reugn · reugn · Oct 23, 2024 · Oct 23, 2024
diff --git a/README.md b/README.md
@@ -37,11 +37,12 @@ If you don't already have one, create a key in [Google AI Studio](https://makers
 The system chat message must begin with an exclamation mark and is used for internal operations.
 A short list of supported system commands:
 
-| Command | Description
-| ---     | ---
-| !q      | Quit the application
-| !p      | Delete the history used as chat context by the model
-| !m      | Toggle input mode (single-line <-> multi-line)
+| Command | Description                                          |
+|---------|------------------------------------------------------|
+| !q      | Quit the application                                 |
+| !p      | Delete the history used as chat context by the model |
+| !i      | Toggle input mode (single-line <-> multi-line)       |
+| !m      | Select generative model                              |
 
 ### CLI help
 ```console
@@ -54,7 +55,8 @@ Usage:
 Flags:
   -f, --format         render markdown-formatted response (default true)
   -h, --help           help for this command
-  -m, --multiline      read input as a multi-line string
+  -m, --model string   generative model name (default "gemini-pro")
+      --multiline      read input as a multi-line string
   -s, --style string   markdown format style (ascii, dark, light, pink, notty, dracula) (default "auto")
   -t, --term string    multi-line input terminator (default "$")
   -v, --version        version for this command

diff --git a/cmd/gemini/main.go b/cmd/gemini/main.go
@@ -22,15 +22,16 @@ func run() int {
 	}
 
 	var opts cli.ChatOpts
+	rootCmd.Flags().StringVarP(&opts.Model, "model", "m", gemini.DefaultModel, "generative model name")
 	rootCmd.Flags().BoolVarP(&opts.Format, "format", "f", true, "render markdown-formatted response")
 	rootCmd.Flags().StringVarP(&opts.Style, "style", "s", "auto",
 		"markdown format style (ascii, dark, light, pink, notty, dracula)")
-	rootCmd.Flags().BoolVarP(&opts.Multiline, "multiline", "m", false, "read input as a multi-line string")
+	rootCmd.Flags().BoolVar(&opts.Multiline, "multiline", false, "read input as a multi-line string")
 	rootCmd.Flags().StringVarP(&opts.Terminator, "term", "t", "$", "multi-line input terminator")
 
 	rootCmd.RunE = func(_ *cobra.Command, _ []string) error {
 		apiKey := os.Getenv(apiKeyEnv)
-		chatSession, err := gemini.NewChatSession(context.Background(), apiKey)
+		chatSession, err := gemini.NewChatSession(context.Background(), opts.Model, apiKey)
 		if err != nil {
 			return err
 		}

diff --git a/gemini/chat_session.go b/gemini/chat_session.go
@@ -2,28 +2,36 @@ package gemini
 
 import (
 	"context"
+	"sync"
 
 	"github.com/google/generative-ai-go/genai"
 	"google.golang.org/api/option"
 )
 
-// ChatSession represents a gemini-pro powered chat session.
+const DefaultModel = "gemini-pro"
+
+// ChatSession represents a gemini powered chat session.
 type ChatSession struct {
-	ctx     context.Context
+	ctx context.Context
+
 	client  *genai.Client
 	session *genai.ChatSession
+
+	loadModels sync.Once
+	models     []string
 }
 
-// NewChatSession returns a new ChatSession.
-func NewChatSession(ctx context.Context, apiKey string) (*ChatSession, error) {
+// NewChatSession returns a new [ChatSession].
+func NewChatSession(ctx context.Context, model, apiKey string) (*ChatSession, error) {
 	client, err := genai.NewClient(ctx, option.WithAPIKey(apiKey))
 	if err != nil {
 		return nil, err
 	}
+
 	return &ChatSession{
 		ctx:     ctx,
 		client:  client,
-		session: client.GenerativeModel("gemini-pro").StartChat(),
+		session: client.GenerativeModel(model).StartChat(),
 	}, nil
 }
 
@@ -37,12 +45,36 @@ func (c *ChatSession) SendMessageStream(input string) *genai.GenerateContentResp
 	return c.session.SendMessageStream(c.ctx, genai.Text(input))
 }
 
+// SetGenerativeModel sets the name of the generative model for the chat.
+// It preserves the history from the previous chat session.
