import { chatContent, imageMetadata } from "../chat-content"
import { generateKeyPairSync, randomUUID } from "node:crypto"
import { sql } from "drizzle-orm"
import type { FastifyInstance } from "fastify"
import { CollaborationService, rows } from "./service"
import { fail, hash, overview, Principal, sequence, text, UserContext, uuid } from "./types"
import { FederationKey, Headers, instanceUrl, safeTransport, signedHeaders, Transport, validatePublicKey, verifyHeaders } from "./transport"

type Options = {
    apiUrl: string; enabled: boolean;
    disabledReason?: string;
    seal: (value: string) => any; unseal: (value: any) => string;
    transport?: Transport;
}

export class FederationService {
    readonly origin: string
    readonly transport: Transport
    private keyPromise?: Promise<FederationKey & { instanceId: string }>
    private syncing = new Map<string, Promise<any>>()
    private working = false
    constructor(readonly service: CollaborationService, readonly options: Options) {
        this.origin = options.apiUrl.replace(/\/$/, "")
        this.transport = options.transport || safeTransport
    }
    enabled() {
        if (!this.options.enabled) fail(this.options.disabledReason || "Der Betreiber muss die Föderation zuerst aktivieren", 503)
        instanceUrl(this.origin)
    }
    async keys() {
        this.enabled()
        if (!this.keyPromise) this.keyPromise = (async () => {
            let [identity] = await rows(this.service.db, sql`SELECT * FROM collaboration_federation_identity WHERE singleton`)
            if (!identity) {
                const pair = generateKeyPairSync("ed25519")
                const pub = pair.publicKey.export({ format: "pem", type: "spki" }).toString()
                const secret = this.options.seal(pair.privateKey.export({ format: "pem", type: "pkcs8" }).toString())
                await this.service.db.execute(sql`INSERT INTO collaboration_federation_identity(instance_id,key_id,public_key,private_key_cipher)
                    VALUES (${randomUUID()},${randomUUID()},${pub},${JSON.stringify(secret)}::jsonb) ON CONFLICT DO NOTHING`)
                ;[identity] = await rows(this.service.db, sql`SELECT * FROM collaboration_federation_identity WHERE singleton`)
            }
            return { instanceId: identity.instance_id, keyId: identity.key_id, publicKey: identity.public_key, privateKey: this.options.unseal(identity.private_key_cipher) }
        })().catch(error => { this.keyPromise = undefined; throw error })
        return this.keyPromise
    }
    async discovery() {
        const keys = await this.keys()
        return { version: 1, origin: this.origin, instanceId: keys.instanceId, keyId: keys.keyId, publicKey: keys.publicKey }
    }
    contact(principal: Principal) { return `${this.origin}/federation/actors/${principal.id}` }
    async allowed(tenantId: number, origin: string, db: any = this.service.db) {
        const [partner] = await rows(db, sql`SELECT * FROM collaboration_partners WHERE tenant_id=${tenantId} AND origin=${origin} AND active`)
        if (!partner) fail("Partnerinstanz ist für diesen Mandanten nicht freigegeben", 403)
        return partner
    }
    async settings(ctx: UserContext, input?: any) {
        if (!ctx.manage || !(await this.service.currentUser(ctx.userId, ctx.tenantId)).manage) fail("Keine Berechtigung", 403)
        if (input) {
            this.enabled()
            const origin = instanceUrl(text(input.origin, 1000))
            if (origin === this.origin) fail("Diese Instanz benötigt keine Partnerfreigabe")
            if (typeof input.active !== "boolean") fail("Ungültiger Partnerstatus")
            if (!input.active) {
                await this.service.db.execute(sql`UPDATE collaboration_partners SET active=false,updated_at=now() WHERE tenant_id=${ctx.tenantId} AND origin=${origin}`)
            } else {
                await this.service.rateLimit(`partner-discovery:${ctx.tenantId}`, 10, 600)
                const data = await this.transport(`${origin}/.well-known/fedeo-federation`, "GET", {})
                if (data.version !== 1 || data.origin !== origin) fail("Inkompatible Instanzadresse oder Protokollversion")
                const instanceId = uuid(data.instanceId), keyId = uuid(data.keyId), publicKey = validatePublicKey(data.publicKey)
                const existing = await rows(this.service.db, sql`SELECT instance_id,key_id,public_key FROM collaboration_partners WHERE origin=${origin}`)
