tiding up

2 files changed, 523 insertions, 30 deletions

diff --git a/cmd/internal/hexai-action/main.go b/cmd/internal/hexai-action/main.go
index 8bcc3cd..b8ba524 100644
--- a/cmd/internal/hexai-action/main.go
+++ b/cmd/internal/hexai-action/main.go
@@ -6,24 +6,62 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"path/filepath"
+	"time"
 
 	"codeberg.org/snonux/hexai/internal/hexaiaction"
+	"codeberg.org/snonux/hexai/internal/tmux"
+	"golang.org/x/term"
 )
 
 func main() {
 	infile := flag.String("infile", "", "Read input from this file instead of stdin")
 	outfile := flag.String("outfile", "", "Write output to this file instead of stdout")
+	// Tmux/UI flags
+	forceTmux := flag.Bool("tmux", false, "Force running the UI in a tmux split-pane (auto if not set)")
+	noTmux := flag.Bool("no-tmux", false, "Disable tmux mode even if available")
+	uiChild := flag.Bool("ui-child", false, "INTERNAL: run interactive UI and write to -outfile atomically")
+	tmuxTarget := flag.String("tmux-target", "", "tmux split target (advanced)")
+	tmuxSplit := flag.String("tmux-split", "v", "tmux split orientation: v or h")
+	tmuxPercent := flag.Int("tmux-percent", 33, "tmux split size percentage (1-100)")
 	flag.Parse()
 
-	in, out, closeIn, closeOut, err := openIO(*infile, *outfile)
-	if err != nil {
-		fmt.Fprintln(os.Stderr, err)
-		os.Exit(1)
+	// Child mode: run TUI and write atomically to -outfile
+	if *uiChild {
+		if err := runChild(*infile, *outfile); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		return
+	}
+
+	// Parent mode: decide inline vs tmux
+	if shouldRunInTmux(*forceTmux, *noTmux) {
+		if err := runInTmuxParent(*tmuxTarget, *tmuxSplit, *tmuxPercent); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		return
 	}
-	defer closeIn()
-	defer closeOut()
 
