import React, { useEffect, useRef, useState } from 'react';
import { Dialog, DialogTitle, DialogContent, DialogActions, useMediaQuery } from '@mui/material';
import EditableAreaMap from './EditableAreaMap';
import './SiteGeometryModal.css';

export async function siteGeometryRequest(projectId, apiBaseUrl, method, body) {
  const token = localStorage.getItem('accessToken');
  const response = await fetch(`${apiBaseUrl}/api/customer-projects/projects/${projectId}/site-geometry${method === 'POST' ? '/geocode' : ''}`, {
    method, headers: { ...(token ? { Authorization: `Bearer ${token}` } : {}), 'Content-Type': 'application/json' },
    ...(body ? { body: JSON.stringify(body) } : {})
  });
  const result = await response.json();
  if (!response.ok) throw new Error(result.error || 'Kortområdet kunne ikke hentes.');
  return result;
}
const savedPoints = geometry => geometry?.areas?.[0]?.geometry.coordinates[0].slice(0,-1) || [];
function preview(points) {
  if (points.length < 3) return 0;
  const r = Math.PI / 180;
  return Math.abs(points.reduce((sum,p,i) => {
    const next = points[(i+1)%points.length];
    return sum + (next[0]-p[0])*r*(2+Math.sin(p[1]*r)+Math.sin(next[1]*r));
  },0))*6371008.8**2/2;
}
export default function SiteGeometryModal({ projectId, apiBaseUrl = '', address = '', roof = false, onSave, onDelete, onClose, onManual, api }) {
  const pointList = useRef(null);
  const addressInput = useRef(null);
  const mobile = useMediaQuery('(max-width:600px)');
  const [saved,setSaved] = useState(null);
  const [revision,setRevision] = useState(0);
  const [points,setPoints] = useState([]);
  const [center,setCenter] = useState([56,10]);
  const [query,setQuery] = useState(address);
  const [candidates,setCandidates] = useState([]);
  const [error,setError] = useState('');
  const [loading,setLoading] = useState(true);
  const [loadFailed,setLoadFailed] = useState(false);
  const [loadAttempt,setLoadAttempt] = useState(0);
  const [busy,setBusy] = useState(false);
  const [drawing,setDrawing] = useState(true);
  const [deleteConfirm,setDeleteConfirm] = useState(false);
  const [status,setStatus] = useState('');
  const request = (method,body) => api ? api(method,body) : siteGeometryRequest(projectId,apiBaseUrl,method,body);
  useEffect(() => {
    let active = true;
    const load = async () => {
      setLoading(true);setLoadFailed(false);setError('');
      try {
        const result = await (api ? api('GET') : siteGeometryRequest(projectId,apiBaseUrl,'GET'));
        if (!active) return;
        const {geometry} = result;
        setRevision(result.revision ?? geometry?.revision ?? 0);
        setSaved(geometry);const next=savedPoints(geometry);setPoints(next);
        setDrawing(!next.length);
        if (next.length) setCenter([next[0][1],next[0][0]]);
      } catch(e) {
        if (active) {setError(e.message);setLoadFailed(true);}
      } finally {
        if (active) {
          setLoading(false);
          if (loadAttempt > 0) addressInput.current?.focus();
        }
      }
    };
    load();
    return () => { active=false; };
  },[projectId,apiBaseUrl,api,loadAttempt]);
  const unavailable = busy || loading || loadFailed;
  const dirty = JSON.stringify(points) !== JSON.stringify(savedPoints(saved));
  const discard = () => !dirty || window.confirm('Du har ændringer, der ikke er gemt. Kassér ændringerne?');
  const close = () => { if (!busy && discard()) onClose(); };
  useEffect(() => {
    if (!dirty) return undefined;
    const warn = event => { event.preventDefault(); event.returnValue=''; };
    window.addEventListener('beforeunload',warn);
    return () => window.removeEventListener('beforeunload',warn);
  },[dirty]);
  const save = async () => {
    setBusy(true);setError('');
    try {
      const {geometry} = await request('PUT',{expectedRevision:revision,geometry:{type:'Polygon',coordinates:[[...points,points[0]]]}});
      if (geometry?.schema !== 'site_geometry_v1' || !Number.isFinite(geometry?.totals?.groundAreaM2) || !geometry?.revision) throw new Error('Serveren returnerede ikke et gyldigt område.');
      setSaved(geometry);setRevision(geometry.revision);onSave(geometry);
    } catch(e) { setError(e.message); } finally { setBusy(false); }
  };
  const remove = async () => {
    setBusy(true);setError('');setStatus('');
    try {
      const result = await request('DELETE',{expectedRevision:revision});
      if (result?.geometry !== null || result?.deleted !== true || !Number.isSafeInteger(result?.revision) || result.revision <= revision) {
        throw new Error('Serveren bekræftede ikke sletningen med en ny revision.');
      }
      setSaved(null);setPoints([]);setRevision(result.revision);setDrawing(true);setDeleteConfirm(false);
      setStatus('Kortområdet er slettet. Kortbaserede mængder kan ikke længere bruges.');
      onDelete?.(result);
    } catch(e) { setError(e.message);setDeleteConfirm(false); } finally { setBusy(false); }
  };
  const search = async event => {
    event.preventDefault();setBusy(true);setError('');
    try { setCandidates((await request('POST',{query})).candidates); }
    catch(e) {setError(e.message);} finally {setBusy(false);}
  };
  const updatePoint = (index,axis,value) => setPoints(current => current.map((p,i) => i===index ? p.map((v,a) => a===axis ? value : v) : p));