                if (existing.some(p => p.instance_id !== instanceId || p.key_id !== keyId || p.public_key !== publicKey)) fail("Instanzschlüssel hat sich geändert. Eine erneute Vertrauensprüfung durch den Betreiber ist erforderlich.", 409)
                await this.service.db.execute(sql`INSERT INTO collaboration_partners(tenant_id,origin,instance_id,key_id,public_key)
                    VALUES (${ctx.tenantId},${origin},${instanceId},${keyId},${publicKey}) ON CONFLICT(tenant_id,origin) DO UPDATE SET active=true,updated_at=now()`)
            }
        }
        return { enabled: this.options.enabled, disabledReason: this.options.disabledReason, origin: this.origin, partners: (await rows(this.service.db,
            sql`SELECT origin,active,public_key FROM collaboration_partners WHERE tenant_id=${ctx.tenantId} ORDER BY origin`)).map(p => ({ origin: p.origin, active: p.active, fingerprint: hash(p.public_key) })) }
    }
    async call(tenantId: number, origin: string, action: string, payload: any) {
        this.enabled()
        await this.allowed(tenantId, origin)
        const body = JSON.stringify({ version: 1, action, ...payload })
        const target = `${origin}/federation/v1/rpc`
        const result = await this.transport(target, "POST", signedHeaders(await this.keys(), this.origin, target, body), body)
        if (result?.version !== 1 || !("data" in result)) fail("Inkompatible Föderationsantwort", 502)
        return result.data
    }
    async authenticate(body: string, headers: Headers) {
        this.enabled()
        const origin = instanceUrl(headers["x-fedeo-origin"] || "")
        const partners = await rows(this.service.db, sql`SELECT DISTINCT key_id,public_key FROM collaboration_partners WHERE origin=${origin} AND active`)
        if (partners.length !== 1) fail("Unbekannte oder gesperrte Partnerinstanz", 401)
        const verified = verifyHeaders({ keyId: partners[0].key_id, publicKey: partners[0].public_key }, `${this.origin}/federation/v1/rpc`, body, headers)
        const nonce = uuid(verified.nonce)
        const [accepted] = await rows(this.service.db, sql`INSERT INTO collaboration_federation_nonces(origin,nonce,expires_at)
            VALUES (${origin},${nonce},now()+interval '10 minutes') ON CONFLICT DO NOTHING RETURNING nonce`)
        if (!accepted) fail("Signatur wurde bereits verwendet", 401)
        await this.service.rateLimit(`federation:${origin}`, 600, 60)
        return origin
    }
    async resolveContact(ctx: UserContext, address: string): Promise<Principal> {
        const localPrefix = `${this.origin}/federation/actors/`
        if (address.startsWith(localPrefix)) {
            const actorId = uuid(address.slice(localPrefix.length))
            const [principal] = await rows(this.service.db, sql`SELECT * FROM collaboration_principals WHERE id=${actorId} AND kind='user'`)
            if (!principal) fail("Kontakt nicht gefunden", 404)
            return this.service.assertPrincipal(principal)
        }
        const match = /^(https:\/\/.+)\/federation\/actors\/([0-9a-f-]{36})$/i.exec(address)
        if (!match) fail("Ungültige persönliche Kontaktadresse")
        const origin = instanceUrl(match[1]), actorId = uuid(match[2])
        const actor = await this.call(ctx.tenantId, origin, "actor.lookup", { actorId })
        if (uuid(actor.id) !== actorId) fail("Kontaktidentität stimmt nicht überein", 502)
        const name = text(actor.name), organisation = text(actor.organisation)
        const [principal] = await rows(this.service.db, sql`INSERT INTO collaboration_principals(kind,remote_origin,remote_actor_id,display_name)
            VALUES ('remote',${origin},${actorId},${`${name} · ${organisation}`}) ON CONFLICT(remote_origin,remote_actor_id) WHERE kind='remote'
            DO UPDATE SET display_name=excluded.display_name RETURNING *`)
        return principal
    }
    async enqueue(db: any, entry: { key: string; ctx: UserContext; origin: string; action: string; payload: any; roomId?: string; bindingId?: string }) {
        const [job] = await rows(db, sql`INSERT INTO collaboration_outbox(dedup_key,tenant_id,principal_id,origin,action,payload,room_id,binding_id)
            VALUES (${entry.key},${entry.ctx.tenantId},${entry.ctx.principal.id},${entry.origin},${entry.action},${JSON.stringify(entry.payload)}::jsonb,${entry.roomId || null},${entry.bindingId || null})
            ON CONFLICT(dedup_key) DO UPDATE SET dedup_key=excluded.dedup_key RETURNING *`)
        if (JSON.stringify(job.payload) !== JSON.stringify(entry.payload)) {
            // JSONB key order differs: compare the actual command values instead of its serialization.
