import { useState, useEffect, useRef } from "react";
import { RED, GREEN } from "../constants/index.js";

import { useApp } from "../context/AppContext.jsx";

const getToken = () => localStorage.getItem("vf_token");
const authHdrs = () => ({ "Content-Type": "application/json", Authorization: `Bearer ${getToken()}` });

async function apiFetch(path, options = {}) {
  const res = await fetch(`/api${path}`, { ...options, headers: { ...authHdrs(), ...(options.headers || {}) } });
  if (!res.ok) {
    const data = await res.json().catch(() => ({}));
    throw new Error(data.error || `HTTP ${res.status}`);
  }
  return res.json();
}

function fmtDatum(iso) {
  if (!iso) return "—";
  const d = new Date(iso);
  return `${d.getDate()}-${d.getMonth() + 1}-${d.getFullYear()}`;
}

function RolSelect({ value, onChange, opties, T, darkMode }) {
  const [open, setOpen] = useState(false);
  const ref = useRef(null);

  useEffect(() => {
    const handler = (e) => { if (ref.current && !ref.current.contains(e.target)) setOpen(false); };
    document.addEventListener("mousedown", handler);
    return () => document.removeEventListener("mousedown", handler);
  }, []);

  return (
    <div ref={ref} style={{ position: "relative", width: "100%" }}>
      <button type="button" onClick={() => setOpen((o) => !o)} style={{
        width: "100%", background: T.inputBg, border: `1px solid ${T.inputBorder}`,
        borderRadius: 8, color: T.text, padding: "8px 10px", fontSize: 13,
        cursor: "pointer", display: "flex", justifyContent: "space-between", alignItems: "center",
        boxSizing: "border-box",
      }}>
        <span>{value}</span>
        <span style={{ fontSize: 10, color: T.muted }}>▼</span>
      </button>
      {open && (
        <div style={{
          position: "absolute", top: "calc(100% + 4px)", left: 0, right: 0, zIndex: 999,
          background: T.card, border: `1px solid ${T.inputBorder}`,
          borderRadius: 8, overflow: "hidden",
          boxShadow: darkMode ? "0 8px 24px rgba(0,0,0,0.5)" : "0 8px 24px rgba(0,0,0,0.15)",
        }}>
          {opties.map((o) => (
            <div key={o} onClick={() => { onChange(o); setOpen(false); }} style={{
              padding: "9px 12px", fontSize: 13, cursor: "pointer",
              color: o === value ? T.accentTekst : T.text,
              background: o === value ? T.inputBg : "transparent",
            }}
            onMouseEnter={(e) => e.currentTarget.style.background = "rgba(14,221,212,0.10)"}
            onMouseLeave={(e) => e.currentTarget.style.background = o === value ? T.inputBg : "transparent"}
            >
              {o}
            </div>
          ))}
        </div>
      )}
    </div>
  );
}

export default function GebruikersBeheer({ onClose }) {
  const { currentUser, darkMode, T } = useApp();

  const [users,      setUsers]      = useState([]);
  const [loadErr,    setLoadErr]    = useState("");
  const [showAdd,    setShowAdd]    = useState(false);
  const [editUser,   setEditUser]   = useState(null); // user object dat bewerkt wordt
  const [nieuwNaam,  setNieuwNaam]  = useState("");
  const [nieuwEmail, setNieuwEmail] = useState("");
  const [nieuwWw,    setNieuwWw]    = useState("");
  const [nieuwRol,   setNieuwRol]   = useState("Viewer");
  const [editNaam,   setEditNaam]   = useState("");
  const [editEmail,  setEditEmail]  = useState("");
  const [editWw,     setEditWw]     = useState("");
  const [err,        setErr]        = useState("");
  const [saving,     setSaving]     = useState(false);

  const rollen = ["Admin", "Bewerker", "Viewer"];

  useEffect(() => {
    apiFetch("/users")
      .then(setUsers)
      .catch((e) => setLoadErr(e.message));
  }, []);

  const is = {
    background: T.inputBg, border: `1px solid ${T.inputBorder}`,
    borderRadius: 8, color: T.text, padding: "8px 10px",
    fontSize: 13, outline: "none", boxSizing: "border-box", width: "100%",
  };

