import { nostrClient } from "../nostrClientFacade.js";
import { devLogger } from "../utils/logger.js";
import { relaySubscriptionService } from "./relaySubscriptionService.js";
import { HEX64_REGEX } from "../utils/hex.js";

const DEFAULT_PROFILE_IMAGE = "assets/svg/default-profile.svg";

const inFlight = new Map();

function normalizePubkey(pubkey) {
  if (typeof pubkey !== "string") {
    return "";
  }

  const trimmed = pubkey.trim();
  if (!trimmed || !HEX64_REGEX.test(trimmed)) {
    return "";
  }

  return trimmed.toLowerCase();
}

function resolveRelays(relays, nostr) {
  if (Array.isArray(relays) && relays.length) {
    return relays.filter((relay) => typeof relay === "string" && relay.trim());
  }

  if (Array.isArray(nostr?.readRelays) && nostr.readRelays.length) {
    return nostr.readRelays.filter((relay) => typeof relay === "string" && relay.trim());
  }

  if (Array.isArray(nostr?.relays) && nostr.relays.length) {
    return nostr.relays.filter((relay) => typeof relay === "string" && relay.trim());
  }

  return [];
}

function parseProfileEvent(event, defaultProfileImage) {
  if (!event || typeof event !== "object" || !event.content) {
    return null;
  }

  try {
    const data = JSON.parse(event.content);
    const profile = {
      name: data?.display_name || data?.name || "Unknown",
      picture: data?.picture || defaultProfileImage,
    };

    const about = typeof data?.about === "string" ? data.about : "";
    if (about) {
      profile.about = about;
    }

    const website = typeof data?.website === "string" ? data.website : "";
    if (website) {
      profile.website = website;
    }

    const banner = typeof data?.banner === "string" ? data.banner : "";
    if (banner) {
      profile.banner = banner;
    }

    const lud16 = typeof data?.lud16 === "string" ? data.lud16 : "";
    if (lud16) {
      profile.lud16 = lud16;
    }

    const lud06 = typeof data?.lud06 === "string" ? data.lud06 : "";
    if (lud06) {
      profile.lud06 = lud06;
    }

    return profile;
  } catch (error) {
    devLogger.warn("[profileMetadata] Failed to parse profile event", error);
    return null;
  }
}

async function performProfileFetch({
  pubkeys,
  nostr,
  relays,
  logger,
  defaultProfileImage,
} = {}) {
  if (!nostr?.pool || typeof nostr.pool.list !== "function") {
    logger.warn("[profileMetadata] Relay pool is not ready; skipping profile fetch.");
    return new Map();
  }

  const relayUrls = resolveRelays(relays, nostr);
  if (!relayUrls.length) {
    logger.warn("[profileMetadata] No relays configured; skipping profile fetch.");
    return new Map();
  }

  const filter = {
    kinds: [0],
    authors: pubkeys,
    limit: pubkeys.length,
  };

  const newestProfiles = new Map();

  // Prefer the L1 SubscriptionManager: ONE deduped, health-gated list() across
  // all relays (the pool merges per-relay results) instead of a manual
  // per-relay fan-out. Falls back to the legacy per-relay path in manager-less
  // environments (tests / mock clients).
  const manager =
    typeof nostr.getSubscriptionManager === "function"
      ? nostr.getSubscriptionManager()
      : null;

  let events = [];
  if (manager) {
    try {
      const result = await manager.list({ filters: [filter], relays: relayUrls });
      events = Array.isArray(result) ? result : [];
    } catch (error) {
      logger.warn("[profileMetadata] Batched profile fetch failed:", error);
    }
  } else {
    const results = await Promise.allSettled(
      relayUrls.map((relayUrl) =>
        nostr.pool
          .list([relayUrl], [filter])
          .then((relayEvents) => ({ relayUrl, relayEvents }))
      )
    );
    results.forEach((result, index) => {
      if (result.status !== "fulfilled") {
        logger.warn(
          `[profileMetadata] Failed to fetch profiles from relay ${relayUrls[index]}:`,
          result.reason,
        );
        return;
      }
      if (Array.isArray(result.value.relayEvents)) {
        events.push(...result.value.relayEvents);
      }
    });
  }