            if (job.payload.input?.text !== entry.payload.input?.text || job.payload.actorId !== entry.payload.actorId || job.payload.roomId !== entry.payload.roomId || job.payload.input?.revision !== entry.payload.input?.revision
                || (job.payload.input?.image?.dataUrl || null) !== (entry.payload.input?.image?.dataUrl || null)
                || (job.payload.input?.image?.name || null) !== (entry.payload.input?.image?.name || null)) fail("Auftrags-ID wurde bereits anders verwendet", 409)
        }
        return job
    }
    async invite(ctx: UserContext, roomId: string, target: Principal, invitationId: string, db: any = this.service.db) {
        this.enabled()
        await this.allowed(ctx.tenantId, target.remote_origin!, db)
        await this.enqueue(db, { key: `invite:${invitationId}`, ctx, origin: target.remote_origin!, roomId,
            action: "invitation.deliver", payload: { actorId: ctx.principal.id, targetActorId: target.remote_actor_id, invitationId } })
    }
    async deliveries(ctx: UserContext, roomId: string) {
        await this.service.manager(this.service.db, ctx, await this.service.roomRow(this.service.db, roomId))
        return rows(this.service.db, sql`SELECT payload->>'invitationId' AS id,status,last_error AS error FROM collaboration_outbox
            WHERE tenant_id=${ctx.tenantId} AND room_id=${roomId} AND action='invitation.deliver' ORDER BY created_at DESC LIMIT 100`)
    }
    async retryInvitation(ctx: UserContext, roomId: string, invitationId: string) {
        await this.service.manager(this.service.db, ctx, await this.service.roomRow(this.service.db, roomId))
        const [job] = await rows(this.service.db, sql`UPDATE collaboration_outbox o SET status='pending',attempts=0,next_attempt_at=now(),last_error=null
            FROM collaboration_invitations i WHERE i.id=${uuid(invitationId)} AND i.room_id=${roomId} AND i.status='pending' AND i.expires_at>now()
              AND o.dedup_key='invite:' || i.id::text AND o.tenant_id=${ctx.tenantId} AND o.room_id=${roomId} AND o.status='failed' RETURNING o.*`)
        if (!job) fail("Einladung kann nicht erneut zugestellt werden", 409)
        await this.deliver(job)
        return { queued: true }
    }
    async changed(roomId: string, db: any) {
        if (!this.options.enabled) return
        const [room] = await rows(db, sql`SELECT r.tenant_id,r.created_by,p.id AS actor_id FROM collaboration_rooms r
            JOIN collaboration_principals p ON p.tenant_id=r.tenant_id AND p.user_id=r.created_by AND p.kind='user' WHERE r.id=${roomId}`)
        if (!room) return
        const members = await rows(db, sql`SELECT p.* FROM collaboration_members m JOIN collaboration_principals p ON p.id=m.principal_id
            WHERE m.room_id=${roomId} AND p.kind='remote'`)
        for (const p of members) await db.execute(sql`INSERT INTO collaboration_outbox(dedup_key,tenant_id,principal_id,origin,action,payload,room_id)
            VALUES (${`change:${randomUUID()}`},${room.tenant_id},${room.actor_id},${p.remote_origin},'room.changed',
            ${JSON.stringify({ roomId, targetActorId: p.remote_actor_id })}::jsonb,${roomId})`)
        const withdrawn = await rows(db, sql`SELECT i.id,p.remote_origin,p.remote_actor_id FROM collaboration_invitations i
            JOIN collaboration_principals p ON p.id=i.target_principal_id WHERE i.room_id=${roomId} AND i.status='revoked' AND p.kind='remote'`)
        for (const i of withdrawn) await db.execute(sql`INSERT INTO collaboration_outbox(dedup_key,tenant_id,principal_id,origin,action,payload,room_id)
            VALUES (${`withdraw:${i.id}`},${room.tenant_id},${room.actor_id},${i.remote_origin},'invitation.withdrawn',
            ${JSON.stringify({ invitationId: i.id, targetActorId: i.remote_actor_id })}::jsonb,${roomId}) ON CONFLICT(dedup_key) DO NOTHING`)
    }
    async rpc(origin: string, request: any) {
        if (!request || request.version !== 1 || typeof request.action !== "string") fail("Protokollversion nicht unterstützt")
        const action = request.action
        if (["actor.lookup", "invitation.deliver", "invitation.withdrawn", "room.changed"].includes(action)) {
            const actorId = uuid(action === "actor.lookup" ? request.actorId : request.targetActorId)
            const [principal] = await rows(this.service.db, sql`SELECT * FROM collaboration_principals WHERE id=${actorId} AND kind='user'`)
            if (!principal) fail("Kontakt nicht gefunden", 404)
            await this.allowed(Number(principal.tenant_id), origin)
            await this.service.assertPrincipal(principal)
            if (action === "actor.lookup") {
                const [tenant] = await rows(this.service.db, sql`SELECT name FROM tenants WHERE id=${principal.tenant_id}`)
                return { id: principal.id, name: principal.display_name, organisation: tenant.name }
            }
            if (action === "room.changed") {
