import { useCallback, useEffect, useRef, useState } from 'react'
import { createPortal } from 'react-dom'

const COLORS = ['#c0392b', '#8e44ad', '#16a085', '#7f8c8d', '#d35400', '#2c3e50', '#27ae60', '#b9770e']
const clamp = (v, a, b) => Math.min(b, Math.max(a, v))

// Map with pan (drag the background), zoom (wheel / pinch) and draggable tokens. Coordinates are image pixels.
// Everybody pans and zooms for themselves; token moves go out through onMove(id, x, y) which returns a promise.
export function MapView({ map, image, tokens, onMove, selected, onSelect, grid: showGrid, tool, onClick, onHover, overlay, children }) {
  const box = useRef(null)
  const [view, setView] = useState({ tx: 0, ty: 0, s: 1 })
  const [drag, setDrag] = useState(null)
  const viewRef = useRef(view)
  viewRef.current = view
  const pointers = useRef(new Map())
  const fitted = useRef('')

  const fit = useCallback(() => {
    const r = box.current?.getBoundingClientRect()
    if (!r || !r.width || !map) return
    const s = Math.min(r.width / map.w, r.height / map.h) * 0.96
    setView({ s, tx: (r.width - map.w * s) / 2, ty: (r.height - map.h * s) / 2 })
  }, [map?.id, map?.w, map?.h]) // eslint-disable-line

  useEffect(() => { // fit once per map, as soon as the box has a size
    if (!map || fitted.current === map.id) return
    const t = setInterval(() => { if (box.current?.getBoundingClientRect().width) { fit(); fitted.current = map.id; clearInterval(t) } }, 50)
    return () => clearInterval(t)
  }, [map?.id, fit]) // eslint-disable-line

  const zoomAt = (mx, my, f) => setView((v) => {
    const s = clamp(v.s * f, 0.05, 8)
    return { s, tx: mx - (mx - v.tx) * (s / v.s), ty: my - (my - v.ty) * (s / v.s) }
  })

  useEffect(() => {
    const el = box.current
    if (!el) return
    const wheel = (e) => {
      e.preventDefault()
      const r = el.getBoundingClientRect()
      zoomAt(e.clientX - r.left, e.clientY - r.top, Math.exp(-e.deltaY * (e.ctrlKey ? 0.01 : 0.0015)))
    }
    el.addEventListener('wheel', wheel, { passive: false })
    return () => el.removeEventListener('wheel', wheel)
  }, [])

  const down = (e) => {
    if (e.target.closest('.maptoken, .mapui, .mapdoor')) return
    box.current.setPointerCapture(e.pointerId)
    pointers.current.set(e.pointerId, { x: e.clientX, y: e.clientY, sx: e.clientX, sy: e.clientY })
    if (pointers.current.size === 1) onSelect?.(null)
    else pointers.current.forEach((p, k) => pointers.current.set(k, { ...p, sx: -1e9 })) // two fingers: pinch, not a click
  }
  const move = (e) => {
    if (onHover) onHover(toWorld(e), viewRef.current.s)
    const p = pointers.current.get(e.pointerId)
    if (!p) return
    const r = box.current.getBoundingClientRect()
    if (pointers.current.size === 2) { // pinch
      const [a, b] = [...pointers.current.values()]
      const before = Math.hypot(a.x - b.x, a.y - b.y)
      const o = pointers.current.get(e.pointerId)
      const now = { ...o, x: e.clientX, y: e.clientY, sx: -1e9 }
      pointers.current.set(e.pointerId, now)
      const [c, d] = [...pointers.current.values()]
      const after = Math.hypot(c.x - d.x, c.y - d.y)
      if (before > 0) zoomAt((c.x + d.x) / 2 - r.left, (c.y + d.y) / 2 - r.top, after / before)
      return
    }
    const dx = e.clientX - p.x, dy = e.clientY - p.y
    pointers.current.set(e.pointerId, { ...p, x: e.clientX, y: e.clientY })
    setView((v) => ({ ...v, tx: v.tx + dx, ty: v.ty + dy }))
  }
  const up = (e) => {
    const p = pointers.current.get(e.pointerId)
    pointers.current.delete(e.pointerId)
    // a press that barely moved is a click on the map (used by the drawing tools)
    if (p && onClick && e.type === 'pointerup' && Math.hypot(e.clientX - p.sx, e.clientY - p.sy) < 5) onClick(toWorld(e), viewRef.current.s, e)
  }

