feat(llm): add Ollama provider + provider selection and CLI override; update README and logsv0.0.1

3 files changed, 165 insertions, 10 deletions

diff --git a/internal/llm/ollama.go b/internal/llm/ollama.go
new file mode 100644
index 0000000..495b5c2
--- /dev/null
+++ b/internal/llm/ollama.go
@@ -0,0 +1,124 @@
+package llm
+
+import (
+    "bytes"
+    "context"
+    "encoding/json"
+    "errors"
+    "fmt"
+    "net/http"
+    "os"
+    "strings"
+    "time"
+
+    "hexai/internal/logging"
+)
+
+// ollamaClient implements Client against a local Ollama server.
+type ollamaClient struct {
+    httpClient   *http.Client
+    baseURL      string
+    defaultModel string
+}
+
+func newOllamaFromEnv() Client {
+    // Prefer OLLAMA_BASE_URL, fall back to OLLAMA_HOST, then default.
+    base := strings.TrimSpace(os.Getenv("OLLAMA_BASE_URL"))
+    if base == "" {
+        base = strings.TrimSpace(os.Getenv("OLLAMA_HOST"))
+    }
+    if base == "" {
+        base = "http://localhost:11434"
+    }
+    model := strings.TrimSpace(os.Getenv("OLLAMA_MODEL"))
+    if model == "" {
+        model = "qwen2.5-coder:latest"
+    }
+    return &ollamaClient{
+        httpClient:   &http.Client{Timeout: 30 * time.Second},
+        baseURL:      strings.TrimRight(base, "/"),
+        defaultModel: model,
+    }
+}
+
+type ollamaChatRequest struct {
+    Model   string      `json:"model"`
+    Messages []oaMessage `json:"messages"`
+    Stream  bool        `json:"stream"`
+    Options any         `json:"options,omitempty"`
+}
+
+type ollamaChatResponse struct {
+    Message struct {
+        Role    string `json:"role"`
+        Content string `json:"content"`
+    } `json:"message"`
+    Done  bool   `json:"done"`
+    Error string `json:"error,omitempty"`
+}
+
+func (c *ollamaClient) Chat(ctx context.Context, messages []Message, opts ...RequestOption) (string, error) {
+    o := Options{Model: c.defaultModel}
+    for _, opt := range opts { opt(&o) }
+    if o.Model == "" { o.Model = c.defaultModel }
+
+    start := time.Now()
+    logging.Logf("llm/ollama ", "chat start model=%s temp=%.2f max_tokens=%d stop=%d messages=%d", o.Model, o.Temperature, o.MaxTokens, len(o.Stop), len(messages))
+    for i, m := range messages {
+        logging.Logf("llm/ollama ", "msg[%d] role=%s size=%d preview=%s%s%s", i, m.Role, len(m.Content), logging.AnsiCyan, logging.PreviewForLog(m.Content), logging.AnsiBase)
+    }
+
+    req := ollamaChatRequest{Model: o.Model, Stream: false}
+    req.Messages = make([]oaMessage, len(messages))
+    for i, m := range messages { req.Messages[i] = oaMessage{Role: m.Role, Content: m.Content} }
+
+    // Build options map only if any option is set
+    optsMap := map[string]any{}
+    if o.Temperature != 0 { optsMap["temperature"] = o.Temperature }
+    if o.MaxTokens > 0 { optsMap["num_predict"] = o.MaxTokens }
+    if len(o.Stop) > 0 { optsMap["stop"] = o.Stop }
+    if len(optsMap) > 0 { req.Options = optsMap }
+
+    body, err := json.Marshal(req)
+    if err != nil { return "", err }
+
+    endpoint := c.baseURL + "/api/chat"
+    logging.Logf("llm/ollama ", "POST %s", endpoint)
+    httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, bytes.NewReader(body))
+    if err != nil { return "", err }
+    httpReq.Header.Set("Content-Type", "application/json")
+
+    resp, err := c.httpClient.Do(httpReq)
+    if err != nil {
+        logging.Logf("llm/ollama ", "%shttp error after %s: %v%s", logging.AnsiRed, time.Since(start), err, logging.AnsiBase)
+        return "", err
+    }
+    defer resp.Body.Close()
+    if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+        var apiErr ollamaChatResponse
+        _ = json.NewDecoder(resp.Body).Decode(&apiErr)
+        if strings.TrimSpace(apiErr.Error) != "" {
+            logging.Logf("llm/ollama ", "%sapi error status=%d msg=%s duration=%s%s", logging.AnsiRed, resp.StatusCode, apiErr.Error, time.Since(start), logging.AnsiBase)
+            return "", fmt.Errorf("ollama error: %s (status %d)", apiErr.Error, resp.StatusCode)
+        }
+        logging.Logf("llm/ollama ", "%shttp non-2xx status=%d duration=%s%s", logging.AnsiRed, resp.StatusCode, time.Since(start), logging.AnsiBase)
+        return "", fmt.Errorf("ollama http error: status %d", resp.StatusCode)
+    }
+
+    var out ollamaChatResponse
+    if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
+        logging.Logf("llm/ollama ", "%sdecode error after %s: %v%s", logging.AnsiRed, time.Since(start), err, logging.AnsiBase)
+        return "", err
+    }
+    if strings.TrimSpace(out.Message.Content) == "" {
+        logging.Logf("llm/ollama ", "%sempty content returned duration=%s%s", logging.AnsiRed, time.Since(start), logging.AnsiBase)
+        return "", errors.New("ollama: empty content")
+    }
+    content := out.Message.Content
+    logging.Logf("llm/ollama ", "success size=%d preview=%s%s%s duration=%s", len(content), logging.AnsiGreen, logging.PreviewForLog(content), logging.AnsiBase, time.Since(start))
+    return content, nil
+}
+
+// Provider metadata
+func (c *ollamaClient) Name() string         { return "ollama" }
+func (c *ollamaClient) DefaultModel() string { return c.defaultModel }
diff --git a/internal/llm/openai.go b/internal/llm/openai.go
index 279eca4..dbcee4d 100644
--- a/internal/llm/openai.go
+++ b/internal/llm/openai.go
@@ -15,10 +15,10 @@ import (
 