                await this.service.db.execute(sql`UPDATE collaboration_remote_bindings SET sync_at=null
                    WHERE principal_id=${principal.id} AND origin=${origin} AND room_id=${uuid(request.roomId)} AND status='active'`)
                return { received: true }
            }
            if (action === 'invitation.withdrawn') {
                const [binding] = await rows(this.service.db, sql`SELECT * FROM collaboration_remote_bindings WHERE principal_id=${principal.id}
                    AND origin=${origin} AND invitation_id=${uuid(request.invitationId)} AND status='pending'`)
                if (binding) await this.revokeBinding(binding)
                return { received: true }
            }
            const offer = request.offer
            if (!offer || !["participant", "reader"].includes(offer.role) || typeof offer.overviewAllowed !== "boolean") fail("Ungültige Einladung")
            const invitationId = uuid(request.invitationId), roomId = uuid(offer.roomId)
            const snapshot = { name: text(offer.name), topic: text(offer.topic, 1000, true), ownerName: text(offer.ownerName),
                role: offer.role, overviewAllowed: offer.overviewAllowed, expiresAt: new Date(offer.expiresAt).toISOString(),
                createdAt: new Date(offer.createdAt).toISOString(), generation: sequence(offer.generation) }
            if (!snapshot.generation) fail("Einladungsgeneration fehlt")
            if (new Date(snapshot.expiresAt).getTime() <= Date.now()) fail("Einladung ist abgelaufen", 410)
            await this.service.db.transaction(async db => {
                const [updated] = await rows(db, sql`INSERT INTO collaboration_remote_bindings(tenant_id,principal_id,origin,room_id,invitation_id,invitation)
                    VALUES (${principal.tenant_id},${principal.id},${origin},${roomId},${invitationId},${JSON.stringify(snapshot)}::jsonb)
                    ON CONFLICT(principal_id,origin,room_id) DO UPDATE SET invitation_id=excluded.invitation_id,invitation=excluded.invitation,
                        status='pending',snapshot=null,revision=0,last_read_seq=0,sync_seq=0
                    WHERE collaboration_remote_bindings.invitation_id<>excluded.invitation_id
                      AND coalesce((collaboration_remote_bindings.invitation->>'generation')::bigint,0)<${snapshot.generation} RETURNING id`)
                if (updated) {
                    await db.execute(sql`DELETE FROM collaboration_remote_messages WHERE binding_id=${updated.id}`)
                    await db.execute(sql`UPDATE collaboration_outbox SET status='failed',last_error='Neue Teilnahme erforderlich' WHERE binding_id=${updated.id} AND status='pending'`)
                }
            })
            return { received: true }
        }
        const actorId = uuid(request.actorId)
        const [principal] = await rows(this.service.db, sql`SELECT * FROM collaboration_principals WHERE kind='remote' AND remote_origin=${origin} AND remote_actor_id=${actorId}`)
        if (!principal) fail("Teilnehmer nicht eingeladen", 403)
        if (action === "invitation.accept" || action === "invitation.decline") {
            const [invite] = await rows(this.service.db, sql`SELECT i.*,r.tenant_id FROM collaboration_invitations i JOIN collaboration_rooms r ON r.id=i.room_id WHERE i.id=${uuid(request.invitationId)} AND i.target_principal_id=${principal.id}`)
            if (!invite) fail("Einladung nicht gefunden", 404)
            await this.allowed(Number(invite.tenant_id), origin)
            if (action === "invitation.decline") return this.service.decline(principal, invite.id)
            return this.service.accept(principal, invite.id)
        }
        const room = await this.service.roomRow(this.service.db, uuid(request.roomId))
        await this.allowed(Number(room.tenant_id), origin)
        if (action === "room.get") return this.service.room(principal, room.id)
        if (action === "messages.get") return this.service.messages(principal, room.id, request.input)
        if (action === "messages.send") return this.service.send(principal, room.id, request.input)
        if (action === "image.get") return this.service.image(principal, room.id, request.input)
        if (action === "reactions.get") return this.service.reactions(principal, room.id, request.input)
        if (action === "reactions.set") return this.service.react(principal, room.id, request.input)
        if (action === "members.get") return { members: await this.service.members(principal, room.id) }
        if (action === "read") return this.service.markRead(principal, room.id, request.input?.seq)
        fail("Unbekannte Föderationsaktion")
    }
    async list(ctx: UserContext) {
        if (!this.options.enabled) return { rooms: [], invitations: [] }
        const bindings = await rows(this.service.db, sql`SELECT b.* FROM collaboration_remote_bindings b JOIN collaboration_partners p ON p.tenant_id=b.tenant_id AND p.origin=b.origin AND p.active
