package common

import (
	"io"
	"time"

	"github.com/fogleman/gg"
)

const (
	BlogTitle   = "Prose"
	BlogURL     = "https://prose.nsood.in"
	BlogSummary = "Where I infodump in Markdown and nobody can stop me."
)

func RSSDatetime(timestamp int64) string {
	return time.Unix(timestamp, 0).Format("Mon, 02 Jan 2006 15:04:05 MST")
}

func CreateImage(title, summary, url string, out io.Writer) error {
	imgWidth, imgHeight, imgPaddingX, imgPaddingY := 1200, 600, 50, 100
	accentHeight, spacerHeight := 12.5, 20.0
	titleSize, summarySize, urlSize := 63.0, 42.0, 27.0
	lineHeight := 1.05
	textWidth := float64(imgWidth - 2*imgPaddingX)

	draw := gg.NewContext(imgWidth, imgHeight)

	titleFont, err := gg.LoadFontFace("static/fonts/Nunito-Bold.ttf", titleSize)
	if err != nil {
		return err
	}
	summaryFont, err := gg.LoadFontFace("static/fonts/Nunito-LightItalic.ttf", summarySize)
	if err != nil {
		return err
	}
	urlFont, err := gg.LoadFontFace("static/fonts/JetBrainsMono-ExtraLight.ttf", urlSize)
	if err != nil {
		return err
	}

	draw.SetFontFace(titleFont)
	wrappedTitle := draw.WordWrap(title, textWidth)
	draw.SetFontFace(summaryFont)
	wrappedSummary := draw.WordWrap(summary, textWidth)

	draw.SetHexColor("#fff")
	draw.DrawRectangle(0, 0, float64(imgWidth), float64(imgHeight))
	draw.Fill()
	draw.SetHexColor("#3498db")
	draw.DrawRectangle(0, float64(imgHeight)-accentHeight, float64(imgWidth), accentHeight)
	draw.Fill()

	offset := float64(imgPaddingY)

	draw.SetFontFace(titleFont)
	draw.SetHexColor("#333")
	for _, line := range wrappedTitle {
		draw.DrawString(line, float64(imgPaddingX), offset)
		offset += lineHeight * titleSize
	}
	offset += spacerHeight

	draw.SetFontFace(summaryFont)
	draw.SetHexColor("#999")
	for _, line := range wrappedSummary {
		draw.DrawString(line, float64(imgPaddingX), offset)
		offset += lineHeight * summarySize
	}

	draw.SetHexColor("#333")
	draw.SetFontFace(urlFont)
	urlY := float64(imgHeight - imgPaddingY)
	draw.DrawStringWrapped(url, float64(imgPaddingX), urlY, 0, 0, textWidth, lineHeight, gg.AlignRight)

	return draw.EncodePNG(out)
}