  const addUser = async () => {
    if (!nieuwNaam.trim() || !nieuwEmail.trim() || !nieuwWw.trim()) {
      setErr("Naam, e-mail en wachtwoord zijn verplicht.");
      return;
    }
    setSaving(true);
    try {
      const u = await apiFetch("/users", {
        method: "POST",
        body: JSON.stringify({ naam: nieuwNaam, email: nieuwEmail, wachtwoord: nieuwWw, rol: nieuwRol }),
      });
      setUsers((prev) => [...prev, u]);
      setNieuwNaam(""); setNieuwEmail(""); setNieuwWw(""); setErr("");
      setShowAdd(false);
    } catch (e) {
      setErr(e.message);
    } finally {
      setSaving(false);
    }
  };

  const openEdit = (u) => {
    setEditUser(u);
    setEditNaam(u.naam);
    setEditEmail(u.email);
    setEditWw("");
    setErr("");
  };

  const saveEdit = async () => {
    if (!editNaam.trim() || !editEmail.trim()) { setErr("Naam en e-mail zijn verplicht."); return; }
    setSaving(true);
    try {
      const patch = { naam: editNaam.trim(), email: editEmail.trim() };
      if (editWw) patch.wachtwoord = editWw;
      const updated = await apiFetch(`/users/${editUser.id}`, {
        method: "PATCH",
        body: JSON.stringify(patch),
      });
      setUsers((prev) => prev.map((x) => x.id === editUser.id ? { ...x, ...updated } : x));
      setEditUser(null); setErr("");
    } catch (e) { setErr(e.message); }
    finally { setSaving(false); }
  };

  const toggleActief = async (u) => {
    try {
      const updated = await apiFetch(`/users/${u.id}`, {
        method: "PATCH",
        body: JSON.stringify({ actief: !u.actief }),
      });
      setUsers((prev) => prev.map((x) => x.id === u.id ? { ...x, ...updated } : x));
    } catch (e) { setErr(e.message); }
  };

  const removeUser = async (id) => {
    try {
      await apiFetch(`/users/${id}`, { method: "DELETE" });
      setUsers((prev) => prev.filter((u) => u.id !== id));
    } catch (e) { setErr(e.message); }
  };

  const th = {
    padding: "8px 12px", fontSize: 11, color: T.muted, fontWeight: 600,
    textAlign: "left", borderBottom: `1px solid ${T.border}`,
    background: T.card, textTransform: "uppercase", letterSpacing: "0.05em",
  };
  const td = { padding: "10px 12px", fontSize: 13, color: T.text, borderBottom: `1px solid ${T.border}` };

  return (
    <div
      onClick={onClose}
      style={{
        position: "fixed", inset: 0, zIndex: 400,
        background: "rgba(0,0,0,0.55)", backdropFilter: "blur(4px)",
        display: "flex", alignItems: "center", justifyContent: "center",
      }}
    >
      <div
        onClick={(e) => e.stopPropagation()}
        style={{
          background: T.popupBg, border: `1px solid ${T.border}`,
          borderRadius: 16, width: "100%", maxWidth: 700,
          maxHeight: "90vh", display: "flex", flexDirection: "column",
          boxShadow: "0 16px 48px rgba(0,0,0,0.4)",
          overflow: "hidden",
        }}
      >
        {/* Header */}
        <div style={{
          display: "flex", alignItems: "center", justifyContent: "space-between",
          padding: "18px 22px", borderBottom: `1px solid ${T.border}`, flexShrink: 0,
        }}>
          <div>
            <span style={{ fontWeight: 700, fontSize: 15, color: T.text }}>Gebruikersbeheer</span>
            <span style={{ marginLeft: 10, fontSize: 11, fontWeight: 600, color: T.accentTekst,
              background: T.inputBg, borderRadius: 99, padding: "2px 8px", border: `1px solid ${T.inputBorder}`,
            }}>
              {users.length} gebruiker{users.length !== 1 ? "s" : ""}
            </span>
          </div>
          <button onClick={onClose} style={{
            background: "transparent", border: "none", cursor: "pointer",
            color: T.muted, fontSize: 20, lineHeight: 1, padding: 4,
          }}>×</button>
        </div>