            WHERE b.principal_id=${ctx.principal.id} AND b.tenant_id=${ctx.tenantId} AND b.status IN ('active','pending')`)
        const result: { rooms: any[]; invitations: any[] } = { rooms: [], invitations: [] }
        for (const b of bindings) {
            if (b.status === "pending" && new Date(b.invitation.expiresAt).getTime() > Date.now()) result.invitations.push({ ...b.invitation, id: b.id, remote: true })
            if (b.status === "active") {
                const [unread] = await rows(this.service.db, sql`SELECT count(*)::int AS count FROM collaboration_remote_messages WHERE binding_id=${b.id} AND seq>${b.last_read_seq} AND (payload->>'own')='false'`)
                result.rooms.push({ id: b.id, name: b.snapshot?.name || b.invitation.name, topic: b.snapshot?.topic || b.invitation.topic,
                    ownerName: b.invitation.ownerName, status: b.snapshot?.status || 'active', remote: true, unread: unread.count })
            }
        }
        return result
    }
    async binding(ctx: UserContext, bindingId: string) {
        const [binding] = await rows(this.service.db, sql`SELECT * FROM collaboration_remote_bindings WHERE id=${uuid(bindingId)} AND principal_id=${ctx.principal.id} AND tenant_id=${ctx.tenantId}`)
        return binding
    }
    async accept(ctx: UserContext, id: string, decline = false) {
        const binding = await this.binding(ctx, id)
        if (!binding) return { found: false }
        this.enabled()
        if (!['pending', 'active'].includes(binding.status)) fail("Einladung ist nicht mehr gültig", 410)
        const result = await this.call(ctx.tenantId, binding.origin, decline ? "invitation.decline" : "invitation.accept", { actorId: ctx.principal.id, invitationId: binding.invitation_id })
        if (!decline && uuid(result.roomId) !== binding.room_id) fail("Falscher Unterraum in Föderationsantwort", 502)
        await this.service.db.transaction(async db => {
            const [updated] = await rows(db, sql`UPDATE collaboration_remote_bindings SET status=${decline ? "declined" : "active"},sync_at=null
                WHERE id=${binding.id} AND invitation_id=${binding.invitation_id} AND status IN ('pending','active') RETURNING id`)
            if (!updated) fail("Einladung ist nicht mehr aktuell", 410)
            if (!decline && binding.status === 'pending') {
                await db.execute(sql`DELETE FROM collaboration_remote_messages WHERE binding_id=${binding.id}`)
                await db.execute(sql`UPDATE collaboration_outbox SET status='failed',last_error='Neue Teilnahme erforderlich' WHERE binding_id=${binding.id} AND status='pending'`)
            }
        })
        if (!decline) await this.sync(ctx, { ...binding, status: 'active' })
        return { found: true, result: decline ? { declined: true } : { roomId: binding.id } }
    }
    async revokeBinding(binding: any) {
        await this.service.db.transaction(async db => {
            const [revoked] = await rows(db, sql`UPDATE collaboration_remote_bindings SET status='revoked',snapshot=null WHERE id=${binding.id} AND invitation_id=${binding.invitation_id} RETURNING id`)
            if (!revoked) return
            await db.execute(sql`DELETE FROM collaboration_remote_messages WHERE binding_id=${binding.id}`)
            await db.execute(sql`UPDATE collaboration_outbox SET status='failed',last_error='Zugang entzogen' WHERE binding_id=${binding.id} AND status='pending'`)
        })
    }
    async sync(ctx: UserContext, binding: any) {
        if (this.syncing.has(binding.id)) return this.syncing.get(binding.id)
        const operation = this.syncOnce(ctx, binding).finally(() => this.syncing.delete(binding.id))
        this.syncing.set(binding.id, operation)
        return operation
    }
    async syncOnce(ctx: UserContext, binding: any) {
        try {
            const detail = await this.call(ctx.tenantId, binding.origin, "room.get", { actorId: ctx.principal.id, roomId: binding.room_id })
            if (uuid(detail.id) !== binding.room_id || !['active', 'archived'].includes(detail.status) || typeof detail.canSend !== 'boolean') fail("Ungültige Unterraumantwort", 502)
            const snapshot = { id: binding.id, name: text(detail.name), topic: text(detail.topic, 1000, true), status: detail.status,
                canSend: detail.canSend, historyFromSeq: sequence(detail.historyFromSeq), revision: sequence(detail.revision),
                lastReadSeq: sequence(detail.lastReadSeq), overview: null }
            const page = await this.call(ctx.tenantId, binding.origin, "messages.get", { actorId: ctx.principal.id, roomId: binding.room_id, input: { after: Math.max(Number(binding.sync_seq || 0), snapshot.historyFromSeq - 1) } })
            await this.cache(binding, page.messages, snapshot)
            return { ...snapshot, overview: detail.overview ? overview(detail.overview) : null, offline: false }
        } catch (error: any) {
