docs: improve and expand documentation across all code modules

- Replace brief or missing comments with detailed package-level and function-level documentation throughout the file
- Add structured doc comments explaining configuration options, exchange types, and the purpose of each functional option
- Improve field comments in the options struct for clarity and consistency
- Add documentation for internal helper functions and the options constructor
- Remove or replace terse single-line comments with more informative, multi-line doc comments

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

Author: appleboy

options.go

@@ -7,14 +7,36 @@ import (
 	"github.com/golang-queue/queue/core"
 )
 
-// defined in rabbitmq client package.
+/*
+Package rabbitmq provides configuration options and helper functions
+for setting up and customizing RabbitMQ workers and queues in the golang-queue system.
+This file defines the available exchange types, the options struct, and a set of functional
+options for flexible configuration.
+*/
+
+/*
+Predefined RabbitMQ exchange types for use in configuration.
+- ExchangeDirect: Direct exchange type.
+- ExchangeFanout: Fanout exchange type.
+- ExchangeTopic: Topic exchange type.
+- ExchangeHeaders: Headers exchange type.
+*/
 const (
 	ExchangeDirect  = "direct"
 	ExchangeFanout  = "fanout"
 	ExchangeTopic   = "topic"
 	ExchangeHeaders = "headers"
 )
 
+/*
+isVaildExchange checks if the provided exchange name is one of the supported types.
+
+Parameters:
+- name: The exchange type name to validate.
+
+Returns:
+- bool: true if the exchange type is valid, false otherwise.
+*/
 func isVaildExchange(name string) bool {
 	switch name {
 	case ExchangeDirect, ExchangeFanout, ExchangeTopic, ExchangeHeaders:
@@ -24,97 +46,193 @@ func isVaildExchange(name string) bool {
 	}
 }
 
-// Option for queue system
+/*
+Option is a functional option type for configuring the options struct.
+It allows for flexible and composable configuration of RabbitMQ workers and queues.
+*/
 type Option func(*options)
 
-// AMQP 0-9-1 Model Explained
-// ref: https://www.rabbitmq.com/tutorials/amqp-concepts.html
+/*
+options struct holds all configuration parameters for a RabbitMQ worker or queue.
+
+Fields:
+- runFunc: The function to execute for each task.
+- logger: Logger instance for logging.
+- addr: AMQP server URI.
+- queue: Name of the queue to use.
+- tag: Consumer tag for identification.
+- exchangeName: Name of the AMQP exchange.
+- exchangeType: Type of the AMQP exchange (direct, fanout, topic, headers).
+- autoAck: Whether to enable automatic message acknowledgment.
+- routingKey: AMQP routing key for message delivery.
+*/
 type options struct {
-	runFunc func(context.Context, core.TaskMessage) error
-	logger  queue.Logger
-	addr    string
-	queue   string
-	tag     string
-	// Durable AMQP exchange name
-	exchangeName string
-	//  Exchange Types: Direct, Fanout, Topic and Headers
-	exchangeType string
+	runFunc      func(context.Context, core.TaskMessage) error
+	logger       queue.Logger
+	addr         string
+	queue        string
+	tag          string
+	exchangeName string // Durable AMQP exchange name
+	exchangeType string // Exchange Types: Direct, Fanout, Topic and Headers
 	autoAck      bool
-	// AMQP routing key
-	routingKey string
+	routingKey   string // AMQP routing key
 }
 
-// WithAddr setup the URI
+/*
+WithAddr sets the AMQP server URI.
+
+Parameters:
+- addr: The AMQP URI to connect to.
+
+Returns:
+- Option: Functional option to set the address.
+*/
 func WithAddr(addr string) Option {
 	return func(w *options) {
 		w.addr = addr
 	}
 }
 
-// WithExchangeName setup the Exchange name
-// Exchanges are AMQP 0-9-1 entities where messages are sent to.
-// Exchanges take a message and route it into zero or more queues.
+/*
+WithExchangeName sets the name of the AMQP exchange.
+
+Parameters:
+- val: The exchange name.
+
+Returns:
+- Option: Functional option to set the exchange name.
+
+Exchanges are AMQP 0-9-1 entities where messages are sent to.
+Exchanges take a message and route it into zero or more queues.
+*/
 func WithExchangeName(val string) Option {
 	return func(w *options) {
 		w.exchangeName = val
 	}
 }
 