  const toWorld = (ev) => {
    const r = box.current.getBoundingClientRect(), v = viewRef.current
    return { x: (ev.clientX - r.left - v.tx) / v.s, y: (ev.clientY - r.top - v.ty) / v.s,
      inside: ev.clientX >= r.left && ev.clientX <= r.right && ev.clientY >= r.top && ev.clientY <= r.bottom }
  }
  const startToken = (e, t) => {
    e.stopPropagation()
    if (!t.can_move) { onSelect?.(t.id); return }
    e.preventDefault()
    const from = { x: e.clientX, y: e.clientY }
    let moved = false, last = 0
    const clampPos = (p) => ({ x: clamp(p.x, 0, map.w), y: clamp(p.y, 0, map.h) })
    const mv = (ev) => {
      if (!moved && Math.hypot(ev.clientX - from.x, ev.clientY - from.y) < 4) return
      moved = true
      const p = toWorld(ev)
      setDrag({ id: t.id, ...clampPos(p), out: !p.inside })
      if (t.x != null && p.inside && Date.now() - last > 120) { last = Date.now(); const c = clampPos(p); onMove(t.id, c.x, c.y) }
    }
    const end = (ev) => {
      window.removeEventListener('pointermove', mv); window.removeEventListener('pointerup', end); window.removeEventListener('pointercancel', end)
      if (!moved) { setDrag(null); onSelect?.(t.id); return }
      const p = toWorld(ev)
      if (!p.inside) { setDrag(null); return }
      const c = clampPos(p)
      Promise.resolve(onMove(t.id, c.x, c.y)).finally(() => setDrag(null)) // keep the local position until the server has it
    }
    window.addEventListener('pointermove', mv); window.addEventListener('pointerup', end); window.addEventListener('pointercancel', end)
  }

  const unplaced = tokens.filter((t) => t.x == null && t.can_move)
  const d = (t) => t.size * map.grid
  return (
    <div className={`mapbox ${tool && tool !== 'select' ? 'drawing' : ''}`} ref={box} onPointerDown={down} onPointerMove={move} onPointerUp={up} onPointerCancel={up}>
      <div className="mapworld" style={{ width: map.w, height: map.h, transform: `translate(${view.tx}px, ${view.ty}px) scale(${view.s})` }}>
        {image && <img src={image.src} style={{ position: 'absolute', left: image.x, top: image.y }} width={image.w} height={image.h} alt="" draggable={false} />}
        {showGrid && <div className="mapgrid" style={{ backgroundSize: `${map.grid}px ${map.grid}px` }} />}
        {overlay}
        {tokens.map((t) => {
          const dr = drag?.id === t.id ? drag : null
          const x = dr ? dr.x : t.x, y = dr ? dr.y : t.y
          if (x == null || (dr && dr.out)) return null
          return (
            <div key={t.id} className={`maptoken ${t.kind} ${t.hidden ? 'hid' : ''} ${selected === t.id ? 'sel' : ''} ${t.can_move ? 'mov' : ''}`}
              style={{ left: x - d(t) / 2, top: y - d(t) / 2, width: d(t), height: d(t), '--tc': t.color, fontSize: Math.max(8, d(t) * 0.45) }}
              onPointerDown={(e) => startToken(e, t)} title={t.name + (t.hidden ? ' (hidden from players)' : '')}>
              <span>{(t.name || '?').trim().slice(0, 2)}</span>
              <em style={{ fontSize: Math.max(9, map.grid * 0.28) }}>{t.name}</em>
            </div>
          )
        })}
      </div>
      {unplaced.length > 0 && (
        <div className="maptray mapui" role="group" aria-label="Tokens not on the map yet">
          <span className="small muted">Drag onto the map:</span>
          {unplaced.map((t) => (
            <button key={t.id} className="traytoken" style={{ '--tc': t.color }} onPointerDown={(e) => startToken(e, t)} title="Drag onto the map">{t.name}</button>
          ))}
        </div>
      )}
      <div className="mapzoom mapui">
        <button className="ghost" onClick={() => { const r = box.current.getBoundingClientRect(); zoomAt(r.width / 2, r.height / 2, 1.3) }} aria-label="Zoom in">＋</button>
        <button className="ghost" onClick={() => { const r = box.current.getBoundingClientRect(); zoomAt(r.width / 2, r.height / 2, 1 / 1.3) }} aria-label="Zoom out">－</button>
        <button className="ghost" onClick={fit} aria-label="Fit the map to the window" title="Fit">⤢</button>
      </div>
      {children}
    </div>
  )
}