            if ([401,403,404,410].includes(error.statusCode)) { await this.revokeBinding(binding); throw error }
            const current = await this.binding(ctx, binding.id)
            if (!current || current.status !== 'active' || current.invitation_id !== binding.invitation_id) fail('Zugang ist nicht mehr aktiv', 410)
            await this.service.db.execute(sql`UPDATE collaboration_remote_bindings SET last_error='Partnerinstanz nicht erreichbar',sync_at=now() WHERE id=${binding.id} AND invitation_id=${binding.invitation_id}`)
            if (current.snapshot) return { ...current.snapshot, id: binding.id, overview: null, offline: true }
            throw error
        }
    }
    async cache(binding: any, messages: any[], snapshot?: any) {
        if (!Array.isArray(messages) || messages.length > 50) fail("Ungültige Nachrichtenantwort", 502)
        const projected = messages.map(m => ({ id: uuid(m.id), clientId: uuid(m.clientId), seq: sequence(m.seq), body: text(m.body, 10000, Boolean(m.image)), image: imageMetadata(m.image),
            senderName: text(m.senderName, 400), senderKind: ['user','guest','remote'].includes(m.senderKind) ? m.senderKind : 'remote',
            own: m.own === true, createdAt: new Date(m.createdAt).toISOString() }))
        await this.service.db.transaction(async db => {
            const [current] = await rows(db, sql`SELECT * FROM collaboration_remote_bindings WHERE id=${binding.id} FOR UPDATE`)
            if (current.status !== 'active' || current.invitation_id !== binding.invitation_id) fail("Zugang ist nicht mehr aktiv", 410)
            if (snapshot && Number(current.revision) > snapshot.revision) fail('Teilnahmerechte haben sich geändert', 409)
            if (snapshot) {
                await db.execute(sql`UPDATE collaboration_remote_bindings SET snapshot=${JSON.stringify(snapshot)}::jsonb,revision=${snapshot.revision},
                    sync_at=now(),last_error=null,sync_seq=GREATEST(sync_seq,${Math.max(0, ...projected.map(m => m.seq))}),last_read_seq=GREATEST(last_read_seq,${snapshot.lastReadSeq}) WHERE id=${binding.id}`)
                await db.execute(sql`DELETE FROM collaboration_remote_messages WHERE binding_id=${binding.id} AND seq<${snapshot.historyFromSeq}`)
            }
            const from = snapshot?.historyFromSeq || current.snapshot?.historyFromSeq || 0
            for (const message of projected.filter(m => m.seq >= from)) await db.execute(sql`INSERT INTO collaboration_remote_messages(binding_id,id,seq,payload)
                VALUES (${binding.id},${message.id},${message.seq},${JSON.stringify(message)}::jsonb)
                ON CONFLICT(binding_id,id) DO UPDATE SET payload=excluded.payload`)
        })
    }
    async memberRequest(ctx: UserContext, id: string, action: string, input: any = {}) {
        let binding = await this.binding(ctx, id)
        if (!binding) return { found: false }
        this.enabled()
        if (binding.status !== 'active') fail("Unterraum nicht freigegeben", 404)
        await this.allowed(ctx.tenantId, binding.origin)
        if (action === "send") {
            if (!binding.snapshot?.canSend) fail("Unterraum ist nicht zum Schreiben freigegeben", 403)
            const content = await chatContent(input)
            const command = { actorId: ctx.principal.id, roomId: binding.room_id,
                input: { clientId: uuid(input.clientId), text: content.body, image: content.image, revision: Number(binding.revision) } }
            const job = await this.enqueue(this.service.db, { key: `message:${binding.id}:${command.input.clientId}`, ctx, origin: binding.origin,
                action: 'messages.send', payload: command, bindingId: binding.id })
            await this.deliver(job)
            const [message] = await rows(this.service.db, sql`SELECT payload FROM collaboration_remote_messages WHERE binding_id=${binding.id} AND payload->>'clientId'=${command.input.clientId}`)
            const [currentJob] = await rows(this.service.db, sql`SELECT * FROM collaboration_outbox WHERE id=${job.id}`)
            if (currentJob.status === 'failed') fail(currentJob.last_error || "Nachricht konnte nicht gesendet werden", 409)
            return { found: true, result: message?.payload || this.pendingMessage(currentJob) }
        }
        if (["image", "reactions", "react"].includes(action)) {
            const rpc = action === "image" ? "image.get" : action === "react" ? "reactions.set" : "reactions.get"
            try {
                const result = await this.call(ctx.tenantId, binding.origin, rpc, { actorId: ctx.principal.id, roomId: binding.room_id,
                    input: { ...input, revision: Number(binding.revision) } })
                return { found: true, result }
            } catch (error: any) {
                if ([401, 403, 404, 410].includes(error.statusCode)) {
                    // A missing image/message is not by itself evidence of revoked room access.
