import { useState, useEffect } from "react";
import {
  getGroceryLists,
  createGroceryList,
  updateGroceryList,
  deleteGroceryList,
  shareGroceryList,
  getGroceryListShares,
  unshareGroceryList,
  searchUsers,
  togglePinGroceryList,
} from "../groceryApi";

function GroceryLists({ user, onShowToast }) {
  const [lists, setLists] = useState([]);
  const [selectedList, setSelectedList] = useState(null);
  const [loading, setLoading] = useState(true);
  const [editingList, setEditingList] = useState(null);
  const [showShareModal, setShowShareModal] = useState(null);
  const [shares, setShares] = useState([]);
  const [userSearch, setUserSearch] = useState("");
  const [searchResults, setSearchResults] = useState([]);
  const [sharePermission, setSharePermission] = useState(false);

  // New list form
  const [newListName, setNewListName] = useState("");
  const [showNewListForm, setShowNewListForm] = useState(false);

  // Edit form
  const [editName, setEditName] = useState("");
  const [editItems, setEditItems] = useState([]);
  const [newItem, setNewItem] = useState("");

  useEffect(() => {
    loadLists();
  }, []);

  // Restore selected list from localStorage after lists are loaded
  useEffect(() => {
    if (lists.length > 0) {
      try {
        const savedListId = localStorage.getItem("selectedGroceryListId");
        if (savedListId) {
          const listToSelect = lists.find(list => list.id === parseInt(savedListId));
          if (listToSelect) {
            setSelectedList(listToSelect);
          }
        }
      } catch (err) {
        console.error("Failed to restore selected list", err);
      }
    }
  }, [lists]);

  const loadLists = async () => {
    try {
      setLoading(true);
      const data = await getGroceryLists();
      setLists(data);
    } catch (error) {
      onShowToast(error.message, "error");
    } finally {
      setLoading(false);
    }
  };

  const handleCreateList = async (e) => {
    e.preventDefault();
    if (!newListName.trim()) return;

    try {
      const newList = await createGroceryList({
        name: newListName.trim(),
        items: [],
      });
      setLists([newList, ...lists]);
      setNewListName("");
      setShowNewListForm(false);
      onShowToast("רשימת קניות נוצרה בהצלחה", "success");
    } catch (error) {
      onShowToast(error.message, "error");
    }
  };

  const handleSelectList = (list) => {
    setSelectedList(list);
    setEditingList(null);
    try {
      localStorage.setItem("selectedGroceryListId", list.id.toString());
    } catch (err) {
      console.error("Failed to save selected list", err);
    }
  };

  const handleEditList = (list) => {
    setEditingList(list);
    setEditName(list.name);
    setEditItems([...list.items]);
    setNewItem("");
  };

  const handleAddItem = () => {
    if (!newItem.trim()) return;
    setEditItems([...editItems, newItem.trim()]);
    setNewItem("");
  };

  const handleRemoveItem = (index) => {
    setEditItems(editItems.filter((_, i) => i !== index));
  };

  const handleToggleItem = (index) => {
    const updated = [...editItems];
    const item = updated[index];
    if (item.startsWith("✓ ")) {
      updated[index] = item.substring(2);
    } else {
      updated[index] = "✓ " + item;
    }
    setEditItems(updated);
  };

  const handleToggleItemInView = async (index) => {
    if (!selectedList || !selectedList.can_edit) return;
    
    const updated = [...selectedList.items];
    const item = updated[index];
    if (item.startsWith("✓ ")) {
      updated[index] = item.substring(2);
    } else {
      updated[index] = "✓ " + item;
    }
    
    try {
      const updatedList = await updateGroceryList(selectedList.id, {
        items: updated,
      });
      
      setLists(lists.map((l) => (l.id === updatedList.id ? updatedList : l)));
      setSelectedList(updatedList);
    } catch (error) {
      onShowToast(error.message, "error");
    }
  };

  const handleSaveList = async () => {
    if (!editName.trim()) {
      onShowToast("שם הרשימה לא יכול להיות ריק", "error");
      return;
    }

