import { publishVideoReaction } from "./nostr.js";
import { normalizePointerInput, pointerKey } from "./nostr/watchHistory.js";
import { devLogger, userLogger } from "./utils/logger.js";

const pointerStates = new Map();
const pointerHandlers = new Map();

function clonePointerDescriptor(pointer) {
  if (!pointer || typeof pointer !== "object") {
    return null;
  }
  const descriptor = {
    type: pointer.type === "a" ? "a" : "e",
    value:
      typeof pointer.value === "string" && pointer.value.trim()
        ? pointer.value.trim()
        : "",
  };
  if (typeof pointer.relay === "string" && pointer.relay.trim()) {
    descriptor.relay = pointer.relay.trim();
  }
  return descriptor;
}

function canonicalizePointerForState(pointerInput) {
  const normalized = normalizePointerInput(pointerInput);
  if (!normalized) {
    return null;
  }
  const key = pointerKey(normalized);
  if (!key) {
    return null;
  }
  const descriptor = clonePointerDescriptor(normalized);
  return descriptor ? { key, pointer: descriptor } : null;
}

function ensurePointerState(key, pointer) {
  let state = pointerStates.get(key);
  if (!state) {
    state = {
      pointer: pointer ? clonePointerDescriptor(pointer) : null,
      totals: new Map(),
      reactionsByPubkey: new Map(),
      lastUpdatedAt: 0,
    };
    pointerStates.set(key, state);
    return state;
  }
  if (pointer) {
    const descriptor = clonePointerDescriptor(pointer);
    if (!state.pointer) {
      state.pointer = descriptor;
    } else if (descriptor?.relay && !state.pointer.relay) {
      state.pointer = { ...state.pointer, relay: descriptor.relay };
    }
  }
  return state;
}

function normalizeReactionEvent(event) {
  if (!event || typeof event !== "object") {
    return null;
  }
  const pubkey =
    typeof event.pubkey === "string" && event.pubkey.trim()
      ? event.pubkey.trim().toLowerCase()
      : "";
  if (!pubkey) {
    return null;
  }
  let content = "+";
  if (typeof event.content === "string") {
    content = event.content;
  } else if (event.content !== undefined && event.content !== null) {
    try {
      content = String(event.content);
    } catch (error) {
      content = "+";
    }
  }
  if (!content) {
    content = "+";
  }
  const createdAt = Number.isFinite(event.created_at)
    ? Math.max(0, Math.floor(event.created_at))
    : 0;
  const eventId =
    typeof event.id === "string" && event.id.trim() ? event.id.trim() : "";
  return { pubkey, content, created_at: createdAt, eventId };
}

function incrementContentCount(state, content) {
  if (typeof content !== "string") {
    return;
  }
  const existing = state.totals.get(content) || 0;
  state.totals.set(content, existing + 1);
}

function decrementContentCount(state, content) {
  if (typeof content !== "string") {
    return;
  }
  const existing = state.totals.get(content);
  if (!existing) {
    return;
  }
  if (existing <= 1) {
    state.totals.delete(content);
  } else {
    state.totals.set(content, existing - 1);
  }
}

function applyReactionToState(key, pointer, event) {
  const normalized = normalizeReactionEvent(event);
  if (!normalized) {
    return false;
  }
  const state = ensurePointerState(key, pointer);
  const existing = state.reactionsByPubkey.get(normalized.pubkey);

  if (existing) {
    if (existing.created_at > normalized.created_at) {
      return false;
    }
    if (
      existing.created_at === normalized.created_at &&
      existing.eventId &&
      normalized.eventId &&
      existing.eventId === normalized.eventId &&
      existing.content === normalized.content
    ) {
      return false;
    }
    if (
      existing.created_at === normalized.created_at &&
      existing.eventId &&
      !normalized.eventId &&
      existing.content === normalized.content
    ) {
      return false;
    }
  }

  let changed = false;
  if (!existing) {
    incrementContentCount(state, normalized.content);
    changed = true;
  } else {
    if (existing.content !== normalized.content) {
      decrementContentCount(state, existing.content);
      incrementContentCount(state, normalized.content);
      changed = true;
    }
  }

  if (
    !existing ||
    existing.created_at !== normalized.created_at ||
    existing.eventId !== normalized.eventId ||
    existing.content !== normalized.content
  ) {
    state.reactionsByPubkey.set(normalized.pubkey, normalized);
    state.lastUpdatedAt = Date.now();
    if (!changed) {
      changed = true;
    }
  }

  return changed;
}

function snapshotState(state) {
  const counts = {};
  let total = 0;
  for (const [content, count] of state.totals.entries()) {
    counts[content] = count;
    total += count;
  }
  const reactions = {};
  for (const [pubkey, record] of state.reactionsByPubkey.entries()) {
    reactions[pubkey] = {
      content: record.content,
      created_at: record.created_at,
      eventId: record.eventId,
    };
  }
  return {
    pointer: state.pointer ? { ...state.pointer } : null,
    total,
    counts,
    reactions,
    lastUpdatedAt: state.lastUpdatedAt,
  };
}

function notifyHandlers(key) {
  const handlers = pointerHandlers.get(key);
  if (!handlers || !handlers.size) {
    return;
  }
  const state = pointerStates.get(key);
  if (!state) {
    return;
  }
  const snapshot = snapshotState(state);
  for (const handler of handlers) {
    if (typeof handler !== "function") {
      continue;
    }
    try {
      handler(snapshot);
    } catch (error) {
      userLogger.warn("[reactionCounter] Reaction handler threw:", error);
    }
  }
}

function subscribeToPointer(pointerInput, handler) {
  if (typeof handler !== "function") {
    return () => {};
  }

