import React, { useState } from 'react';
import {
  Users,
  User as UserIcon,
  X,
  Plus,
  Trash2,
  Lock,
  Check,
} from 'lucide-react';
import { User, Team, UnifiedShare } from '../lib/types';
import { UserAutocomplete } from '../features/UserAutocomplete';
import { UserAvatar } from './UserAvatar';

export interface UnifiedShareModalProps {
  isOpen: boolean;
  onClose: () => void;
  title?: string;
  resourceName: string;
  resourceIcon?: string | React.ReactNode;
  isOwner: boolean;
  currentUserId?: string;
  shares: UnifiedShare[];
  teams: Team[];
  collaborators: User[];
  allowRoleSelection?: boolean; // Default true (editor vs viewer)
  onAddShare: (targetType: 'team' | 'user', targetId: string, permission: 'editor' | 'viewer') => Promise<void>;
  onRemoveShare: (shareId: string) => Promise<void>;
}

export const UnifiedShareModal: React.FC<UnifiedShareModalProps> = ({
  isOpen,
  onClose,
  title = 'Freigeben & Berechtigungen',
  resourceName,
  resourceIcon,
  isOwner,
  currentUserId,
  shares,
  teams,
  collaborators,
  allowRoleSelection = true,
  onAddShare,
  onRemoveShare,
}) => {
  const [shareType, setShareType] = useState<'team' | 'user'>('team');
  const [selectedTeamId, setSelectedTeamId] = useState('');
  const [selectedUser, setSelectedUser] = useState<User | null>(null);
  const [selectedPermission, setSelectedPermission] = useState<'editor' | 'viewer'>('editor');
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);

  if (!isOpen) return null;

  const handleAdd = async (e: React.FormEvent) => {
    e.preventDefault();
    setError(null);
    const targetId = shareType === 'team' ? selectedTeamId : selectedUser?.id;
    if (!targetId) {
      setError(shareType === 'team' ? 'Bitte eine Gruppe auswählen' : 'Bitte einen Benutzer auswählen');
      return;
    }

    setLoading(true);
    try {
      await onAddShare(shareType, targetId, selectedPermission);
      setSelectedTeamId('');
      setSelectedUser(null);
    } catch (err: any) {
      setError(err?.message || 'Fehler beim Hinzufügen der Freigabe');
    } finally {
      setLoading(false);
    }
  };

  const handleRemove = async (shareId: string) => {
    if (!window.confirm('Möchtest du diese Freigabe wirklich aufheben?')) return;
    setError(null);
    setLoading(true);
    try {
      await onRemoveShare(shareId);
    } catch (err: any) {
      setError(err?.message || 'Fehler beim Entfernen der Freigabe');
    } finally {
      setLoading(false);
    }
  };

  const excludedUserIds = [
    ...(currentUserId ? [currentUserId] : []),
    ...shares.filter((s) => s.targetType === 'user').map((s) => s.targetId),
  ];

  const availableTeams = teams.filter(
    (t) => !shares.some((s) => s.targetType === 'team' && s.targetId === t.id)
  );

  return (
    <div
      className="fixed inset-0 !m-0 modal-overlay z-50 flex items-center justify-center p-4 bg-black/60 backdrop-blur-xs"
      onClick={(e) => {
        if (e.target === e.currentTarget) onClose();
      }}
    >
      <div className="panel-surface w-full max-w-lg p-5 shadow-panel rounded-card border border-border space-y-4 animate-in fade-in zoom-in-95 duration-150">
        {/* Header */}
        <div className="flex items-center justify-between pb-3 border-b border-border">
          <div className="flex items-center gap-2.5 min-w-0">
            <div className="w-8 h-8 rounded-btn bg-accent/15 text-accent flex items-center justify-center shrink-0">
              {resourceIcon ? (
                typeof resourceIcon === 'string' ? (
                  <span className="text-base">{resourceIcon}</span>
                ) : (
                  resourceIcon
                )
              ) : (
                <Users className="w-4 h-4" />
              )}
            </div>
            <div className="min-w-0">
              <h3 className="text-sm font-bold text-main truncate">{title}</h3>
              <p className="text-[11px] text-muted truncate">
                Objekt: <span className="font-semibold text-main">{resourceName}</span>
              </p>
            </div>
          </div>
          <button
            type="button"
            onClick={onClose}
            className="p-1.5 text-muted hover:text-main rounded-btn hover:bg-panel transition-colors cursor-pointer"
            title="Schließen"
          >
            <X className="w-4 h-4" />
          </button>
        </div>

