package display

import (
	"fmt"
	"image"
	"image/color"
	"log"
	"sync"

	"golang.org/x/image/font"
	"golang.org/x/image/font/inconsolata"
	"golang.org/x/image/math/fixed"
	"periph.io/x/conn/v3/i2c"
	"periph.io/x/conn/v3/i2c/i2creg"
	"periph.io/x/devices/v3/ssd1306"
	"periph.io/x/host/v3"
)

type displaySsd1306 struct {
	mutex  sync.Mutex
	logger *log.Logger

	font font.Face
	bus  i2c.BusCloser
	dev  *ssd1306.Dev
	img  *image.Gray
}

func newSsd1306(logger *log.Logger) (Display, error) {
	if _, err := host.Init(); err != nil {
		return nil, fmt.Errorf("drivers init: %w(may be i2c is disabled)", err)
	}

	// Setup device
	bus, err := i2creg.Open("")
	if err != nil {
		return nil, fmt.Errorf("open i2c bus: %w", err)
	}
	opts := ssd1306.Opts{
		W:             128,
		H:             32,
		Rotated:       false,
		Sequential:    true,
		SwapTopBottom: false,
	}
	dev, err := ssd1306.NewI2C(bus, &opts)
	if err != nil {
		return nil, fmt.Errorf("create i2c: %w", err)
	}

	// Create image
	img := image.NewGray(image.Rect(0, 0, dev.Bounds().Dx(), dev.Bounds().Dy()))

	return &displaySsd1306{
		logger: logger,
		font:   inconsolata.Regular8x16,
		bus:    bus,
		dev:    dev,
		img:    img,
	}, nil
}

func (d *displaySsd1306) GetImg() *image.Gray {
	d.mutex.Lock()
	defer d.mutex.Unlock()

	return d.img
}

func (d *displaySsd1306) GetFont() font.Face {
	return d.font
}

func (d *displaySsd1306) Clear() error {
	d.mutex.Lock()
	defer d.mutex.Unlock()

	for i := range d.img.Pix {
		d.img.Pix[i] = 0
	}
	return nil
}

func (d *displaySsd1306) PutText(x, y int, text string) error {
	d.mutex.Lock()
	defer d.mutex.Unlock()

	// Create font drawer
	col := color.Gray{255}
	point := fixed.Point26_6{X: fixed.I(x), Y: fixed.I(y)}

	drawer := &font.Drawer{
		Dst:  d.img,
		Src:  image.NewUniform(col),
		Face: d.font,
		Dot:  point,
	}
	drawer.DrawString(text)

	d.dev.Draw(d.img.Bounds(), d.img, image.Point{})
	return nil
}

func (d *displaySsd1306) Close() error {
	d.mutex.Lock()
	defer d.mutex.Unlock()

	if err := d.bus.Close(); err != nil {
		d.logger.Println("Close i2c bus:", err.Error())
	}
	return nil
}