package personagen

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"net/http"
	"time"

	"git.threesix.ai/jordan/persona-community-5/pkg/mediagen"
	"git.threesix.ai/jordan/persona-community-5/pkg/persona"
	"git.threesix.ai/jordan/persona-community-5/pkg/queue"
	"git.threesix.ai/jordan/persona-community-5/pkg/realtime"
	"git.threesix.ai/jordan/persona-community-5/pkg/storage"
	"git.threesix.ai/jordan/persona-community-5/pkg/textgen"
)

// anchorFetchClient is used to download anchor images from storage URLs.
var anchorFetchClient = &http.Client{Timeout: 30 * time.Second}

// Stage constants matching domain.PersonaStage in the API service.
const (
	StageSpec         = "spec"
	StageAnchor       = "anchor"
	StageAvatar       = "avatar"
	StageBanner       = "banner"
	StageGalleryBatch = "gallery_batch"
	StageVideo        = "video"
)

// Video motion types in generation order.
var videoOrder = []persona.MotionType{
	persona.MotionSmileReveal,
	persona.MotionPersonality,
	persona.MotionLifestyle,
	persona.MotionInvitation,
}

// PipelineDeps holds dependencies for the staged pipeline handler.
type PipelineDeps struct {
	TextGen  *textgen.Manager
	MediaGen *mediagen.Manager
	Store    storage.Store
	Pub      realtime.EventPublisher
	Personas PersonaStore
	Queue    queue.Producer
	Logger   *slog.Logger
}

// StagedQueueHandler returns a queue.Handler for processing persona_generate jobs
// using a stage-based pipeline. Each stage processes one unit of work, updates the
// persona row, publishes a job_update SSE event, and enqueues the next stage.
//
// Job payload: {"persona_id": "...", "stage": "spec|anchor|avatar|banner|gallery_batch|video"}
func StagedQueueHandler(deps PipelineDeps) queue.Handler {
	return func(ctx context.Context, job *queue.Job) error {
		personaID, _ := job.Payload["persona_id"].(string)
		if personaID == "" {
			return fmt.Errorf("missing persona_id in persona_generate job payload")
		}
		stage, _ := job.Payload["stage"].(string)
		if stage == "" {
			return fmt.Errorf("missing stage in persona_generate job payload")
		}

		logger := deps.Logger.With("job_id", job.ID, "persona_id", personaID, "stage", stage)
		logger.Info("processing persona generation stage")

		var err error
		switch stage {
		case StageSpec:
			err = handleStageSpec(ctx, deps, personaID, job.ID, logger)
		case StageAnchor:
			err = handleStageAnchor(ctx, deps, personaID, job.ID, logger)
		case StageAvatar:
			err = handleStageAvatar(ctx, deps, personaID, job.ID, logger)
		case StageBanner:
			err = handleStageBanner(ctx, deps, personaID, job.ID, logger)
		case StageGalleryBatch:
			err = handleStageGalleryBatch(ctx, deps, personaID, job.ID, logger)
		case StageVideo:
			err = handleStageVideo(ctx, deps, personaID, job.ID, logger)
		default:
			err = fmt.Errorf("unknown stage: %s", stage)
		}

		if err != nil {
			logger.Error("stage failed", "error", err)
			publishJobUpdate(deps.Pub, personaID, stage, "error", 0, err.Error())
		}
		return err
	}
}

// handleStageSpec generates the persona spec via LLM and updates the persona row.
func handleStageSpec(ctx context.Context, deps PipelineDeps, personaID, jobID string, logger *slog.Logger) error {
	rec, err := deps.Personas.GetByID(ctx, personaID)
	if err != nil {
		return fmt.Errorf("load persona: %w", err)
	}

	// Update status to generating.
	rec.Status = "generating"
	if err := deps.Personas.Update(ctx, rec); err != nil {
		return fmt.Errorf("update persona status: %w", err)
	}

	svc := New(deps.TextGen, deps.MediaGen, deps.Store, logger)
	seed := SeedParams{
		Description: rec.Description,
		Gender:      rec.Gender,
		Name:        rec.Name,
	}

	spec, err := svc.GenerateSpec(ctx, seed)
	if err != nil {
		rec.Status = "failed"
		_ = deps.Personas.Update(ctx, rec)
		return fmt.Errorf("spec generation: %w", err)
	}