        <div style={{ padding: "16px 22px", overflowY: "auto", flex: 1 }}>
          {loadErr && (
            <div style={{ color: RED, fontSize: 13, marginBottom: 12 }}>{loadErr}</div>
          )}

          {/* Tabel */}
          <div style={{ overflowX: "auto", marginBottom: 16 }}>
            <table style={{ width: "100%", borderCollapse: "collapse" }}>
              <thead>
                <tr>
                  <th style={th}>Naam</th>
                  <th style={th}>E-mail</th>
                  <th style={th}>Aangemaakt</th>
                  <th style={th}>Admin</th>
                  <th style={th}></th>
                </tr>
              </thead>
              <tbody>
                {users.map((u) => {
                  const initials = u.naam.split(" ").map((w) => w[0]).join("").toUpperCase().slice(0, 2);
                  const isSelf = u.id === currentUser?.id || u.email === currentUser?.email;
                  return (
                    <tr key={u.id} style={{ opacity: u.actief ? 1 : 0.5 }}>
                      <td style={td}>
                        <div style={{ display: "flex", alignItems: "center", gap: 10 }}>
                          <div style={{
                            width: 32, height: 32, borderRadius: "50%",
                            background: T.inputBg, display: "flex",
                            alignItems: "center", justifyContent: "center",
                            fontSize: 12, fontWeight: 700, color: T.accentTekst, flexShrink: 0,
                          }}>
                            {initials}
                          </div>
                          <span style={{ fontWeight: 600 }}>{u.naam}</span>
                          {isSelf && (
                            <span style={{
                              fontSize: 10, fontWeight: 700, color: T.accentTekst,
                              background: T.inputBg, borderRadius: 99,
                              padding: "1px 7px", border: `1px solid ${T.inputBorder}`,
                            }}>jij</span>
                          )}
                        </div>
                      </td>
                      <td style={{ ...td, color: T.muted }}>{u.email}</td>
                      <td style={{ ...td, color: T.muted }}>{fmtDatum(u.aangemaakt)}</td>
                      <td style={td}>
                        {u.rol === "Admin"
                          ? <span style={{ fontSize: 18 }}>⭐</span>
                          : <span style={{ fontSize: 13, color: T.muted }}>—</span>
                        }
                      </td>
                      <td style={{ ...td, whiteSpace: "nowrap" }}>
                        <div style={{ display: "flex", gap: 6, alignItems: "center" }}>
                          <button onClick={() => openEdit(u)} style={{
                            padding: "3px 8px", background: T.inputBg,
                            border: `1px solid ${T.inputBorder}`, borderRadius: 6,
                            color: T.accentTekst, cursor: "pointer", fontSize: 12,
                          }}>✏️</button>
                          {!isSelf && (
                            <>
                              <button onClick={() => toggleActief(u)} style={{
                                padding: "3px 8px", borderRadius: 6, cursor: "pointer",
                                fontSize: 11, fontWeight: 700,
                                background: u.actief ? "rgba(16,185,129,0.12)" : "rgba(239,68,68,0.1)",
                                border: `1px solid ${u.actief ? "rgba(16,185,129,0.4)" : "rgba(239,68,68,0.3)"}`,
                                color: u.actief ? GREEN : RED,
                              }}>
                                {u.actief ? "Actief" : "Inactief"}
                              </button>
                              <button onClick={() => removeUser(u.id)} style={{
                                padding: "3px 8px", background: "rgba(239,68,68,0.1)",
                                border: "1px solid rgba(239,68,68,0.25)", borderRadius: 6,
                                color: RED, cursor: "pointer", fontSize: 13,
                              }}>×</button>
                            </>
                          )}
                        </div>
                      </td>
                    </tr>
                  );
                })}
              </tbody>
            </table>
          </div>

          {err && (
            <div style={{ color: RED, fontSize: 12, marginBottom: 12, padding: "6px 10px", background: "rgba(239,68,68,0.1)", borderRadius: 8, border: "1px solid rgba(239,68,68,0.25)" }}>
              {err}
            </div>
          )}