    try {
      const updated = await updateGroceryList(editingList.id, {
        name: editName.trim(),
        items: editItems,
      });
      
      setLists(lists.map((l) => (l.id === updated.id ? updated : l)));
      if (selectedList?.id === updated.id) {
        setSelectedList(updated);
      }
      setEditingList(null);
      onShowToast("רשימת קניות עודכנה בהצלחה", "success");
    } catch (error) {
      onShowToast(error.message, "error");
    }
  };

  const handleDeleteList = async (listId) => {
    if (!confirm("האם אתה בטוח שברצונך למחוק רשימת קניות זו?")) return;

    try {
      await deleteGroceryList(listId);
      setLists(lists.filter((l) => l.id !== listId));
      if (selectedList?.id === listId) {
        setSelectedList(null);
      }
      setEditingList(null);
      onShowToast("רשימת קניות נמחקה בהצלחה", "success");
    } catch (error) {
      onShowToast(error.message, "error");
    }
  };

  const handleTogglePin = async (list) => {
    try {
      const updated = await togglePinGroceryList(list.id);
      setLists(lists.map((l) => (l.id === updated.id ? updated : l)));
      if (selectedList?.id === updated.id) {
        setSelectedList(updated);
      }
      const message = updated.is_pinned
        ? "רשימה הוצמדה לדף הבית"
        : "רשימה הוסרה מדף הבית";
      onShowToast(message, "success");
    } catch (error) {
      onShowToast(error.message, "error");
    }
  };

  const handleShowShareModal = async (list) => {
    setShowShareModal(list);
    setUserSearch("");
    setSearchResults([]);
    setSharePermission(false);
    
    try {
      const sharesData = await getGroceryListShares(list.id);
      setShares(sharesData);
    } catch (error) {
      onShowToast(error.message, "error");
    }
  };

  const handleSearchUsers = async (query) => {
    setUserSearch(query);
    if (query.trim().length < 2) {
      setSearchResults([]);
      return;
    }

    try {
      const results = await searchUsers(query);
      setSearchResults(results);
    } catch (error) {
      onShowToast(error.message, "error");
    }
  };

  const handleShareWithUser = async (userId, username) => {
    try {
      const share = await shareGroceryList(showShareModal.id, {
        user_identifier: username,
        can_edit: sharePermission,
      });
      
      setShares([...shares, share]);
      setUserSearch("");
      setSearchResults([]);
      setSharePermission(false);
      onShowToast(`רשימה שותפה עם ${share.display_name}`, "success");
    } catch (error) {
      onShowToast(error.message, "error");
    }
  };

  const handleUnshare = async (userId) => {
    try {
      await unshareGroceryList(showShareModal.id, userId);
      setShares(shares.filter((s) => s.shared_with_user_id !== userId));
      onShowToast("שיתוף הוסר בהצלחה", "success");
    } catch (error) {
      onShowToast(error.message, "error");
    }
  };

  if (loading) {
    return <div className="loading">טוען רשימות קניות...</div>;
  }

  return (
    <div className="grocery-lists-container">
      <div className="grocery-lists-header">
        <h2>רשימות הקניות שלי</h2>
        <button
          className="btn primary"
          onClick={() => setShowNewListForm(!showNewListForm)}
        >
          {showNewListForm ? "ביטול" : "+ רשימה חדשה"}
        </button>
      </div>

      {showNewListForm && (
        <form className="new-list-form" onSubmit={handleCreateList}>
          <input
            type="text"
            placeholder="שם הרשימה..."
            value={newListName}
            onChange={(e) => setNewListName(e.target.value)}
            autoFocus
          />
          <button type="submit" className="btn primary">
            צור רשימה
          </button>
        </form>
      )}