        {error && (
          <div className="p-2.5 bg-status-danger/10 border border-status-danger/30 text-status-danger rounded text-xs">
            {error}
          </div>
        )}

        {/* Add Share Section (Only if owner / manager) */}
        {isOwner ? (
          <form onSubmit={handleAdd} className="space-y-3 p-3 bg-panel-elevated border border-border rounded-card">
            <div className="flex items-center justify-between gap-2">
              <span className="text-xs font-semibold text-main">Freigabe hinzufügen:</span>
              <div className="flex items-center gap-1">
                <button
                  type="button"
                  onClick={() => {
                    setShareType('team');
                    setSelectedUser(null);
                    setError(null);
                  }}
                  className={`h-7 px-2.5 text-xs rounded-btn font-medium flex items-center gap-1.5 border transition-colors cursor-pointer ${
                    shareType === 'team'
                      ? 'bg-panel border-accent text-accent font-semibold shadow-xs'
                      : 'bg-canvas border-border text-muted hover:text-main'
                  }`}
                >
                  <Users className="w-3.5 h-3.5" />
                  <span>Gruppe</span>
                </button>
                <button
                  type="button"
                  onClick={() => {
                    setShareType('user');
                    setSelectedTeamId('');
                    setError(null);
                  }}
                  className={`h-7 px-2.5 text-xs rounded-btn font-medium flex items-center gap-1.5 border transition-colors cursor-pointer ${
                    shareType === 'user'
                      ? 'bg-panel border-accent text-accent font-semibold shadow-xs'
                      : 'bg-canvas border-border text-muted hover:text-main'
                  }`}
                >
                  <UserIcon className="w-3.5 h-3.5" />
                  <span>Benutzer</span>
                </button>
              </div>
            </div>

            {shareType === 'team' ? (
              <div className="flex flex-col sm:flex-row gap-2">
                <select
                  value={selectedTeamId}
                  onChange={(e) => setSelectedTeamId(e.target.value)}
                  className="input-field bg-panel h-8 px-2.5 text-xs flex-1 cursor-pointer"
                  disabled={loading}
                >
                  <option value="" className="bg-panel text-muted">-- Gruppe auswählen --</option>
                  {availableTeams.map((t) => (
                    <option key={t.id} value={t.id} className="bg-panel text-main">
                      👥 {t.name} ({t.members?.length || 1} Mitglieder)
                    </option>
                  ))}
                </select>
                {allowRoleSelection && (
                  <select
                    value={selectedPermission}
                    onChange={(e) => setSelectedPermission(e.target.value as 'editor' | 'viewer')}
                    className="input-field bg-panel h-8 px-2.5 text-xs w-full sm:w-36 cursor-pointer shrink-0"
                    disabled={loading}
                  >
                    <option value="editor" className="bg-panel text-main">Bearbeiten</option>
                    <option value="viewer" className="bg-panel text-main">Nur Lesen</option>
                  </select>
                )}
              </div>
            ) : (
              <div className="flex flex-col sm:flex-row gap-2">
                <div className="flex-1">
                  <UserAutocomplete
                    users={collaborators}
                    selectedUser={selectedUser}
                    onSelectUser={setSelectedUser}
                    excludeUserIds={excludedUserIds}
                    disabled={loading}
                    placeholder="Benutzer suchen (Name oder @Benutzername)…"
                  />
                </div>
                {allowRoleSelection && (
                  <select
                    value={selectedPermission}
                    onChange={(e) => setSelectedPermission(e.target.value as 'editor' | 'viewer')}
                    className="input-field bg-panel h-8 px-2.5 text-xs w-full sm:w-36 cursor-pointer shrink-0"
                    disabled={loading}
                  >
                    <option value="editor" className="bg-panel text-main">Bearbeiten</option>
                    <option value="viewer" className="bg-panel text-main">Nur Lesen</option>
                  </select>
                )}
              </div>
            )}

