import { useState, useEffect, useCallback } from 'react'
import useTheme from '../theme.jsx'
import useAuth from '../auth.jsx'

export default function StatusBar({ view, sources = [], sourceId, setSourceId, versions = [], versionId }) {
  const { dark, setDark } = useTheme()
  const { user, logout } = useAuth()
  const showVersion = view === 'baseline' || view === 'forecast'
  const selectedVersion = versions.find(v => String(v.id) === String(versionId))

  const [info, setInfo]     = useState(null)
  const [showInfo, setShow] = useState(false)
  const [copied, setCopied] = useState(false)
  // Forecast.jsx mirrors the pivot's own updating state onto this event. The
  // viewer shows the same thing as a beaker in its settings panel, which is
  // exactly where you cannot see it once the panel is closed.
  const [busy, setBusy]     = useState(false)

  const refreshInfo = useCallback(async () => {
    if (!versionId || !showVersion) { setInfo(null); return }
    try {
      const r = await fetch(`/api/versions/${versionId}/table-info`)
      setInfo(r.ok ? await r.json() : null)
    } catch { setInfo(null) }
  }, [versionId, showVersion])

  useEffect(() => { refreshInfo() }, [refreshInfo])

  // operations broadcast this after a write so the row count stays honest
  useEffect(() => {
    const onChange = () => refreshInfo()
    window.addEventListener('pf-data-changed', onChange)
    return () => window.removeEventListener('pf-data-changed', onChange)
  }, [refreshInfo])

  useEffect(() => {
    const onBusy = (e) => setBusy(!!e.detail?.busy)
    window.addEventListener('pf-pivot-busy', onBusy)
    return () => window.removeEventListener('pf-pivot-busy', onBusy)
  }, [])

  async function copyTable() {
    if (!info?.fc_table) return
    try {
      await navigator.clipboard.writeText(info.fc_table)
      setCopied(true)
      setTimeout(() => setCopied(false), 1200)
    } catch {}
  }

  const fmt = (n) => n == null ? '—' : n.toLocaleString()

  return (
    <div className="bg-white border-b border-gray-200 px-3 h-9 flex items-center gap-3 shrink-0 text-xs relative">
      {/* Source is a Setup concern: the raw table name means nothing to someone
          editing a forecast, and a version carries its own source, so picking a
          forecast in the sidebar settles it everywhere else. */}
      {view === 'setup' && (
        <>
          <span className="text-gray-400">Source</span>
          <select
            value={sourceId || ''}
            onChange={e => setSourceId(e.target.value)}
            disabled={sources.length === 0}
            className="border border-gray-200 rounded px-2 py-0.5 bg-white"
          >
            {sources.length === 0
              ? <option value="">— no sources —</option>
              : sources.map(s => <option key={s.id} value={s.id}>{s.tname}</option>)}
          </select>
        </>
      )}

      {showVersion && (
        <>
          {/* What is open, and how big it is -- the two things a forecaster
              wants from a status bar. The physical table it writes to is an
              implementation detail and means nothing to a sales account, so it
              has moved into the hover panel and onto the Baseline page, which
              is where a version's plumbing is managed. */}
          {info && (
            <>
              <span className="text-gray-200">|</span>
              <span
                onMouseEnter={() => setShow(true)}
                onMouseLeave={() => setShow(false)}
                className="font-medium text-gray-700 cursor-default"
                title="Hover for the write target and row breakdown"
              >
                {selectedVersion?.name || '—'}
              </span>
              <span className={`font-mono ${info.exists ? 'text-gray-400' : 'text-amber-700'}`}>
                {info.exists ? `${fmt(info.rows)} rows` : 'not created'}
              </span>

              {showInfo && (
                <div className="absolute top-9 left-0 z-30 bg-white border border-gray-200 rounded shadow-lg p-3 text-xs min-w-[260px]">
                  <div className="text-gray-400 uppercase tracking-wide mb-2" style={{ fontSize: '10px' }}>Write target</div>
                  <div className="grid grid-cols-[auto_1fr] gap-x-3 gap-y-1">
                    <span className="text-gray-400">table</span>
                    {/* Still copyable, just no longer the headline: pasting it
                        into psql is the reason it was ever on screen. */}
                    <button
                      onClick={copyTable}
                      title="Click to copy table name"
                      className="font-mono text-gray-700 text-left hover:text-blue-700"
                    >
                      {copied ? 'copied!' : info.fc_table}
                    </button>
                    <span className="text-gray-400">reads from</span>
                    <span className="font-mono text-gray-700">{info.source}</span>
                    <span className="text-gray-400">total rows</span>
                    <span className="font-mono text-gray-700">{fmt(info.rows)}</span>
                  </div>
                  {info.by_iter?.length > 0 && (
                    <>
                      <div className="text-gray-400 uppercase tracking-wide mt-3 mb-1" style={{ fontSize: '10px' }}>Rows by iter</div>
                      <table className="w-full">
                        <tbody>
                          {info.by_iter.map(r => (
                            <tr key={r.pf_iter}>
                              <td className="text-gray-500 capitalize pr-3">{r.pf_iter}</td>
                              <td className="text-right font-mono text-gray-700">{fmt(r.n)}</td>
                            </tr>
                          ))}
                        </tbody>
                      </table>
                    </>
                  )}
                </div>
              )}
            </>
          )}
        </>
      )}

      {/* Left of the ml-auto block, so it sits beside the pivot's own figures
          rather than out among the account controls. Occupies no space at all
          when idle: a permanently reserved slot reads as a thing that is broken
          when empty. */}
      {busy && view === 'forecast' && (
        <span
          className="flex items-center gap-1.5 text-blue-600"
          title="The pivot is rebuilding its view — sorting, filtering, or changing depth on a large grain takes a moment"
        >
          <svg width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor"
               strokeWidth="3" strokeLinecap="round" className="animate-spin">
            <path d="M12 3a9 9 0 1 0 9 9" />
          </svg>
          Calculating…
        </span>
      )}

      <div className="ml-auto flex items-center gap-2">
        {user && (
          <>
            <span className="text-gray-500" title={`Signed in as ${user.username}`}>
              {user.display_name || user.username}
            </span>
            <button
              onClick={logout}
              className="text-xs text-gray-500 hover:text-gray-700 border border-gray-200 px-2 py-0.5 rounded"
              title="Sign out"
            >
              Sign out
            </button>
          </>
        )}
        <button
          onClick={() => setDark(d => !d)}
          className="w-6 h-6 flex items-center justify-center rounded hover:bg-gray-100"
          title={dark ? 'Switch to light mode' : 'Switch to dark mode'}
        >
          {dark ? (
            <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
              <circle cx="12" cy="12" r="4"/>
              <line x1="12" y1="2" x2="12" y2="5"/>
              <line x1="12" y1="19" x2="12" y2="22"/>
              <line x1="4.93" y1="4.93" x2="7.05" y2="7.05"/>
              <line x1="16.95" y1="16.95" x2="19.07" y2="19.07"/>
              <line x1="2" y1="12" x2="5" y2="12"/>
              <line x1="19" y1="12" x2="22" y2="12"/>
              <line x1="4.93" y1="19.07" x2="7.05" y2="16.95"/>
              <line x1="16.95" y1="7.05" x2="19.07" y2="4.93"/>
            </svg>
          ) : (
            <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
              <path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z"/>
            </svg>
          )}
        </button>
      </div>
    </div>
  )
}