-	if err := hexaiaction.Run(context.Background(), in, out, os.Stderr); err != nil {
+	// Inline path: only if we have a TTY for UI; otherwise echo input
+	if isTTY(os.Stdout.Fd()) && isTTY(os.Stdin.Fd()) {
+		in, out, closeIn, closeOut, err := openIO(*infile, *outfile)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		defer closeIn()
+		defer closeOut()
+        if err := hexaiactionRun(context.Background(), in, out, os.Stderr); err != nil {
+            fmt.Fprintln(os.Stderr, err)
+            os.Exit(1)
+        }
+        return
+    }
+
+	// Fallback: no TTY and tmux not available; echo input to output
+	if err := echoThrough(*infile, *outfile); err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
 	}
@@ -54,3 +92,147 @@ func openIO(infile, outfile string) (io.Reader, io.Writer, func(), func(), error
 	}
 	return in, out, closeIn, closeOut, nil
 }
+
+// runChild runs the interactive flow and writes the final output atomically to outfile.
+var hexaiactionRun = hexaiaction.Run
+
+func runChild(infile, outfile string) error {
+	if outfile == "" {
+		// No atomic handoff needed; just run normally to stdout
+		in, out, closeIn, closeOut, err := openIO(infile, "")
+		if err != nil {
+			return err
+		}
+		defer closeIn()
+		defer closeOut()
+        return hexaiactionRun(context.Background(), in, out, os.Stderr)
+	}
+	tmp := outfile + ".tmp"
+	in, out, closeIn, closeOut, err := openIO(infile, tmp)
+	if err != nil {
+		return err
+	}
+	defer closeIn()
+    if err := hexaiactionRun(context.Background(), in, out, os.Stderr); err != nil {
+        // On error, try to echo input to tmp to avoid blocking
+        closeOut()
+        if copyErr := echoThrough(infile, tmp); copyErr != nil {
+            return fmt.Errorf("hexai-action child: %v; echo failed: %v", err, copyErr)
+        }
+	} else {
+		closeOut()
+	}
+	return os.Rename(tmp, outfile)
+}
+
+var isTTYFn = isTTY
+var tmuxAvailableFn = tmux.Available
+var splitRunFn = tmux.SplitRun
+var osExecutableFn = os.Executable
+
+func shouldRunInTmux(forceTmux, noTmux bool) bool {
+	if noTmux {
+		return false
+	}
+	if forceTmux {
+		return true
+	}
+	// Auto: prefer tmux when stdio are not TTYs (Helix :pipe scenario)
+    if !(isTTYFn(os.Stdin.Fd()) && isTTYFn(os.Stdout.Fd())) && tmuxAvailableFn() {
+        return true
+    }
+	return false
+}
+
+func isTTY(fd uintptr) bool { return term.IsTerminal(int(fd)) }
+
+func runInTmuxParent(target, split string, percent int) error {
+	// Prepare temp files
+	dir, err := os.MkdirTemp("", "hexai-action-")
+	if err != nil {
+		return err
+	}
+	defer func() { _ = os.RemoveAll(dir) }()
+	inPath := filepath.Join(dir, "input.txt")
+	outPath := filepath.Join(dir, "reply.txt")
+	// Read stdin and persist to inPath
+	if err := persistStdin(inPath); err != nil {
+		return err
+	}
+	// Build child argv
+	exe, err := osExecutableFn()
+	if err != nil {
+		return err
+	}
+	argv := []string{exe, "-ui-child", "-infile", inPath, "-outfile", outPath}
+	// Spawn tmux split
+	opts := tmux.SplitOpts{Target: target, Vertical: split != "h", Percent: percent}
+	if err := splitRunFn(opts, argv); err != nil {
+		return err
+	}
+	// Wait for outfile to appear
+	if err := waitForFile(outPath, 60*time.Second); err != nil {
+		return err
+	}
+	// Print to stdout
+	return catFileToStdout(outPath)
+}
+
+func persistStdin(path string) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = f.Close() }()
+	if _, err := io.Copy(f, os.Stdin); err != nil {
+		return err
+	}
+	return f.Sync()
+}
+
+func waitForFile(path string, timeout time.Duration) error {
+	deadline := time.Now().Add(timeout)
+	for {
+		if _, err := os.Stat(path); err == nil {
+			return nil
+		}
+		if time.Now().After(deadline) {
+			return fmt.Errorf("hexai-action: timeout waiting for reply file")
+		}
+		time.Sleep(200 * time.Millisecond)
+	}
+}
+
+func catFileToStdout(path string) error {
+	f, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = f.Close() }()
+	_, err = io.Copy(os.Stdout, f)
+	return err
+}
+
+func echoThrough(infile, outfile string) error {
+	// Read from infile or stdin and write to outfile or stdout
+	var in io.Reader = os.Stdin
+	var out io.Writer = os.Stdout
+	if infile != "" {
+		f, err := os.Open(infile)
+		if err != nil {
+			return err
+		}
+		defer func() { _ = f.Close() }()
+		in = f
+	}
+	if outfile != "" {
+		f, err := os.Create(outfile)
+		if err != nil {
+			return err
+		}
+		defer func() { _ = f.Close() }()
+		out = f
+	}
+	_, err := io.Copy(out, in)
+	return err
+}
diff --git a/cmd/internal/hexai-action/main_test.go b/cmd/internal/hexai-action/main_test.go
index 9603826..16bb2ed 100644
--- a/cmd/internal/hexai-action/main_test.go
+++ b/cmd/internal/hexai-action/main_test.go
@@ -1,44 +1,355 @@
 package main
 
 import (
+    "context"
+    "fmt"
     "io"
     "os"
     "path/filepath"
+    "strings"
     "testing"
+
+    "codeberg.org/snonux/hexai/internal/tmux"
 )
 
