package orchestrator

import (
	"context"
	"fmt"
	"log"
	"time"

	"vetting/internal/events"
	"vetting/internal/model"
	"vetting/internal/store"
)

// Runner is the authoritative mutator for run state. All state
// transitions go through (*Runner).Transition so the DB update and
// the event publication happen together.
type Runner struct {
	Runs     *store.Runs
	Hosts    *store.Hosts
	Stages   *store.Stages
	EventHub *events.Hub
}

func (r *Runner) Transition(ctx context.Context, runID int64, trigger Trigger) (model.RunState, error) {
	run, err := r.Runs.Get(ctx, runID)
	if err != nil {
		return "", fmt.Errorf("get run: %w", err)
	}
	next, err := Next(run.State, trigger)
	if err != nil {
		return "", err
	}
	if err := r.Runs.SetState(ctx, runID, next); err != nil {
		return "", fmt.Errorf("persist transition: %w", err)
	}
	log.Printf("run %d: %s -> %s (%s)", runID, run.State, next, trigger)
	r.publishTileUpdate(ctx, run.HostID)
	return next, nil
}

// StartStage marks a stage row running and publishes a tile refresh.
func (r *Runner) StartStage(ctx context.Context, runID int64, name string) error {
	if err := r.Stages.StartByName(ctx, runID, name); err != nil {
		return err
	}
	run, err := r.Runs.Get(ctx, runID)
	if err == nil {
		r.publishTileUpdate(ctx, run.HostID)
	}
	return nil
}

func (r *Runner) publishTileUpdate(ctx context.Context, hostID int64) {
	host, err := r.Hosts.Get(ctx, hostID)
	if err != nil {
		log.Printf("publishTileUpdate: get host %d: %v", hostID, err)
		return
	}
	latest, err := r.Runs.LatestForHost(ctx, hostID)
	if err != nil {
		log.Printf("publishTileUpdate: latest run: %v", err)
		return
	}
	payload := renderTileSSE(ctx, *host, latest)
	r.EventHub.Publish(events.Event{Name: fmt.Sprintf("tile-%d", hostID), Payload: payload})
}

// TileRenderer renders a single tile fragment. Registered at startup
// so the orchestrator package stays free of template / store-enrichment
// imports. The closure is expected to do any DB lookups itself (spec-
// diff count, hold-key path, …) before handing the data to the
// template package.
var TileRenderer func(ctx context.Context, host model.Host, latest *model.Run) string

func renderTileSSE(ctx context.Context, host model.Host, latest *model.Run) string {
	if TileRenderer == nil {
		return fmt.Sprintf(`<article id="host-%d">state change</article>`, host.ID)
	}
	return TileRenderer(ctx, host, latest)
}

// TouchHeartbeat is called on every agent heartbeat so the orchestrator
// can record last-seen; Phase 2 just logs, Phase 3+ will update a
// last_seen_at column.
func (r *Runner) TouchHeartbeat(runID int64) {
	_ = runID
	_ = time.Now()
}

// Override re-enters a held stage after the operator has acknowledged
// the failure condition (e.g. wipe-probe override). It jumps
// FailedHolding → StateFor(failed_stage), clears the failed marker, and
// publishes a tile refresh so the UI drops the hold banner.
func (r *Runner) Override(ctx context.Context, runID int64, flagsJSON string) (model.RunState, error) {
	run, err := r.Runs.Get(ctx, runID)
	if err != nil {
		return "", fmt.Errorf("get run: %w", err)
	}
	if run.FailedStage == "" {
		return "", fmt.Errorf("override: run has no failed_stage")
	}
	next, err := NextForOverride(run.State, run.FailedStage)
	if err != nil {
		return "", err
	}
	if err := r.Runs.SetOverrideFlags(ctx, runID, flagsJSON); err != nil {
		return "", fmt.Errorf("persist override flags: %w", err)
	}
	if err := r.Runs.SetState(ctx, runID, next); err != nil {
		return "", fmt.Errorf("override transition: %w", err)
	}
	if err := r.Runs.ClearFailedStage(ctx, runID); err != nil {
		log.Printf("override: clear failed_stage: %v", err)
	}
	log.Printf("run %d: %s -> %s (OperatorOverride stage=%s flags=%s)", runID, run.State, next, run.FailedStage, flagsJSON)
	r.publishTileUpdate(ctx, run.HostID)
	return next, nil
}