import { NostrEvent } from '@nostr/tools/pure'
import { decodeNostrURI } from '@nostr/tools/nip19'
import { normalizeURL } from '@nostr/tools/utils'

import { getInboxRelaysFor, getOutboxRelaysFor, getWindowNostr, pool } from './nostr.js'
import { debounce } from './utils.js'

export default class NostrRSVP extends HTMLElement {
  static observedAttributes = ['ref']

  root: HTMLDivElement
  eventData: NostrEvent | null = null
  setSeq = 0

  constructor() {
    super()

    this.attachShadow({ mode: 'open' })
    const { shadowRoot } = this

    this.root = document.createElement('div')
    shadowRoot!.appendChild(this.root)
  }

  connectedCallback() {
    this.style.display = 'block'
    this.style.width = 'fit-content'
    this.style.height = 'fit-content'
    this.set()
  }

  attributeChangedCallback() {
    this.set()
  }

  set: () => void = debounce(async () => {
    let seq = ++this.setSeq
    let input = this.getAttribute('ref')
    if (!input) return

    let { type, data } = decodeNostrURI(input)
    let relays: string[] = []
    let author: string | undefined
    let filter: any

    if (type === 'nevent') {
      let d = data as any
      relays = d.relays || []
      author = d.author
      filter = { ids: [d.id] }
    } else if (type === 'naddr') {
      let d = data as any
      relays = d.relays || []
      author = d.pubkey
      filter = {
        authors: [d.pubkey],
        kinds: [d.kind],
        '#d': [d.identifier],
      }
    } else if (/^[0-9a-f]{64}$/.test(input)) {
      filter = { ids: [input] }
    } else {
      return
    }

    let hints = relays.map(normalizeURL)

    if (author) {
      let authorRelays = await getOutboxRelaysFor(author)
      hints.push(...authorRelays)
      if (seq !== this.setSeq) return
    }

    let evt = await pool.get(hints, filter)
    if (seq !== this.setSeq) return
    if (!evt || (evt.kind !== 31922 && evt.kind !== 31923)) {
      this.root.innerHTML = '<p part="error">Not a valid calendar event.</p>'
      return
    }

    this.eventData = evt

    const title = evt.tags.find((t: string[]) => t[0] === 'title')?.[1] || 'Untitled Event'

    let timeStr = ''
    if (evt.kind === 31922) {
      const start = evt.tags.find((t: string[]) => t[0] === 'start')?.[1]
      const end = evt.tags.find((t: string[]) => t[0] === 'end')?.[1] || start
      timeStr = `${start}${end !== start ? ` to ${end}` : ''}`
    } else {
      const start = evt.tags.find((t: string[]) => t[0] === 'start')?.[1]
      const end = evt.tags.find((t: string[]) => t[0] === 'end')?.[1]
      if (start) {
        const startDate = new Date(parseInt(start) * 1000)
        timeStr = startDate.toLocaleString()
        if (end) {
          const endDate = new Date(parseInt(end) * 1000)
          timeStr += ` to ${endDate.toLocaleString()}`
        }
      }
    }

    const identifier = evt.tags.find((t: string[]) => t[0] === 'd')?.[1] || ''

    this.root.innerHTML = ''
    const container = document.createElement('div')
    container.setAttribute('part', 'container')

    const titleEl = document.createElement('p')
    titleEl.setAttribute('part', 'title')
    titleEl.title = identifier
    titleEl.textContent = title
    container.appendChild(titleEl)

    const timeEl = document.createElement('p')
    timeEl.setAttribute('part', 'time')
    timeEl.textContent = timeStr
    container.appendChild(timeEl)

    const descEl = document.createElement('p')
    descEl.setAttribute('part', 'description')
    descEl.textContent = evt.content
    container.appendChild(descEl)

    const buttonsDiv = document.createElement('div')
    buttonsDiv.setAttribute('part', 'buttons')

    const add = (part: string, label: string, slotName: string, status: 'accepted' | 'tentative' | 'declined') => {
      let button = document.createElement('button')
      button.setAttribute('part', part)
      const slot = document.createElement('slot')
      slot.name = slotName
      slot.textContent = label
      button.appendChild(slot)
      button.addEventListener('click', () => this.sendRSVP(status))
      buttonsDiv.appendChild(button)
    }
    add('button accepted', 'Going', 'accepted', 'accepted')
    add('button tentative', 'Maybe', 'tentative', 'tentative')
    add('button declined', 'Not going', 'declined', 'declined')
    container.appendChild(buttonsDiv)

    this.root.appendChild(container)
  }, 200)

  async sendRSVP(status: 'accepted' | 'tentative' | 'declined') {
    if (!this.eventData) {
      console.error('Cannot RSVP: missing event data')
      return
    }
    const buttonsDiv = this.root.querySelector('[part="buttons"]')
    const showResult = (part: string, slotName: string, msg: string) => {
      if (!buttonsDiv) return
      buttonsDiv.innerHTML = ''
      const p = document.createElement('p')
      p.setAttribute('part', part)
      const slot = document.createElement('slot')
      slot.name = slotName
      slot.textContent = msg
      p.appendChild(slot)
      buttonsDiv.appendChild(p)
    }

    try {
      const signedEvent = await (
        await getWindowNostr()
      ).signEvent({
        kind: 31925,
        created_at: Math.floor(Date.now() / 1000),
        content: '',
        tags: [
          ['e', this.eventData.id],
          [
            'a',
            `${this.eventData.kind}:${this.eventData.pubkey}:${this.eventData.tags.find((t: string[]) => t[0] === 'd')?.[1]}`,
          ],
          ['d', Math.random().toString().substring(8)],
          ['status', status],
          ['p', this.eventData.pubkey],
        ],
      })
      const pubs = pool.publish(await getInboxRelaysFor(this.eventData!.pubkey), signedEvent)
      await Promise.any(pubs)

      showResult('rsvp-sent', 'rsvp-sent', `RSVP sent: ${status}`)
    } catch (error) {
      console.error('failed to send RSVP:', error)
      showResult('rsvp-failed', 'rsvp-failed', `failed to send RSVP: ${String(error)}`)
    }
  }
}

window.customElements.define('nostr-rsvp', NostrRSVP)