package labels

import (
	"fmt"
	"image"
	"image/color"
	"image/draw"
	"strings"

	"github.com/skip2/go-qrcode"

	"git.georgsen.dk/hwlab/internal/netbox"
)

const CableLabelHeight = 180

// CableLabelData holds fields for the cable-specific label template (per LBL-03).
type CableLabelData struct {
	HWID         string  // e.g. "HW-00042"
	Name         string  // e.g. "USB-C 2m Cable"
	USBVersion   string  // e.g. "USB 3.2 Gen 2"
	MaxSpeedGbps float64 // e.g. 10.0
	MaxWatts     int     // e.g. 100
	TestDate     string  // ISO 8601 or "" for "Not tested"
}

// RenderCable produces a 384x180 label bitmap for a cable item.
// Layout: QR code left (96x96), text right with 4 lines:
//
//	Line 1: HW ID
//	Line 2: Name (truncated)
//	Line 3: USB version + speed (e.g. "USB 3.2 Gen 2 / 10 Gbps")
//	Line 4: Max power + test date (e.g. "100W  Tested: 2026-04-13")
//
// Returns an error if HWID does not match HW-\d{5} (T-04-07 mitigation).
func RenderCable(d CableLabelData) (image.Image, error) {
	if !hwIDPattern.MatchString(d.HWID) {
		return nil, fmt.Errorf("labels: invalid HWID %q: must match HW-NNNNN", d.HWID)
	}
	if d.Name == "" {
		d.Name = "Unknown Cable"
	}
	testDateStr := d.TestDate
	if testDateStr == "" {
		testDateStr = "Not tested"
	}

	img := image.NewNRGBA(image.Rect(0, 0, LabelWidth, CableLabelHeight))
	draw.Draw(img, img.Bounds(), image.NewUniform(color.NRGBA{R: 255, G: 255, B: 255, A: 255}), image.Point{}, draw.Src)

	// QR code — vertically centered in 180px height
	qr, err := qrcode.New(BaseURL+d.HWID, qrcode.Low)
	if err != nil {
		return nil, fmt.Errorf("labels: QR generation failed: %w", err)
	}
	qr.DisableBorder = true
	qrImg := qr.Image(QRSize)
	qrOffsetY := (CableLabelHeight - QRSize) / 2
	qrDst := image.Rect(QROffsetX, qrOffsetY, QROffsetX+QRSize, qrOffsetY+QRSize)
	draw.Draw(img, qrDst, qrImg, image.Point{}, draw.Over)

	// Text lines (4 lines across 180px height)
	drawText(img, TextOffsetX, 30, d.HWID)
	drawText(img, TextOffsetX, 62, truncate(d.Name, 30))
	speedLine := fmt.Sprintf("%s / %.0f Gbps", d.USBVersion, d.MaxSpeedGbps)
	drawText(img, TextOffsetX, 94, truncate(speedLine, 30))
	powerLine := fmt.Sprintf("%dW  Tested: %s", d.MaxWatts, testDateStr)
	drawText(img, TextOffsetX, 126, truncate(powerLine, 30))

	return img, nil
}

// IsCableDevice returns true if the NetBox device record represents a cable.
// Detection: Name contains "cable" (case-insensitive) OR AINotes contains "cable".
// This is a heuristic — real cable detection uses device_type in Phase 5.
func IsCableDevice(d netbox.Device) bool {
	nameLower := strings.ToLower(d.Name)
	notesLower := strings.ToLower(d.CustomFields.AINotes)
	return strings.Contains(nameLower, "cable") || strings.Contains(notesLower, "cable")
}