	// Serialize full spec to JSON for storage.
	specJSON, err := json.Marshal(spec)
	if err != nil {
		return fmt.Errorf("marshal spec: %w", err)
	}

	// Update persona with spec data.
	rec.SpecJSON = specJSON
	rec.Name = spec.Name.First
	if spec.Name.Last != "" {
		rec.Name = spec.Name.First + " " + spec.Name.Last
	}
	rec.Handle = generateHandleFromSpec(spec)
	rec.Tags = extractTags(spec)

	if err := deps.Personas.Update(ctx, rec); err != nil {
		return fmt.Errorf("update persona spec: %w", err)
	}

	publishJobUpdate(deps.Pub, personaID, StageSpec, "complete", 100, "")

	// Enqueue anchor stage.
	if _, err := deps.Queue.Enqueue(ctx, "persona_generate", map[string]any{
		"persona_id": personaID,
		"stage":      StageAnchor,
	}); err != nil {
		return fmt.Errorf("enqueue anchor stage: %w", err)
	}

	logger.Info("spec stage complete, anchor enqueued")
	return nil
}

// handleStageAnchor generates the anchor (position 1) image.
func handleStageAnchor(ctx context.Context, deps PipelineDeps, personaID, jobID string, logger *slog.Logger) error {
	rec, err := deps.Personas.GetByID(ctx, personaID)
	if err != nil {
		return fmt.Errorf("load persona: %w", err)
	}

	spec, err := unmarshalSpec(rec.SpecJSON)
	if err != nil {
		return err
	}

	svc := New(deps.TextGen, deps.MediaGen, deps.Store, logger)

	// Generate position 1 (the identity anchor).
	if err := svc.generatePosition(ctx, spec, 1); err != nil {
		return fmt.Errorf("anchor generation: %w", err)
	}

	// Find position 1 URL.
	var anchorURL string
	for _, img := range spec.ImageMatrix {
		if img.Position == 1 {
			anchorURL = img.URL
			break
		}
	}

	rec.AnchorURL = anchorURL
	rec.ImageURLs = appendIfMissing(rec.ImageURLs, anchorURL)

	// Update spec JSON with the generated image URL/status.
	updatedSpec, _ := json.Marshal(spec)
	rec.SpecJSON = updatedSpec

	if err := deps.Personas.Update(ctx, rec); err != nil {
		return fmt.Errorf("update persona anchor: %w", err)
	}

	publishJobUpdate(deps.Pub, personaID, StageAnchor, "complete", 100, "")

	// Enqueue avatar, banner, and gallery_batch in parallel.
	for _, nextStage := range []string{StageAvatar, StageBanner, StageGalleryBatch} {
		if _, err := deps.Queue.Enqueue(ctx, "persona_generate", map[string]any{
			"persona_id": personaID,
			"stage":      nextStage,
		}); err != nil {
			return fmt.Errorf("enqueue %s stage: %w", nextStage, err)
		}
	}

	logger.Info("anchor stage complete, avatar/banner/gallery_batch enqueued")
	return nil
}

// handleStageAvatar generates the circular portrait avatar.
func handleStageAvatar(ctx context.Context, deps PipelineDeps, personaID, jobID string, logger *slog.Logger) error {
	rec, err := deps.Personas.GetByID(ctx, personaID)
	if err != nil {
		return fmt.Errorf("load persona: %w", err)
	}

	spec, err := unmarshalSpec(rec.SpecJSON)
	if err != nil {
		return err
	}

	svc := New(deps.TextGen, deps.MediaGen, deps.Store, logger)

	// Restore anchor from storage for identity consistency.
	if err := restoreAnchor(ctx, svc, deps.Store, spec); err != nil {
		logger.Warn("could not restore anchor for avatar", "error", err)
	}

	avatarBytes, err := svc.GenerateAvatar(ctx, spec)
	if err != nil {
		return fmt.Errorf("avatar generation: %w", err)
	}

	storagePath := fmt.Sprintf("personas/%s/avatar.png", spec.ID)
	url, err := deps.Store.Upload(ctx, storagePath, avatarBytes, "image/png")
	if err != nil {
		return fmt.Errorf("upload avatar: %w", err)
	}

	rec.AvatarURL = url
	if err := deps.Personas.Update(ctx, rec); err != nil {
		return fmt.Errorf("update persona avatar: %w", err)
	}

	publishJobUpdate(deps.Pub, personaID, StageAvatar, "complete", 100, "")
	logger.Info("avatar stage complete")
	return nil
}

