import { useEffect, useState } from 'react'
import { useZino } from '../api/provider.jsx'
import ClampText from './ClampText.jsx'
import { STAGES } from '../api/config.js'
import './Timeline.css'

/** Which employee holds which role — used to badge an entry as machine work. */
const AI_ROLES = {
  ai_intake: 'Intake & Attribution',
  ai_engage: 'Engage',
  ai_kyc: 'KYC & Evidence',
  ai_advisor: 'Advisor',
  ai_uw_referral: 'Underwriting Referral',
}

/**
 * The fields worth surfacing per activity — an agent's reasoning, a rule's
 * output, a call's notes. Everything else stays in the file below; a timeline
 * that shows every field is a table, not a story.
 */
const NARRATIVE = [
  ['attribution_reason', 'Attribution'],
  ['eligibility_reason', 'Eligibility'],
  ['dedupe_match_ref', 'Duplicate of'],
  ['contact_notes', 'Call'],
  ['ai_recommendation_rationale', 'Recommendation'],
  ['quoted_breakup', 'How the premium was reached'],
  ['kyc_mismatch_notes', 'KYC'],
  ['referral_analysis', 'Referral analysis'],
  ['uw_decision_notes', 'Underwriting decision'],
  ['documents_notes', 'Documents'],
]

const MONEY = new Set(['quoted_premium', 'commission_amount', 'sme_value_at_risk', 'motor_idv'])

function when(ts) {
  if (!ts) return ''
  const d = new Date(ts)
  const mins = Math.round((Date.now() - d.getTime()) / 60000)
  const rel = mins < 1 ? 'just now'
    : mins < 60 ? `${mins}m ago`
    : mins < 1440 ? `${Math.round(mins / 60)}h ago`
    : `${Math.round(mins / 1440)}d ago`
  return `${d.toLocaleString('en-IN', { day: 'numeric', month: 'short', hour: '2-digit', minute: '2-digit' })} · ${rel}`
}

export default function Timeline({ instanceId }) {
  const { client } = useZino()
  const [rows, setRows] = useState(null)
  const [err, setErr] = useState(null)
  // DATA_UPDATE entries are the platform writing fields, not anyone deciding
  // anything. They are the bulk of a busy trail and they are hidden until asked
  // for — the story is what people and agents did.
  const [showSys, setShowSys] = useState(false)

  useEffect(() => {
    let dead = false
    client.audit(instanceId)
      .then((r) => { if (!dead) setRows(Array.isArray(r) ? r : (r?.data ?? [])) })
      .catch((e) => { if (!dead) setErr(e) })
    return () => { dead = true }
  }, [client, instanceId])

  if (err) return <div className="tl__err">Could not load the timeline — {err.status} {err.message}</div>
  if (!rows) return <p className="tl__loading">Loading the timeline…</p>
  if (!rows.length) return <p className="tl__loading">Nothing has happened yet.</p>

  // Oldest first: a timeline reads forwards.
  const ordered = [...rows].sort((a, b) => String(a.created_at).localeCompare(String(b.created_at)))

  const items = ordered.map((r, i) => {
    const roles = r.user_roles || []
    const aiRole = roles.find((x) => AI_ROLES[x])
    const isSystem = r.activity_id === 'DATA_UPDATE'
    const kind = aiRole ? 'ai' : isSystem ? 'sys' : 'human'
    const d = r.data || {}
    return {
      key: r.id ?? i,
      kind,
      actor: aiRole ? AI_ROLES[aiRole] : (r.user_name || 'System'),
      what: isSystem ? 'Data updated' : (r.activity_name || r.activity_id),
      stage: STAGES.find((s) => s.uid === r.execution_state),
      when: when(r.created_at),
      narrative: NARRATIVE
        .map(([k, label]) => [label, d[k]])
        .filter(([, v]) => v !== undefined && v !== null && String(v).trim() !== ''),
      figures: Object.entries(d)
        .filter(([k, v]) => MONEY.has(k) && v)
        .map(([k, v]) => [k.replace(/_/g, ' '), '₹' + Number(v).toLocaleString('en-IN')]),
    }
  })

  const sysCount = items.filter((it) => it.kind === 'sys').length
  const visible = showSys ? items : items.filter((it) => it.kind !== 'sys')

  return (
    <>
      {sysCount ? (
        <button type="button" className="tl__toggle" onClick={() => setShowSys((v) => !v)}>
          {showSys ? 'Hide' : 'Show'} {sysCount} system update{sysCount === 1 ? '' : 's'}
        </button>
      ) : null}

      <ol className="tl">
        {visible.map((it) => (
          <li key={it.key} className={'tl__item tl__item--' + it.kind}>
            <span className="tl__dot" aria-hidden="true" />
            <div className="tl__body">
              <div className="tl__head">
                <strong className="tl__what">{it.what}</strong>
                {it.stage ? <span className="tl__stage">→ {it.stage.name}</span> : null}
              </div>
              <div className="tl__meta">
                <span className={'tl__who tl__who--' + it.kind}>
                  {it.kind === 'ai' ? 'AI' : it.kind === 'sys' ? 'system' : 'person'} · {it.actor}
                </span>
                <span className="tl__when">{it.when}</span>
              </div>

              {it.narrative.map(([label, v]) => (
                <div className="tl__say" key={label}>
                  <span className="tl__saylabel">{label}</span>
                  <ClampText text={String(v)} lines={2} threshold={120} />
                </div>
              ))}

              {it.figures.length ? (
                <div className="tl__figs">
                  {it.figures.map(([k, v]) => (
                    <span key={k}><em>{k}</em> {v}</span>
                  ))}
                </div>
              ) : null}
            </div>
          </li>
        ))}
      </ol>
    </>
  )
}