// ── The leaderboard ───────────────────────────────────────────────────────
//
// Per wipe when a wipe is selected, all-time when it is not (R12). The two are
// the same rows summed differently rather than two sets of counters, so they can
// never disagree — which is worth knowing here because it means "All time" is
// not a slower or less accurate answer, it is the same table without a WHERE.
//
// It does NOT poll. A leaderboard moves on the scale of a session; a table that
// re-sorted itself under the reader's cursor every twenty seconds would be worse
// than one that is four minutes old, and the page has a `Refresh` on the tab
// strip for anybody who disagrees.
//
// RunicNPC (runicnpc stage 4). Where the server has NPC profiles, "Rank by"
// offers each one's kills, counted as the profile says (D247, D250), and opening
// a player's row shows their kills of each profile for the wipe shown (D252).

import { useState } from 'react'

import { ErrorState, Loading, useAsync } from '../core.js'
import Empty from './Empty.jsx'
import { ago, contrastInk, count, duration, shortId } from '../lib/format.js'
import api from '../api.js'

// `sort` is the API's own vocabulary (`kills`, `deaths`, `npcKills`, `playtime`),
// and the column it maps to is this file's. Keeping them in one list is what
// stops a header that sorts by something other than what it says.
const COLUMNS = [
  { key: 'kills', label: 'Kills', sort: 'kills', value: (r) => count(r.kills) },
  { key: 'deaths', label: 'Deaths', sort: 'deaths', value: (r) => count(r.deaths) },
  { key: 'npcKills', label: 'NPC kills', sort: 'npcKills', value: (r) => count(r.npcKills) },
  { key: 'structures', label: 'Structures', sort: null, value: (r) => count(r.structures) },
  { key: 'playtimeSec', label: 'Played', sort: 'playtime', value: (r) => duration(r.playtimeSec) },
]

export default function Leaderboard({ serverId, wipeId, sort, onSort }) {
  const { data: npc } = useAsync(() => api.servers.npcProfiles(serverId).catch(() => ({ profiles: [] })), [serverId])
  const [profileId, setProfileId] = useState('')
  const profiles = (npc && npc.profiles) || []
  const picked = profiles.find((p) => String(p.id) === String(profileId))

  const picker = profiles.length > 0 && (
    <label className="sans" style={{ display: 'flex', gap: 8, alignItems: 'baseline', fontSize: '0.82rem', marginBottom: 10 }}>
      <span style={{ color: 'var(--dim)' }}>Rank by</span>
      <select
        value={profileId}
        onChange={(e) => setProfileId(e.target.value)}
        style={{ background: 'transparent', color: 'var(--ink)', border: '1px solid var(--line)', borderRadius: 6, padding: '4px 6px', font: 'inherit' }}
      >
        <option value="">Overall</option>
        {profiles.map((p) => <option key={p.id} value={p.id}>{p.label} kills</option>)}
      </select>
      {picked && <span style={{ color: 'var(--dim)' }}>{SCOPE_NOTE[picked.killsScope] || ''}</span>}
    </label>
  )

  if (picked) {
    return (
      <div>
        {picker}
        <ProfileBoard serverId={serverId} wipeId={wipeId} profile={picked} />
      </div>
    )
  }

  return (
    <div>
      {picker}
      <Overall serverId={serverId} wipeId={wipeId} sort={sort} onSort={onSort} />
    </div>
  )
}

/** How a profile's kills are counted, in the reader's words (D247). */
const SCOPE_NOTE = {
  server: 'Counted on this server.',
  name: 'Counted on every server with this NPC.',
  profile: 'Counted wherever this NPC is placed.',
}

function Overall({ serverId, wipeId, sort, onSort }) {
  const [open, setOpen] = useState(null)
  const { data, loading, error } = useAsync(
    () => api.servers.leaderboard(serverId, { wipe: wipeId, sort, limit: 50 }),
    [serverId, wipeId, sort],
  )

  const rows = data ? data.leaderboard : []
  // Present on every row or on none — the server decides per request.
  const showLastSeen = rows.some((row) => 'lastSeen' in row)

  if (loading) return <Loading />
  if (error) return <ErrorState error={error} />

  if (rows.length === 0) {
    return (
      <Empty
        title="No scores yet"
        message={
          wipeId
            ? 'Nobody has done anything countable on this wipe yet.'
            : 'This server has not reported anything countable yet.'
        }
      />
    )
  }