-// TestOpenIO_InOutFiles verifies that openIO opens the specified files
-// and that writing via the returned writer persists to disk.
-func TestOpenIO_InOutFiles(t *testing.T) {
+func TestShouldRunInTmux_Preferences(t *testing.T) {
+    // no-tmux overrides
+    if shouldRunInTmux(false, true) {
+        t.Fatal("expected false when no-tmux is set")
+    }
+    // force tmux overrides
+    if !shouldRunInTmux(true, false) {
+        t.Fatal("expected true when -tmux is set")
+    }
+}
+
+func TestShouldRunInTmux_Auto(t *testing.T) {
+    oldIsTTY := isTTYFn
+    oldAvail := tmuxAvailableFn
+    t.Cleanup(func() { isTTYFn = oldIsTTY; tmuxAvailableFn = oldAvail })
+    // Simulate Helix :pipe (no TTY) and tmux available
+    isTTYFn = func(_ uintptr) bool { return false }
+    tmuxAvailableFn = func() bool { return true }
+    if !shouldRunInTmux(false, false) {
+        t.Fatal("expected true when not TTY and tmux available")
+    }
+    // Simulate TTY present: prefer inline
+    isTTYFn = func(_ uintptr) bool { return true }
+    if shouldRunInTmux(false, false) {
+        t.Fatal("expected false when TTY present")
+    }
+    // Simulate tmux not available
+    isTTYFn = func(_ uintptr) bool { return false }
+    tmuxAvailableFn = func() bool { return false }
+    if shouldRunInTmux(false, false) {
+        t.Fatal("expected false when tmux unavailable")
+    }
+}
+
+func TestPersistStdin_WritesFile(t *testing.T) {
+    dir := t.TempDir()
+    path := filepath.Join(dir, "in.txt")
+    // Point os.Stdin to a temp file with content
+    src := filepath.Join(dir, "src.txt")
+    if err := os.WriteFile(src, []byte("hello world"), 0o600); err != nil {
+        t.Fatalf("write src: %v", err)
+    }
+    f, err := os.Open(src)
+    if err != nil { t.Fatalf("open src: %v", err) }
+    old := os.Stdin
+    os.Stdin = f
+    t.Cleanup(func() { os.Stdin = old; _ = f.Close() })
+    if err := persistStdin(path); err != nil {
+        t.Fatalf("persistStdin error: %v", err)
+    }
+    b, err := os.ReadFile(path)
+    if err != nil { t.Fatalf("read out: %v", err) }
+    if string(b) != "hello world" {
+        t.Fatalf("unexpected content %q", string(b))
+    }
+}
+
+func TestEchoThrough(t *testing.T) {
+    dir := t.TempDir()
+    in := filepath.Join(dir, "in.txt")
+    out := filepath.Join(dir, "out.txt")
+    if err := os.WriteFile(in, []byte("hello"), 0o600); err != nil {
+        t.Fatalf("write in: %v", err)
+    }
+    if err := echoThrough(in, out); err != nil {
+        t.Fatalf("echoThrough: %v", err)
+    }
+    b, _ := os.ReadFile(out)
+    if string(b) != "hello" {
+        t.Fatalf("unexpected: %q", string(b))
+    }
+}
+
+func TestEchoThrough_StdinStdout(t *testing.T) {
+    // set stdin
+    rIn, wIn, _ := os.Pipe()
+    _, _ = wIn.Write([]byte("PIPE"))
+    _ = wIn.Close()
+    oldIn := os.Stdin
+    os.Stdin = rIn
+    defer func() { os.Stdin = oldIn; _ = rIn.Close() }()
+    // capture stdout
+    r, w, _ := os.Pipe()
+    oldOut := os.Stdout
+    os.Stdout = w
+    defer func() { os.Stdout = oldOut; _ = r.Close(); _ = w.Close() }()
+    if err := echoThrough("", ""); err != nil { t.Fatalf("echoThrough: %v", err) }
+    _ = w.Close()
+    data, _ := io.ReadAll(r)
+    if string(data) != "PIPE" {
+        t.Fatalf("stdout: %q", string(data))
+    }
+}
+
+func TestWaitForFile(t *testing.T) {
     dir := t.TempDir()
-    inPath := filepath.Join(dir, "in.txt")
-    outPath := filepath.Join(dir, "out.txt")
+    p := filepath.Join(dir, "x")
+    go func() {
+        // create shortly after
+        f, _ := os.Create(p)
+        defer f.Close()
+        f.WriteString("ok")
+    }()
+    if err := waitForFile(p, 2_000_000_000); err != nil { // 2s
+        t.Fatalf("waitForFile: %v", err)
+    }
+}
 
-    // Prepare input file
-    want := "hello world"
-    if err := os.WriteFile(inPath, []byte(want), 0o600); err != nil {
-        t.Fatalf("write infile: %v", err)
+func TestCatFileToStdout(t *testing.T) {
+    dir := t.TempDir()
+    p := filepath.Join(dir, "f")
+    if err := os.WriteFile(p, []byte("abc"), 0o600); err != nil {
+        t.Fatalf("write: %v", err)
+    }
+    // capture stdout
+    old := os.Stdout
+    r, w, _ := os.Pipe()
+    os.Stdout = w
+    defer func() { os.Stdout = old; _ = r.Close(); _ = w.Close() }()
+    if err := catFileToStdout(p); err != nil {
+        t.Fatalf("catFileToStdout: %v", err)
+    }
+    _ = w.Close()
+    buf, _ := io.ReadAll(r)
+    if string(buf) != "abc" {
+        t.Fatalf("stdout = %q", string(buf))
     }
+}
+
+func TestRunInTmuxParent_Stubbed(t *testing.T) {
+    dir := t.TempDir()
+    // set stdin content
+    src := filepath.Join(dir, "stdin.txt")
+    _ = os.WriteFile(src, []byte("input"), 0o600)
+    f, _ := os.Open(src)
+    oldStdin := os.Stdin
+    os.Stdin = f
+    defer func() { os.Stdin = oldStdin; _ = f.Close() }()
 
