package libnmdc

import (
	"strings"
)

type adcState int

const (
	adcStateProtocol adcState = 0
	adcStateIdentify adcState = 1
	adcStateVerify   adcState = 2
	adcStateNormal   adcState = 3
	adcStateData     adcState = 4
)

type AdcProtocol struct {
	hc       *HubConnection
	state    adcState
	sid      string
	supports map[string]struct{}
}

func NewAdcProtocol(hc *HubConnection) Protocol {
	proto := AdcProtocol{
		hc:       hc,
		state:    adcStateProtocol,
		supports: make(map[string]struct{}),
	}

	// Start logging in
	hc.SayRaw("HSUP ADBASE ADTIGR\n")

	return &proto
}

func (this *AdcProtocol) ProcessCommand(msg string) {
	this.hc.processEvent(HubEvent{EventType: EVENT_DEBUG_MESSAGE, Message: msg})

	if len(msg) == 0 {
		return
	}

	parts := strings.Split(msg, " ")
	switch parts[0] {

	case "ISUP":
		if !(this.state == adcStateProtocol || this.state == adcStateNormal) {
			this.malformed(parts)
			return
		}
		for _, supportflag := range parts[1:] {
			if len(supportflag) < 2 {
				this.malformed(parts)
				return
			}

			if supportflag[0:2] == "AD" {
				this.supports[supportflag[2:]] = struct{}{}
			} else if supportflag[0:2] == "RM" {
				delete(this.supports, supportflag[2:])
			} else {
				this.malformed(parts)
				return
			}
		}
		if this.state == adcStateProtocol {
			this.state = adcStateIdentify
		}

	case "ISID":
		if this.state != adcStateIdentify {
			this.malformed(parts)
			return
		}
		this.sid = parts[1]

	case "IINF":
		flags := make(map[string]string)
		for _, flag := range parts[1:] {
			if len(flag) < 2 {
				this.malformed(parts)
				return
			}
			flags[flag[0:2]] = flag[2:]
		}

		// Possibilities: User MyINFO (Normal state), or, hub telling information about itself (Identify->Normal state)
		if (this.state == adcStateIdentify || this.state == adcStateVerify) && flags["CT"] == "32" {
			// Hub telling information about itself
			this.handleInfo(flags)

			// Transition to state VERIFY and send our own info
			this.hc.SayRaw("BINF " + this.escape(this.sid) + " GARBAGE") // FIXME send a real info string
			this.state = adcStateVerify

		} else if this.state == adcStateNormal {
			// OK
			this.handleInfo(flags)

		} else {
			this.malformed(parts)
			return
		}

	case "IGPA":
		//

	default:
		this.malformed(parts)
	}
}

func (this *AdcProtocol) handleInfo(flags map[string]string) {
	if flags["CT"] == "32" {

		// IINF DEADCH++\sTest\shub VE2.12.1\s(r"[unknown]")\sRelease HI1 NIADCH++ APADCH++ CT32
		// AP: extension 3.24 "Application and version separation in INF"
		// HI:

		// Hub properties updated
		hubName, ok := flags["DE"]
		if ok {
			this.hc.HubName = this.unescape(hubName)
			this.hc.processEvent(HubEvent{EventType: EVENT_HUBNAME_CHANGED, Nick: this.hc.HubName})
		}

	} else {
		// User MyINFO
		// TODO

	}
}

func (this *AdcProtocol) enterNormalState() {
	this.state = adcStateNormal
	this.hc.processEvent(HubEvent{EventType: EVENT_CONNECTION_STATE_CHANGED, StateChange: CONNECTIONSTATE_CONNECTED})
	this.hc.State = CONNECTIONSTATE_CONNECTED
}

func (this *AdcProtocol) malformed(parts []string) {
	this.hc.processEvent(HubEvent{EventType: EVENT_DEBUG_MESSAGE, Message: "Ignoring malformed, unhandled, or out-of-state protocol command '" + parts[0] + "'"})
}

func (this *AdcProtocol) escape(plaintext string) string {
	// The string "\s" escapes space, "\n" newline and "\\" backslash. This version of the protocol reserves all other escapes for future use; any message containing unknown escapes must be discarded.
	v1 := strings.Replace(plaintext, `\`, `\\`, -1)
	v2 := strings.Replace(v1, "\n", `\n`, -1)
	return strings.Replace(v2, " ", `\s`, -1)
}

func (this *AdcProtocol) unescape(encoded string) string {
	v1 := strings.Replace(encoded, `\s`, " ", -1)
	v2 := strings.Replace(v1, `\n`, "\n", -1)
	return strings.Replace(v2, `\\`, `\`, -1)
}

func (this *AdcProtocol) SayPublic(msg string) {
}

func (this *AdcProtocol) SayPrivate(user, message string) {
}

func (this *AdcProtocol) ProtoMessageSeparator() string {
	return "\n"
}