            <div className="flex justify-end pt-1">
              <button
                type="submit"
                disabled={loading || (shareType === 'team' ? !selectedTeamId : !selectedUser)}
                className="btn-primary text-xs h-8 px-3.5 flex items-center gap-1.5 cursor-pointer disabled:opacity-50"
              >
                <Plus className="w-3.5 h-3.5" />
                <span>
                  {loading
                    ? 'Wird gespeichert…'
                    : shareType === 'team'
                    ? 'Gruppe freigeben'
                    : 'Benutzer hinzufügen'}
                </span>
              </button>
            </div>
          </form>
        ) : (
          <div className="p-3 bg-panel-elevated border border-border rounded-card text-xs text-muted flex items-center gap-2">
            <Lock className="w-4 h-4 text-faint shrink-0" />
            <span>Nur der Eigentümer kann neue Freigaben einrichten.</span>
          </div>
        )}

        {/* Active Shares List */}
        <div className="space-y-2">
          <div className="flex items-center justify-between text-xs font-semibold text-muted uppercase tracking-wider px-0.5">
            <span>Aktive Freigaben</span>
            <span className="font-mono text-[11px] font-normal lowercase">
              {shares.length} {shares.length === 1 ? 'Freigabe' : 'Freigaben'}
            </span>
          </div>

          <div className="space-y-1.5 max-h-56 overflow-y-auto pr-0.5">
            {shares.length === 0 ? (
              <div className="p-4 bg-canvas border border-border rounded-card text-xs text-muted flex items-center gap-2.5 justify-center text-center">
                <Lock className="w-4 h-4 text-faint shrink-0" />
                <span>Dieses Element ist aktuell privat (nur für dich sichtbar).</span>
              </div>
            ) : (
              shares.map((sh) => {
                const isTeam = sh.targetType === 'team';
                const roleLabel =
                  sh.permission === 'viewer' || sh.role === 'viewer' ? 'Leser' : 'Bearbeiter';

                return (
                  <div
                    key={sh.id}
                    className="p-2.5 bg-canvas border border-border rounded-btn flex items-center justify-between gap-3 text-xs hover:border-border/80 transition-colors"
                  >
                    <div className="flex items-center gap-2.5 min-w-0">
                      {isTeam ? (
                        <div className="w-7 h-7 rounded-full flex items-center justify-center shrink-0 bg-accent/15 text-accent border border-accent/25">
                          <Users className="w-3.5 h-3.5" />
                        </div>
                      ) : (
                        <UserAvatar
                          avatarUrl={sh.avatarUrl || collaborators.find((c) => c.id === sh.targetId)?.avatarUrl}
                          name={sh.targetName || sh.targetEmail}
                          size="sm"
                          className="border border-border/80"
                        />
                      )}
                      <div className="truncate">
                        <div className="font-medium text-main truncate flex items-center gap-1.5">
                          <span className="truncate">{sh.targetName || (isTeam ? 'Gruppe' : sh.targetEmail || 'Benutzer')}</span>
                          <span
                            className={`text-[9px] uppercase font-semibold px-1 py-0.2 rounded ${
                              isTeam ? 'badge-neutral' : 'bg-surface-2 text-faint'
                            }`}
                          >
                            {isTeam ? 'Gruppe' : 'Benutzer'}
                          </span>
                        </div>
                        {sh.targetEmail && sh.targetEmail !== sh.targetName && (
                          <div className="text-[11px] text-muted truncate">{sh.targetEmail}</div>
                        )}
                      </div>
                    </div>

                    <div className="flex items-center gap-2 shrink-0">
                      <span
                        className={`text-[10px] px-2 py-0.5 rounded font-semibold ${
                          roleLabel === 'Bearbeiter'
                            ? 'bg-accent/15 text-accent border border-accent/30'
                            : 'bg-surface-2 text-muted border border-border'
                        }`}
                      >
                        {roleLabel}
                      </span>
                      {isOwner && (
                        <button
                          type="button"
                          onClick={() => handleRemove(sh.id)}
                          disabled={loading}
                          className="p-1 text-faint hover:text-status-err rounded transition-colors cursor-pointer"
                          title="Freigabe entfernen"
                        >
                          <Trash2 className="w-3.5 h-3.5" />
                        </button>
                      )}
                    </div>
                  </div>
                );
              })
            )}
          </div>
        </div>

        {/* Footer */}
        <div className="pt-2 border-t border-border flex justify-end">
          <button
            type="button"
            onClick={onClose}
            className="btn-action text-xs h-8 px-4 cursor-pointer"
          >
            Schließen
          </button>
        </div>
      </div>
    </div>
  );
};