feat: add download features to llm models

backend/internal/ai/ollama.go

@@ -7,31 +7,51 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"time"
 )
 
-type ollamaProvider struct {
+// OllamaModelInfo holds detailed info about an installed Ollama model.
+type OllamaModelInfo struct {
+	Name       string `json:"name"`
+	Size       int64  `json:"size"`
+	ModifiedAt string `json:"modified_at"`
+	Details    struct {
+		ParameterSize     string `json:"parameter_size"`
+		QuantizationLevel string `json:"quantization_level"`
+		Family            string `json:"family"`
+	} `json:"details"`
+}
+
+// OllamaProvider implements Provider for Ollama and also exposes model management operations.
+type OllamaProvider struct {
 	endpoint string
 	model    string
 	client   *http.Client
 }
 
-func newOllama(endpoint, model string) *ollamaProvider {
+func newOllama(endpoint, model string) *OllamaProvider {
 	if endpoint == "" {
 		endpoint = "http://ollama:11434"
 	}
 	if model == "" {
 		model = "llama3"
 	}
-	return &ollamaProvider{
+	return &OllamaProvider{
 		endpoint: endpoint,
 		model:    model,
 		client:   &http.Client{},
 	}
 }
 
-func (p *ollamaProvider) Name() string { return "ollama" }
+// NewOllamaManager creates an OllamaProvider for model management (pull/delete/list).
+func NewOllamaManager(endpoint string) *OllamaProvider {
+	return newOllama(endpoint, "")
+}
 
-func (p *ollamaProvider) Summarize(ctx context.Context, prompt string, opts GenOptions) (string, error) {
+
+func (p *OllamaProvider) Name() string { return "ollama" }
+
+func (p *OllamaProvider) Summarize(ctx context.Context, prompt string, opts GenOptions) (string, error) {
 	numCtx := 32768
 	if opts.NumCtx > 0 {
 		numCtx = opts.NumCtx
@@ -72,7 +92,19 @@ func (p *ollamaProvider) Summarize(ctx context.Context, prompt string, opts GenO
 	return result.Response, nil
 }
 
-func (p *ollamaProvider) ListModels(ctx context.Context) ([]string, error) {
+func (p *OllamaProvider) ListModels(ctx context.Context) ([]string, error) {
+	infos, err := p.ListModelsDetailed(ctx)
+	if err != nil {
+		return nil, err
+	}
+	names := make([]string, len(infos))
+	for i, m := range infos {
+		names[i] = m.Name
+	}
+	return names, nil
+}
+
+func (p *OllamaProvider) ListModelsDetailed(ctx context.Context) ([]OllamaModelInfo, error) {
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, p.endpoint+"/api/tags", nil)
 	if err != nil {
 		return nil, err
@@ -85,16 +117,52 @@ func (p *ollamaProvider) ListModels(ctx context.Context) ([]string, error) {
 
 	raw, _ := io.ReadAll(resp.Body)
 	var result struct {
-		Models []struct {
-			Name string `json:"name"`
-		} `json:"models"`
+		Models []OllamaModelInfo `json:"models"`
 	}
 	if err := json.Unmarshal(raw, &result); err != nil {
 		return nil, err
 	}
-	var models []string
-	for _, m := range result.Models {
-		models = append(models, m.Name)
-	}
-	return models, nil
+	return result.Models, nil
+}
+
+// PullModel pulls (downloads) a model from Ollama Hub. Blocks until complete.
+func (p *OllamaProvider) PullModel(ctx context.Context, name string) error {
+	body, _ := json.Marshal(map[string]interface{}{"name": name, "stream": false})
+	// Use a long-timeout client since model downloads can take many minutes
+	client := &http.Client{Timeout: 60 * time.Minute}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, p.endpoint+"/api/pull", bytes.NewReader(body))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	resp, err := client.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	raw, _ := io.ReadAll(resp.Body)
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("ollama pull error %d: %s", resp.StatusCode, raw)
+	}
+	return nil
+}
+
+// DeleteModel removes a model from local storage.
+func (p *OllamaProvider) DeleteModel(ctx context.Context, name string) error {
+	body, _ := json.Marshal(map[string]string{"name": name})
+	req, err := http.NewRequestWithContext(ctx, http.MethodDelete, p.endpoint+"/api/delete", bytes.NewReader(body))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	resp, err := p.client.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusNoContent {
+		raw, _ := io.ReadAll(resp.Body)
+		return fmt.Errorf("ollama delete error %d: %s", resp.StatusCode, raw)
+	}
+	return nil
 }