-    in, out, cin, cout, err := openIO(inPath, outPath)
-    if err != nil {
-        t.Fatalf("openIO: %v", err)
+    // capture stdout
+    oldStdout := os.Stdout
+    r, w, _ := os.Pipe()
+    os.Stdout = w
+    defer func() { os.Stdout = oldStdout; _ = r.Close(); _ = w.Close() }()
+
+    // stub seams
+    oldExec := osExecutableFn
+    oldSplit := splitRunFn
+    oldRun := hexaiactionRun
+    osExecutableFn = func() (string, error) { return "/bin/hexai-action", nil }
+    splitRunFn = func(opts tmux.SplitOpts, argv []string) error {
+        // find -outfile path and write content to simulate child
+        for i := 0; i < len(argv)-1; i++ {
+            if argv[i] == "-outfile" && i+1 < len(argv) {
+                _ = os.WriteFile(argv[i+1], []byte("OUT:"+strings.Join(argv, ",")), 0o600)
+                break
+            }
+        }
+        return nil
+    }
+    // Ensure child mode won't try to run the real TUI if invoked in tests.
+    hexaiactionRun = func(_ context.Context, _ io.Reader, w io.Writer, _ io.Writer) error {
+        _, _ = io.WriteString(w, "child-stub")
+        return nil
     }
-    defer cin()
-    defer cout()
+    defer func() { osExecutableFn = oldExec; splitRunFn = oldSplit; hexaiactionRun = oldRun }()
 
-    // Copy through to simulate main's behavior
-    if _, err := io.Copy(out.(io.Writer), in); err != nil {
-        t.Fatalf("copy: %v", err)
+    if err := runInTmuxParent("", "v", 33); err != nil {
+        t.Fatalf("runInTmuxParent: %v", err)
     }
+    _ = w.Close()
+    got, _ := io.ReadAll(r)
+    if !strings.HasPrefix(string(got), "OUT:") {
+        t.Fatalf("unexpected stdout: %q", string(got))
+    }
+}
 
-    // Verify outfile content
-    got, err := os.ReadFile(outPath)
-    if err != nil {
-        t.Fatalf("read outfile: %v", err)
+func TestRunChild_StubbedOutfile(t *testing.T) {
+    dir := t.TempDir()
+    in := filepath.Join(dir, "in.txt")
+    out := filepath.Join(dir, "out.txt")
+    _ = os.WriteFile(in, []byte("sel"), 0o600)
+    old := hexaiactionRun
+    hexaiactionRun = func(_ context.Context, _ io.Reader, w io.Writer, _ io.Writer) error {
+        _, _ = io.WriteString(w, "RESULT")
+        return nil
     }
-    if string(got) != want {
-        t.Fatalf("mismatch: got %q want %q", string(got), want)
+    defer func() { hexaiactionRun = old }()
+    if err := runChild(in, out); err != nil {
+        t.Fatalf("runChild: %v", err)
+    }
+    b, _ := os.ReadFile(out)
+    if string(b) != "RESULT" {
+        t.Fatalf("unexpected outfile: %q", string(b))
     }
 }
 
