package internal

import (
	"bytes"
	"fmt"
	"image"
	"image/color"
	"strconv"
	"time"

	"git.velvettear.de/velvettear/loggo"
	"git.velvettear.de/velvettear/slideshow-api/internal/config"
	color_thief "github.com/kennykarnama/color-thief"
)

// extract the given amount of dominant colors of raw image bytes
func GetColorPalette(data []byte) (string, error) {
	var palette string
	timestamp := time.Now().UnixMilli()
	amount := config.PaletteColors
	img, _, error := image.Decode(bytes.NewReader(data))
	if error != nil {
		loggo.ErrorTimed("encountered an error decoding the provided raw image bytes to an image", timestamp, error.Error())
		return palette, error
	}
	colors, error := color_thief.GetPalette(img, amount, config.PaletteAlgorithm)
	if error != nil {
		loggo.ErrorTimed("encountered an error generating the color palette from raw image bytes", timestamp, "colors: "+strconv.Itoa(amount))
		return palette, error
	} else {
		loggo.DebugTimed("generated color palette from raw image bytes", timestamp, "colors: "+strconv.Itoa(amount))
	}
	for index, color := range colors {
		if index > 0 {
			palette += "\n"
		}
		tmp := strconv.Itoa(index)
		if len(tmp) < 2 {
			tmp = "0" + tmp
		}
		tmp = "SLIDESHOW_COLOR" + tmp
		palette += tmp + "=\"" + rgbToHex(color) + "\""
	}
	return palette, nil
}

// extract the given amount of dominant colors of an image
func getColorPalette(image string) ([]color.Color, error) {
	var colors []color.Color
	timestamp := time.Now().UnixMilli()
	amount := config.PaletteColors
	colors, error := color_thief.GetPaletteFromFile(image, amount, config.PaletteAlgorithm)
	if error != nil {
		loggo.ErrorTimed("encountered an error generating the color palette from image", timestamp, "image: "+image, "colors: "+strconv.Itoa(amount))
	} else {
		loggo.DebugTimed("generated color palette from image", timestamp, "image: "+image, "colors: "+strconv.Itoa(amount))
	}
	return colors, error
}

// parse rgb color values to hex
func rgbToHex(color color.Color) string {
	r, g, b, _ := color.RGBA()
	return fmt.Sprintf("#%02x%02x%02x", uint8(r>>8), uint8(g>>8), uint8(b>>8))
}