-// WithExchangeType setup the Exchange type
-// The routing algorithm used depends on the exchange type and rules called bindings.
-// AMQP 0-9-1 brokers provide four exchange types:
-// Direct exchange	(Empty string) and amq.direct
-// Fanout exchange	amq.fanout
-// Topic exchange	amq.topic
-// Headers exchange	amq.match (and amq.headers in RabbitMQ)
+/*
+WithExchangeType sets the type of the AMQP exchange.
+
+Parameters:
+- val: The exchange type (direct, fanout, topic, headers).
+
+Returns:
+- Option: Functional option to set the exchange type.
+
+The routing algorithm used depends on the exchange type and rules called bindings.
+AMQP 0-9-1 brokers provide four exchange types:
+- Direct exchange (Empty string) and amq.direct
+- Fanout exchange amq.fanout
+- Topic exchange amq.topic
+- Headers exchange amq.match (and amq.headers in RabbitMQ)
+*/
 func WithExchangeType(val string) Option {
 	return func(w *options) {
 		w.exchangeType = val
 	}
 }
 
-// WithRoutingKey setup  AMQP routing key
+/*
+WithRoutingKey sets the AMQP routing key.
+
+Parameters:
+- val: The routing key.
+
+Returns:
+- Option: Functional option to set the routing key.
+*/
 func WithRoutingKey(val string) Option {
 	return func(w *options) {
 		w.routingKey = val
 	}
 }
 
-// WithAddr setup the tag
+/*
+WithTag sets the consumer tag for the worker.
+
+Parameters:
+- val: The consumer tag.
+
+Returns:
+- Option: Functional option to set the tag.
+*/
 func WithTag(val string) Option {
 	return func(w *options) {
 		w.tag = val
 	}
 }
 
-// WithAutoAck enable message auto-ack
+/*
+WithAutoAck enables or disables automatic message acknowledgment.
+
+Parameters:
+- val: true to enable auto-ack, false to disable.
+
+Returns:
+- Option: Functional option to set autoAck.
+*/
 func WithAutoAck(val bool) Option {
 	return func(w *options) {
 		w.autoAck = val
 	}
 }
 
-// WithQueue setup the queue name
+/*
+WithQueue sets the name of the queue to use.
+
+Parameters:
+- val: The queue name.
+
+Returns:
+- Option: Functional option to set the queue name.
+*/
 func WithQueue(val string) Option {
 	return func(w *options) {
 		w.queue = val
 	}
 }
 
-// WithRunFunc setup the run func of queue
+/*
+WithRunFunc sets the function to execute for each task.
+
+Parameters:
+- fn: The function to run for each task message.
+
+Returns:
+- Option: Functional option to set the run function.
+*/
 func WithRunFunc(fn func(context.Context, core.TaskMessage) error) Option {
 	return func(w *options) {
 		w.runFunc = fn
 	}
 }
 
-// WithLogger set custom logger
+/*
+WithLogger sets a custom logger for the worker or queue.
+
+Parameters:
+- l: The logger instance.
+
+Returns:
+- Option: Functional option to set the logger.
+*/
 func WithLogger(l queue.Logger) Option {
 	return func(w *options) {
 		w.logger = l
 	}
 }
 
+/*
+newOptions creates a new options struct with default values,
+then applies any provided functional options to override defaults.
+
+Parameters:
+- opts: Variadic list of Option functions to customize the configuration.
+
+Returns:
+- options: The fully configured options struct.
+*/
 func newOptions(opts ...Option) options {
 	defaultOpts := options{
 		addr:         "amqp://guest:guest@localhost:5672/",
@@ -130,12 +248,12 @@ func newOptions(opts ...Option) options {
 		},
 	}
 
-	// Loop through each option
+	// Apply each provided option to override defaults
 	for _, opt := range opts {
-		// Call the option giving the instantiated
 		opt(&defaultOpts)
 	}
 
+	// Validate the exchange type
 	if !isVaildExchange(defaultOpts.exchangeType) {
 		defaultOpts.logger.Fatal("invaild exchange type: ", defaultOpts.exchangeType)
 	}