package service

import (
	"context"
	"fmt"
	"image"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"

	"materialanalyzer/internal/embedding"
	"materialanalyzer/internal/imageproc"
	"materialanalyzer/internal/model"
	"materialanalyzer/internal/output"
	"materialanalyzer/internal/validation"
)

const (
	SchemaVersion   = "material_asset_v2"
	AnalyzerVersion = "2.0.0"
	FeatureSchema   = "2026.07"
	Generator       = "Material Analyzer"
)

type ProcessorConfig struct {
	OutputDir         string
	CacheDir          string
	Force             bool
	AllowFallback     bool
	EmbeddingProvider embedding.Provider
	SemanticProvider  SemanticProvider
}

type Processor struct {
	cfg    ProcessorConfig
	client *http.Client
}

type ProcessResult struct {
	SKU      string
	AssetDir string
	Skipped  bool
	Warnings []string
	Width    int
	Height   int
}

func NewProcessor(cfg ProcessorConfig, client *http.Client) *Processor {
	if cfg.OutputDir == "" {
		cfg.OutputDir = "MaterialAssets"
	}
	if cfg.CacheDir == "" {
		cfg.CacheDir = filepath.Join("cache", "images")
	}
	if cfg.EmbeddingProvider == nil {
		cfg.EmbeddingProvider = embedding.LocalProvider{}
	}
	if cfg.SemanticProvider == nil {
		cfg.SemanticProvider = RuleBasedSemanticProvider{}
	}
	return &Processor{cfg: cfg, client: client}
}

func (p *Processor) Process(ctx context.Context, product model.Product) (ProcessResult, error) {
	result := ProcessResult{SKU: product.SKU}
	assetDir := output.AssetDir(p.cfg.OutputDir, product.SKU)
	result.AssetDir = assetDir
	if !p.cfg.Force && output.AssetExists(assetDir) {
		result.Skipped = true
		return result, nil
	}

	source, loaded, warnings, err := p.loadFirstImage(ctx, product)
	if err != nil {
		return result, err
	}

	analysis := imageproc.PrepareAnalysisImage(loaded.Image, source)
	result.Width = analysis.OriginalWidth
	result.Height = analysis.OriginalHeight
	if analysis.RoomLike {
		warnings = append(warnings, "main material image looks room-like; analyzed lower floor crop and flagged for cleanup")
	}

	visual, hist := imageproc.ExtractVisual(analysis.Image)
	texture := imageproc.ExtractTexture(analysis.Image)
	canonical := imageproc.ExtractCanonicalStatistics(analysis.Image, visual, texture)

	if err := output.EnsureAssetDir(assetDir); err != nil {
		return result, fmt.Errorf("create asset dir: %w", err)
	}
	if err := output.WriteImages(assetDir, analysis.Image); err != nil {
		return result, fmt.Errorf("write preview images: %w", err)
	}
	previewPath := filepath.Join(assetDir, "preview.jpg")

	semantic, err := p.cfg.SemanticProvider.Analyze(ctx, previewPath, product, visual, texture)
	if err != nil {
		if !p.cfg.AllowFallback {
			return result, fmt.Errorf("semantic provider %s: %w", p.cfg.SemanticProvider.Name(), err)
		}
		warnings = append(warnings, fmt.Sprintf("semantic provider %s failed; used local fallback: %v", p.cfg.SemanticProvider.Name(), err))
		semantic = BuildSemantic(product, visual, texture)
	}
	specific := BuildMaterialSpecific(product, visual, texture, semantic)

	if err := output.WriteHistogram(assetDir, hist); err != nil {
		return result, fmt.Errorf("write histogram: %w", err)
	}

	embeddingResult, err := p.cfg.EmbeddingProvider.Embed(ctx, embedding.Request{
		ImagePath: previewPath, Product: product, Histogram: hist, Visual: visual, Texture: texture, Semantic: semantic,
	})
	if err != nil {
		if !p.cfg.AllowFallback {
			return result, fmt.Errorf("embedding provider %s: %w", p.cfg.EmbeddingProvider.Name(), err)
		}
		warnings = append(warnings, fmt.Sprintf("embedding provider %s failed; used local fallback: %v", p.cfg.EmbeddingProvider.Name(), err))
		embeddingResult, err = (embedding.LocalProvider{}).Embed(ctx, embedding.Request{
			ImagePath: previewPath, Product: product, Histogram: hist, Visual: visual, Texture: texture, Semantic: semantic,
		})
		if err != nil {
			return result, fmt.Errorf("local embedding fallback: %w", err)
		}
	}
	manifest, err := embedding.WriteBinary(filepath.Join(assetDir, "embedding.bin"), embeddingResult)
	if err != nil {
		return result, fmt.Errorf("write embeddings: %w", err)
	}

