fix: manually query terminal for background color

This drops the dependency on `github.com/charmbracelet/x/input` and
`github.com/erikgeiser/coninput` by manually parsing the terminal
response to the background color query using `ansi`.

Since we moved `x/input` to Bubble Tea, and the code is no longer
maintained, we need a different approach to query the terminal for the
background color. This is basically doing the same thing as before, but
manually parsing the response instead of using the `x/input` package.

Fixes: charmbracelet/x#248
Supersedes: charmbracelet/x#249

go.mod

@@ -7,15 +7,14 @@ require (
 	github.com/charmbracelet/colorprofile v0.1.2
 	github.com/charmbracelet/x/ansi v0.4.2
 	github.com/charmbracelet/x/exp/golden v0.0.0-20240806155701-69247e0abc2a
-	github.com/charmbracelet/x/input v0.2.0
 	github.com/charmbracelet/x/term v0.2.0
 	github.com/lucasb-eyer/go-colorful v1.2.0
+	github.com/muesli/cancelreader v0.2.2
 	github.com/rivo/uniseg v0.4.7
 	golang.org/x/sys v0.24.0
 )
 
 require (
-	github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect
-	github.com/muesli/cancelreader v0.2.2 // indirect
 	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
+	golang.org/x/exp v0.0.0-20231006140011-7918f672742d // indirect
 )

go.sum

@@ -6,12 +6,8 @@ github.com/charmbracelet/x/ansi v0.4.2 h1:0JM6Aj/g/KC154/gOP4vfxun0ff6itogDYk41k
 github.com/charmbracelet/x/ansi v0.4.2/go.mod h1:dk73KoMTT5AX5BsX0KrqhsTqAnhZZoCBjs7dGWp4Ktw=
 github.com/charmbracelet/x/exp/golden v0.0.0-20240806155701-69247e0abc2a h1:G99klV19u0QnhiizODirwVksQB91TJKV/UaTnACcG30=
 github.com/charmbracelet/x/exp/golden v0.0.0-20240806155701-69247e0abc2a/go.mod h1:wDlXFlCrmJ8J+swcL/MnGUuYnqgQdW9rhSD61oNMb6U=
-github.com/charmbracelet/x/input v0.2.0 h1:1Sv+y/flcqUfUH2PXNIDKDIdT2G8smOnGOgawqhwy8A=
-github.com/charmbracelet/x/input v0.2.0/go.mod h1:KUSFIS6uQymtnr5lHVSOK9j8RvwTD4YHnWnzJUYnd/M=
 github.com/charmbracelet/x/term v0.2.0 h1:cNB9Ot9q8I711MyZ7myUR5HFWL/lc3OpU8jZ4hwm0x0=
 github.com/charmbracelet/x/term v0.2.0/go.mod h1:GVxgxAbjUrmpvIINHIQnJJKpMlHiZ4cktEQCN6GWyF0=
-github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f h1:Y/CXytFA4m6baUTXGLOoWe4PQhGxaX0KpnayAqC48p4=
-github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f/go.mod h1:vw97MGsxSvLiUE2X8qFplwetxpGLQrlU1Q9AUEIzCaM=
 github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
 github.com/muesli/cancelreader v0.2.2 h1:3I4Kt4BQjOR54NavqnDogx/MIoWBFa0StPA8ELUXHmA=
@@ -21,6 +17,6 @@ github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUc
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavMF/ppJZNG9ZpyihvCd0w101no=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e/go.mod h1:RbqR21r5mrJuqunuUZ/Dhy/avygyECGrLceyNeo4LiM=
 golang.org/x/exp v0.0.0-20231006140011-7918f672742d h1:jtJma62tbqLibJ5sFQz8bKtEM8rJBtfilJ2qTU199MI=
-golang.org/x/sys v0.0.0-20210809222454-d867a43fc93e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/exp v0.0.0-20231006140011-7918f672742d/go.mod h1:ldy0pHrwJyGW56pPQzzkH36rKxoZW1tw7ZJpeKx+hdo=
 golang.org/x/sys v0.24.0 h1:Twjiwq9dn6R1fQcyiK+wQyHWfaz/BJB+YIpzU/Cv3Xg=
 golang.org/x/sys v0.24.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

terminal.go

@@ -4,10 +4,13 @@ import (
 	"fmt"
 	"image/color"
 	"io"
+	"strconv"
+	"strings"
 	"time"
 