// Name, size, colour and visibility of one token (used in the live table and in the map editor)
export function TokenForm({ t, onChange, onDelete, onDuplicate }) {
  return (
    <div className="tokenform">
      <input value={t.name} maxLength={40} aria-label="Token name" onChange={(e) => onChange({ name: e.target.value })} />
      <label className="small chk">Size <input type="number" min="0.25" max="8" step="0.25" value={t.size} onChange={(e) => onChange({ size: Number(e.target.value) || 1 })} /> sq.</label>
      <span className="swatches">{COLORS.map((c) => <button key={c} className={`swatch ${t.color === c ? 'on' : ''}`} style={{ background: c }} aria-label={`Colour ${c}`} onClick={() => onChange({ color: c })} />)}</span>
      <label className="small chk"><input type="checkbox" checked={!!t.hidden} onChange={(e) => onChange({ hidden: e.target.checked })} /> Hidden from players</label>
      <span className="row">
        {onDuplicate && <button className="ghost" onClick={onDuplicate}>Duplicate</button>}
        <button className="ghost danger" onClick={onDelete}>Remove</button>
      </span>
    </div>
  )
}

const uid = () => Math.random().toString(36).slice(2, 12)

// Walls and doors as a line layer on top of the map (DM only). In the live view doors can be clicked to open or close them.
export function WallLayer({ map, walls, draft, hover, onDoor }) {
  const line = (w, extra = {}) => (
    <line key={w.id} x1={w.x1} y1={w.y1} x2={w.x2} y2={w.y2} vectorEffect="non-scaling-stroke"
      className={`wl ${w.kind} ${w.open ? 'open' : ''}`} {...extra} />
  )
  return (
    <svg className="walllayer" width={map.w} height={map.h} style={{ position: 'absolute', left: 0, top: 0, overflow: 'visible', pointerEvents: 'none' }}>
      {walls.filter((w) => !(onDoor && w.kind === 'door')).map((w) => line(w))}
      {walls.filter((w) => onDoor && w.kind === 'door').map((w) => (
        <g key={w.id} className="mapdoor" onClick={() => onDoor(w)} style={{ pointerEvents: 'stroke', cursor: 'pointer' }}>
          <title>{w.open ? 'Open door, click to close' : 'Closed door, click to open'}</title>
          <line x1={w.x1} y1={w.y1} x2={w.x2} y2={w.y2} stroke="transparent" strokeWidth="16" vectorEffect="non-scaling-stroke" style={{ pointerEvents: 'stroke' }} />
          {line(w, { style: { pointerEvents: 'none' } })}
        </g>
      ))}
      {draft && hover && <line x1={draft.x} y1={draft.y} x2={hover.x} y2={hover.y} vectorEffect="non-scaling-stroke" className="wl draft" />}
      {draft && <circle cx={draft.x} cy={draft.y} r="4" vectorEffect="non-scaling-stroke" className="wldot" />}
    </svg>
  )
}

const distToSeg = (p, w) => {
  const dx = w.x2 - w.x1, dy = w.y2 - w.y1, L = dx * dx + dy * dy
  const t = L === 0 ? 0 : clamp(((p.x - w.x1) * dx + (p.y - w.y1) * dy) / L, 0, 1)
  return Math.hypot(w.x1 + t * dx - p.x, w.y1 + t * dy - p.y)
}

