import { Injectable, Logger, OnModuleInit } from '@nestjs/common';
import { PlatformGraphqlService } from './platform-graphql.service';

/**
 * Maps Ozonetel agent identifiers (unique — e.g. "ramaiahadmin",
 * "globalhealthx", "global") to the platform Agent entity UUID. Used by
 * ingest paths (webhook, dispose, CDR enrichment, backfill) so every Call
 * ends up with the correct `agent` relation regardless of how Ozonetel
 * formats the display name (AgentName collisions, transfer chains like
 * "A -> B -> C", etc.).
 *
 * The cache is case-insensitive because Ozonetel occasionally mixes
 * casing ("global" vs "Global" vs "GLOBAL") across webhook/CDR responses.
 */
@Injectable()
export class AgentLookupService implements OnModuleInit {
    private readonly logger = new Logger(AgentLookupService.name);
    private readonly uuidByOzonetelId = new Map<string, string>();
    private readonly uuidByDisplayName = new Map<string, string>();

    constructor(private readonly platform: PlatformGraphqlService) {}

    async onModuleInit() {
        await this.refresh();
    }

    async refresh(): Promise<void> {
        try {
            const data = await this.platform.query<any>(
                `{ agents(first: 100) { edges { node { id ozonetelAgentId ozonetelDisplayName } } } }`,
            );
            const edges = data?.agents?.edges ?? [];
            this.uuidByOzonetelId.clear();
            this.uuidByDisplayName.clear();
            for (const edge of edges) {
                const n = edge.node;
                if (n.ozonetelAgentId) {
                    this.uuidByOzonetelId.set(n.ozonetelAgentId.toLowerCase(), n.id);
                }
                if (n.ozonetelDisplayName) {
                    this.uuidByDisplayName.set(n.ozonetelDisplayName.toLowerCase().trim(), n.id);
                }
            }
            this.logger.log(`[AGENT-LOOKUP] Loaded ${this.uuidByOzonetelId.size} agents (${this.uuidByDisplayName.size} with display name)`);
        } catch (err) {
            this.logger.warn(`[AGENT-LOOKUP] Refresh failed: ${err}`);
        }
    }

    async resolveByOzonetelId(ozonetelId: string | null | undefined): Promise<string | null> {
        if (!ozonetelId) return null;
        const key = ozonetelId.toLowerCase();
        const cached = this.uuidByOzonetelId.get(key);
        if (cached) return cached;
        // Cache miss — refresh once (handles late-provisioned agents)
        await this.refresh();
        return this.uuidByOzonetelId.get(key) ?? null;
    }

    // Resolve by Ozonetel display name (e.g. "Ganesh Bandi") — used by
    // missed-call webhook backfill where only AgentName (display) is available.
    async resolveByDisplayName(displayName: string | null | undefined): Promise<string | null> {
        if (!displayName) return null;
        const key = displayName.toLowerCase().trim();
        const cached = this.uuidByDisplayName.get(key);
        if (cached) return cached;
        await this.refresh();
        return this.uuidByDisplayName.get(key) ?? null;
    }
}