Project refactor, add anthropic API support

- Split pkg/cli/cmd.go into new pkg/cmd package
- Split pkg/cli/functions.go into pkg/lmcli/tools package
- Refactor pkg/cli/openai.go to pkg/lmcli/provider/openai

Other changes:

- Made models configurable
- Slight config reorganization

pkg/lmcli/lmcli.go

@@ -0,0 +1,97 @@
+package lmcli
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"git.mlow.ca/mlow/lmcli/pkg/lmcli/provider"
+	"git.mlow.ca/mlow/lmcli/pkg/lmcli/provider/anthropic"
+	"git.mlow.ca/mlow/lmcli/pkg/lmcli/provider/openai"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+)
+
+type Context struct {
+	Config Config
+	Store  ConversationStore
+}
+
+func NewContext() (*Context, error) {
+	configFile := filepath.Join(configDir(), "config.yaml")
+	config, err := NewConfig(configFile)
+	if err != nil {
+		Fatal("%v\n", err)
+	}
+
+	databaseFile := filepath.Join(dataDir(), "conversations.db")
+	db, err := gorm.Open(sqlite.Open(databaseFile), &gorm.Config{})
+	if err != nil {
+		return nil, fmt.Errorf("Error establishing connection to store: %v", err)
+	}
+	s, err := NewSQLStore(db)
+	if err != nil {
+		Fatal("%v\n", err)
+	}
+
+	return &Context{*config, s}, nil
+}
+
+func (c *Context) GetCompletionProvider(model string) (provider.ChatCompletionClient, error) {
+	for _, m := range *c.Config.Anthropic.Models {
+		if m == model {
+			anthropic := &anthropic.AnthropicClient{
+				APIKey: *c.Config.Anthropic.APIKey,
+			}
+			return anthropic, nil
+		}
+	}
+	for _, m := range *c.Config.OpenAI.Models {
+		if m == model {
+			openai := &openai.OpenAIClient{
+				APIKey: *c.Config.OpenAI.APIKey,
+			}
+			return openai, nil
+		}
+	}
+	return nil, fmt.Errorf("unknown model: %s", model)
+}
+
+func configDir() string {
+	var configDir string
+
+	xdgConfigHome := os.Getenv("XDG_CONFIG_HOME")
+	if xdgConfigHome != "" {
+		configDir = filepath.Join(xdgConfigHome, "lmcli")
+	} else {
+		userHomeDir, _ := os.UserHomeDir()
+		configDir = filepath.Join(userHomeDir, ".config/lmcli")
+	}
+
+	os.MkdirAll(configDir, 0755)
+	return configDir
+}
+
+func dataDir() string {
+	var dataDir string
+
+	xdgDataHome := os.Getenv("XDG_DATA_HOME")
+	if xdgDataHome != "" {
+		dataDir = filepath.Join(xdgDataHome, "lmcli")
+	} else {
+		userHomeDir, _ := os.UserHomeDir()
+		dataDir = filepath.Join(userHomeDir, ".local/share/lmcli")
+	}
+
+	os.MkdirAll(dataDir, 0755)
+	return dataDir
+}
+
+func Fatal(format string, args ...any) {
+	fmt.Fprintf(os.Stderr, format, args...)
+	os.Exit(1)
+}
+
+func Warn(format string, args ...any) {
+	fmt.Fprintf(os.Stderr, format, args...)
+}