// Full-screen editor for a map in the DM's library: grid, enemies and NPCs, walls and doors for line of sight.
export function MapEditor({ id, onClose }) {
  const [m, setM] = useState(null)
  const [tokens, setTokens] = useState([])
  const [walls, setWalls] = useState([])
  const [name, setName] = useState('')
  const [grid, setGrid] = useState(40)
  const [sight, setSight] = useState(0)
  const [showGrid, setShowGrid] = useState(true)
  const [snap, setSnap] = useState(false)
  const [tool, setTool] = useState('select')
  const [draft, setDraft] = useState(null)
  const [hover, setHover] = useState(null)
  const [sel, setSel] = useState(null)
  const [err, setErr] = useState('')
  const [dirty, setDirty] = useState(false)
  useEffect(() => {
    fetch(`/api/maps/${id}`).then((r) => r.json()).then((d) => {
      setM(d); setTokens(d.tokens.map((t) => ({ ...t, kind: 'npc', can_move: true }))); setWalls(d.walls); setName(d.name); setGrid(d.grid); setSight(d.sight || 0)
    })
  }, [id])
  useEffect(() => {
    const k = (e) => { if (e.key === 'Escape') { setDraft(null); if (tool !== 'select') setTool('select') } }
    window.addEventListener('keydown', k)
    return () => window.removeEventListener('keydown', k)
  }, [tool])
  // the full-size image, loaded once for the editor
  const [image, setImage] = useState(null)
  useEffect(() => { if (m) setImage({ src: `/api/maps/${id}/image`, x: 0, y: 0, w: m.w, h: m.h }) }, [m?.id]) // eslint-disable-line
  if (!m) return null
  const gridNum = Number(grid) >= 4 ? Number(grid) : m.grid
  const cur = tokens.find((t) => t.id === sel)
  const patch = (tid, p) => { setTokens((ts) => ts.map((t) => (t.id === tid ? { ...t, ...p } : t))); setDirty(true) }
  const addWalls = (list) => { setWalls((w) => [...w, ...list.map((x) => ({ id: uid(), ...x }))]); setDirty(true) }
  const add = () => {
    const n = tokens.length + 1
    const t = { id: uid(), kind: 'npc', can_move: true, name: `Enemy ${n}`, x: m.w / 2 + (n % 5) * gridNum, y: m.h / 2 + (n % 3) * gridNum, size: 1, color: COLORS[0], hidden: false }
    setTokens([...tokens, t]); setSel(t.id); setDirty(true)
  }
  const snapPt = (p, s) => { // join onto existing corners first, then the grid
    let best = null, bd = 12 / s
    for (const w of walls) for (const [x, y] of [[w.x1, w.y1], [w.x2, w.y2]]) { const d = Math.hypot(x - p.x, y - p.y); if (d < bd) { bd = d; best = { x, y } } }
    if (best) return best
    if (snap) return { x: clamp(Math.round(p.x / gridNum) * gridNum, 0, m.w), y: clamp(Math.round(p.y / gridNum) * gridNum, 0, m.h) }
    return { x: clamp(p.x, 0, m.w), y: clamp(p.y, 0, m.h) }
  }
  const click = (world, s) => {
    if (tool === 'select') return
    if (tool === 'erase') {
      let best = null, bd = 10 / s
      for (const w of walls) { const d = distToSeg(world, w); if (d < bd) { bd = d; best = w } }
      if (best) { setWalls(walls.filter((w) => w.id !== best.id)); setDirty(true) }
      return
    }
    const p = snapPt(world, s)
    if (!draft) { setDraft(p); return }
    if (Math.hypot(p.x - draft.x, p.y - draft.y) < 1) { setDraft(null); return } // click the same point again: finish
    if (tool === 'wall') { addWalls([{ x1: draft.x, y1: draft.y, x2: p.x, y2: p.y, kind: 'wall' }]); setDraft(p) }
    else if (tool === 'door') { addWalls([{ x1: draft.x, y1: draft.y, x2: p.x, y2: p.y, kind: 'door' }]); setDraft(null) }
    else if (tool === 'rect') {
      addWalls([[draft.x, draft.y, p.x, draft.y], [p.x, draft.y, p.x, p.y], [p.x, p.y, draft.x, p.y], [draft.x, p.y, draft.x, draft.y]].map(([x1, y1, x2, y2]) => ({ x1, y1, x2, y2, kind: 'wall' })))
      setDraft(null)
    }
  }
  const save = async () => {
    setErr('')
    const r = await fetch(`/api/maps/${id}`, { method: 'PUT', headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ name, grid: Number(grid), sight: Number(sight) || 0, walls,
        tokens: tokens.map(({ id: i, name: n, x, y, size, color, hidden }) => ({ id: i, name: n, x, y, size, color, hidden })) }) })
    if (!r.ok) { setErr((await r.json().catch(() => ({}))).detail || 'Could not save'); return false }
    setDirty(false); return true
  }
