package application

import (
	"git.openprivacy.ca/openprivacy/libricochet-go"
	"git.openprivacy.ca/openprivacy/libricochet-go/connection"
	"git.openprivacy.ca/openprivacy/libricochet-go/connectivity"
	"git.openprivacy.ca/openprivacy/libricochet-go/identity"
	"git.openprivacy.ca/openprivacy/libricochet-go/log"
	"net"
	"sync"
)

const (
	// RicochetPort is the default port used by ricochet applications
	RicochetPort = 9878
)

// RicochetApplication bundles many useful constructs that are
// likely standard in a ricochet application
type RicochetApplication struct {
	contactManager ContactManagerInterface
	v3identity     identity.Identity
	name           string
	ls             connectivity.ListenService
	acn            connectivity.ACN
	instances      []*Instance
	lock           sync.Mutex
	aif            InstanceFactory
}

// Init initializes the underlying RicochetApplication datastructure, making it ready for use
func (ra *RicochetApplication) Init(acn connectivity.ACN, name string, v3identity identity.Identity, af InstanceFactory, cm ContactManagerInterface) {
	ra.acn = acn
	ra.name = name
	ra.v3identity = v3identity
	ra.aif = af
	ra.contactManager = cm
}

// TODO: Reimplement OnJoin, OnLeave Events.
func (ra *RicochetApplication) handleConnection(conn net.Conn) {
	rc, err := goricochet.NegotiateVersionInbound(conn)
	if err != nil {
		log.Errorln("There was an error")
		conn.Close()
		return
	}

	ich := connection.HandleInboundConnection(rc)

	err = ich.ProcessAuthAsV3Server(ra.v3identity, ra.contactManager.LookupContactV3)

	if err != nil {
		log.Errorf("There was an error authenticating the connection: %v", err)
		conn.Close()
		return
	}

	rai := ra.aif.GetApplicationInstance(rc)
	ra.lock.Lock()
	ra.instances = append(ra.instances, rai)
	ra.lock.Unlock()
	rc.Process(rai)

	// rc.Process ends when the connection ends.
	// Remove it from the application's list of instances
	ra.lock.Lock()
	for i, x := range ra.instances {
		if x == rai {
			ra.instances = append(ra.instances[:i], ra.instances[i+1:]...)
			break
		}
	}
	ra.lock.Unlock()
}

// HandleApplicationInstance delegates handling of a given Instance to the Application.
func (ra *RicochetApplication) HandleApplicationInstance(rai *Instance) {
	ra.lock.Lock()
	ra.instances = append(ra.instances, rai)
	ra.lock.Unlock()
}

// Open a connection to another Ricochet peer at onionAddress. Infof they are unknown to use, use requestMessage (otherwise can be blank)
func (ra *RicochetApplication) Open(onionAddress string, requestMessage string) (*Instance, error) {
	rc, err := goricochet.Open(ra.acn, onionAddress)
	if err != nil {
		log.Errorf("Error in application.Open(): %v\n", err)
		return nil, err
	}

	och := connection.HandleOutboundConnection(rc)

	_, err = och.ProcessAuthAsV3Client(ra.v3identity)

	if err != nil {
		log.Errorf("There was an error authenticating the connection: %v", err)
		return nil, err
	}
	rai := ra.aif.GetApplicationInstance(rc)
	go rc.Process(rai)

	ra.HandleApplicationInstance(rai)
	return rai, nil
}

// Broadcast performs the given function do() over all application instance (all connected peers)
func (ra *RicochetApplication) Broadcast(do func(rai *Instance)) {
	ra.lock.Lock()
	for _, rai := range ra.instances {
		do(rai)
	}
	ra.lock.Unlock()
}

// Shutdown stops a RicochetApplication, terminating all child processes and resources
func (ra *RicochetApplication) Shutdown() {
	ra.lock.Lock()
	ra.ls.Close()
	for _, instance := range ra.instances {
		instance.Connection.Close()
	}
	ra.lock.Unlock()
}

// Close kills a connection by a given Onion Address
func (ra *RicochetApplication) Close(onion string) {
	ra.lock.Lock()
	for _, instance := range ra.instances {
		if instance.RemoteHostname == onion {
			instance.Connection.Close()
		}
	}
	ra.lock.Unlock()
}

// ConnectionCount returns the number of concurrent connections to the application
func (ra *RicochetApplication) ConnectionCount() int {
	return len(ra.instances)
}

// Run handles a Listen object and Accepts and handles new connections
func (ra *RicochetApplication) Run(ls connectivity.ListenService) {
	if !ra.v3identity.Initialized() || ra.contactManager == nil {
		return
	}
	ra.lock.Lock()
	ra.ls = ls
	ra.lock.Unlock()
	var err error
	for err == nil {
		conn, err := ra.ls.Accept()
		if err == nil {
			go ra.handleConnection(conn)
		} else {
			return
		}
	}
}