package p2p

import (
	"time"
)

// Config holds configuration for a Bzzz P2P node
type Config struct {
	// Network configuration
	ListenAddresses []string
	NetworkID       string

	// Discovery configuration
	EnableMDNS     bool
	MDNSServiceTag string

	// DHT configuration
	EnableDHT        bool
	DHTBootstrapPeers []string
	DHTMode          string // "client", "server", "auto"
	DHTProtocolPrefix string

	// Connection limits and rate limiting
	MaxConnections      int
	MaxPeersPerIP       int
	ConnectionTimeout   time.Duration
	LowWatermark        int           // Connection manager low watermark
	HighWatermark       int           // Connection manager high watermark
	DialsPerSecond      int           // Dial rate limiting
	MaxConcurrentDials  int           // Maximum concurrent outbound dials
	MaxConcurrentDHT    int           // Maximum concurrent DHT queries
	JoinStaggerMS       int           // Join stagger delay in milliseconds

	// Security configuration
	EnableSecurity bool

	// Pubsub configuration
	EnablePubsub           bool
	BzzzTopic             string    // Task coordination topic
	HmmmTopic             string    // Meta-discussion topic
	MessageValidationTime time.Duration
}

// Option is a function that modifies the node configuration
type Option func(*Config)

// DefaultConfig returns a default configuration for Bzzz nodes
func DefaultConfig() *Config {
	return &Config{
		// Listen on specific port 3333 for TCP
		ListenAddresses: []string{
			"/ip4/0.0.0.0/tcp/3333",
			"/ip6/::/tcp/3333",
		},
		NetworkID: "CHORUS-network",

		// Discovery settings - mDNS disabled for Swarm by default
		EnableMDNS:     false, // Disabled for container environments
		MDNSServiceTag: "CHORUS-peer-discovery",

		// DHT settings (disabled by default for local development)
		EnableDHT:        false,
		DHTBootstrapPeers: []string{},
		DHTMode:          "auto",
		DHTProtocolPrefix: "/CHORUS",

		// Connection limits and rate limiting for scaling
		MaxConnections:      50,
		MaxPeersPerIP:       3,
		ConnectionTimeout:   30 * time.Second,
		LowWatermark:        32,  // Keep at least 32 connections
		HighWatermark:       128, // Trim above 128 connections
		DialsPerSecond:      5,   // Limit outbound dials to prevent storms
		MaxConcurrentDials:  10,  // Maximum concurrent outbound dials
		MaxConcurrentDHT:    16,  // Maximum concurrent DHT queries
		JoinStaggerMS:       0,   // No stagger by default (set by assignment)

		// Security enabled by default
		EnableSecurity: true,

		// Pubsub for coordination and meta-discussion
		EnablePubsub:           true,
		BzzzTopic:             "CHORUS/coordination/v1",
		HmmmTopic:            "hmmm/meta-discussion/v1",
		MessageValidationTime: 10 * time.Second,
	}
}

// WithListenAddresses sets the addresses to listen on
func WithListenAddresses(addrs ...string) Option {
	return func(c *Config) {
		c.ListenAddresses = addrs
	}
}

// WithNetworkID sets the network ID
func WithNetworkID(networkID string) Option {
	return func(c *Config) {
		c.NetworkID = networkID
	}
}

// WithMDNS enables or disables mDNS discovery
func WithMDNS(enabled bool) Option {
	return func(c *Config) {
		c.EnableMDNS = enabled
	}
}

// WithMDNSServiceTag sets the mDNS service tag
func WithMDNSServiceTag(tag string) Option {
	return func(c *Config) {
		c.MDNSServiceTag = tag
	}
}

// WithMaxConnections sets the maximum number of connections
func WithMaxConnections(max int) Option {
	return func(c *Config) {
		c.MaxConnections = max
	}
}

// WithConnectionTimeout sets the connection timeout
func WithConnectionTimeout(timeout time.Duration) Option {
	return func(c *Config) {
		c.ConnectionTimeout = timeout
	}
}

// WithSecurity enables or disables security
func WithSecurity(enabled bool) Option {
	return func(c *Config) {
		c.EnableSecurity = enabled
	}
}

// WithPubsub enables or disables pubsub
func WithPubsub(enabled bool) Option {
	return func(c *Config) {
		c.EnablePubsub = enabled
	}
}

// WithTopics sets the Bzzz and HMMM topic names
func WithTopics(chorusTopic, hmmmTopic string) Option {
	return func(c *Config) {
		c.BzzzTopic = chorusTopic
		c.HmmmTopic = hmmmTopic
	}
}

// WithDHT enables or disables DHT discovery
func WithDHT(enabled bool) Option {
	return func(c *Config) {
		c.EnableDHT = enabled
	}
}

// WithDHTBootstrapPeers sets the DHT bootstrap peers
func WithDHTBootstrapPeers(peers []string) Option {
	return func(c *Config) {
		c.DHTBootstrapPeers = peers
	}
}

// WithDHTMode sets the DHT mode
func WithDHTMode(mode string) Option {
	return func(c *Config) {
		c.DHTMode = mode
	}
}

// WithDHTProtocolPrefix sets the DHT protocol prefix
func WithDHTProtocolPrefix(prefix string) Option {
	return func(c *Config) {
		c.DHTProtocolPrefix = prefix
	}
}

// WithConnectionManager sets connection manager watermarks
func WithConnectionManager(low, high int) Option {
	return func(c *Config) {
		c.LowWatermark = low
		c.HighWatermark = high
	}
}

// WithDialRateLimit sets the dial rate limiting
func WithDialRateLimit(dialsPerSecond, maxConcurrent int) Option {
	return func(c *Config) {
		c.DialsPerSecond = dialsPerSecond
		c.MaxConcurrentDials = maxConcurrent
	}
}

// WithDHTRateLimit sets the DHT query rate limiting
func WithDHTRateLimit(maxConcurrentDHT int) Option {
	return func(c *Config) {
		c.MaxConcurrentDHT = maxConcurrentDHT
	}
}

// WithJoinStagger sets the join stagger delay in milliseconds
func WithJoinStagger(delayMS int) Option {
	return func(c *Config) {
		c.JoinStaggerMS = delayMS
	}
}