+func (c *ChatSession) SetGenerativeModel(model string) {
+	history := c.session.History
+	c.session = c.client.GenerativeModel(model).StartChat()
+	c.session.History = history
+}
+
+// ListModels returns a list of the supported generative model names.
+func (c *ChatSession) ListModels() []string {
+	c.loadModels.Do(func() {
+		c.models = []string{DefaultModel}
+		iter := c.client.ListModels(c.ctx)
+		for {
+			modelInfo, err := iter.Next()
+			if err != nil {
+				break
+			}
+			c.models = append(c.models, modelInfo.Name)
+		}
+	})
+	return c.models
+}
+
 // ClearHistory clears chat history.
 func (c *ChatSession) ClearHistory() {
 	c.session.History = make([]*genai.Content, 0)
 }
 
-// Close closes the genai.Client.
+// Close closes the chat session.
 func (c *ChatSession) Close() error {
 	return c.client.Close()
 }
diff --git a/go.mod b/go.mod
@@ -6,6 +6,7 @@ require (
 	github.com/charmbracelet/glamour v0.7.0
 	github.com/chzyer/readline v1.5.1
 	github.com/google/generative-ai-go v0.18.0
+	github.com/manifoldco/promptui v0.9.0
 	github.com/muesli/termenv v0.15.2
 	github.com/spf13/cobra v1.8.1
 	google.golang.org/api v0.196.0

diff --git a/go.sum b/go.sum
@@ -25,10 +25,13 @@ github.com/aymerick/douceur v0.2.0/go.mod h1:wlT5vV2O3h55X9m7iVYN0TBM0NH/MmbLnd3
 github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
 github.com/charmbracelet/glamour v0.7.0 h1:2BtKGZ4iVJCDfMF229EzbeR1QRKLWztO9dMtjmqZSng=
 github.com/charmbracelet/glamour v0.7.0/go.mod h1:jUMh5MeihljJPQbJ/wf4ldw2+yBP59+ctV36jASy7ps=
+github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
 github.com/chzyer/logex v1.2.1 h1:XHDu3E6q+gdHgsdTPH6ImJMIp436vR6MPtH8gP05QzM=
 github.com/chzyer/logex v1.2.1/go.mod h1:JLbx6lG2kDbNRFnfkgvh4eRJRPX1QCoOIWomwysCBrQ=
+github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
 github.com/chzyer/readline v1.5.1 h1:upd/6fQk4src78LMRzh5vItIt361/o4uq553V8B5sGI=
 github.com/chzyer/readline v1.5.1/go.mod h1:Eh+b79XXUwfKfcPLepksvw2tcLE/Ct21YObkaSkeBlk=
+github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
 github.com/chzyer/test v1.0.0 h1:p3BQDXSxOhOG0P9z6/hGnII4LGiEPOYBhs8asl/fC04=
 github.com/chzyer/test v1.0.0/go.mod h1:2JlltgoNkt4TW/z9V/IzDdFaMTM2JPIi26O1pF38GC8=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
@@ -93,6 +96,8 @@ github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 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/manifoldco/promptui v0.9.0 h1:3V4HzJk1TtXW1MTZMP7mdlwbBpIinw3HztaIlYthEiA=
+github.com/manifoldco/promptui v0.9.0/go.mod h1:ka04sppxSGFAtxX0qhlYQjISsg9mR4GWtQEhdbn6Pgg=
 github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
 github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mattn/go-runewidth v0.0.9/go.mod h1:H031xJmbD/WCDINGzjvQ9THkh0rPKHF+m2gUSrubnMI=
@@ -169,6 +174,7 @@ golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
 golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20181122145206-62eef0e2fa9b/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

diff --git a/internal/cli/chat.go b/internal/cli/chat.go
@@ -11,6 +11,7 @@ import (
 
 // ChatOpts represents Chat configuration options.
 type ChatOpts struct {
+	Model      string
 	Format     bool
 	Style      string
 	Multiline  bool

diff --git a/internal/cli/command.go b/internal/cli/command.go
@@ -17,7 +17,8 @@ const (
 	systemCmdPrefix          = "!"
 	systemCmdQuit            = "!q"
 	systemCmdPurgeHistory    = "!p"
-	systemCmdToggleInputMode = "!m"
+	systemCmdSelectInputMode = "!i"
+	systemCmdSelectModel     = "!m"
 )
 
 type command interface {
@@ -44,18 +45,39 @@ func (c *systemCommand) run(message string) bool {
 	case systemCmdPurgeHistory:
 		c.chat.model.ClearHistory()
 		c.print("Cleared the chat history.")
