import { Event, EventTemplate, getEventHash, signEvent, nip19, SimplePool } from 'nostr-tools'
import type { Article, NostrProfile } from '@/types/nostr'
import type { SimplePoolWithSub } from '@/types/nostr-tools-extended'
import { parseArticleFromEvent } from './nostrEventParsing'
import { getPrivateContent as getPrivateContentFromPool } from './nostrPrivateMessages'
import { checkZapReceipt as checkZapReceiptHelper } from './nostrZapVerification'
import { subscribeWithTimeout } from './nostrSubscription'

const RELAY_URL = process.env.NEXT_PUBLIC_NOSTR_RELAY_URL ?? 'wss://relay.damus.io'

class NostrService {
  private pool: SimplePool | null = null
  private privateKey: string | null = null
  private publicKey: string | null = null

  constructor() {
    if (typeof window !== 'undefined') {
      this.initializePool()
    }
  }

  private initializePool() {
    this.pool = new SimplePool()
  }

  setPrivateKey(privateKey: string) {
    this.privateKey = privateKey
    try {
      const decoded = nip19.decode(privateKey)
      if (decoded.type === 'nsec' && typeof decoded.data === 'string') {
        this.privateKey = decoded.data
      }
    } catch (_e) {
      // Assume it's already a hex string
    }
  }

  getPrivateKey(): string | null {
    return this.privateKey
  }

  getPublicKey(): string | null {
    return this.publicKey
  }

  setPublicKey(publicKey: string) {
    this.publicKey = publicKey
    try {
      const decoded = nip19.decode(publicKey)
      if (decoded.type === 'npub' && typeof decoded.data === 'string') {
        this.publicKey = decoded.data
      }
    } catch (_e) {
      // Assume it's already a hex string
    }
  }

  async publishEvent(eventTemplate: EventTemplate): Promise<Event | null> {
    if (!this.privateKey || !this.pool) {
      throw new Error('Private key not set or pool not initialized')
    }

    const unsignedEvent = {
      pubkey: this.publicKey ?? '',
      ...eventTemplate,
      created_at: eventTemplate.created_at ?? Math.floor(Date.now() / 1000),
    }

    const event = {
      ...unsignedEvent,
      id: getEventHash(unsignedEvent),
      sig: signEvent(unsignedEvent, this.privateKey),
    } as Event

    try {
      const pubs = this.pool.publish([RELAY_URL], event)
      await Promise.all(pubs)
      return event
    } catch (e) {
      throw new Error(`Publish failed: ${e}`)
    }
  }

  subscribeToArticles(callback: (article: Article) => void, limit: number = 100): () => void {
    if (typeof window === 'undefined') {
      throw new Error('Cannot subscribe on server side')
    }

    if (!this.pool) {
      this.initializePool()
    }

    if (!this.pool) {
      throw new Error('Pool not initialized')
    }

    const filters = [
      {
        kinds: [1], // Text notes (includes both articles and presentation articles)
        limit,
      },
    ]

    const pool = this.pool as SimplePoolWithSub
    const sub = pool.sub([RELAY_URL], filters)

    sub.on('event', (event: Event) => {
      try {
        const article = parseArticleFromEvent(event)
        if (article) {
          callback(article)
        }
      } catch (e) {
        console.error('Error parsing article:', e)
      }
    })

    return () => {
      sub.unsub()
    }
  }

  getArticleById(eventId: string): Promise<Article | null> {
    if (!this.pool) {
      throw new Error('Pool not initialized')
    }

    const filters = [{ ids: [eventId], kinds: [1] }]
    return subscribeWithTimeout(this.pool, filters, parseArticleFromEvent, 5000)
  }

  getPrivateContent(eventId: string, authorPubkey: string): Promise<string | null> {
    if (!this.privateKey || !this.pool || !this.publicKey) {
      throw new Error('Private key not set or pool not initialized')
    }

    return getPrivateContentFromPool(this.pool, eventId, authorPubkey, this.privateKey, this.publicKey)
  }

  getProfile(pubkey: string): Promise<NostrProfile | null> {
    if (!this.pool) {
      throw new Error('Pool not initialized')
    }

    const filters = [
      {
        kinds: [0],
        authors: [pubkey],
        limit: 1,
      },
    ]

    const parseProfile = (event: Event) => {
      try {
        const profile = JSON.parse(event.content) as NostrProfile
        return { ...profile, pubkey }
      } catch (error) {
        console.error('Error parsing profile:', error)
        return null
      }
    }

    return subscribeWithTimeout(this.pool, filters, parseProfile, 5000)
  }


  async createZapRequest(targetPubkey: string, targetEventId: string, amount: number): Promise<Event> {
    if (!this.privateKey) {
      throw new Error('Private key not set')
    }

    const zapRequest: EventTemplate = {
      kind: 9734, // Zap request
      created_at: Math.floor(Date.now() / 1000),
      tags: [
        ['p', targetPubkey],
        ['e', targetEventId],
        ['amount', amount.toString()],
        ['relays', RELAY_URL],
      ],
      content: '',
    }

    const event = await this.publishEvent(zapRequest)
    if (!event) {
      throw new Error('Failed to create zap request')
    }
    return event
  }

  // Check if user has paid for an article by looking for zap receipts
  checkZapReceipt(
    targetPubkey: string,
    targetEventId: string,
    amount: number,
    userPubkey?: string
  ): Promise<boolean> {
    if (!this.publicKey || !this.pool) {
      return Promise.resolve(false)
    }

    // Use provided userPubkey or fall back to current public key
    const checkPubkey = userPubkey ?? this.publicKey

    return checkZapReceiptHelper(this.pool, targetPubkey, targetEventId, amount, checkPubkey)
  }

  /**
   * Get the pool instance (for use by other services)
   */
  getPool(): SimplePool | null {
    return this.pool
  }
}

export const nostrService = new NostrService()