// handleStageBanner generates the 3:1 landscape banner image.
func handleStageBanner(ctx context.Context, deps PipelineDeps, personaID, jobID string, logger *slog.Logger) error {
	rec, err := deps.Personas.GetByID(ctx, personaID)
	if err != nil {
		return fmt.Errorf("load persona: %w", err)
	}

	spec, err := unmarshalSpec(rec.SpecJSON)
	if err != nil {
		return err
	}

	svc := New(deps.TextGen, deps.MediaGen, deps.Store, logger)

	// Restore anchor for identity consistency.
	if err := restoreAnchor(ctx, svc, deps.Store, spec); err != nil {
		logger.Warn("could not restore anchor for banner", "error", err)
	}

	bannerBytes, err := svc.GenerateBanner(ctx, spec, "lifestyle")
	if err != nil {
		return fmt.Errorf("banner generation: %w", err)
	}

	storagePath := fmt.Sprintf("personas/%s/banner.png", spec.ID)
	url, err := deps.Store.Upload(ctx, storagePath, bannerBytes, "image/png")
	if err != nil {
		return fmt.Errorf("upload banner: %w", err)
	}

	rec.BannerURL = url
	if err := deps.Personas.Update(ctx, rec); err != nil {
		return fmt.Errorf("update persona banner: %w", err)
	}

	publishJobUpdate(deps.Pub, personaID, StageBanner, "complete", 100, "")
	logger.Info("banner stage complete")
	return nil
}

// handleStageGalleryBatch generates the next 10 unfilled image positions.
func handleStageGalleryBatch(ctx context.Context, deps PipelineDeps, personaID, jobID string, logger *slog.Logger) error {
	rec, err := deps.Personas.GetByID(ctx, personaID)
	if err != nil {
		return fmt.Errorf("load persona: %w", err)
	}

	spec, err := unmarshalSpec(rec.SpecJSON)
	if err != nil {
		return err
	}

	svc := New(deps.TextGen, deps.MediaGen, deps.Store, logger)

	// Restore anchor for identity consistency.
	if err := restoreAnchor(ctx, svc, deps.Store, spec); err != nil {
		logger.Warn("could not restore anchor for gallery batch", "error", err)
	}

	// Find unfilled positions (skip position 1 which is the anchor, already done).
	var unfilled []int
	for _, img := range spec.ImageMatrix {
		if img.Status != persona.ImageStatusComplete && img.Position != 1 {
			unfilled = append(unfilled, img.Position)
		}
	}

	// Take up to 10 positions for this batch.
	batchSize := 10
	if len(unfilled) < batchSize {
		batchSize = len(unfilled)
	}
	batch := unfilled[:batchSize]

	for _, pos := range batch {
		if err := svc.generatePosition(ctx, spec, pos); err != nil {
			logger.Error("gallery image generation failed", "position", pos, "error", err)
			return fmt.Errorf("gallery position %d: %w", pos, err)
		}

		// Find the URL for this position.
		var imgURL string
		for _, img := range spec.ImageMatrix {
			if img.Position == pos {
				imgURL = img.URL
				break
			}
		}
		rec.ImageURLs = appendIfMissing(rec.ImageURLs, imgURL)
	}

	// Update spec JSON with new image URLs/statuses.
	updatedSpec, _ := json.Marshal(spec)
	rec.SpecJSON = updatedSpec

	if err := deps.Personas.Update(ctx, rec); err != nil {
		return fmt.Errorf("update persona gallery: %w", err)
	}

	// Count total completed images (including anchor).
	completedImages := countCompletedImages(spec)
	totalImages := len(spec.ImageMatrix)
	progress := (completedImages * 100) / totalImages

	publishJobUpdate(deps.Pub, personaID, StageGalleryBatch, "complete", progress, "")

