package services

import (
	"git.saqut.com/saqut/mwse/internal/protocol"
	"git.saqut.com/saqut/mwse/internal/ws"
)

// ---- relationship helpers ------------------------------------------------
//
// "Secure" reachability comes in two forms: a mutual pairing, or co-membership of
// a room. These helpers centralise the checks the original Client.isSecure /
// getSucureClients spread across files (and fix their bugs).

// isPaired reports a *mutual* pairing between a and b.
func isPaired(a, b *ws.Client) bool {
	return a.HasPair(b.ID) && b.HasPair(a.ID)
}

// shareRoom reports whether a and b are members of at least one common room.
func shareRoom(hub *ws.Hub, a, b *ws.Client) bool {
	for _, rid := range a.Rooms() {
		if r, ok := hub.Room(rid); ok && r.Has(b.ID) {
			return true
		}
	}
	return false
}

// isSecure reports whether a may address the client with id peerID.
func isSecure(hub *ws.Hub, a *ws.Client, peerID string) bool {
	peer, ok := hub.Client(peerID)
	if !ok {
		return false
	}
	return isPaired(a, peer) || shareRoom(hub, a, peer)
}

// secureClients returns the connected peers c may exchange info with: those c has
// paired toward, and those sharing a room with c.
func secureClients(hub *ws.Hub, c *ws.Client) (pairs, roompairs map[string]*ws.Client) {
	pairs = make(map[string]*ws.Client)
	for _, id := range c.Pairs() {
		if pc, ok := hub.Client(id); ok {
			pairs[id] = pc
		}
	}
	roompairs = make(map[string]*ws.Client)
	for _, rid := range c.Rooms() {
		r, ok := hub.Room(rid)
		if !ok {
			continue
		}
		for _, m := range r.Members() {
			if m.ID == c.ID {
				continue
			}
			roompairs[m.ID] = m
		}
	}
	return pairs, roompairs
}

func registerAuth(hub *ws.Hub) {
	// On disconnect: tell secure peers we are gone, then remove EVERY pairing edge
	// that references this client (both directions) so no stale id is ever left on
	// a surviving peer. Using the outgoing+incoming indexes keeps this O(degree),
	// not O(all clients), and prevents unbounded growth under churn.
	hub.OnDisconnect(func(c *ws.Client) {
		pairs, roompairs := secureClients(hub, c)

		notified := make(map[string]bool)
		notify := func(set map[string]*ws.Client) {
			for id, peer := range set {
				if notified[id] {
					continue
				}
				notified[id] = true
				peer.Signal("peer/disconnect", map[string]any{"id": c.ID})
			}
		}
		notify(pairs)
		notify(roompairs)

		cleaned := make(map[string]bool)
		for _, peerID := range append(c.Pairs(), c.PairedBy()...) {
			if cleaned[peerID] {
				continue
			}
			cleaned[peerID] = true
			if peer, ok := hub.Client(peerID); ok {
				peer.ForgetPeer(c.ID)
			}
		}
	})

	hub.Register("auth/pair-system", func(c *ws.Client, m protocol.Message) any {
		switch m.Str("value") {
		case "everybody":
			c.SetRequiredPair(true)
			return success()
		case "disable":
			c.SetRequiredPair(false)
			return success()
		}
		return fail("INVALID_VALUE")
	})

	hub.Register("my/socketid", func(c *ws.Client, m protocol.Message) any {
		return c.ID
	})

	hub.Register("auth/public", func(c *ws.Client, m protocol.Message) any {
		c.SetRequiredPair(false)
		return map[string]any{"value": "success", "mode": "public"}
	})

	hub.Register("auth/private", func(c *ws.Client, m protocol.Message) any {
		c.SetRequiredPair(true)
		return map[string]any{"value": "success", "mode": "private"}
	})

	// request/pair: ask `to` to pair with us. We record our side of the edge and
	// notify the target; they complete it with accept/pair.
	hub.Register("request/pair", func(c *ws.Client, m protocol.Message) any {
		to := m.Str("to")
		target, ok := hub.Client(to)
		if !ok {
			return fail("CLIENT_NOT_FOUND")
		}
		if isPaired(c, target) {
			return map[string]any{"status": "success", "message": "ALREADY-PAIRED"}
		}
		if c.HasPair(to) {
			return fail("ALREADY-REQUESTED")
		}
		c.AddPair(target)
		target.Signal("request/pair", map[string]any{"from": c.ID, "info": c.Info()})
		return map[string]any{"status": "success", "message": "REQUESTED"}
	})

	// accept/pair: complete a pairing the peer `to` requested from us.
	hub.Register("accept/pair", func(c *ws.Client, m protocol.Message) any {
		to := m.Str("to")
		requester, ok := hub.Client(to)
		if !ok {
			return fail("CLIENT_NOT_FOUND")
		}
		if isPaired(c, requester) {
			return map[string]any{"status": "success", "message": "ALREADY-PAIRED"}
		}
		if !requester.HasPair(c.ID) {
			return fail("NOT_REQUESTED_PAIR")
		}
		c.AddPair(requester)
		requester.Signal("accepted/pair", map[string]any{"from": c.ID, "info": c.Info()})
		return success()
	})

	// reject/pair and end/pair both tear the edge down in both directions and
	// notify the other side.
	teardown := func(c *ws.Client, m protocol.Message) any {
		to := m.Str("to")
		other, ok := hub.Client(to)
		if !ok {
			return fail("CLIENT_NOT_FOUND")
		}
		c.RemovePair(other)
		other.RemovePair(c)
		other.Signal("end/pair", map[string]any{"from": c.ID})
		return success()
	}
	hub.Register("reject/pair", teardown)
	hub.Register("end/pair", teardown)

	hub.Register("pair/list", func(c *ws.Client, m protocol.Message) any {
		var list []string
		for _, id := range c.Pairs() {
			if other, ok := hub.Client(id); ok && other.HasPair(c.ID) {
				list = append(list, id)
			}
		}
		return map[string]any{"type": "pair/list", "value": list}
	})

	hub.Register("is/reachable", func(c *ws.Client, m protocol.Message) any {
		to := m.Str("to")
		other, ok := hub.Client(to)
		if !ok {
			return false
		}
		if other.RequiredPair() && !other.HasPair(c.ID) {
			return false
		}
		return true
	})

	// auth/info: set our metadata and push the change to every secure peer.
	hub.Register("auth/info", func(c *ws.Client, m protocol.Message) any {
		name := m.Str("name")
		value := m.Get("value")
		c.SetInfo(name, value)

		pairs, roompairs := secureClients(hub, c)
		payload := map[string]any{"from": c.ID, "name": name, "value": value}
		for _, peer := range pairs {
			peer.Signal("pair/info", payload)
		}
		for _, peer := range roompairs {
			peer.Signal("pair/info", payload)
		}
		return success()
	})

	hub.Register("peer/info", func(c *ws.Client, m protocol.Message) any {
		peerID := m.Str("peer")
		if !isSecure(hub, c, peerID) {
			return map[string]any{"status": "fail", "message": "unaccessible user"}
		}
		peer, _ := hub.Client(peerID)
		return map[string]any{"status": "success", "info": peer.Info()}
	})
}