduleDef> = self.schedules.read().await.values().cloned().collect();
        out.sort_by(|a, b| a.id.cmp(&b.id));
        out
    }

    pub async fn get(&self, id: &str) -> Option<ScheduleDef> {
        self.schedules.read().await.get(id).cloned()
    }

    pub async fn put(&self, def: ScheduleDef) -> Result<ScheduleDef, String> {
        let json = serde_json::to_vec_pretty(&def).map_err(|e| e.to_string())?;
        ops::put(&self.store, &schedule_key(&def.id), json.into()).await?;
        self.schedules.write().await.insert(def.id.clone(), def.clone());
        Ok(def)
    }

    pub async fn delete(&self, id: &str) -> Result<bool, String> {
        // Object_store's delete is idempotent — silently OKs missing keys.
        let _ = ops::delete(&self.store, &schedule_key(id)).await;
        Ok(self.schedules.write().await.remove(id).is_some())
    }

    /// Update completion metadata + persist. Used by the scheduler
    /// after a run finishes (success or failure).
    pub async fn record_run(
        &self,
        id: &str,
        outcome: RunOutcome,
    ) -> Result<(), String> {
        let mut guard = self.schedules.write().await;
        let Some(def) = guard.get_mut(id) else {
            return Err(format!("schedule '{id}' not registered"));
        };
        def.last_run_at = Some(outcome.at);
        if outcome.success {
            def.run_count += 1;
        } else {
            def.failure_count += 1;
        }
        def.next_run_at = compute_next_run_at(&def.trigger, outcome.at, def.next_run_at);
        def.last_outcome = Some(outcome);

        let json = serde_json::to_vec_pretty(def).map_err(|e| e.to_string())?;
        let key = schedule_key(id);
        let store = self.store.clone();
        // Drop the write lock before async I/O.
        drop(guard);
        ops::put(&store, &key, json.into()).await?;
        Ok(())
    }
}

// =================== Scheduler task ===================

/// Long-running task that fires due schedules. Spawned at gateway
/// startup. Stop semantics: drop the handle (the loop exits when its
/// store is the only reference left, or sooner if you wire a stop signal).
pub struct Scheduler {
    pub store: ScheduleStore,
    pub ingest: SchedulerIngestDeps,
    /// Polling cadence for the loop itself. The schedules' own intervals
    /// are independent — this just controls how granularly we check
    /// "is anything due?" Default 10s.
    pub tick_secs: u64,
}

/// What the scheduler needs to actually run an ingest. We pass in only
/// what's needed — keeps the dep set narrow.
#[derive(Clone)]
pub struct SchedulerIngestDeps {
    pub store: Arc<dyn ObjectStore>,
    pub registry: catalogd::registry::Registry,
    pub buckets: Arc<storaged::registry::BucketRegistry>,
    /// Optional Phase 16.5 hook — push a DatasetAppended event if any
    /// HNSW index is bound to the dataset that just got refreshed.
    pub agent_handle: Option<vectord::agent::AgentHandle>,
    pub index_registry: vectord::index_registry::IndexRegistry,
}

impl Scheduler {
    /// Spawn the loop in the background. Returns immediately.
    pub fn spawn(self) {
        tokio::spawn(async move {
            self.run().await;
        });
    }

    async fn run(self) {
        tracing::info!("scheduler started — tick={}s", self.tick_secs);
        let in_flight: Arc<RwLock<HashSet<String>>> = Arc::new(RwLock::new(HashSet::new()));

        loop {
            tokio::time::sleep(std::time::Duration::from_secs(self.tick_secs)).await;
            let now = Utc::now();
            let due: Vec<ScheduleDef> = self.store.list().await
                .into_iter()
                .filter(|s| s.is_due(now))
                .collect();
            if due.is_empty() { continue; }

            for def in due {
                {
                    let in_flight_guard = in_flight.read().await;
                    if in_flight_guard.contains(&def.id) {
                        // Previous run still going — skip this tick.
                        // We don't reschedule; next tick re-evaluates.
                        continue;
                    }
                }

                let store = self.store.clone();
                let ingest = self.ingest.clone();
                let in_flight = in_flight.clone();
                let id = def.id.clone();

