package alert

import (
	"context"
	"fmt"
	"log/slog"
	"time"

	"gitea.dcglab.co.uk/steve/restic-manager/internal/notification"
	"gitea.dcglab.co.uk/steve/restic-manager/internal/store"
)

// Alert kind constants — keep in lockstep with the engine logic and
// the UI tag-colour table.
const (
	// KindBackupFailed is raised when a backup job finishes with
	// status "failed" and resolved on next backup success.
	KindBackupFailed = "backup_failed"

	// KindForgetFailed mirrors KindBackupFailed for forget jobs.
	KindForgetFailed = "forget_failed"

	// KindPruneFailed mirrors KindBackupFailed for prune jobs.
	KindPruneFailed = "prune_failed"

	// KindCheckFailed is raised at "critical" severity (repository
	// integrity is at risk) when a check job fails.
	KindCheckFailed = "check_failed"

	// KindStaleSchedule is declared for completeness but intentionally
	// left as a no-op in v1. The precise "expected to have fired but
	// didn't" logic requires a store helper that lands in a follow-up
	// task. Ask the team before implementing.
	KindStaleSchedule = "stale_schedule"

	// KindAgentOffline is raised when a host's last_seen_at is older
	// than the 15-minute floor and resolved when the host reconnects.
	KindAgentOffline = "agent_offline"
)

// raiseAndNotify is the standard raise pattern: store.RaiseOrTouch
// deduplicates, and notification.Hub.Dispatch fires only on the first
// raise (didRaise=true). Subsequent occurrences of the same open alert
// are "touched" (last_seen_at bumped) without a second notification.
func (e *Engine) raiseAndNotify(ctx context.Context, hostID, kind, severity, message string, when time.Time) {
	id, didRaise, err := e.store.RaiseOrTouch(ctx, hostID, kind, severity, message, when)
	if err != nil {
		slog.Warn("alert: raise", "kind", kind, "host_id", hostID, "err", err)
		return
	}
	if !didRaise {
		return
	}
	host, err := e.store.GetHost(ctx, hostID)
	hostName := hostID
	if err == nil {
		hostName = host.Name
	}
	go e.hub.Dispatch(ctx, notification.Payload{
		Event:    notification.EventRaised,
		AlertID:  id,
		Severity: severity,
		Kind:     kind,
		HostID:   hostID,
		HostName: hostName,
		Message:  message,
		RaisedAt: when,
	})
}

// resolveAndNotify clears every open (or acknowledged) alert for
// (host_id, kind) via store.AutoResolve, then fires alert.resolved
// for each row that was actually open. Best-effort — errors are
// logged but do not propagate.
func (e *Engine) resolveAndNotify(ctx context.Context, hostID, kind string, when time.Time) {
	open, err := e.store.ListAlerts(ctx, store.AlertFilter{
		Status: "open", HostID: hostID,
	})
	if err != nil {
		return
	}
	openAcked, _ := e.store.ListAlerts(ctx, store.AlertFilter{
		Status: "acknowledged", HostID: hostID,
	})
	all := append(open, openAcked...)
	if err := e.store.AutoResolve(ctx, hostID, kind, when); err != nil {
		slog.Warn("alert: auto-resolve", "kind", kind, "host_id", hostID, "err", err)
		return
	}
	host, _ := e.store.GetHost(ctx, hostID)
	hostName := hostID
	if host != nil {
		hostName = host.Name
	}
	for _, a := range all {
		if a.Kind != kind {
			continue
		}
		go e.hub.Dispatch(ctx, notification.Payload{
			Event:    notification.EventResolved,
			AlertID:  a.ID,
			Severity: a.Severity,
			Kind:     a.Kind,
			HostID:   hostID,
			HostName: hostName,
			Message:  fmt.Sprintf("Auto-resolved (%s)", kind),
			RaisedAt: when,
		})
	}
}