Add Ollama SDK with Core Functionality and Documentation

- Introduced the Ollama SDK, providing a comprehensive interface for interacting with Ollama AI models, including text generation, chat conversations, embeddings, and model management.
- Implemented core components such as Client, Config, and various request/response entities to facilitate API interactions.
- Added structured error handling with specific error types for improved clarity and debugging.
- Included a README and usage guide to assist developers in integrating the SDK into their applications, ensuring a smooth onboarding experience.
- Established a fluent API for chat interactions and streaming responses, enhancing usability and flexibility for developers.

pkg/ollama/config.go

@@ -0,0 +1,91 @@
+package ollama
+
+import (
+	"time"
+)
+
+// Config represents the configuration for the Ollama SDK
+type Config struct {
+	// BaseURL is the base URL of the Ollama API server
+	BaseURL string `env:"OLLAMA_BASE_URL" default:"http://localhost:11434"`
+
+	// Timeout is the timeout for HTTP requests
+	Timeout time.Duration `env:"OLLAMA_TIMEOUT" default:"300s"`
+
+	// RetryAttempts is the number of retry attempts for failed requests
+	RetryAttempts int `env:"OLLAMA_RETRY_ATTEMPTS" default:"3"`
+
+	// RetryDelay is the delay between retry attempts
+	RetryDelay time.Duration `env:"OLLAMA_RETRY_DELAY" default:"2s"`
+
+	// EnableLogging enables request/response logging
+	EnableLogging bool `env:"OLLAMA_ENABLE_LOGGING" default:"true"`
+
+	// UserAgent is the user agent string for HTTP requests
+	UserAgent string `env:"OLLAMA_USER_AGENT" default:"TenderManagement-OllamaSDK/1.0"`
+
+	// DefaultModel is the default model to use if none is specified
+	DefaultModel string `env:"OLLAMA_DEFAULT_MODEL" default:"llama2"`
+
+	// DefaultTemperature is the default temperature for text generation
+	DefaultTemperature float64 `env:"OLLAMA_DEFAULT_TEMPERATURE" default:"0.7"`
+
+	// DefaultTopP is the default top_p value for text generation
+	DefaultTopP float64 `env:"OLLAMA_DEFAULT_TOP_P" default:"0.9"`
+
+	// DefaultMaxTokens is the default maximum number of tokens to generate
+	DefaultMaxTokens int `env:"OLLAMA_DEFAULT_MAX_TOKENS" default:"1000"`
+
+	// EnableStreaming enables streaming responses by default
+	EnableStreaming bool `env:"OLLAMA_ENABLE_STREAMING" default:"false"`
+}
+
+// DefaultConfig returns a default configuration for the Ollama SDK
+func DefaultConfig() *Config {
+	return &Config{
+		BaseURL:            "http://localhost:11434",
+		Timeout:            300 * time.Second,
+		RetryAttempts:      3,
+		RetryDelay:         2 * time.Second,
+		EnableLogging:      true,
+		UserAgent:          "TenderManagement-OllamaSDK/1.0",
+		DefaultModel:       "llama2",
+		DefaultTemperature: 0.7,
+		DefaultTopP:        0.9,
+		DefaultMaxTokens:   1000,
+		EnableStreaming:    false,
+	}
+}
+
+// Validate validates the configuration
+func (c *Config) Validate() error {
+	if c.BaseURL == "" {
+		return ErrInvalidConfig("BaseURL cannot be empty")
+	}
+
+	if c.Timeout <= 0 {
+		return ErrInvalidConfig("Timeout must be positive")
+	}
+
+	if c.RetryAttempts < 0 {
+		return ErrInvalidConfig("RetryAttempts cannot be negative")
+	}
+
+	if c.RetryDelay < 0 {
+		return ErrInvalidConfig("RetryDelay cannot be negative")
+	}
+
+	if c.DefaultTemperature < 0 || c.DefaultTemperature > 2 {
+		return ErrInvalidConfig("DefaultTemperature must be between 0 and 2")
+	}
+
+	if c.DefaultTopP < 0 || c.DefaultTopP > 1 {
+		return ErrInvalidConfig("DefaultTopP must be between 0 and 1")
+	}
+
+	if c.DefaultMaxTokens < 0 {
+		return ErrInvalidConfig("DefaultMaxTokens cannot be negative")
+	}
+
+	return nil
+}