import { useEffect, useState } from 'react'
import { useZino } from '../api/provider.jsx'
import './ActivityForm.css'

/**
 * Renders whatever /view/form-screens returns for an activity — labels, types,
 * select options and which fields are mandatory — and submits it straight back.
 *
 * Nothing about this form is defined in the frontend. Add a field to the
 * activity in Studio, redeploy, and it appears here with no code change. That
 * is the point: the workflow is the source of truth, and a hardcoded form would
 * quietly drift from it.
 */
export default function ActivityForm({ activityUid, instanceId, onDone, onCancel }) {
  const { client } = useZino()
  const [schema, setSchema] = useState(null)
  const [values, setValues] = useState({})
  const [error, setError] = useState(null)
  const [busy, setBusy] = useState(false)

  useEffect(() => {
    let dead = false
    setSchema(null); setError(null); setValues({})
    client.formSchema(activityUid, instanceId)
      .then((s) => { if (!dead) setSchema(s) })
      .catch((e) => { if (!dead) setError(e) })
    return () => { dead = true }
  }, [client, activityUid, instanceId])

  function set(id, v) { setValues((p) => ({ ...p, [id]: v })) }

  async function submit(e) {
    e.preventDefault()
    setBusy(true); setError(null)
    // Send only fields the activity defines. A submission is schema-validated
    // and an unknown field is fatal, so empties are dropped rather than sent.
    const payload = {}
    for (const f of schema.fields) {
      const v = values[f.id]
      if (v === undefined || v === '' || (Array.isArray(v) && v.length === 0)) continue
      payload[f.id] = f.data_type === 'number' ? Number(v) : v
    }
    try {
      const res = instanceId
        ? await client.activity(instanceId, activityUid, payload)
        : await client.start(activityUid, payload)
      onDone?.(res)
    } catch (err) {
      setError(err)
    } finally {
      setBusy(false)
    }
  }

  if (error && !schema) return <div className="af__err">Could not load the form — {error.status} {error.message}</div>
  if (!schema) return <p className="af__loading">Loading the form…</p>

  return (
    <form className="af" onSubmit={submit}>
      <div className="af__grid">
        {schema.fields.map((f) => {
          const opts = f.properties?.options || []
          const v = values[f.id] ?? (f.data_type === 'multiselect' ? [] : '')
          return (
            <label key={f.uid} className={'af__field' + (f.data_type === 'longtext' ? ' af__field--wide' : '')}>
              <span>{f.name}{f.mandatory ? <em className="af__req">required</em> : null}</span>

              {f.data_type === 'select' ? (
                <select value={v} onChange={(e) => set(f.id, e.target.value)}>
                  <option value="">—</option>
                  {opts.map((o) => <option key={o.value} value={o.value}>{o.label}</option>)}
                </select>
              ) : f.data_type === 'multiselect' ? (
                <div className="af__multi">
                  {opts.map((o) => (
                    <button
                      key={o.value} type="button"
                      className={'af__chip' + (v.includes(o.value) ? ' is-on' : '')}
                      onClick={() => set(f.id, v.includes(o.value) ? v.filter((x) => x !== o.value) : [...v, o.value])}
                    >{o.label}</button>
                  ))}
                </div>
              ) : f.data_type === 'longtext' ? (
                <textarea rows={3} value={v} onChange={(e) => set(f.id, e.target.value)} />
              ) : (
                <input
                  type={f.data_type === 'number' ? 'number' : f.data_type === 'date' ? 'date' : 'text'}
                  value={v} onChange={(e) => set(f.id, e.target.value)}
                />
              )}
            </label>
          )
        })}
      </div>

      {error ? (
        <div className="af__err">
          <strong>{error.status}</strong> {error.message}
          {error.status === 403 || String(error.message).includes('permission denied') ? (
            <p>This is the workflow refusing, not the console. The signed-in role does not hold this activity.</p>
          ) : null}
        </div>
      ) : null}

      <div className="af__actions">
        {onCancel ? <button type="button" className="af__ghost" onClick={onCancel}>Cancel</button> : null}
        <button type="submit" className="af__submit" disabled={busy}>
          {busy ? 'Submitting…' : 'Submit'}
        </button>
      </div>
    </form>
  )
}