  const canonical = canonicalizePointerForState(pointerInput);
  if (!canonical) {
    return () => {};
  }

  const { key, pointer } = canonical;
  const state = ensurePointerState(key, pointer);
  let handlers = pointerHandlers.get(key);
  if (!handlers) {
    handlers = new Set();
    pointerHandlers.set(key, handlers);
  }
  handlers.add(handler);

  if (state) {
    try {
      handler(snapshotState(state));
    } catch (error) {
      userLogger.warn("[reactionCounter] Reaction handler threw:", error);
    }
  }

  return () => {
    unsubscribeFromPointer(pointer, handler);
  };
}

function unsubscribeFromPointer(pointerInput, handler) {
  const canonical = canonicalizePointerForState(pointerInput);
  if (!canonical) {
    return;
  }

  const { key } = canonical;
  const handlers = pointerHandlers.get(key);
  if (!handlers) {
    return;
  }

  if (handler && typeof handler === "function") {
    handlers.delete(handler);
  } else {
    handlers.clear();
  }

  if (handlers.size === 0) {
    pointerHandlers.delete(key);
  }
}

function getPointerSnapshot(pointerInput) {
  const canonical = canonicalizePointerForState(pointerInput);
  if (!canonical) {
    return null;
  }

  const state = pointerStates.get(canonical.key);
  if (!state) {
    return null;
  }

  return snapshotState(state);
}

export function ingestLocalReaction({ event, pointer }) {
  if (!event || !pointer) {
    return;
  }
  try {
    const canonical = canonicalizePointerForState(pointer);
    if (!canonical) {
      return;
    }
    const changed = applyReactionToState(canonical.key, canonical.pointer, event);
    if (changed) {
      notifyHandlers(canonical.key);
    }
  } catch (error) {
    userLogger.warn("[reactionCounter] Failed to ingest local reaction:", error);
  }
}

export const reactionCounter = {
  async publish(pointer, options = {}) {
    try {
      const publishOptions = { ...options };

      const pointerRelayFromPointer = (() => {
        if (Array.isArray(pointer) && pointer.length >= 3) {
          const relay = pointer[2];
          if (typeof relay === "string" && relay.trim()) {
            return relay.trim();
          }
        }
        if (pointer && typeof pointer === "object") {
          const relay = pointer.relay;
          if (typeof relay === "string" && relay.trim()) {
            return relay.trim();
          }
        }
        return "";
      })();

      const pointerRelay =
        typeof publishOptions.pointerRelay === "string" && publishOptions.pointerRelay.trim()
          ? publishOptions.pointerRelay.trim()
          : pointerRelayFromPointer;

      if (pointerRelay && !publishOptions.pointerRelay) {
        publishOptions.pointerRelay = pointerRelay;
      }

      const enrichedPointer = (() => {
        if (!pointerRelay) {
          return pointer;
        }

        if (Array.isArray(pointer) && pointer.length >= 2) {
          const [type, value] = pointer;
          return [type, value, pointerRelay];
        }

        if (pointer && typeof pointer === "object") {
          return { ...pointer, relay: pointerRelay };
        }

        return pointer;
      })();

      const explicitAuthor =
        typeof publishOptions.targetAuthorPubkey === "string" &&
        publishOptions.targetAuthorPubkey.trim()
          ? publishOptions.targetAuthorPubkey.trim()
          : "";

      if (!explicitAuthor) {
        const fallbackAuthor = (() => {
          if (
            typeof publishOptions.authorPubkey === "string" &&
            publishOptions.authorPubkey.trim()
          ) {
            return publishOptions.authorPubkey.trim();
          }
          if (
            typeof publishOptions.currentVideoPubkey === "string" &&
            publishOptions.currentVideoPubkey.trim()
          ) {
            return publishOptions.currentVideoPubkey.trim();
          }
          if (
            publishOptions.video &&
            typeof publishOptions.video.pubkey === "string" &&
            publishOptions.video.pubkey.trim()
          ) {
            return publishOptions.video.pubkey.trim();
          }
          return "";
        })();

        if (fallbackAuthor) {
          publishOptions.targetAuthorPubkey = fallbackAuthor;
        }
      }

      const result = await publishVideoReaction(enrichedPointer, publishOptions);
      if (!result || !result.ok) {
        userLogger.warn(
          "[reactionCounter] Reaction publish rejected by relays:",
          result?.results || result
        );
      } else if (Array.isArray(result.acceptedRelays)) {
        devLogger.info(
          `[reactionCounter] Reaction accepted by ${result.acceptedRelays.length} relay(s):`,
          result.acceptedRelays.join(", ")
        );
        const eventPayload = result.event || {
          pubkey:
            typeof publishOptions.actorPubkey === "string"
              ? publishOptions.actorPubkey
              : undefined,
          content: publishOptions.content,
          created_at: publishOptions.created_at,
        };
        if (eventPayload && eventPayload.pubkey) {
          ingestLocalReaction({
            pointer: enrichedPointer,
            event: eventPayload,
          });
        }
      }
      return result;
    } catch (error) {
      userLogger.warn("[reactionCounter] Failed to publish reaction event:", error);
      throw error;
    }
  },
};

reactionCounter.ingestLocalReaction = ingestLocalReaction;
reactionCounter.subscribe = subscribeToPointer;
reactionCounter.unsubscribe = unsubscribeFromPointer;
reactionCounter.getSnapshot = getPointerSnapshot;

export default reactionCounter;
export {
  subscribeToPointer as subscribeToReactions,
  unsubscribeFromPointer as unsubscribeFromReactions,
  getPointerSnapshot as getReactionSnapshot,
};