add dependency checker for whisper-cli and ffmpeg

internal/deps/deps.go

@@ -0,0 +1,64 @@
+package deps
+
+import (
+	"os/exec"
+	"strings"
+)
+
+// Status represents the installation status of a dependency
+type Status struct {
+	Installed bool
+	Path      string
+	Version   string
+}
+
+// CheckWhisperCli checks if whisper-cli is installed and returns its status
+func CheckWhisperCli() Status {
+	path, err := exec.LookPath("whisper-cli")
+	if err != nil {
+		return Status{Installed: false}
+	}
+
+	status := Status{
+		Installed: true,
+		Path:      path,
+	}
+
+	// try to get version - whisper-cli --version outputs version info
+	cmd := exec.Command(path, "--version")
+	output, err := cmd.Output()
+	if err == nil {
+		// parse first line as version
+		lines := strings.Split(string(output), "\n")
+		if len(lines) > 0 {
+			status.Version = strings.TrimSpace(lines[0])
+		}
+	}
+
+	return status
+}
+
+// CheckFFmpeg checks if ffmpeg is installed and returns its status
+func CheckFFmpeg() Status {
+	path, err := exec.LookPath("ffmpeg")
+	if err != nil {
+		return Status{Installed: false}
+	}
+
+	status := Status{
+		Installed: true,
+		Path:      path,
+	}
+
+	// ffmpeg -version outputs version info on first line
+	cmd := exec.Command(path, "-version")
+	output, err := cmd.Output()
+	if err == nil {
+		lines := strings.Split(string(output), "\n")
+		if len(lines) > 0 {
+			status.Version = strings.TrimSpace(lines[0])
+		}
+	}
+
+	return status
+}

internal/deps/deps_test.go

@@ -0,0 +1,71 @@
+package deps
+
+import (
+	"os/exec"
+	"testing"
+)
+
+func TestCheckWhisperCli(t *testing.T) {
+	status := CheckWhisperCli()
+
+	// behavior depends on system - just verify no panic and correct structure
+	if status.Installed {
+		if status.Path == "" {
+			t.Error("installed but path empty")
+		}
+	} else {
+		if status.Path != "" {
+			t.Error("not installed but path non-empty")
+		}
+	}
+}
+
+func TestCheckWhisperCli_NotInstalled(t *testing.T) {
+	// if whisper-cli is not in PATH, should return Installed=false
+	_, err := exec.LookPath("whisper-cli")
+	if err != nil {
+		status := CheckWhisperCli()
+		if status.Installed {
+			t.Error("expected Installed=false when whisper-cli not in PATH")
+		}
+		if status.Path != "" {
+			t.Error("expected empty path when not installed")
+		}
+	} else {
+		t.Skip("whisper-cli is installed, can't test not-installed case")
+	}
+}
+
+func TestCheckFFmpeg(t *testing.T) {
+	status := CheckFFmpeg()
+
+	if status.Installed {
+		if status.Path == "" {
+			t.Error("installed but path empty")
+		}
+	} else {
+		if status.Path != "" {
+			t.Error("not installed but path non-empty")
+		}
+	}
+}
+
+func TestCheckFFmpeg_Installed(t *testing.T) {
+	// ffmpeg is commonly installed - test if available
+	_, err := exec.LookPath("ffmpeg")
+	if err == nil {
+		status := CheckFFmpeg()
+		if !status.Installed {
+			t.Error("ffmpeg in PATH but Installed=false")
+		}
+		if status.Path == "" {
+			t.Error("ffmpeg installed but path empty")
+		}
+		// version should be populated
+		if status.Version == "" {
+			t.Error("ffmpeg installed but version empty")
+		}
+	} else {
+		t.Skip("ffmpeg not installed, can't test installed case")
+	}
+}

progress.txt

@@ -158,4 +158,12 @@ Started: Sun Feb  1 12:22:47 AM CET 2026
   - `TestNewTranscriber/unknown_model_returns_error` - returns error for unknown model
   - `TestNewTranscriber/streaming_model_returns_error` - returns error for streaming model
 - `go test ./internal/transcriber/...` passes
-- Typecheck passes
+- Typecheck passes
+
+### Task 18: Create dependency checker for whisper-cli
+- Created `internal/deps/deps.go`
+- Status struct: Installed bool, Path string, Version string
+- CheckWhisperCli() uses exec.LookPath, tries --version (whisper-cli doesn't support it, but handles gracefully)
+- CheckFFmpeg() same pattern, version extraction works
+- Both return Installed=false when binary not found, no errors thrown
+- All tests passing, typecheck passes

tasks/prd.jsonc

@@ -432,7 +432,7 @@
 				"No errors thrown, just returns status",
 				"Typecheck passes"
 			],
-			"passes": false
+			"passes": true
 		},
 		{
 			"title": "Create whisper model info and download management",