  for (const event of events) {
    const pubkey = normalizePubkey(event?.pubkey);
    if (!pubkey) {
      continue;
    }

    const createdAt = Number.isFinite(event?.created_at) ? event.created_at : 0;
    const previous = newestProfiles.get(pubkey);
    if (previous && previous.createdAt >= createdAt) {
      continue;
    }

    const profile = parseProfileEvent(event, defaultProfileImage);
    if (!profile) {
      continue;
    }

    newestProfiles.set(pubkey, { createdAt, profile, event });
  }

  return newestProfiles;
}

export async function fetchProfileMetadataBatch({
  pubkeys,
  nostr = nostrClient,
  relays = null,
  logger = devLogger,
  defaultProfileImage = DEFAULT_PROFILE_IMAGE,
} = {}) {
  const normalizedPubkeys = Array.isArray(pubkeys)
    ? pubkeys.map(normalizePubkey).filter(Boolean)
    : [];

  if (!normalizedPubkeys.length) {
    return new Map();
  }

  const uniquePubkeys = Array.from(new Set(normalizedPubkeys));
  const results = new Map();
  const waiters = [];
  const toFetch = [];

  uniquePubkeys.forEach((pubkey) => {
    const existing = inFlight.get(pubkey);
    if (existing) {
      logger.debug?.("[profileMetadata] Reusing in-flight profile fetch", {
        pubkey,
      });
      waiters.push(
        existing.then((entry) => {
          if (entry) {
            results.set(pubkey, entry);
          }
        }),
      );
      return;
    }
    toFetch.push(pubkey);
  });

  let batchPromise = null;
  if (toFetch.length) {
    logger.debug?.("[profileMetadata] Fetching profile metadata", {
      count: toFetch.length,
    });
    const fetchPromise = performProfileFetch({
      pubkeys: toFetch,
      nostr,
      relays,
      logger,
      defaultProfileImage,
    });

    toFetch.forEach((pubkey) => {
      const perPubkeyPromise = fetchPromise
        .then((map) => map.get(pubkey) || null)
        .finally(() => {
          if (inFlight.get(pubkey) === perPubkeyPromise) {
            inFlight.delete(pubkey);
          }
        });
      inFlight.set(pubkey, perPubkeyPromise);
    });

    batchPromise = fetchPromise.then((map) => {
      map.forEach((value, pubkey) => results.set(pubkey, value));
    });
  }

  await Promise.all([...waiters, batchPromise].filter(Boolean));

  return results;
}

export async function fetchProfileMetadata(pubkey, options = {}) {
  const normalized = normalizePubkey(pubkey);
  if (!normalized) {
    return null;
  }

  const results = await fetchProfileMetadataBatch({
    pubkeys: [normalized],
    ...options,
  });

  return results.get(normalized) || null;
}

export function ensureProfileMetadataSubscription({
  pubkey,
  nostr = nostrClient,
  relays = null,
  logger = devLogger,
  defaultProfileImage = DEFAULT_PROFILE_IMAGE,
  onProfile,
} = {}) {
  const normalized = normalizePubkey(pubkey);
  if (!normalized || !nostr?.pool) {
    return null;
  }

  const relayUrls = resolveRelays(relays, nostr);
  const filters = [{ kinds: [0], authors: [normalized], limit: 1 }];
  const key = `profile:${normalized}`;

  return relaySubscriptionService.ensureSubscription({
    key,
    pool: nostr.pool,
    relays: relayUrls,
    filters,
    label: "profile-metadata",
    onEvent: (event) => {
      if (!event || event.pubkey !== normalized) {
        return;
      }
      const profile = parseProfileEvent(event, defaultProfileImage);
      if (!profile) {
        return;
      }
      if (typeof onProfile === "function") {
        try {
          onProfile({ profile, event });
        } catch (error) {
          logger.warn("[profileMetadata] onProfile callback threw", error);
        }
      }
    },
  });
}