-	case systemCmdToggleInputMode:
+	case systemCmdSelectInputMode:
+		multiline, err := selectInputMode(c.chat.opts.Multiline)
+		if err != nil {
+			c.error(err)
+			break
+		}
+		if multiline == c.chat.opts.Multiline {
+			c.printSelectedCurrent()
+			break
+		}
+		c.chat.opts.Multiline = multiline
 		if c.chat.opts.Multiline {
-			c.print("
F438
;Switched to single-line input mode.")
-			c.chat.reader.HistoryEnable()
-			c.chat.opts.Multiline = false
-		} else {
 			c.print("Switched to multi-line input mode.")
 			// disable history for multi-line messages since it is
 			// unusable for future requests
 			c.chat.reader.HistoryDisable()
-			c.chat.opts.Multiline = true
+		} else {
+			c.print("Switched to single-line input mode.")
+			c.chat.reader.HistoryEnable()
+		}
+	case systemCmdSelectModel:
+		model, err := selectModel(c.chat.opts.Model, c.chat.model.ListModels())
+		if err != nil {
+			c.error(err)
+			break
+		}
+		if model == c.chat.opts.Model {
+			c.printSelectedCurrent()
+			break
 		}
+		c.chat.opts.Model = model
+		c.chat.model.SetGenerativeModel(model)
+		c.print(fmt.Sprintf("Selected '%s' generative model.", model))
 	default:
 		c.print("Unknown system command.")
 	}
@@ -66,6 +88,14 @@ func (c *systemCommand) print(message string) {
 	fmt.Printf("%s%s\n", c.chat.prompt.cli, message)
 }
 
+func (c *systemCommand) printSelectedCurrent() {
+	fmt.Printf("%sThe selection is unchanged.\n", c.chat.prompt.cli)
+}
+
+func (c *systemCommand) error(err error) {
+	fmt.Printf(color.Red("%s%s\n"), c.chat.prompt.cli, err)
+}
+
 type geminiCommand struct {
 	chat    *Chat
 	spinner *spinner
@@ -104,7 +134,7 @@ func (c *geminiCommand) runBlocking(message string) {
 		var buf strings.Builder
 		for _, candidate := range response.Candidates {
 			for _, part := range candidate.Content.Parts {
-				buf.WriteString(fmt.Sprintf("%s", part))
+				fmt.Fprintf(&buf, "%s", part)
 			}
 		}
 		output, err := glamour.Render(buf.String(), c.chat.opts.Style)
@@ -138,6 +168,6 @@ func (c *geminiCommand) runStreaming(message string) {
 }
 
 func (c *geminiCommand) printFlush(message string) {
-	fmt.Fprintf(c.writer, "%s", message)
-	c.writer.Flush()
+	_, _ = c.writer.WriteString(message)
+	_ = c.writer.Flush()
 }
diff --git a/internal/cli/select.go b/internal/cli/select.go
@@ -0,0 +1,51 @@
+package cli
+
+import (
+	"slices"
+
+	"github.com/manifoldco/promptui"
+)
+
+var (
+	inputMode = []string{"single-line", "multi-line"}
+)
+
+// selectModel returns the selected generative model name.
+func selectModel(current string, models []string) (string, error) {
+	prompt := promptui.Select{
+		Label:        "Select generative model",
+		HideSelected: true,
+		Items:        models,
+		CursorPos:    slices.Index(models, current),
+	}
+
+	_, result, err := prompt.Run()
+	if err != nil {
+		return "", err
+	}
+
+	return result, nil
+}
+
+// selectInputMode returns true if multiline input is selected;
+// otherwise, it returns false.
+func selectInputMode(multiline bool) (bool, error) {
+	var cursorPos int
+	if multiline {
+		cursorPos = 1
+	}
+
+	prompt := promptui.Select{
+		Label:        "Select input mode",
+		HideSelected: true,
+		Items:        inputMode,
+		CursorPos:    cursorPos,
+	}
+
+	_, result, err := prompt.Run()
+	if err != nil {
+		return false, err
+	}
+
+	return result == inputMode[1], nil
+}