                in_flight.write().await.insert(id.clone());

                tokio::spawn(async move {
                    let t0 = std::time::Instant::now();
                    let outcome = run_schedule(&def, &ingest).await;
                    let elapsed = t0.elapsed().as_secs_f32();
                    let outcome = RunOutcome {
                        at: Utc::now(),
                        success: outcome.is_ok(),
                        message: match &outcome {
                            Ok(s) => s.clone(),
                            Err(e) => e.clone(),
                        },
                        rows: outcome.as_ref().ok().and_then(parse_rows_from_message),
                        duration_secs: elapsed,
                    };
                    if let Err(e) = store.record_run(&id, outcome).await {
                        tracing::warn!("scheduler: record_run({id}): {e}");
                    }
                    in_flight.write().await.remove(&id);
                });
            }
        }
    }
}

/// Pluck a "rows=N" hint out of a success message — best-effort, no
/// hard contract. Lets us surface row counts in the schedule status
/// endpoint without forcing every ingest path to return structured
/// stats here.
fn parse_rows_from_message(msg: &String) -> Option<usize> {
    msg.split_whitespace()
        .find_map(|tok| tok.strip_prefix("rows=").and_then(|n| n.parse().ok()))
}

/// Fire one schedule's ingest. Returns Ok(success_message) or Err(reason).
pub async fn run_schedule(
    def: &ScheduleDef,
    deps: &SchedulerIngestDeps,
) -> Result<String, String> {
    tracing::info!("scheduler: firing '{}' ({})", def.id, def.kind.label());
    match &def.kind {
        ScheduleKind::Mysql { dsn, table, dataset_name, batch_size, order_by } => {
            let req = crate::my_stream::MyStreamRequest {
                dsn: dsn.clone(),
                table: table.clone(),
                dataset_name: dataset_name.clone(),
                batch_size: *batch_size,
                order_by: order_by.clone(),
                limit: None,
            };
            run_mysql(req, deps).await
        }
        ScheduleKind::Postgres { dsn, table, dataset_name, batch_size, order_by } => {
            let req = crate::pg_stream::PgStreamRequest {
                dsn: dsn.clone(),
                table: table.clone(),
                dataset_name: dataset_name.clone(),
                batch_size: *batch_size,
                order_by: order_by.clone(),
                limit: None,
            };
            run_postgres(req, deps).await
        }
    }
}

async fn run_mysql(
    req: crate::my_stream::MyStreamRequest,
    deps: &SchedulerIngestDeps,
) -> Result<String, String> {
    let (parquet, result) = crate::my_stream::stream_table_to_parquet(&req).await?;
    if result.rows == 0 {
        return Ok(format!("rows=0 — table empty"));
    }
    persist_and_register(
        &parquet, &result.table, req.dataset_name.as_deref(),
        result.rows, "mysql", &req.dsn, deps,
    ).await
}

async fn run_postgres(
    req: crate::pg_stream::PgStreamRequest,
    deps: &SchedulerIngestDeps,
) -> Result<String, String> {
    let (parquet, result) = crate::pg_stream::stream_table_to_parquet(&req).await?;
    if result.rows == 0 {
        return Ok(format!("rows=0 — table empty"));
    }
    persist_and_register(
        &parquet, &result.table, req.dataset_name.as_deref(),
        result.rows, "postgresql", &req.dsn, deps,
    ).await
}

/// Shared write+register path. Mirrors the HTTP ingest handlers in
/// service.rs so the scheduled path produces identical catalog output:
/// PII detection, lineage with redacted DSN, mark-stale + agent trigger.
async fn persist_and_register(
    parquet: &bytes::Bytes,
    table: &str,
    dataset_name_override: Option<&str>,
    rows: usize,
    source_system: &str,
    dsn: &str,
    deps: &SchedulerIngestDeps,
) -> Result<String, String> {
    use shared::types::{ColumnMeta, Lineage, ObjectRef, SchemaFingerprint, Sensitivity};

    let (schema, _) = shared::arrow_helpers::parquet_to_record_batches(parquet)
        .map_err(|e| format!("reparse parquet: {e}"))?;