+func TestRunChild_StubbedStdout(t *testing.T) {
+    dir := t.TempDir()
+    in := filepath.Join(dir, "in.txt")
+    _ = os.WriteFile(in, []byte("sel"), 0o600)
+    // capture stdout
+    oldStdout := os.Stdout
+    r, w, _ := os.Pipe()
+    os.Stdout = w
+    defer func() { os.Stdout = oldStdout; _ = r.Close(); _ = w.Close() }()
+    old := hexaiactionRun
+    hexaiactionRun = func(_ context.Context, _ io.Reader, w io.Writer, _ io.Writer) error {
+        _, _ = io.WriteString(w, "STDOUT-RESULT")
+        return nil
+    }
+    defer func() { hexaiactionRun = old }()
+    if err := runChild(in, ""); err != nil {
+        t.Fatalf("runChild: %v", err)
+    }
+    _ = w.Close()
+    data, _ := io.ReadAll(r)
+    if string(data) != "STDOUT-RESULT" {
+        t.Fatalf("stdout: %q", string(data))
+    }
+}
+
+func TestRunChild_ErrorFallback(t *testing.T) {
+    dir := t.TempDir()
+    in := filepath.Join(dir, "in.txt")
+    out := filepath.Join(dir, "out.txt")
+    _ = os.WriteFile(in, []byte("INPUT"), 0o600)
+    old := hexaiactionRun
+    hexaiactionRun = func(_ context.Context, _ io.Reader, _ io.Writer, _ io.Writer) error {
+        return fmt.Errorf("boom")
+    }
+    defer func() { hexaiactionRun = old }()
+    if err := runChild(in, out); err != nil {
+        t.Fatalf("runChild: %v", err)
+    }
+    b, _ := os.ReadFile(out)
+    if string(b) != "INPUT" {
+        t.Fatalf("expected fallback echo, got %q", string(b))
+    }
+}
+
+func TestWaitForFile_Timeout(t *testing.T) {
+    dir := t.TempDir()
+    p := filepath.Join(dir, "nope")
+    if err := waitForFile(p, 10_000_000); err == nil { // 10ms
+        t.Fatal("expected timeout error")
+    }
+}
+
+func TestOpenIO_InfileOutfile(t *testing.T) {
+    dir := t.TempDir()
+    in := filepath.Join(dir, "i")
+    out := filepath.Join(dir, "o")
+    _ = os.WriteFile(in, []byte("X"), 0o600)
+    r, w, ci, co, err := openIO(in, out)
+    if err != nil { t.Fatalf("openIO: %v", err) }
+    defer ci(); defer co()
+    if _, err := io.Copy(w, r); err != nil { t.Fatalf("copy: %v", err) }
+    b, _ := os.ReadFile(out)
+    if string(b) != "X" { t.Fatalf("got %q", string(b)) }
+}
+
+func TestRunInTmuxParent_ExecutableError(t *testing.T) {
+    old := osExecutableFn
+    osExecutableFn = func() (string, error) { return "", fmt.Errorf("no exe") }
+    defer func() { osExecutableFn = old }()
+    // set stdin content
+    r, w, _ := os.Pipe()
+    _, _ = w.Write([]byte("x"))
+    _ = w.Close()
+    oldIn := os.Stdin
+    os.Stdin = r
+    defer func() { os.Stdin = oldIn; _ = r.Close() }()
+    if err := runInTmuxParent("", "v", 33); err == nil {
+        t.Fatal("expected error from missing executable")
+    }
+}
+
+func TestRunInTmuxParent_SplitError(t *testing.T) {
+    oldExec := osExecutableFn
+    osExecutableFn = func() (string, error) { return "/bin/hexai-action", nil }
+    oldSplit := splitRunFn
+    splitRunFn = func(_ tmux.SplitOpts, _ []string) error { return fmt.Errorf("split failed") }
+    defer func() { osExecutableFn = oldExec; splitRunFn = oldSplit }()
+    // set stdin
+    r, w, _ := os.Pipe()
+    _, _ = w.Write([]byte("x"))
+    _ = w.Close()
+    oldIn := os.Stdin
+    os.Stdin = r
+    defer func() { os.Stdin = oldIn; _ = r.Close() }()
+    if err := runInTmuxParent("", "v", 33); err == nil {
+        t.Fatal("expected split error")
+    }
+}
+
+func TestEchoThrough_OutfileError(t *testing.T) {
+    dir := t.TempDir()
+    in := filepath.Join(dir, "i.txt")
+    _ = os.WriteFile(in, []byte("x"), 0o600)
+    // Outfile inside non-existent subdir -> Create should fail
+    out := filepath.Join(dir, "nope", "out.txt")
+    if err := echoThrough(in, out); err == nil {
+        t.Fatal("expected echoThrough outfile error")
+    }
+}
+
+func TestPersistStdin_Error(t *testing.T) {
+    // Parent directory missing -> Create should fail
+    dir := t.TempDir()
+    p := filepath.Join(dir, "missing", "x.txt")
+    // set stdin to something
+    r, w, _ := os.Pipe()
+    _, _ = w.Write([]byte("x"))
+    _ = w.Close()
+    old := os.Stdin
+    os.Stdin = r
+    defer func() { os.Stdin = old; _ = r.Close() }()
+    if err := persistStdin(p); err == nil {
+        t.Fatal("expected persistStdin error")
+    }
+}
+
+func TestCatFileToStdout_Error(t *testing.T) {
+    if err := catFileToStdout("/nonexistent/path/file.txt"); err == nil {
+        t.Fatal("expected error for missing file")
+    }
+}
+
+func TestOpenIO_Errors(t *testing.T) {
+    // Non-existent infile
+    if _, _, _, _, err := openIO("/definitely/missing/file.txt", ""); err == nil {
+        t.Fatal("expected infile error")
+    }
+    // Outfile in missing dir
+    dir := t.TempDir()
+    out := filepath.Join(dir, "nope", "x.txt")
+    if _, _, _, _, err := openIO("", out); err == nil {
+        t.Fatal("expected outfile error")
+    }
+}