From 2a5bbe4fbbf8b5471bc3052051eed5477c308fd1 Mon Sep 17 00:00:00 2001
From: Laura <milanbartky@gmail.com>
Date: Thu, 19 Jun 2025 16:29:27 +0200
Subject: [PATCH] webp

---
 go.mod                      | 10 ++++-
 go.sum                      |  6 +++
 internal/builtins/webp.go   |  8 ++++
 internal/codec/detect.go    |  4 ++
 internal/codec/webp/webp.go | 87 +++++++++++++++++++++++++++++++++++++
 5 files changed, 114 insertions(+), 1 deletion(-)
 create mode 100644 internal/builtins/webp.go
 create mode 100644 internal/codec/webp/webp.go

diff --git a/go.mod b/go.mod
index 818f443..fbc8673 100644
--- a/go.mod
+++ b/go.mod
@@ -4,4 +4,12 @@ go 1.24.2
 
 require github.com/urfave/cli/v3 v3.3.8
 
-require golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8
+require (
+	github.com/gen2brain/webp v0.5.5
+	golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8
+)
+
+require (
+	github.com/ebitengine/purego v0.8.3 // indirect
+	github.com/tetratelabs/wazero v1.9.0 // indirect
+)
diff --git a/go.sum b/go.sum
index eaef168..1c0b020 100644
--- a/go.sum
+++ b/go.sum
@@ -1,9 +1,15 @@
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/ebitengine/purego v0.8.3 h1:K+0AjQp63JEZTEMZiwsI9g0+hAMNohwUOtY0RPGexmc=
+github.com/ebitengine/purego v0.8.3/go.mod h1:iIjxzd6CiRiOG0UyXP+V1+jWqUXVjPKLAI0mRfJZTmQ=
+github.com/gen2brain/webp v0.5.5 h1:MvQR75yIPU/9nSqYT5h13k4URaJK3gf9tgz/ksRbyEg=
+github.com/gen2brain/webp v0.5.5/go.mod h1:xOSMzp4aROt2KFW++9qcK/RBTOVC2S9tJG66ip/9Oc0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/tetratelabs/wazero v1.9.0 h1:IcZ56OuxrtaEz8UYNRHBrUa9bYeX9oVY93KspZZBf/I=
+github.com/tetratelabs/wazero v1.9.0/go.mod h1:TSbcXCfFP0L2FGkRPxHphadXPjo1T6W+CseNNY7EkjM=
 github.com/urfave/cli/v3 v3.3.8 h1:BzolUExliMdet9NlJ/u4m5vHSotJ3PzEqSAZ1oPMa/E=
 github.com/urfave/cli/v3 v3.3.8/go.mod h1:FJSKtM/9AiiTOJL4fJ6TbMUkxBXn7GO9guZqoZtpYpo=
 golang.org/x/image v0.0.0-20191009234506-e7c1f5e7dbb8 h1:hVwzHzIUGRjiF7EcUjqNxk3NCfkPxbDKRdnNE1Rpg0U=
diff --git a/internal/builtins/webp.go b/internal/builtins/webp.go
new file mode 100644
index 0000000..31d202c
--- /dev/null
+++ b/internal/builtins/webp.go
@@ -0,0 +1,8 @@
+//go:build webp || core || full
+// +build webp core full
+
+package builtins
+
+import (
+	_ "github.com/coalaura/ffwebp/internal/codec/webp"
+)
diff --git a/internal/codec/detect.go b/internal/codec/detect.go
index 577323f..217f010 100644
--- a/internal/codec/detect.go
+++ b/internal/codec/detect.go
@@ -46,6 +46,10 @@ func Sniff(reader io.Reader) (*Sniffed, io.Reader, error) {
 	for _, codec := range codecs {
 		confidence, header, err := codec.Sniff(ra)
 		if err != nil {
+			if errors.Is(err, io.EOF) {
+				continue
+			}
+
 			return nil, nil, err
 		}
 
diff --git a/internal/codec/webp/webp.go b/internal/codec/webp/webp.go
new file mode 100644
index 0000000..e4ca401
--- /dev/null
+++ b/internal/codec/webp/webp.go
@@ -0,0 +1,87 @@
+package bmp
+
+import (
+	"bytes"
+	"fmt"
+	"image"
+	"io"
+
+	"github.com/gen2brain/webp"
+
+	"github.com/coalaura/ffwebp/internal/codec"
+	"github.com/coalaura/ffwebp/internal/logx"
+	"github.com/coalaura/ffwebp/internal/opts"
+	"github.com/urfave/cli/v3"
+)
+
+var (
+	method int
+	exact  bool
+)
+
+func init() {
+	codec.Register(impl{})
+}
+
+type impl struct{}
+
+func (impl) String() string {
+	return "webp"
+}
+
+func (impl) Extensions() []string {
+	return []string{"webp"}
+}
+
+func (impl) Flags(flags []cli.Flag) []cli.Flag {
+	return append(flags,
+		&cli.IntFlag{
+			Name:        "webp.method",
+			Usage:       "WebP: quality/speed trade-off (0=fast, 6=slower-better)",
+			Value:       4,
+			Destination: &method,
+			Validator: func(v int) error {
+				if v < 0 || v > 6 {
+					return fmt.Errorf("invalid webp.method: %d (must be 0-6)", v)
+				}
+
+				return nil
+			},
+		},
+		&cli.BoolFlag{
+			Name:        "webp.exact",
+			Usage:       "WebP: preserve exact RGB values in transparent areas",
+			Value:       false,
+			Destination: &exact,
+		},
+	)
+}
+
+func (impl) Sniff(rd io.ReaderAt) (int, []byte, error) {
+	buf := make([]byte, 12)
+
+	if _, err := rd.ReadAt(buf, 0); err != nil {
+		return 0, nil, err
+	}
+
+	if bytes.Equal(buf[0:4], []byte("RIFF")) && bytes.Equal(buf[8:12], []byte("WEBP")) {
+		return 100, buf[:12], nil
+	}
+
+	return 0, nil, nil
+}
+
+func (impl) Decode(reader io.Reader) (image.Image, error) {
+	return webp.Decode(reader)
+}
+
+func (impl) Encode(writer io.Writer, img image.Image, options opts.Common) error {
+	logx.Printf("webp: quality=%d lossless=%t method=%d exact=%t\n", options.Quality, options.Lossless, method, exact)
+
+	return webp.Encode(writer, img, webp.Options{
+		Quality:  options.Quality,
+		Lossless: options.Lossless,
+		Method:   method,
+		Exact:    exact,
+	})
+}