	// If fewer than totalImages are complete, enqueue another gallery_batch.
	if completedImages < totalImages {
		if _, err := deps.Queue.Enqueue(ctx, "persona_generate", map[string]any{
			"persona_id": personaID,
			"stage":      StageGalleryBatch,
		}); err != nil {
			return fmt.Errorf("enqueue next gallery batch: %w", err)
		}
		logger.Info("gallery batch complete, more images needed", "completed", completedImages, "total", totalImages)
	} else {
		// All images done, enqueue first video.
		if _, err := deps.Queue.Enqueue(ctx, "persona_generate", map[string]any{
			"persona_id": personaID,
			"stage":      StageVideo,
		}); err != nil {
			return fmt.Errorf("enqueue video stage: %w", err)
		}
		logger.Info("all gallery images complete, video stage enqueued")
	}

	return nil
}

// handleStageVideo generates the next missing video.
func handleStageVideo(ctx context.Context, deps PipelineDeps, personaID, jobID string, logger *slog.Logger) error {
	rec, err := deps.Personas.GetByID(ctx, personaID)
	if err != nil {
		return fmt.Errorf("load persona: %w", err)
	}

	spec, err := unmarshalSpec(rec.SpecJSON)
	if err != nil {
		return err
	}

	svc := New(deps.TextGen, deps.MediaGen, deps.Store, logger)

	// Restore anchor for identity consistency.
	if err := restoreAnchor(ctx, svc, deps.Store, spec); err != nil {
		logger.Warn("could not restore anchor for video", "error", err)
	}

	// Find the next missing video in order.
	completedVideos := len(rec.VideoURLs)
	if completedVideos >= len(videoOrder) {
		// All videos done — mark complete.
		rec.Status = "complete"
		if err := deps.Personas.Update(ctx, rec); err != nil {
			return fmt.Errorf("update persona complete: %w", err)
		}
		publishJobUpdate(deps.Pub, personaID, StageVideo, "complete", 100, "")
		logger.Info("all videos complete, persona generation finished")
		return nil
	}

	motionType := videoOrder[completedVideos]
	logger.Info("generating video", "motion_type", motionType, "index", completedVideos)

	videoSpec, err := svc.GenerateVideo(ctx, spec, motionType)
	if err != nil {
		// Videos are best-effort — log the failure and continue to next.
		logger.Warn("video generation failed (non-fatal)", "motion_type", motionType, "error", err)
		publishJobUpdate(deps.Pub, personaID, StageVideo, "error", 0, fmt.Sprintf("%s video failed: %s", motionType, err.Error()))
	} else {
		rec.VideoURLs = append(rec.VideoURLs, videoSpec.URL)
	}

	// Update spec JSON.
	updatedSpec, _ := json.Marshal(spec)
	rec.SpecJSON = updatedSpec

	if err := deps.Personas.Update(ctx, rec); err != nil {
		return fmt.Errorf("update persona video: %w", err)
	}

	// Check if more videos needed (count by index, not by success).
	nextIndex := completedVideos + 1
	if nextIndex < len(videoOrder) {
		if _, err := deps.Queue.Enqueue(ctx, "persona_generate", map[string]any{
			"persona_id": personaID,
			"stage":      StageVideo,
		}); err != nil {
			return fmt.Errorf("enqueue next video: %w", err)
		}
		progress := (nextIndex * 100) / len(videoOrder)
		publishJobUpdate(deps.Pub, personaID, StageVideo, "complete", progress, "")
		logger.Info("video stage complete, next video enqueued", "completed", nextIndex, "total", len(videoOrder))
	} else {
		// All videos done — mark persona complete.
		rec.Status = "complete"
		if err := deps.Personas.Update(ctx, rec); err != nil {
			return fmt.Errorf("update persona complete: %w", err)
		}
		publishJobUpdate(deps.Pub, personaID, StageVideo, "complete", 100, "")
		logger.Info("all videos complete, persona generation finished")
	}

	return nil
}

// publishJobUpdate sends a job_update SSE event to channel:personas.
func publishJobUpdate(pub realtime.EventPublisher, personaID, stage, status string, progress int, errMsg string) {
	event := &realtime.SSEEvent{
		Type:     "job_update",
		Progress: progress,
		Result: map[string]any{
			"persona_id": personaID,
			"stage":      stage,
			"status":     status,
			"progress":   progress,
		},
	}
	if errMsg != "" {
		event.Error = errMsg
	}
	if err := pub.SendToChannel("channel:personas", event); err != nil {
		slog.Warn("failed to publish job_update event", "error", err, "persona_id", personaID, "stage", stage)
	}
}