  return (
    <div style={{ overflowX: 'auto' }}>
      <table className="sans" style={{ width: '100%', borderCollapse: 'collapse', fontSize: '0.86rem' }}>
        <thead>
          <tr style={{ textAlign: 'left', color: 'var(--dim)', fontSize: '0.72rem', letterSpacing: '0.08em' }}>
            <th style={{ ...cell, textTransform: 'uppercase' }}>Player</th>
            {COLUMNS.map((column) => (
              <th key={column.key} style={{ ...cell, textAlign: 'right', textTransform: 'uppercase' }}>
                {column.sort ? (
                  <button
                    type="button"
                    onClick={() => onSort(column.sort)}
                    aria-label={`Sort by ${column.label}`}
                    style={{
                      cursor: 'pointer',
                      background: 'none',
                      border: 'none',
                      padding: 0,
                      font: 'inherit',
                      letterSpacing: 'inherit',
                      textTransform: 'inherit',
                      color: column.sort === sort ? 'var(--accent-bright)' : 'var(--dim)',
                    }}
                  >
                    {column.label}
                  </button>
                ) : (
                  column.label
                )}
              </th>
            ))}
            {/* The server withholds `lastSeen` below the operator's presence
                audience — a gather tally refreshes it every minute somebody plays,
                so it would name who is online. The column goes with it rather
                than rendering a row of dashes that look like "never". */}
            {showLastSeen && (
              <th style={{ ...cell, textAlign: 'right', textTransform: 'uppercase' }}>Last seen</th>
            )}
          </tr>
        </thead>
        <tbody>
          {rows.map((row, index) => [
            <tr
              key={row.steamId}
              onClick={() => setOpen(open === row.steamId ? null : row.steamId)}
              title="Open for this player’s kills of each NPC"
              style={{ borderTop: '1px solid var(--line-soft, var(--line))', cursor: 'pointer' }}
            >
              <td style={cell}>
                <span style={{ color: 'var(--dim)', marginRight: 8 }}>{open === row.steamId ? '▾' : '▸'} {index + 1}</span>
                {/* A player this module has never seen NAMED is shown by the tail
                    of their id rather than as a blank: the row is real, and a
                    nameless one reads as a rendering fault. */}
                <strong style={{ color: 'var(--ink)' }}>{row.name || shortId(row.steamId)}</strong>
                {/* The chat titles this player holds now (phase 17, D137) — the
                    same ones the game shows, ranked on the current wipe whichever
                    wipe this table is showing. Absent on an older module. */}
                {(row.titles || []).map((title, i) => (
                  <span
                    key={`${title.text}-${i}`}
                    className="sans"
                    style={{
                      marginLeft: 6,
                      padding: '1px 6px',
                      borderRadius: 999,
                      fontSize: '0.7rem',
                      fontWeight: 600,
                      background: title.color,
                      color: contrastInk(title.color),
                    }}
                  >
                    {title.text}
                  </span>
                ))}
              </td>
              {COLUMNS.map((column) => (
                <td key={column.key} style={{ ...cell, textAlign: 'right' }}>
                  {column.value(row)}
                </td>
              ))}
              {showLastSeen && (
                <td style={{ ...cell, textAlign: 'right', color: 'var(--dim)' }}>{ago(row.lastSeen)}</td>
              )}
            </tr>,
            open === row.steamId && (
              <tr key={`${row.steamId}-npcs`}>
                <td colSpan={COLUMNS.length + 1 + (showLastSeen ? 1 : 0)} style={{ ...cell, whiteSpace: 'normal', paddingLeft: 34 }}>
                  <PlayerNpcKills serverId={serverId} steamId={row.steamId} wipeId={wipeId} />
                </td>
              </tr>
            ),
          ])}
        </tbody>
      </table>
    </div>
  )
}

/** An opened row (D252): the player's kills of each RunicNPC profile, for the wipe shown. */
function PlayerNpcKills({ serverId, steamId, wipeId }) {
  const { data, loading, error } = useAsync(() => api.servers.npcKills(serverId, steamId, { wipe: wipeId }), [serverId, steamId, wipeId])
  if (loading) return <span className="sans" style={{ color: 'var(--dim)', fontSize: '0.8rem' }}>Loading…</span>
  if (error) return <span className="sans" style={{ color: 'var(--dim)', fontSize: '0.8rem' }}>Their NPC kills could not be loaded.</span>
  const kills = (data && data.kills) || []
  if (kills.length === 0) return <span className="sans" style={{ color: 'var(--dim)', fontSize: '0.8rem' }}>No kills of this server’s NPC profiles{wipeId ? ' this wipe' : ''}.</span>
  return (
    <span className="sans" style={{ fontSize: '0.82rem' }}>
      {kills.map((k, i) => (
        <span key={k.profile}>
          {i > 0 && <span style={{ color: 'var(--dim)' }}> · </span>}
          {k.label} <strong style={{ color: 'var(--ink)' }}>{count(k.kills)}</strong>
        </span>
      ))}
    </span>
  )
}

/** One profile's ranking (D250): who has killed the most of it. */
function ProfileBoard({ serverId, wipeId, profile }) {
  const { data, loading, error } = useAsync(
    () => api.servers.npcLeaderboard(serverId, { profile: profile.id, wipe: wipeId, limit: 50 }),
    [serverId, wipeId, profile.id],
  )
  if (loading) return <Loading />
  if (error) return <ErrorState error={error} />
  const rows = (data && data.leaderboard) || []
  if (rows.length === 0) {
    return <Empty title="No kills yet" message={`Nobody has killed a ${profile.label}${wipeId ? ' this wipe' : ''} yet.`} />
  }
  return (
    <div style={{ overflowX: 'auto' }}>
      <table className="sans" style={{ width: '100%', borderCollapse: 'collapse', fontSize: '0.86rem' }}>
        <thead>
          <tr style={{ textAlign: 'left', color: 'var(--dim)', fontSize: '0.72rem', letterSpacing: '0.08em', textTransform: 'uppercase' }}>
            <th style={cell}>Player</th>
            <th style={{ ...cell, textAlign: 'right' }}>{profile.label} kills</th>
          </tr>
        </thead>
        <tbody>
          {rows.map((row, index) => (
            <tr key={row.steamId} style={{ borderTop: '1px solid var(--line-soft, var(--line))' }}>
              <td style={cell}>
                <span style={{ color: 'var(--dim)', marginRight: 8 }}>{index + 1}</span>
                <strong style={{ color: 'var(--ink)' }}>{row.name || shortId(row.steamId)}</strong>
                {(row.titles || []).map((title, i) => (
                  <span
                    key={`${title.text}-${i}`}
                    style={{ marginLeft: 6, padding: '1px 6px', borderRadius: 999, fontSize: '0.7rem', fontWeight: 600, background: title.color, color: contrastInk(title.color) }}
                  >
                    {title.text}
                  </span>
                ))}
              </td>
              <td style={{ ...cell, textAlign: 'right' }}>{count(row.kills)}</td>
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  )
}

const cell = { padding: '8px 10px', whiteSpace: 'nowrap' }