      <div className="grocery-lists-layout">
        {/* Lists Sidebar */}
        <div className="lists-sidebar">
          {lists.length === 0 ? (
            <p className="empty-message">אין רשימות קניות עדיין</p>
          ) : (
            lists.map((list) => (
              <div key={list.id} className="list-item-wrapper">
                <div
                  className={`list-item ${selectedList?.id === list.id ? "active" : ""}`}
                  onClick={() => handleSelectList(list)}
                >
                  <div className="list-item-content">
                    <h4>{list.name}</h4>
                    <p className="list-item-meta">
                      {list.is_owner ? "שלי" : `של ${list.owner_display_name}`}
                      {" · "}
                      {list.items.length} פריטים
                    </p>
                  </div>
                </div>
                {list.is_owner && (
                  <button
                    className="share-icon-btn"
                    onClick={(e) => {
                      e.stopPropagation();
                      handleShowShareModal(list);
                    }}
                    title="שתף רשימה"
                  >
                    <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
                      <circle cx="18" cy="5" r="3"/>
                      <circle cx="6" cy="12" r="3"/>
                      <circle cx="18" cy="19" r="3"/>
                      <line x1="8.59" y1="13.51" x2="15.42" y2="17.49"/>
                      <line x1="15.41" y1="6.51" x2="8.59" y2="10.49"/>
                    </svg>
                  </button>
                )}
              </div>
            ))
          )}
        </div>

        {/* List Details */}
        <div className="list-details">
          {editingList ? (
            <div className="edit-list-form">
              <div className="form-header">
                <h3>עריכת רשימה</h3>
                <button className="btn ghost" onClick={() => setEditingList(null)}>
                  ביטול
                </button>
              </div>

              <div className="form-group">
                <label>שם הרשימה</label>
                <input
                  type="text"
                  value={editName}
                  onChange={(e) => setEditName(e.target.value)}
                />
              </div>

              <div className="form-group">
                <label>פריטים</label>
                <div className="add-item-row">
                  <input
                    type="text"
                    placeholder="הוסף פריט..."
                    value={newItem}
                    onChange={(e) => setNewItem(e.target.value)}
                    onKeyPress={(e) => e.key === "Enter" && (e.preventDefault(), handleAddItem())}
                  />
                  <button type="button" className="btn primary" onClick={handleAddItem}>
                    הוסף
                  </button>
                </div>

                <ul className="items-list">
                  {editItems.map((item, index) => (
                    <li key={index} className="item-row">
                      <button
                        type="button"
                        className="btn-icon"
                        onClick={() => handleToggleItem(index)}
                      >
                        {item.startsWith("✓ ") ? "☑" : "☐"}
                      </button>
                      <span className={item.startsWith("✓ ") ? "checked" : ""}>
                        {item.startsWith("✓ ") ? item.substring(2) : item}
                      </span>
                      <button
                        type="button"
                        className="btn-icon delete"
                        onClick={() => handleRemoveItem(index)}
                      >
                        ✕
                      </button>
                    </li>
                  ))}
                </ul>
              </div>

              <div className="form-actions">
                <button className="btn primary" onClick={handleSaveList}>
                  שמור שינויים
                </button>
                {editingList.is_owner && (
                  <>
                    <button
                      className="btn secondary small"
                      onClick={() => {
                        setEditingList(null);
                        handleShowShareModal(editingList);
                      }}
                      title="שתף רשימה"
                    >
                      ↗️ שתף
                    </button>
                    <button
                      className="btn danger"
                      onClick={() => handleDeleteList(editingList.id)}
                    >
                      מחק רשימה
                    </button>
                  </>
                )}
              </div>
            </div>
          ) : selectedList ? (
            <div className="view-list">
              <div className="view-header">
                <div>
                  <h3>{selectedList.name}</h3>
                  <p className="list-meta">
                    {selectedList.is_owner
                      ? "רשימה שלי"
                      : `משותפת על ידי ${selectedList.owner_display_name}`}
                  </p>
                </div>
                <div className="view-header-actions">
                  {selectedList.is_owner && (
                    <>
                      <button
                        className={`btn-icon-action ${selectedList.is_pinned ? "pinned" : ""}`}
                        onClick={() => handleTogglePin(selectedList)}
                        title={selectedList.is_pinned ? "הסר הצמדה" : "הצמד לדף הבית"}
                      >
                        📌
                      </button>
                      <button
                        className="btn-icon-action"
                        onClick={() => handleShowShareModal(selectedList)}
                        title="שתף רשימה"
                      >
                        <svg xmlns="http://www.w3.org/2000/svg" width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
                          <circle cx="18" cy="5" r="3"/>
                          <circle cx="6" cy="12" r="3"/>
                          <circle cx="18" cy="19" r="3"/>
                          <line x1="8.59" y1="13.51" x2="15.42" y2="17.49"/>
                          <line x1="15.41" y1="6.51" x2="8.59" y2="10.49"/>
                        </svg>
                      </button>
                    </>
                  )}
                  {selectedList.can_edit && (
                    <button
                      className="btn-icon-action"
                      onClick={() => handleEditList(selectedList)}
                      title="ערוך רשימה"
                    >
                      ✏️
                    </button>
                  )}
                </div>
              </div>