// unmarshalSpec deserializes a PersonaSpec from JSON stored on the persona record.
func unmarshalSpec(specJSON json.RawMessage) (*persona.PersonaSpec, error) {
	if len(specJSON) == 0 {
		return nil, fmt.Errorf("persona has no spec_json (spec stage may not have completed)")
	}
	var spec persona.PersonaSpec
	if err := json.Unmarshal(specJSON, &spec); err != nil {
		return nil, fmt.Errorf("unmarshal spec: %w", err)
	}
	return &spec, nil
}

// restoreAnchor downloads the anchor image (position 1) from storage and sets it
// on the service for identity consistency in subsequent generations.
func restoreAnchor(ctx context.Context, svc *Service, store storage.Store, spec *persona.PersonaSpec) error {
	if store == nil {
		return fmt.Errorf("no storage configured")
	}
	// Find position 1 URL from spec.
	var anchorURL string
	for _, img := range spec.ImageMatrix {
		if img.Position == 1 && img.URL != "" {
			anchorURL = img.URL
			break
		}
	}
	if anchorURL == "" {
		return fmt.Errorf("no anchor URL found in spec")
	}

	// Download anchor image from storage URL.
	anchorBytes, err := storage.FetchURL(ctx, anchorFetchClient, anchorURL, 50<<20) // 50 MB max
	if err != nil {
		return fmt.Errorf("fetch anchor image: %w", err)
	}
	svc.SetAnchor(anchorBytes)
	return nil
}

// generateHandleFromSpec creates a URL-safe handle from the spec name.
func generateHandleFromSpec(spec *persona.PersonaSpec) string {
	name := spec.Name.First
	if spec.Name.Last != "" {
		name += " " + spec.Name.Last
	}
	return generateHandle(name)
}

// generateHandle creates a URL-safe handle from a name (same logic as persona-api service).
func generateHandle(name string) string {
	// Reuse the service's handle generation logic.
	h := name
	// Simplified: lowercase, replace non-alphanumeric with underscore, trim.
	result := make([]byte, 0, len(h))
	for _, c := range []byte(h) {
		if (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') {
			result = append(result, c)
		} else if c >= 'A' && c <= 'Z' {
			result = append(result, c+32) // lowercase
		} else {
			if len(result) > 0 && result[len(result)-1] != '_' {
				result = append(result, '_')
			}
		}
	}
	s := string(result)
	if len(s) > 40 {
		s = s[:40]
	}
	// Trim trailing underscores.
	for len(s) > 0 && s[len(s)-1] == '_' {
		s = s[:len(s)-1]
	}
	// Append timestamp suffix.
	suffix := fmt.Sprintf("_%d", now().UnixMilli()%100000)
	return s + suffix
}

// extractTags extracts 8 tags from the spec for the persona row.
func extractTags(spec *persona.PersonaSpec) []string {
	tags := make([]string, 0, 8)

	// Add gender.
	if spec.DNA != nil {
		tags = append(tags, string(spec.DNA.Identity.Gender))
		tags = append(tags, string(spec.DNA.Identity.Ethnicity))
	}

	// Add occupation from identity.
	if spec.Name.First != "" {
		tags = append(tags, spec.Name.First)
	}

	// Add fashion context.
	if spec.Lifestyle.FashionSense.Primary != "" {
		tags = append(tags, string(spec.Lifestyle.FashionSense.Primary))
	}

	// Add interests.
	for _, interest := range spec.Lifestyle.Interests.Creative {
		if len(tags) >= 8 {
			break
		}
		tags = append(tags, interest)
	}
	for _, interest := range spec.Lifestyle.Interests.Active {
		if len(tags) >= 8 {
			break
		}
		tags = append(tags, interest)
	}

	if len(tags) > 8 {
		tags = tags[:8]
	}
	return tags
}

// countCompletedImages counts how many images have status "complete" in the spec.
func countCompletedImages(spec *persona.PersonaSpec) int {
	count := 0
	for _, img := range spec.ImageMatrix {
		if img.Status == persona.ImageStatusComplete {
			count++
		}
	}
	return count
}

// appendIfMissing appends a string to a slice if it's not already present and not empty.
func appendIfMissing(slice []string, s string) []string {
	if s == "" {
		return slice
	}
	for _, existing := range slice {
		if existing == s {
			return slice
		}
	}
	return append(slice, s)
}