  const close = async () => { if (!dirty || window.confirm('Close without saving your changes?')) onClose() }
  const tools = [['select', 'Move tokens'], ['wall', 'Wall'], ['rect', 'Room'], ['door', 'Door'], ['erase', 'Erase']]
  return createPortal(
    <div className="mapeditor" role="dialog" aria-label="Map editor">
      <aside className="card">
        <h3>Map editor</h3>
        <label className="small">Name <input value={name} maxLength={60} onChange={(e) => { setName(e.target.value); setDirty(true) }} /></label>
        <label className="small">Grid: pixels per square <input type="number" min="4" value={grid} onChange={(e) => { setGrid(e.target.value); setDirty(true) }} /></label>
        <label className="small chk"><input type="checkbox" checked={showGrid} onChange={(e) => setShowGrid(e.target.checked)} /> Show grid</label>
        <p className="small muted">Match the grid to the squares on your image. Token sizes are counted in squares.</p>
        <h4>Walls and doors</h4>
        <div className="toolrow" role="group" aria-label="Tool">
          {tools.map(([k, label]) => <button key={k} className={tool === k ? 'on' : 'ghost'} aria-pressed={tool === k} onClick={() => { setTool(k); setDraft(null) }}>{label}</button>)}
        </div>
        <label className="small chk"><input type="checkbox" checked={snap} onChange={(e) => setSnap(e.target.checked)} /> Snap to grid corners</label>
        <p className="small muted">
          {tool === 'wall' && 'Click to set points, the line continues from the last one. Click the same point twice or press Esc to stop.'}
          {tool === 'rect' && 'Click two opposite corners of a room.'}
          {tool === 'door' && 'Click both ends of the door. The DM opens and closes it during play.'}
          {tool === 'erase' && 'Click a wall or door to remove it.'}
          {tool === 'select' && `${walls.length} wall segment${walls.length === 1 ? '' : 's'}. Walls end at existing corners automatically. Players only see what their token can see past them.`}
        </p>
        <div className="row">
          <button className="ghost" disabled={!walls.length} onClick={() => { setWalls(walls.slice(0, -1)); setDirty(true) }}>Undo last</button>
          <button className="ghost danger" disabled={!walls.length} onClick={() => window.confirm('Remove all walls and doors of this map?') && (setWalls([]), setDirty(true))}>Remove all</button>
        </div>
        <label className="small">Sight range in squares (0 = unlimited)
          <input type="number" min="0" max="1000" value={sight} onChange={(e) => { setSight(e.target.value); setDirty(true) }} /></label>
        <h4>Enemies and NPCs</h4>
        <button className="on" onClick={add}>+ Add token</button>
        <ul className="tokenlist">
          {tokens.map((t) => <li key={t.id}><button className={sel === t.id ? 'on' : 'ghost'} onClick={() => setSel(t.id)}><i style={{ background: t.color }} /> {t.name}{t.hidden ? ' (hidden)' : ''}</button></li>)}
          {!tokens.length && <li className="muted small">None yet. Add a token, then drag it onto the map.</li>}
        </ul>
        {cur && <TokenForm t={cur} onChange={(p) => patch(cur.id, p)}
          onDelete={() => { setTokens(tokens.filter((t) => t.id !== cur.id)); setSel(null); setDirty(true) }}
          onDuplicate={() => { const c = { ...cur, id: uid(), name: cur.name.replace(/\s*\d*$/, '') + ' ' + (tokens.length + 1), x: cur.x + gridNum, y: cur.y + gridNum }; setTokens([...tokens, c]); setSel(c.id); setDirty(true) }} />}
        {err && <p className="warn small">{err}</p>}
        <div className="row editactions"><button className="on" disabled={!dirty} onClick={save}>Save</button><button className="ghost" onClick={close}>Close</button></div>
      </aside>
      <div className="mapstage">
        <MapView map={{ ...m, grid: gridNum }} image={image} tokens={tokens} grid={showGrid} selected={sel} onSelect={setSel} tool={tool}
          onClick={click} onHover={draft ? (p, s) => setHover(p) : undefined}
          overlay={<WallLayer map={m} walls={walls} draft={draft} hover={draft ? hover : null} />}
          onMove={(tid, x, y) => { patch(tid, { x, y }); return Promise.resolve() }} />
      </div>
    </div>, document.body)
}