              {selectedList.items.length === 0 ? (
                <p className="empty-message">אין פריטים ברשימה</p>
              ) : (
                <ul className="items-list view-mode">
                  {selectedList.items.map((item, index) => {
                    const isChecked = item.startsWith("✓ ");
                    const itemText = isChecked ? item.substring(2) : item;
                    return (
                      <li key={index} className={`item-row ${isChecked ? "checked" : ""}`}>
                        {selectedList.can_edit ? (
                          <>
                            <button
                              type="button"
                              className="btn-icon"
                              onClick={() => handleToggleItemInView(index)}
                            >
                              {isChecked ? "☑" : "☐"}
                            </button>
                            <span className={isChecked ? "checked-text" : ""}>
                              {itemText}
                            </span>
                          </>
                        ) : (
                          <>
                            <span className="btn-icon">{isChecked ? "☑" : "☐"}</span>
                            <span className={isChecked ? "checked-text" : ""}>
                              {itemText}
                            </span>
                          </>
                        )}
                      </li>
                    );
                  })}
                </ul>
              )}
            </div>
          ) : (
            <div className="empty-state">
              <p>בחר רשימת קניות כדי להציג את הפרטים</p>
            </div>
          )}
        </div>
      </div>

      {/* Share Modal */}
      {showShareModal && (
        <div className="modal-overlay" onClick={() => setShowShareModal(null)}>
          <div className="modal share-modal" onClick={(e) => e.stopPropagation()}>
            <div className="modal-header">
              <h3>שתף רשימה: {showShareModal.name}</h3>
              <button className="btn-close" onClick={() => setShowShareModal(null)}>
                ✕
              </button>
            </div>

            <div className="modal-body">
              <div className="share-search">
                <input
                  type="text"
                  placeholder="חפש משתמש לפי שם משתמש או שם תצוגה..."
                  value={userSearch}
                  onChange={(e) => handleSearchUsers(e.target.value)}
                />
                <label className="checkbox-label">
                  <input
                    type="checkbox"
                    checked={sharePermission}
                    onChange={(e) => setSharePermission(e.target.checked)}
                  />
                  <span>אפשר עריכה</span>
                </label>

                {searchResults.length > 0 && (
                  <ul className="search-results">
                    {searchResults.map((user) => (
                      <li
                        key={user.id}
                        onClick={() => handleShareWithUser(user.id, user.username)}
                      >
                        <div>
                          <strong>{user.display_name}</strong>
                          <span className="username">@{user.username}</span>
                        </div>
                        <button className="btn small">שתף</button>
                      </li>
                    ))}
                  </ul>
                )}
              </div>

              <div className="shares-list">
                <h4>משותף עם:</h4>
                {shares.length === 0 ? (
                  <p className="empty-message">הרשימה לא משותפת עם אף אחד</p>
                ) : (
                  <ul>
                    {shares.map((share) => (
                      <li key={share.id} className="share-item">
                        <div>
                          <strong>{share.display_name}</strong>
                          <span className="username">@{share.username}</span>
                          {share.can_edit && <span className="badge">עורך</span>}
                        </div>
                        <button
                          className="btn danger small"
                          onClick={() => handleUnshare(share.shared_with_user_id)}
                        >
                          הסר
                        </button>
                      </li>
                    ))}
                  </ul>
                )}
              </div>
            </div>
          </div>
        </div>
      )}