 	"github.com/charmbracelet/x/ansi"
-	"github.com/charmbracelet/x/input"
+	"github.com/charmbracelet/x/ansi/parser"
+	"github.com/muesli/cancelreader"
 )
 
 // queryBackgroundColor queries the terminal for the background color.
@@ -24,13 +27,20 @@ import (
 func queryBackgroundColor(in io.Reader, out io.Writer) (c color.Color, err error) {
 	//nolint: errcheck
 	err = queryTerminal(in, out, defaultQueryTimeout,
-		func(events []input.Event) bool {
-			for _, e := range events {
-				switch e := e.(type) {
-				case input.BackgroundColorEvent:
-					c = e.Color
-					continue // we need to consume the next DA1 event
-				case input.PrimaryDeviceAttributesEvent:
+		func(seq string, pa *ansi.Parser) bool {
+			switch {
+			case ansi.HasOscPrefix(seq):
+				switch pa.Cmd {
+				case 11: // OSC 11
+					parts := strings.Split(string(pa.Data[:pa.DataLen]), ";")
+					if len(parts) != 2 {
+						break // invalid, but we still need to parse the next sequence
+					}
+					c = xParseColor(parts[1])
+				}
+			case ansi.HasCsiPrefix(seq):
+				switch pa.Cmd {
+				case 'c' | '?'<<parser.MarkerShift: // DA1
 					return false
 				}
 			}
@@ -44,7 +54,7 @@ const defaultQueryTimeout = time.Second * 2
 // queryTerminalFilter is a function that filters input events using a type
 // switch. If false is returned, the QueryTerminal function will stop reading
 // input.
-type queryTerminalFilter func(events []input.Event) bool
+type queryTerminalFilter func(seq string, pa *ansi.Parser) bool
 
 // queryTerminal queries the terminal for support of various features and
 // returns a list of response events.
@@ -60,9 +70,9 @@ func queryTerminal(
 	filter queryTerminalFilter,
 	query string,
 ) error {
-	rd, err := input.NewDriver(in, "", 0)
+	rd, err := cancelreader.NewReader(in)
 	if err != nil {
-		return fmt.Errorf("could not create driver: %w", err)
+		return fmt.Errorf("could not create cancel reader: %w", err)
 	}
 
 	defer rd.Close() //nolint: errcheck
@@ -81,16 +91,63 @@ func queryTerminal(
 		return fmt.Errorf("could not write query: %w", err)
 	}
 
+	pa := ansi.GetParser()
+	defer ansi.PutParser(pa)
+
+	var buf [256]byte // 256 bytes should be enough for most responses
 	for {
-		events, err := rd.ReadEvents()
+		n, err := rd.Read(buf[:])
 		if err != nil {
-			return fmt.Errorf("could not read events: %s", err)
+			return fmt.Errorf("could not read from input: %w", err)
 		}
 
-		if !filter(events) {
-			break
+		var state byte
+		p := buf[:]
+		for n > 0 {
+			seq, _, read, newState := ansi.DecodeSequence(p[:n], state, pa)
+			if !filter(string(seq), pa) {
+				return nil
+			}
+
+			state = newState
+			n -= read
+			p = p[read:]
 		}
 	}
+}
+
+func shift(x uint64) uint64 {
+	if x > 0xff {
+		x >>= 8
+	}
+	return x
+}
 
+func xParseColor(s string) color.Color {
+	switch {
+	case strings.HasPrefix(s, "rgb:"):
+		parts := strings.Split(s[4:], "/")
+		if len(parts) != 3 {
+			return color.Black
+		}
+
+		r, _ := strconv.ParseUint(parts[0], 16, 32)
+		g, _ := strconv.ParseUint(parts[1], 16, 32)
+		b, _ := strconv.ParseUint(parts[2], 16, 32)
+
+		return color.RGBA{uint8(shift(r)), uint8(shift(g)), uint8(shift(b)), 255} //nolint:gosec
+	case strings.HasPrefix(s, "rgba:"):
+		parts := strings.Split(s[5:], "/")
+		if len(parts) != 4 {
+			return color.Black
+		}
+
+		r, _ := strconv.ParseUint(parts[0], 16, 32)
+		g, _ := strconv.ParseUint(parts[1], 16, 32)
+		b, _ := strconv.ParseUint(parts[2], 16, 32)
+		a, _ := strconv.ParseUint(parts[3], 16, 32)
+
+		return color.RGBA{uint8(shift(r)), uint8(shift(g)), uint8(shift(b)), uint8(shift(a))} //nolint:gosec
+	}
 	return nil
 }