// DM: the map library (in the "Lobby actions" tab)
export function MapLibrary({ activeId, lobbyId, act }) {
  const [list, setList] = useState([])
  const [err, setErr] = useState('')
  const [editing, setEditing] = useState(null)
  const [busy, setBusy] = useState(false)
  const load = useCallback(() => fetch('/api/maps').then((r) => (r.ok ? r.json() : [])).then(setList).catch(() => {}), [])
  useEffect(() => { load() }, [load, editing])
  const upload = async (e) => {
    const f = e.target.files?.[0]
    e.target.value = ''
    if (!f) return
    setErr(''); setBusy(true)
    const r = await fetch(`/api/maps?name=${encodeURIComponent(f.name.replace(/\.[^.]+$/, ''))}`, { method: 'POST', headers: { 'Content-Type': f.type || 'application/octet-stream' }, body: f })
    setBusy(false)
    if (!r.ok) { setErr((await r.json().catch(() => ({}))).detail || 'Upload failed'); return }
    load()
  }
  return (
    <div className="maplib">
      <h4>Maps</h4>
      <label className="uploadbtn">{busy ? 'Uploading…' : '+ Upload map (PNG, JPEG, WebP)'}<input type="file" accept="image/png,image/jpeg,image/webp" onChange={upload} disabled={busy} hidden /></label>
      {err && <p className="warn small">{err}</p>}
      <ul className="maplist">
        {list.map((m) => (
          <li key={m.id} className={m.id === activeId ? 'active' : ''}>
            <strong>{m.name}</strong> <span className="muted small">{m.w}×{m.h}, {m.tokens} token{m.tokens === 1 ? '' : 's'}, {m.walls} wall{m.walls === 1 ? '' : 's'}{!m.mine && ` · from ${m.author}`}</span>
            <span className="row">
              {m.id === activeId
                ? <button className="ghost" onClick={() => act(`/api/lobbies/${lobbyId}/map`, 'PUT', { map_id: null })}>Clear table</button>
                : <button className="on" onClick={() => (!activeId || window.confirm('Replace the current map? Tokens on it are reset to the prepared ones.')) && act(`/api/lobbies/${lobbyId}/map`, 'PUT', { map_id: m.id })}>Show on table</button>}
              {m.mine && <button className="ghost" onClick={() => setEditing(m.id)}>Edit</button>}
              {m.mine && <button className="ghost danger" onClick={() => window.confirm(`Delete the map "${m.name}"?`) && fetch(`/api/maps/${m.id}`, { method: 'DELETE' }).then(load)}>Delete</button>}
            </span>
          </li>
        ))}
        {!list.length && <li className="muted small">No maps yet. Upload an image, then prepare enemies in the editor.</li>}
      </ul>
      {editing && <MapEditor id={editing} onClose={() => setEditing(null)} />}
    </div>
  )
}