          {/* Bewerken modal */}
          {editUser && (
            <div style={{
              background: darkMode ? "rgba(124,58,237,0.06)" : T.inputBg,
              border: `1px solid ${T.inputBorder}`, borderRadius: 10, padding: "16px", marginBottom: 16,
            }}>
              <div style={{ fontSize: 11, color: T.accentTekst, fontWeight: 700, textTransform: "uppercase", letterSpacing: "0.05em", marginBottom: 12 }}>
                {editUser.naam} bewerken
              </div>
              <div style={{ display: "grid", gridTemplateColumns: "1fr 1fr", gap: 10, marginBottom: 10 }}>
                <input placeholder="Naam" value={editNaam} onChange={(e) => setEditNaam(e.target.value)} style={is} />
                <input placeholder="E-mail" value={editEmail} onChange={(e) => setEditEmail(e.target.value)} style={is} />
                <input placeholder="Nieuw wachtwoord (optioneel)" type="password" value={editWw} onChange={(e) => setEditWw(e.target.value)} style={{ ...is, gridColumn: "1 / -1" }} />
              </div>
              <div style={{ display: "flex", gap: 8 }}>
                <button onClick={() => { setEditUser(null); setErr(""); }} style={{
                  flex: 1, padding: "8px", background: "transparent",
                  border: `1px solid ${T.border}`, borderRadius: 8,
                  color: T.muted, cursor: "pointer", fontSize: 13, fontWeight: 600,
                }}>Annuleren</button>
                <button onClick={saveEdit} disabled={saving} style={{
                  flex: 2, padding: "8px",
                  background: T.accentGradient,
                  border: "none", borderRadius: 8, color: "#fff",
                  fontWeight: 700, fontSize: 13, cursor: saving ? "not-allowed" : "pointer",
                }}>{saving ? "Opslaan..." : "Opslaan"}</button>
              </div>
            </div>
          )}

          {/* Nieuwe gebruiker */}
          {showAdd ? (
            <div style={{
              background: darkMode ? "rgba(124,58,237,0.06)" : T.inputBg,
              border: `1px solid ${T.border}`, borderRadius: 10, padding: "16px",
            }}>
              <div style={{ fontSize: 11, color: T.muted, fontWeight: 700, textTransform: "uppercase", letterSpacing: "0.05em", marginBottom: 12 }}>
                Nieuwe gebruiker
              </div>
              <div style={{ display: "grid", gridTemplateColumns: "1fr 1fr", gap: 10, marginBottom: 10 }}>
                <input placeholder="Naam" value={nieuwNaam} onChange={(e) => setNieuwNaam(e.target.value)} style={is} />
                <input placeholder="E-mail" value={nieuwEmail} onChange={(e) => setNieuwEmail(e.target.value)} style={is} />
                <input placeholder="Wachtwoord" type="password" value={nieuwWw} onChange={(e) => setNieuwWw(e.target.value)} style={is} />
                <RolSelect value={nieuwRol} onChange={setNieuwRol} opties={rollen} T={T} darkMode={darkMode} />
              </div>
              <div style={{ display: "flex", gap: 8 }}>
                <button onClick={() => { setShowAdd(false); setErr(""); }} style={{
                  flex: 1, padding: "8px", background: "transparent",
                  border: `1px solid ${T.border}`, borderRadius: 8,
                  color: T.muted, cursor: "pointer", fontSize: 13, fontWeight: 600,
                }}>Annuleren</button>
                <button onClick={addUser} disabled={saving} style={{
                  flex: 2, padding: "8px",
                  background: T.accentGradient,
                  border: "none", borderRadius: 8, color: "#fff",
                  fontWeight: 700, fontSize: 13, cursor: saving ? "not-allowed" : "pointer",
                }}>
                  {saving ? "Opslaan..." : "Toevoegen"}
                </button>
              </div>
            </div>
          ) : (
            <button onClick={() => setShowAdd(true)} style={{
              padding: "8px 18px",
              background: T.accentGradient,
              border: "none", borderRadius: 8, color: "#fff",
              fontWeight: 700, fontSize: 13, cursor: "pointer",
            }}>+ Nieuwe gebruiker</button>
          )}
        </div>

      </div>
    </div>
  );
}