import { useEffect, useRef } from 'react'
import { baseFieldId } from '../api/config.js'
import './Conversation.css'

/**
 * The WhatsApp thread, read out of the audit trail.
 *
 * The trail shows each turn as its own entry among twenty others, so reading a
 * conversation meant scrolling a log and holding the order in your head. Here
 * it is what it is: a thread, oldest first, theirs on the left and ours on the
 * right.
 *
 * WHAT IT CAN AND CANNOT SHOW, said plainly at the foot of the panel rather
 * than left for someone to discover. The console can only show what the
 * workflow RECORDS, so anything sent from inside a trigger node and never
 * written to a field is invisible here however certainly the customer received
 * it. The acceptance confirmation used to be exactly that — the panel showed
 * nothing after "I confirm", which read as though we had ignored somebody
 * agreeing to buy — so 90 writes it into customer_answer and it appears.
 *
 * One send remains absent: the quote, which is a registered WhatsApp template
 * rather than text we compose. The "I have your message" receipt used to be a
 * second — it is gone from the workflow now (97), because it put a line saying
 * only "an answer is coming" between every question and its answer.
 *
 * A thread that quietly omitted any of this would be worse than one that says
 * which parts it holds.
 */
function turnsFrom(rows) {
  if (!Array.isArray(rows)) return []
  const out = []
  // Sorted on (timestamp, id). One submission writes three rows in the same
  // second — the trigger commit, its repeat, and the settle — so a timestamp
  // alone leaves their order to the sort's stability and puts a reply before
  // the message it answers whenever the two land in the same second.
  const ordered = [...rows].sort((a, b) => {
    const t = String(a.created_at).localeCompare(String(b.created_at))
    return t !== 0 ? t : (Number(a.id) || 0) - (Number(b.id) || 0)
  })
  for (const r of ordered) {
    const fields = Array.isArray(r.fields) && r.fields.length
      ? r.fields
      : Object.entries(r.data || {}).map(([k, v]) => ({ field_id: k, value: v }))
    for (const f of fields) {
      const base = baseFieldId(f.field_id)
      const v = typeof f.value === 'string' ? f.value.trim() : ''
      if (!v) continue
      if (base === 'customer_reply') out.push({ side: 'them', text: v, at: r.created_at, key: r.id + '-in' })
      if (base === 'customer_answer') out.push({ side: 'us', text: v, at: r.created_at, key: r.id + '-out' })
    }
  }
  // One submission is recorded three times — the trigger commit, its repeat,
  // and the settle — so the same sentence would print three times.
  //
  // De-duped against the PREVIOUS turn only, not against the whole thread. A
  // customer who asks the same thing twice because the first went unanswered
  // has said it twice, and a thread that silently showed it once would hide
  // exactly the impatience an operator needs to see. Only an immediate repeat
  // of the same side and the same words is the platform talking to itself.
  return out.filter((t, i) => {
    const prev = out[i - 1]
    return !(prev && prev.side === t.side && prev.text === t.text)
  })
}

function at(ts) {
  const d = new Date(ts)
  if (isNaN(d)) return ''
  return d.toLocaleString('en-IN', { day: 'numeric', month: 'short', hour: '2-digit', minute: '2-digit' })
}

export default function Conversation({ rows, name, onClose }) {
  const ref = useRef(null)
  const restore = useRef(null)
  const turns = turnsFrom(rows)

  useEffect(() => {
    restore.current = document.activeElement
    ref.current?.focus()
    const onKey = (e) => { if (e.key === 'Escape') onClose() }
    document.addEventListener('keydown', onKey)
    const prev = document.body.style.overflow
    document.body.style.overflow = 'hidden'
    return () => {
      document.removeEventListener('keydown', onKey)
      document.body.style.overflow = prev
      if (restore.current instanceof HTMLElement) restore.current.focus()
    }
  }, [onClose])

  return (
    <div className="prose__scrim" onClick={onClose} role="presentation">
      <div
        className="prose__dlg conv"
        role="dialog"
        aria-modal="true"
        aria-label="WhatsApp conversation"
        tabIndex={-1}
        ref={ref}
        onClick={(e) => e.stopPropagation()}
      >
        <div className="prose__head">
          <h3>WhatsApp with {name || 'the customer'}</h3>
          <button type="button" onClick={onClose} aria-label="Close">
            <svg viewBox="0 0 14 14" aria-hidden="true">
              <path d="M3.5 3.5l7 7M10.5 3.5l-7 7" fill="none" stroke="currentColor"
                    strokeWidth="1.6" strokeLinecap="round" />
            </svg>
          </button>
        </div>

        <div className="conv__body">
          {turns.length ? turns.map((t) => (
            <div key={t.key} className={'bub bub--' + t.side}>
              <p>{t.text}</p>
              <span>{at(t.at)}</span>
            </div>
          )) : (
            <p className="conv__empty">Nothing has been exchanged on WhatsApp yet.</p>
          )}
        </div>

        <p className="conv__note">
          Shows the customer&apos;s messages and everything written back to them,
          including the acceptance confirmation. One automatic send is not here:
          the quote, which goes out as a registered WhatsApp template rather than
          text we compose.
        </p>
      </div>
    </div>
  )
}