	generatedAt := time.Now().UTC().Format(time.RFC3339)
	asset := model.MaterialAsset{
		SchemaVersion:   SchemaVersion,
		AnalyzerVersion: AnalyzerVersion,
		FeatureSchema:   FeatureSchema,
		Generator:       Generator,
		GeneratedAt:     generatedAt,
		SKU:             product.SKU,
		Category:        product.Category,
		Material:        product.Material,
		Product:         model.NewProductSnapshot(product),
		Input: model.InputInfo{
			ImageURL:            source,
			ImageCachePath:      loaded.SourcePath,
			OriginalWidth:       analysis.OriginalWidth,
			OriginalHeight:      analysis.OriginalHeight,
			AnalysisStrategy:    analysis.Strategy,
			AnalysisRegion:      regionString(analysis.Region),
			RoomLike:            analysis.RoomLike,
			RoomLikeConfidence:  analysis.RoomLikeConfidence,
			RoomLikeReason:      analysis.RoomLikeReason,
			SourceImageFormat:   loaded.Format,
			GeneratedPreview:    "preview.jpg",
			GeneratedThumbnail:  "thumbnail.jpg",
			GeneratedHistogram:  "histogram.json",
			GeneratedEmbeddings: "embedding.bin",
		},
		Visual:           visual,
		Texture:          texture,
		Canonical:        canonical,
		Semantic:         semantic,
		MaterialSpecific: specific,
		Embeddings:       manifest,
		Confidence: map[string]float64{
			"visual":    0.95,
			"texture":   0.90,
			"semantic":  semantic.Confidence,
			"embedding": embeddingConfidence(manifest),
		},
		Warnings: warnings,
	}
	asset.Validation = validation.ValidateAsset(asset, hist)
	if asset.Validation.Status != "valid" {
		return result, fmt.Errorf("asset validation failed: %s", strings.Join(asset.Validation.Errors, "; "))
	}

	if err := output.WriteSemantic(assetDir, semantic); err != nil {
		return result, fmt.Errorf("write semantic json: %w", err)
	}
	if err := output.WriteMaterial(assetDir, asset); err != nil {
		return result, fmt.Errorf("write material json: %w", err)
	}
	if err := output.WriteManifest(assetDir, model.AssetManifest{
		SKU: product.SKU, AnalyzerVersion: AnalyzerVersion, FeatureSchema: FeatureSchema, GeneratedAt: generatedAt,
		Files:  []string{"preview.jpg", "thumbnail.jpg", "material.json", "histogram.json", "embedding.bin", "semantic.json", "manifest.json"},
		Status: "complete", Validation: asset.Validation, Warnings: warnings,
	}); err != nil {
		return result, fmt.Errorf("write manifest: %w", err)
	}
	result.Warnings = warnings
	return result, nil
}

func embeddingConfidence(manifest model.EmbeddingManifest) float64 {
	for _, vector := range manifest.Vectors {
		if vector.Provider != "local" && vector.Provider != "" {
			return 0.92
		}
	}
	return 0.70
}

func (p *Processor) loadFirstImage(ctx context.Context, product model.Product) (string, *imageproc.LoadedImage, []string, error) {
	var warnings []string
	var lastErr error
	for i, source := range imageSources(product) {
		loaded, err := imageproc.LoadImage(ctx, source, p.cfg.CacheDir, p.client)
		if err == nil {
			if i > 0 {
				warnings = append(warnings, "primary image failed; used fallback image source")
			}
			return source, loaded, warnings, nil
		}
		lastErr = err
	}
	if lastErr == nil {
		lastErr = fmt.Errorf("no image source available")
	}
	return "", nil, warnings, fmt.Errorf("load image for %s: %w", product.SKU, lastErr)
}

func imageSources(product model.Product) []string {
	var out []string
	seen := map[string]bool{}
	add := func(v string) {
		v = strings.TrimSpace(v)
		if v == "" || seen[v] {
			return
		}
		seen[v] = true
		out = append(out, v)
	}
	add(product.MainImageURL)
	return out
}

func regionString(rect image.Rectangle) string {
	return fmt.Sprintf("x=%d,y=%d,w=%d,h=%d", rect.Min.X, rect.Min.Y, rect.Dx(), rect.Dy())
}

func RemoveIncompleteAsset(assetDir string) {
	if strings.TrimSpace(assetDir) == "" {
		return
	}
	_ = os.Remove(filepath.Join(assetDir, "material.json"))
}