      <style>{`
        .grocery-lists-container {
          padding: 1rem;
          max-width: 1400px;
          margin: 0 auto;
        }

        .grocery-lists-header {
          display: flex;
          justify-content: space-between;
          align-items: center;
          margin-bottom: 1.5rem;
        }

        .new-list-form {
          display: flex;
          gap: 0.5rem;
          margin-bottom: 1.5rem;
          padding: 1.5rem;
          background: var(--panel-bg);
          border-radius: 12px;
          box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
        }

        .new-list-form input {
          flex: 1;
        }

        .grocery-lists-layout {
          display: grid;
          grid-template-columns: 280px 1fr;
          gap: 1.5rem;
        }

        .lists-sidebar {
          display: flex;
          flex-direction: column;
          gap: 0.5rem;
        }

        .list-item-wrapper {
          position: relative;
          display: flex;
          align-items: center;
          gap: 0.5rem;
        }

        .list-item {
          flex: 1;
          display: flex;
          justify-content: space-between;
          align-items: center;
          padding: 1rem;
          background: var(--panel-bg);
          border-radius: 12px;
          cursor: pointer;
          transition: all 0.2s;
          box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
        }

        .share-icon-btn {
          background: var(--card-soft);
          border: 1px solid var(--border-color);
          padding: 0.5rem;
          cursor: pointer;
          border-radius: 8px;
          transition: all 0.2s;
          display: flex;
          align-items: center;
          justify-content: center;
          color: var(--text-secondary);
          flex-shrink: 0;
          box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
        }

        .share-icon-btn:hover {
          background: var(--accent-soft);
          border-color: var(--accent);
          color: var(--accent);
          transform: scale(1.05);
          box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
        }

        .list-item:hover {
          background: var(--hover-bg);
          box-shadow: 0 2px 6px rgba(0, 0, 0, 0.15);
          transform: translateY(-1px);
        }

        .list-item.active {
          background: var(--primary-color);
          color: white;
        }

        .list-item-content h4 {
          margin: 0 0 0.25rem 0;
        }

        .list-item-meta {
          margin: 0;
          font-size: 0.875rem;
          opacity: 0.8;
        }

        .list-details {
          background: var(--panel-bg);
          border-radius: 16px;
          padding: 2rem;
          min-height: 400px;
          box-shadow: 0 2px 12px rgba(0, 0, 0, 0.1);
        }

        .edit-list-form .form-header {
          display: flex;
          justify-content: space-between;
          align-items: center;
          margin-bottom: 1.5rem;
        }

        .form-group {
          margin-bottom: 1.5rem;
        }

        .form-group label {
          display: block;
          margin-bottom: 0.5rem;
          font-weight: 500;
        }

        .add-item-row {
          display: flex;
          gap: 0.5rem;
          margin-bottom: 1rem;
        }

        .add-item-row input {
          flex: 1;
        }

        .items-list {
          list-style: none;
          padding: 0;
          margin: 0;
        }

        .item-row {
          display: flex;
          align-items: center;
          gap: 0.75rem;
          padding: 1rem 1.25rem;
          background: var(--panel-bg);
          border: 1px solid var(--border-color);
          border-radius: 12px;
          margin-bottom: 0.75rem;
          transition: all 0.2s;
          box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
        }

        .item-row:hover {
          background: var(--hover-bg);
          box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
          transform: translateY(-1px);
        }

        .item-row span {
          flex: 1;
        }

        .item-row span.checked-text {
          text-decoration: line-through;
          opacity: 0.6;
        }

        .item-row span.checked {
          text-decoration: line-through;
          opacity: 0.6;
        }

        .items-list.view-mode .item-row {
          display: flex;
          align-items: center;
          gap: 0.75rem;
          padding: 1rem 1.25rem;
          background: var(--panel-bg);
          border: 1px solid var(--border-color);
          border-radius: 12px;
          margin-bottom: 0.75rem;
          box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
        }