                    await this.sync(ctx, binding)
                }
                throw error
            }
        }
        const detail = await this.sync(ctx, binding)
        binding = await this.binding(ctx, id)
        if (action === "room") return { found: true, result: detail }
        if (action === "members") {
            if (detail.offline) return { found: true, result: { members: [] } }
            const data = await this.call(ctx.tenantId, binding.origin, 'members.get', { actorId: ctx.principal.id, roomId: binding.room_id })
            if (!Array.isArray(data.members) || data.members.length > 500) fail("Ungültige Teilnehmerliste", 502)
            return { found: true, result: { members: data.members.map((m: any) => ({ id: uuid(m.id), name: text(m.name,400), kind: text(m.kind,10), own: m.own === true })) } }
        }
        if (action === "read") {
            const seq = sequence(input.seq)
            if (!detail.offline) await this.call(ctx.tenantId, binding.origin, 'read', { actorId: ctx.principal.id, roomId: binding.room_id, input: { seq } })
            const [max] = await rows(this.service.db, sql`SELECT max(seq) AS seq FROM collaboration_remote_messages WHERE binding_id=${binding.id}`)
            await this.service.db.execute(sql`UPDATE collaboration_remote_bindings SET last_read_seq=GREATEST(last_read_seq,${Math.min(seq,Number(max.seq || 0))}) WHERE id=${binding.id}`)
            return { found: true, result: { read: true } }
        }
        const before = sequence(input.before), after = sequence(input.after)
        if (before && !detail.offline) {
            const page = await this.call(ctx.tenantId, binding.origin, 'messages.get', { actorId: ctx.principal.id, roomId: binding.room_id, input: { before } })
            await this.cache(binding, page.messages)
        }
        const page = await rows(this.service.db, sql`SELECT payload FROM collaboration_remote_messages WHERE binding_id=${binding.id}
            ${before ? sql`AND seq<${before}` : sql``} ${after ? sql`AND seq>${after}` : sql``}
            ORDER BY seq ${after ? sql`ASC` : sql`DESC`} LIMIT 50`)
        const messages = (after ? page : page.reverse()).map(r => r.payload)
        if (!before) {
            const pending = await rows(this.service.db, sql`SELECT * FROM collaboration_outbox WHERE binding_id=${binding.id} AND status IN ('pending','failed') AND (payload->'input'->>'revision')::bigint=${binding.revision} ORDER BY created_at LIMIT 100`)
            messages.push(...pending.map(job => this.pendingMessage(job)))
        }
        return { found: true, result: { messages, hasMore: page.length === 50, offline: detail.offline } }
    }
    pendingMessage(job: any) {
        return { id: job.payload.input.clientId, clientId: job.payload.input.clientId, seq: null, body: job.payload.input.text, image: imageMetadata(job.payload.input.image),
            createdAt: job.created_at, own: true, senderName: 'Du', senderKind: 'user', pending: job.status === 'pending', failed: job.status === 'failed' }
    }
    async deliver(job: any) {
        const [claimed] = await rows(this.service.db, sql`UPDATE collaboration_outbox SET lease_until=now()+interval '30 seconds',attempts=attempts+1
            WHERE id=${job.id} AND status='pending' AND (lease_until IS NULL OR lease_until<now()) RETURNING *`)
        if (!claimed) return
        try {
            let payload = claimed.payload
            if (claimed.action === 'invitation.deliver') {
                const [invitation] = await rows(this.service.db, sql`SELECT i.*,r.name,r.topic,t.name AS owner_name,r.status AS room_status,p.archived,
                    (SELECT id FROM collaboration_audit WHERE subject_id=i.id AND action='invitation.created' LIMIT 1) AS generation
                    FROM collaboration_invitations i JOIN collaboration_rooms r ON r.id=i.room_id JOIN tenants t ON t.id=r.tenant_id
                    LEFT JOIN projects p ON p.id=r.project_id WHERE i.id=${claimed.payload.invitationId}`)
                if (!invitation || invitation.status !== 'pending' || new Date(invitation.expires_at).getTime() <= Date.now() || invitation.room_status !== 'active' || invitation.archived) fail("Einladung ist nicht mehr aktiv",410)
                const inviter = await this.service.currentUser(invitation.invited_by, Number(claimed.tenant_id))
                if (!inviter.manage) fail("Einladung ist nicht mehr gültig",410)
                payload = { ...payload, offer: { roomId: invitation.room_id, name: invitation.name, topic: invitation.topic, ownerName: invitation.owner_name,
                    role: invitation.role, overviewAllowed: invitation.overview_allowed, expiresAt: invitation.expires_at, createdAt: invitation.created_at, generation: Number(invitation.generation) } }
