package pgit

import (
	"bytes"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"os"
	"path/filepath"

	"github.com/alecthomas/chroma/v2"
	"github.com/tdewolff/minify/v2"
	"github.com/tdewolff/minify/v2/css"
)

func Style(theme chroma.Style) string {
	bg := theme.Get(chroma.Background)
	txt := theme.Get(chroma.Text)
	kw := theme.Get(chroma.Keyword)
	nv := theme.Get(chroma.NameVariable)
	cm := theme.Get(chroma.Comment)
	return fmt.Sprintf(`:root {
  --bg-color: %s;
  --text-color: %s;
  --border: %s;
  --link-color: %s;
  --hover: %s;
  --visited: %s;
}`,
		bg.Background.String(),
		txt.Colour.String(),
		cm.Colour.String(),
		nv.Colour.String(),
		kw.Colour.String(),
		nv.Colour.String(),
	)
}

func (c *Config) BundleCSS() (string, error) {
	c.Logger.Info("bundling CSS files")

	m := minify.New()
	m.AddFunc("text/css", css.Minify)

	var buf bytes.Buffer

	pgitCSS, err := StaticFS.ReadFile("static/pgit.css")
	if err != nil {
		return "", fmt.Errorf("failed to read pgit.css: %w", err)
	}
	buf.Write(pgitCSS)
	buf.WriteString("\n")

	varsCSS := Style(*c.Theme)
	buf.WriteString(varsCSS)
	buf.WriteString("\n")

	var syntaxBuf bytes.Buffer
	err = c.Formatter.WriteCSS(&syntaxBuf, c.Theme)
	if err != nil {
		return "", fmt.Errorf("failed to generate syntax.css: %w", err)
	}
	buf.Write(syntaxBuf.Bytes())

	minified, err := m.Bytes("text/css", buf.Bytes())
	if err != nil {
		return "", fmt.Errorf("failed to minify CSS: %w", err)
	}

	hash := sha256.Sum256(minified)
	hashStr := hex.EncodeToString(hash[:8])

	filename := fmt.Sprintf("styles.%s.css", hashStr)

	outPath := filepath.Join(c.Outdir, filename)
	err = os.WriteFile(outPath, minified, 0644)
	if err != nil {
		return "", fmt.Errorf("failed to write CSS bundle: %w", err)
	}

	c.Logger.Info("CSS bundle created", "filename", filename, "size", len(minified))

	return filename, nil
}