 // openAIClient implements Client against OpenAI's Chat Completions API.
 type openAIClient struct {
-	httpClient   *http.Client
-	apiKey       string
-	baseURL      string
-	defaultModel string
+    httpClient   *http.Client
+    apiKey       string
+    baseURL      string
+    defaultModel string
 }
 
 // Colors and base styling are provided by logging.go
@@ -159,3 +159,7 @@ func trimPreview(s string, n int) string {
 	}
 	return s[:n] + "…"
 }
+
+// Provider metadata
+func (c *openAIClient) Name() string          { return "openai" }
+func (c *openAIClient) DefaultModel() string  { return c.defaultModel }
diff --git a/internal/llm/provider.go b/internal/llm/provider.go
index a87d815..f7dad31 100644
--- a/internal/llm/provider.go
+++ b/internal/llm/provider.go
@@ -3,7 +3,8 @@ package llm
 import (
     "context"
     "errors"
-        "os"
+    "os"
+    "strings"
 )
 
 // Message represents a chat-style prompt message.
@@ -17,6 +18,10 @@ type Message struct {
 type Client interface {
     // Chat sends chat messages and returns the assistant text.
     Chat(ctx context.Context, messages []Message, opts ...RequestOption) (string, error)
+    // Name returns the provider's short name (e.g., "openai", "ollama").
+    Name() string
+    // DefaultModel returns the configured default model name.
+    DefaultModel() string
 }
 
 // Options for a request. Providers may ignore unsupported fields.
@@ -38,11 +43,33 @@ func WithStop(stop ...string) RequestOption {
 }
 
 // NewDefault returns the default provider using environment configuration.
-// Currently this is the OpenAI provider using OPENAI_API_KEY.
+// Selection order:
+// 1) HEXAI_LLM_PROVIDER=openai|ollama
+// 2) If OPENAI_API_KEY is set -> OpenAI
+// 3) If any OLLAMA_* vars are set -> Ollama
 func NewDefault() (Client, error) {
-    apiKey := os.Getenv("OPENAI_API_KEY")
-    if apiKey == "" {
-        return nil, errors.New("OPENAI_API_KEY is not set")
+    // Explicit provider selection
+    if p := strings.ToLower(strings.TrimSpace(os.Getenv("HEXAI_LLM_PROVIDER"))); p != "" {
+        switch p {
+        case "openai":
+            apiKey := os.Getenv("OPENAI_API_KEY")
+            if apiKey == "" {
+                return nil, errors.New("OPENAI_API_KEY is not set")
+            }
+            return newOpenAIFromEnv(apiKey), nil
+        case "ollama":
+            return newOllamaFromEnv(), nil
+        default:
+            return nil, errors.New("unknown HEXAI_LLM_PROVIDER: " + p)
+        }
     }
-    return newOpenAIFromEnv(apiKey), nil
+
+    // Auto-detect
+    if apiKey := os.Getenv("OPENAI_API_KEY"); apiKey != "" {
+        return newOpenAIFromEnv(apiKey), nil
+    }
+    if os.Getenv("OLLAMA_BASE_URL") != "" || os.Getenv("OLLAMA_HOST") != "" || os.Getenv("OLLAMA_MODEL") != "" {
+        return newOllamaFromEnv(), nil
+    }
+    return nil, errors.New("no LLM provider configured (set OPENAI_API_KEY or HEXAI_LLM_PROVIDER/OLLAMA_*)")
 }