        .items-list.view-mode .item-row:hover {
          background: var(--hover-bg);
          box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
          transform: translateY(-1px);
        }

        .items-list.view-mode .item-row.checked {
          opacity: 0.7;
          background: var(--card-soft);
        }

        .form-actions {
          display: flex;
          gap: 0.5rem;
          margin-top: 1.5rem;
        }

        .view-header {
          display: flex;
          justify-content: space-between;
          align-items: center;
          margin-bottom: 1.5rem;
          gap: 1rem;
        }

        .view-header > div:first-child {
          flex: 1;
          min-width: 0;
        }

        .view-header h3 {
          margin: 0;
          overflow: hidden;
          text-overflow: ellipsis;
          white-space: nowrap;
        }

        .view-header-actions {
          display: flex;
          gap: 0.5rem;
          flex-shrink: 0;
        }

        .list-meta {
          margin: 0.5rem 0 0 0;
          opacity: 0.7;
        }

        .empty-state,
        .empty-message {
          text-align: center;
          padding: 2rem;
          opacity: 0.6;
        }

        .modal-overlay {
          position: fixed;
          top: 0;
          left: 0;
          right: 0;
          bottom: 0;
          background: rgba(0, 0, 0, 0.5);
          display: flex;
          align-items: center;
          justify-content: center;
          z-index: 1000;
        }

        .share-modal {
          background: var(--panel-bg);
          border-radius: 16px;
          width: 90%;
          max-width: 500px;
          max-height: 80vh;
          overflow-y: auto;
          box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
        }

        .modal-header {
          display: flex;
          justify-content: space-between;
          align-items: center;
          padding: 1.5rem;
          border-bottom: 1px solid var(--border-color);
        }

        .modal-body {
          padding: 1.5rem;
        }

        .share-search input {
          width: 100%;
          margin-bottom: 0.5rem;
        }

        .checkbox-label {
          display: flex;
          align-items: center;
          gap: 0.5rem;
          margin-bottom: 1rem;
          cursor: pointer;
        }

        .search-results {
          list-style: none;
          padding: 0;
          margin: 1rem 0;
          border: 1px solid var(--border-color);
          border-radius: 8px;
          max-height: 200px;
          overflow-y: auto;
        }

        .search-results li {
          display: flex;
          justify-content: space-between;
          align-items: center;
          padding: 0.75rem;
          cursor: pointer;
          border-bottom: 1px solid var(--border-color);
        }

        .search-results li:last-child {
          border-bottom: none;
        }

        .search-results li:hover {
          background: var(--hover-bg);
        }

        .username {
          font-size: 0.875rem;
          opacity: 0.7;
          margin-left: 0.5rem;
        }

        .shares-list {
          margin-top: 2rem;
        }

        .shares-list h4 {
          margin-bottom: 1rem;
        }

        .share-item {
          display: flex;
          justify-content: space-between;
          align-items: center;
          padding: 0.75rem;
          background: var(--hover-bg);
          border-radius: 8px;
          margin-bottom: 0.5rem;
        }

        .badge {
          display: inline-block;
          padding: 0.25rem 0.5rem;
          background: var(--primary-color);
          color: white;
          border-radius: 6px;
          font-size: 0.75rem;
          margin-right: 0.5rem;
        }

        .btn-icon-action {
          background: var(--card-soft);
          border: 1px solid var(--border-color);
          padding: 0.5rem 0.75rem;
          cursor: pointer;
          font-size: 1.25rem;
          border-radius: 8px;
          transition: all 0.2s;
          line-height: 1;
        }

        .btn-icon-action:hover {
          background: var(--hover-bg);
          transform: scale(1.1);
        }

        @media (max-width: 768px) {
          .grocery-lists-layout {
            grid-template-columns: 1fr;
          }

          .lists-sidebar {
            max-height: 300px;
            overflow-y: auto;
          }
        }
      `}</style>
    </div>
  );
}

export default GroceryLists;