    let dataset_name = dataset_name_override.unwrap_or(table).to_string();
    let storage_key = format!("datasets/{}.parquet", dataset_name);
    let parquet_size = parquet.len() as u64;
    let bucket = "primary".to_string();

    let target_store = deps.buckets.get(&bucket)?;
    ops::put(&target_store, &storage_key, parquet.clone()).await?;

    let schema_fp = shared::arrow_helpers::fingerprint_schema(&schema);
    let now = Utc::now();
    deps.registry.register(
        dataset_name.clone(),
        SchemaFingerprint(schema_fp.0),
        vec![ObjectRef {
            bucket: bucket.clone(),
            key: storage_key.clone(),
            size_bytes: parquet_size,
            created_at: now,
        }],
    ).await?;

    let col_names: Vec<&str> = schema.fields().iter().map(|f| f.name().as_str()).collect();
    let sensitivity = shared::pii::detect_dataset_sensitivity(&col_names);
    let columns: Vec<ColumnMeta> = schema.fields().iter().map(|f| {
        let sens = shared::pii::detect_sensitivity(f.name());
        ColumnMeta {
            name: f.name().clone(),
            data_type: f.data_type().to_string(),
            sensitivity: sens.clone(),
            description: String::new(),
            is_pii: matches!(sens, Some(Sensitivity::Pii)),
        }
    }).collect();

    let lineage = Lineage {
        source_system: source_system.to_string(),
        source_file: format!("dsn: {}", redact_dsn(dsn)),
        ingest_job: format!("scheduled-{}-{}", source_system, now.timestamp_millis()),
        ingest_timestamp: now,
        parent_datasets: vec![],
    };

    let _ = deps.registry.update_metadata(&dataset_name, catalogd::registry::MetadataUpdate {
        sensitivity,
        columns: Some(columns),
        lineage: Some(lineage),
        row_count: Some(rows as u64),
        ..Default::default()
    }).await;

    let _ = deps.registry.mark_embeddings_stale(&dataset_name).await;

    if let Some(agent) = &deps.agent_handle {
        let bound = deps.index_registry.list(Some(&dataset_name), None).await;
        for meta in bound {
            let event = vectord::agent::TriggerEvent::dataset_appended(
                meta.index_name.clone(), &dataset_name,
            );
            let _ = agent.enqueue(event).await;
        }
    }

    Ok(format!("rows={rows} dataset={dataset_name} bytes={parquet_size}"))
}

/// Same generic redactor used in service.rs — duplicated here to avoid
/// pulling service::redact_dsn behind a `pub` visibility just for this.
fn redact_dsn(dsn: &str) -> String {
    let scheme_end = match dsn.find("://") {
        Some(i) => i + 3,
        None => return dsn.to_string(),
    };
    let at_idx = match dsn.rfind('@') {
        Some(i) if i > scheme_end => i,
        _ => return dsn.to_string(),
    };
    let userpass = &dsn[scheme_end..at_idx];
    let colon_offset = match userpass.find(':') {
        Some(i) => i,
        None => return dsn.to_string(),
    };
    let colon_idx = scheme_end + colon_offset;
    format!("{}:***{}", &dsn[..colon_idx], &dsn[at_idx..])
}

// =================== Tests ===================

#[cfg(test)]
mod tests {
    use super::*;
    use chrono::Timelike;

    fn mk(secs: u64) -> ScheduleDef {
        ScheduleDef {
            id: "test".into(),
            kind: ScheduleKind::Mysql {
                dsn: "mysql://x@host/db".into(),
                table: "t".into(),
                dataset_name: None,
                batch_size: None,
                order_by: None,
            },
            trigger: ScheduleTrigger::Interval { secs },
            enabled: true,
            created_at: Utc::now(),
            created_by: "tester".into(),
            next_run_at: Utc::now(),
            last_run_at: None,
            last_outcome: None,
            run_count: 0,
            failure_count: 0,
        }
    }

    #[test]
    fn is_due_respects_enabled() {
        let mut s = mk(60);
        s.next_run_at = Utc::now() - Duration::seconds(5);
        assert!(s.is_due(Utc::now()));
        s.enabled = false;
        assert!(!s.is_due(Utc::now()));
    }