            }
            if (claimed.action === 'messages.send') {
                const [principal] = await rows(this.service.db, sql`SELECT * FROM collaboration_principals WHERE id=${claimed.principal_id}`)
                await this.service.assertPrincipal(principal)
                const [binding] = await rows(this.service.db, sql`SELECT * FROM collaboration_remote_bindings WHERE id=${claimed.binding_id} AND status='active'`)
                if (!binding || Number(binding.revision) !== payload.input.revision) fail("Teilnahmerechte haben sich geändert",409)
            }
            const result = await this.call(Number(claimed.tenant_id), claimed.origin, claimed.action, payload)
            if (claimed.action === 'messages.send') {
                const [binding] = await rows(this.service.db, sql`SELECT * FROM collaboration_remote_bindings WHERE id=${claimed.binding_id}`)
                await this.cache(binding, [result])
            }
            await this.service.db.execute(sql`UPDATE collaboration_outbox SET status='sent',lease_until=null,last_error=null WHERE id=${claimed.id}`)
        } catch (error: any) {
            const terminal = (error.statusCode >= 400 && error.statusCode < 500 && error.statusCode !== 429) || claimed.attempts >= 20
            await this.service.db.execute(sql`UPDATE collaboration_outbox SET status=${terminal ? 'failed' : 'pending'},lease_until=null,
                last_error=${String(error.message || 'Zustellung fehlgeschlagen').slice(0,300)},
                next_attempt_at=now()+${Math.min(3600, 2 ** Math.min(claimed.attempts,12)) + Math.floor(Math.random()*5)}*interval '1 second' WHERE id=${claimed.id}`)
        }
    }
    async tick() {
        if (this.working) return
        this.working = true
        try {
            if (this.options.enabled) {
            const jobs = await rows(this.service.db, sql`SELECT * FROM collaboration_outbox WHERE status='pending' AND next_attempt_at<=now()
                AND (lease_until IS NULL OR lease_until<now()) ORDER BY next_attempt_at LIMIT 3`)
            await Promise.allSettled(jobs.map(job => this.deliver(job)))
            const bindings = await rows(this.service.db, sql`SELECT b.*,p.user_id FROM collaboration_remote_bindings b
                JOIN collaboration_principals p ON p.id=b.principal_id
                WHERE b.status='active' AND (b.sync_at IS NULL OR b.sync_at<now()-interval '10 seconds') ORDER BY b.sync_at NULLS FIRST LIMIT 3`)
            await Promise.allSettled(bindings.map(async b => {
                try { await this.sync(await this.service.userContext(b.user_id, Number(b.tenant_id)), b) }
                catch (error: any) { if ([401,403,404,410].includes(error.statusCode)) await this.revokeBinding(b) }
            }))
            }
            await this.service.db.execute(sql`DELETE FROM collaboration_federation_nonces WHERE expires_at<now()`)
            await this.service.db.execute(sql`DELETE FROM collaboration_guest_challenges WHERE expires_at<now()-interval '1 day'`)
            await this.service.db.execute(sql`DELETE FROM collaboration_guest_sessions WHERE expires_at<now()`)
            await this.service.db.execute(sql`DELETE FROM collaboration_rate_limits WHERE resets_at<now()-interval '1 day'`)
        } finally { this.working = false }
    }
}

export async function federationRoutes(server: FastifyInstance, { federation }: { federation: FederationService }) {
    server.removeContentTypeParser('application/json')
    server.addContentTypeParser('application/json', { parseAs: 'string', bodyLimit: 1024 * 1024 }, (req: any, body: string, done) => {
        req.federationBody = body
        try { done(null, JSON.parse(body)) } catch { done(Object.assign(new Error('Ungültiges JSON'), { statusCode: 400 })) }
    })
    server.get('/.well-known/fedeo-federation', async () => federation.discovery())
    server.post('/federation/v1/rpc', { bodyLimit: 1024 * 1024 }, async (req: any, reply) => {
        reply.header('Cache-Control','no-store')
        // Duplicate signature-bearing fields are rejected rather than silently combined.
        const names = req.raw.rawHeaders.filter((_: string, index: number) => index % 2 === 0).map((name: string) => name.toLowerCase())
        for (const header of ['signature','signature-input','content-digest','content-type','x-fedeo-origin']) if (names.filter((name: string) => name === header).length !== 1) fail('Mehrdeutige Signaturfelder',401)
        const origin = await federation.authenticate(req.federationBody, req.headers)
        return { version: 1, data: await federation.rpc(origin, req.body) }
    })
}