package camera

import (
	"bytes"
	"fmt"
	"image"
	"image/color"
	"image/jpeg"
	"time"
)

type MockCamera struct {
	width      int
	height     int
	frameCount int
}

func NewMockCamera(width, height int) *MockCamera {
	return &MockCamera{width: width, height: height}
}

func (mc *MockCamera) ReadFrame() ([]byte, error) {
	mc.frameCount++
	return mc.generateTestCard()
}

func (mc *MockCamera) generateTestCard() ([]byte, error) {
	img := image.NewRGBA(image.Rect(0, 0, mc.width, mc.height))
	offset := mc.frameCount % mc.width

	for y := 0; y < mc.height; y++ {
		for x := 0; x < mc.width; x++ {
			pos := (x + offset) % mc.width
			ratio := float64(pos) / float64(mc.width)
			var r, g, b uint8
			if ratio < 0.33 {
				r = uint8(255 * (1 - ratio/0.33))
				g = uint8(255 * ratio / 0.33)
			} else if ratio < 0.66 {
				g = uint8(255 * (1 - (ratio-0.33)/0.33))
				b = uint8(255 * (ratio - 0.33) / 0.33)
			} else {
				b = uint8(255 * (1 - (ratio-0.66)/0.34))
				r = uint8(255 * (ratio - 0.66) / 0.34)
			}
			img.SetRGBA(x, y, color.RGBA{R: r, G: g, B: b, A: 255})
		}
	}

	// Draw dark overlay bar at top for text area
	for y := 0; y < 40; y++ {
		for x := 0; x < mc.width; x++ {
			img.SetRGBA(x, y, color.RGBA{R: 0, G: 0, B: 0, A: 180})
		}
	}

	// Draw "MOCK CAMERA" text block and frame counter using simple rectangles
	drawTextBlock(img, 10, 10, fmt.Sprintf("MOCK CAMERA | Frame: %d | %s", mc.frameCount, time.Now().Format("15:04:05")))

	// Draw center crosshair
	cx, cy := mc.width/2, mc.height/2
	for i := -20; i <= 20; i++ {
		if cx+i >= 0 && cx+i < mc.width {
			img.SetRGBA(cx+i, cy, color.RGBA{R: 255, G: 255, B: 255, A: 200})
		}
		if cy+i >= 0 && cy+i < mc.height {
			img.SetRGBA(cx, cy+i, color.RGBA{R: 255, G: 255, B: 255, A: 200})
		}
	}

	var buf bytes.Buffer
	if err := jpeg.Encode(&buf, img, &jpeg.Options{Quality: 75}); err != nil {
		return nil, err
	}
	return buf.Bytes(), nil
}

func drawTextBlock(img *image.RGBA, x, y int, text string) {
	white := color.RGBA{R: 255, G: 255, B: 255, A: 255}
	// Simple pixel-based text rendering: each character is a 5x7 block
	for i, ch := range text {
		if ch == ' ' {
			continue
		}
		px := x + i*6
		// Draw a small white dot for each character position
		for dy := 0; dy < 5; dy++ {
			for dx := 0; dx < 4; dx++ {
				if px+dx < img.Bounds().Max.X && y+dy < img.Bounds().Max.Y {
					img.SetRGBA(px+dx, y+dy, white)
				}
			}
		}
	}
}