    #[test]
    fn is_due_respects_future_time() {
        let mut s = mk(60);
        s.next_run_at = Utc::now() + Duration::seconds(60);
        assert!(!s.is_due(Utc::now()));
    }

    #[test]
    fn next_run_since_last_completion_advances() {
        let s = mk(120);
        let completed = Utc::now();
        let next = compute_next_run_at(&s.trigger, completed, completed);
        let delta = next - completed;
        assert_eq!(delta.num_seconds(), 120);
    }

    #[test]
    fn cron_every_minute_fires_within_sixty_seconds() {
        let trig = ScheduleTrigger::Cron { expr: "* * * * *".into() };
        let now = Utc::now();
        let next = compute_next_run_at(&trig, now, now);
        let delta = next - now;
        assert!(delta.num_seconds() > 0 && delta.num_seconds() <= 60,
            "expected next fire within 60s, got {}s", delta.num_seconds());
    }

    #[test]
    fn cron_daily_at_1415_utc_is_within_24h() {
        // 14:15 UTC daily — whether we're before or after 14:15 today, the
        // next fire is at most 24h out.
        let trig = ScheduleTrigger::Cron { expr: "15 14 * * *".into() };
        let now: DateTime<Utc> = "2026-04-20T10:00:00Z".parse().unwrap();
        let next = compute_next_run_at(&trig, now, now);
        assert!(next > now);
        assert!((next - now).num_hours() <= 24);
        // And the minute-of-hour is 15.
        assert_eq!(next.minute(), 15);
        assert_eq!(next.hour(), 14);
    }

    #[test]
    fn cron_weekday_skips_weekend() {
        // 09:00 UTC weekdays only. On a Saturday, next fire is Monday.
        let trig = ScheduleTrigger::Cron { expr: "0 9 * * 1-5".into() };
        // 2026-04-18 is a Saturday.
        let sat: DateTime<Utc> = "2026-04-18T10:00:00Z".parse().unwrap();
        let next = compute_next_run_at(&trig, sat, sat);
        // Monday 2026-04-20 at 09:00 UTC.
        assert_eq!(next, "2026-04-20T09:00:00Z".parse::<DateTime<Utc>>().unwrap());
    }

    #[test]
    fn cron_six_field_seconds_granularity() {
        // 6-field (seconds included): fire every minute at 30s past the minute.
        let trig = ScheduleTrigger::Cron { expr: "30 * * * * *".into() };
        let now = Utc::now();
        let next = compute_next_run_at(&trig, now, now);
        assert_eq!(next.second(), 30);
    }

    #[test]
    fn validate_rejects_bad_cron() {
        let bad = ScheduleTrigger::Cron { expr: "not a cron".into() };
        let err = validate_trigger(&bad).unwrap_err();
        assert!(err.contains("cron"), "error should mention cron, got: {err}");
    }

    #[test]
    fn validate_rejects_wrong_field_count() {
        // 4 fields — neither 5 nor 6.
        let bad = ScheduleTrigger::Cron { expr: "* * * *".into() };
        assert!(validate_trigger(&bad).is_err());
    }

    #[test]
    fn validate_rejects_zero_interval() {
        let bad = ScheduleTrigger::Interval { secs: 0 };
        assert!(validate_trigger(&bad).is_err());
    }

    #[test]
    fn validate_accepts_good_cron() {
        let good = ScheduleTrigger::Cron { expr: "0 */6 * * *".into() };
        assert!(validate_trigger(&good).is_ok());
    }

    #[test]
    fn schedule_kind_label() {
        let k = ScheduleKind::Mysql {
            dsn: "x".into(), table: "customers".into(),
            dataset_name: None, batch_size: None, order_by: None,
        };
        assert_eq!(k.label(), "mysql:customers");
    }

    #[test]
    fn redact_dsn_handles_mysql_and_postgres() {
        assert_eq!(redact_dsn("mysql://u:secret@h/db"), "mysql://u:***@h/db");
        assert_eq!(redact_dsn("postgresql://u:secret@h:5432/db"), "postgresql://u:***@h:5432/db");
        assert_eq!(redact_dsn("mysql://u@h/db"), "mysql://u@h/db"); // no password
    }
}