  return <><Dialog open PaperProps={{ 'aria-modal': true }} fullScreen={mobile} maxWidth="md" fullWidth onClose={close} aria-labelledby="site-geometry-title" className="site-area-dialog">
    <DialogTitle id="site-geometry-title">Mål område på kort</DialogTitle>
    <DialogContent>
      <p>Korttegnet · <a href="https://www.openstreetmap.org/copyright" target="_blank" rel="noreferrer">© OpenStreetMap-bidragsydere</a> · <a href="https://opendatacommons.org/licenses/odbl/1-0/" target="_blank" rel="noreferrer">ODbL</a> · Ikke verificeret{saved?.audit?.updatedAt ? ` · Redigeret ${new Date(saved.audit.updatedAt).toLocaleDateString('da-DK')}` : ''}</p>
      {roof && <p className="site-area-roof">Kortet måler kun grundprojektion. Skråt tagareal kræver et eksplicit taggrundlag med hældning eller en manuel tagopmåling.</p>}
      <form onSubmit={search} className="site-area-search">
        <label>Adresse<input ref={addressInput} autoFocus value={query} maxLength={200} onChange={e => setQuery(e.target.value)} /></label>
        <button disabled={unavailable || query.trim().length<3} type="submit">Søg adresse</button>
      </form>
      {candidates.length > 0 && <ul aria-label="Adresseforslag">{candidates.map((c,i) => <li key={i}><button type="button" onClick={() => {setCenter([c.lat,c.lng]);setCandidates([]);}}>{c.formattedAddress}</button></li>)}</ul>}
      {error && <p id="site-area-error" role="alert">{error}</p>}
      {status && <p role="status">{status}</p>}
      {loading && <p role="status">Henter område…</p>}
      {loadFailed && <div className="site-area-tools">
        <button type="button" disabled={loading} onClick={() => setLoadAttempt(attempt => attempt+1)}>Prøv igen</button>
        <button type="button" onClick={onManual}>Indtast mål uden kort</button>
      </div>}
      <div className="site-area-tools">
        <button type="button" disabled={unavailable} aria-pressed={drawing} onClick={() => setDrawing(true)}>Tegn område</button>
        <button type="button" disabled={unavailable} aria-pressed={!drawing} onClick={() => setDrawing(false)}>Flyt punkter</button>
        {saved
          ? <button type="button" disabled={unavailable} onClick={() => setDeleteConfirm(true)}>Slet gemt område</button>
          : <button type="button" disabled={unavailable || !points.length} onClick={() => setPoints([])}>Ryd tegning</button>}
      </div>
      <p id="site-area-instructions">Tryk på kortet for at tegne. Træk punkter for at redigere. Brug punktlisten til tastatur og præcise koordinater.</p>
      <EditableAreaMap points={points} onChange={setPoints} center={center} drawing={drawing && !unavailable} disabled={unavailable} />
      <button type="button" onClick={() => pointList.current?.focus()}>Forlad kort</button>
      <p aria-live="polite">{roof ? 'Grundprojektion' : 'Grundareal'}: {preview(points).toLocaleString('da-DK',{maximumFractionDigits:1})} m² · Forhåndsvisning</p>
      <details><summary ref={pointList}>Rediger punkter med tastatur</summary>
        {points.map((p,i) => <div className="site-area-point" key={i}>
          <span>Punkt {i+1}</span>
          {[0,1].map(axis => <label key={axis}>{axis===0 ? 'Længdegrad' : 'Breddegrad'}<input type="number" step="0.000001" min={axis===0 ? -180 : -90} max={axis===0 ? 180 : 90} aria-label={`${axis===0 ? 'Længdegrad' : 'Breddegrad'} punkt ${i+1}`} value={p[axis]} disabled={busy} onChange={e => updatePoint(i,axis,Number(e.target.value))}/></label>)}
          <button disabled={busy} onClick={() => setPoints(points.filter((_,index) => index!==i))}>Slet punkt {i+1}</button>
          <button disabled={busy} onClick={() => { const next=points[(i+1)%points.length];setPoints([...points.slice(0,i+1),[(p[0]+next[0])/2,(p[1]+next[1])/2],...points.slice(i+1)]); }}>Indsæt efter punkt {i+1}</button>
        </div>)}
        <button disabled={unavailable} onClick={() => setPoints([...points,[center[1],center[0]]])}>Tilføj punkt ved kortcentrum</button>
      </details>
      {!loadFailed && <button disabled={busy} onClick={() => {if(discard()) onManual();}}>Indtast mål uden kort</button>}
    </DialogContent>
    <DialogActions className="site-area-actions">
      <button disabled={unavailable} onClick={() => {if(discard()) {setPoints(savedPoints(saved));setError('');}}}>Nulstil</button>
      <button disabled={busy} onClick={close}>Annuller</button>
      <button className="site-area-save" disabled={unavailable || points.length<3} onClick={save}>Gem område</button>
    </DialogActions>
  </Dialog>
  <Dialog open={deleteConfirm} fullScreen={mobile} onClose={() => !busy && setDeleteConfirm(false)} aria-labelledby="site-geometry-delete-title">
    <DialogTitle id="site-geometry-delete-title">Slet gemt kortområde permanent?</DialogTitle>
    <DialogContent>
      <p>Området fjernes med revisionsspor. Kortbaserede arbejdspakker og snapshots bliver ugyldige og skal opmåles igen eller erstattes med manuelle mål.</p>
      {dirty && <p>Ikke-gemte ændringer i tegningen bliver også kasseret.</p>}
    </DialogContent>
    <DialogActions>
      <button type="button" disabled={busy} autoFocus onClick={() => setDeleteConfirm(false)}>Behold område</button>
      <button type="button" disabled={busy} onClick={remove}>Slet permanent</button>
    </DialogActions>
  </Dialog></>;
}