package validation

import (
	"fmt"
	"time"

	"materialanalyzer/internal/model"
)

func ValidateAsset(asset model.MaterialAsset, hist model.ColorHistogram) model.ValidationReport {
	report := model.ValidationReport{
		Status:    "valid",
		CheckedAt: time.Now().UTC().Format(time.RFC3339),
	}
	checkRange(&report, "visual.brightness", asset.Visual.Brightness, 0, 1)
	checkRange(&report, "visual.contrast", asset.Visual.Contrast, 0, 1)
	checkRange(&report, "visual.saturation", asset.Visual.Saturation, 0, 1)
	checkRange(&report, "texture.orientation", asset.Texture.PrimaryOrientationDeg, 0, 180)
	if asset.Texture.Entropy <= 0 {
		report.Errors = append(report.Errors, "texture.entropy must be > 0")
	}
	if len(hist.Values) != 256 {
		report.Errors = append(report.Errors, fmt.Sprintf("histogram length = %d, want 256", len(hist.Values)))
	}
	for _, vector := range asset.Embeddings.Vectors {
		if vector.Dimensions <= 0 {
			report.Errors = append(report.Errors, "embedding "+vector.Name+" has invalid dimension")
		}
		if vector.ByteLength != int64(vector.Dimensions*4) {
			report.Errors = append(report.Errors, fmt.Sprintf("embedding %s byte length = %d, want %d", vector.Name, vector.ByteLength, vector.Dimensions*4))
		}
		if vector.Model == "dinov2-large" && vector.Dimensions != 1024 {
			report.Errors = append(report.Errors, "dinov2-large dimension must be 1024")
		}
		if vector.Model == "ViT-L/14" && vector.Dimensions != 768 {
			report.Errors = append(report.Errors, "ViT-L/14 dimension must be 768")
		}
	}
	if asset.Semantic.Description == "" {
		report.Errors = append(report.Errors, "semantic.description is required")
	}
	if asset.Semantic.MaterialType == "" {
		report.Errors = append(report.Errors, "semantic.material_type is required")
	}
	if asset.Semantic.SurfaceFinish == "" {
		report.Errors = append(report.Errors, "semantic.surface_finish is required")
	}
	if asset.Semantic.ColorFamily == "" {
		report.Errors = append(report.Errors, "semantic.color_family is required")
	}
	if asset.Semantic.Confidence <= 0 || asset.Semantic.Confidence > 1 {
		report.Errors = append(report.Errors, "semantic.confidence must be in (0,1]")
	}
	if len(asset.Canonical.BrightnessDistribution) != asset.Canonical.BrightnessHistogramBins {
		report.Warnings = append(report.Warnings, "canonical brightness histogram bin count mismatch")
	}
	if len(asset.Canonical.GradientHistogram) != asset.Canonical.GradientHistogramBins {
		report.Warnings = append(report.Warnings, "canonical gradient histogram bin count mismatch")
	}
	if len(report.Errors) > 0 {
		report.Status = "invalid"
	}
	return report
}

func checkRange(report *model.ValidationReport, name string, value, min, max float64) {
	if value < min || value > max {
		report.Errors = append(report.Errors, fmt.Sprintf("%s = %.4f, want [%.2f,%.2f]", name, value, min, max))
	}
}