import { useState } from "react";
import { useQuery } from "@tanstack/react-query";
import {
  Filter,
  Search,
  TrendingUp,
  TrendingDown,
  Calendar,
  RefreshCw,
  AlertCircle,
  X,
} from "lucide-react";
import { apiClient } from "../lib/api";
import { formatCurrency, formatDate } from "../lib/utils";
import LoadingSpinner from "./LoadingSpinner";
import type { Account, Transaction } from "../types/api";

export default function TransactionsList() {
  const [searchTerm, setSearchTerm] = useState("");
  const [selectedAccount, setSelectedAccount] = useState<string>("");
  const [startDate, setStartDate] = useState("");
  const [endDate, setEndDate] = useState("");
  const [showFilters, setShowFilters] = useState(false);

  const { data: accounts } = useQuery<Account[]>({
    queryKey: ["accounts"],
    queryFn: apiClient.getAccounts,
  });

  const {
    data: transactions,
    isLoading: transactionsLoading,
    error: transactionsError,
    refetch: refetchTransactions,
  } = useQuery<Transaction[]>({
    queryKey: ["transactions", selectedAccount, startDate, endDate],
    queryFn: () =>
      apiClient.getTransactions({
        accountId: selectedAccount || undefined,
        startDate: startDate || undefined,
        endDate: endDate || undefined,
      }),
  });

  const filteredTransactions = (transactions || []).filter((transaction) => {
    // Additional validation (API client should have already filtered out invalid ones)
    if (!transaction || !transaction.account_id) {
      console.warn(
        "Invalid transaction found after API filtering:",
        transaction,
      );
      return false;
    }

    const description = transaction.description || "";
    const creditorName = transaction.creditor_name || "";
    const debtorName = transaction.debtor_name || "";
    const reference = transaction.reference || "";

    const matchesSearch =
      searchTerm === "" ||
      description.toLowerCase().includes(searchTerm.toLowerCase()) ||
      creditorName.toLowerCase().includes(searchTerm.toLowerCase()) ||
      debtorName.toLowerCase().includes(searchTerm.toLowerCase()) ||
      reference.toLowerCase().includes(searchTerm.toLowerCase());

    return matchesSearch;
  });

  const clearFilters = () => {
    setSearchTerm("");
    setSelectedAccount("");
    setStartDate("");
    setEndDate("");
  };

  const hasActiveFilters =
    searchTerm || selectedAccount || startDate || endDate;

  if (transactionsLoading) {
    return (
      <div className="bg-white rounded-lg shadow">
        <LoadingSpinner message="Loading transactions..." />
      </div>
    );
  }

  if (transactionsError) {
    return (
      <div className="bg-white rounded-lg shadow p-6">
        <div className="flex items-center justify-center text-center">
          <div>
            <AlertCircle className="h-12 w-12 text-red-400 mx-auto mb-4" />
            <h3 className="text-lg font-medium text-gray-900 mb-2">
              Failed to load transactions
            </h3>
            <p className="text-gray-600 mb-4">
              Unable to fetch transactions from the Leggen API.
            </p>
            <button
              onClick={() => refetchTransactions()}
              className="inline-flex items-center px-4 py-2 bg-blue-600 text-white rounded-md hover:bg-blue-700 transition-colors"
            >
              <RefreshCw className="h-4 w-4 mr-2" />
              Retry
            </button>
          </div>
        </div>
      </div>
    );
  }

  return (
    <div className="space-y-6">
      {/* Filters */}
      <div className="bg-white rounded-lg shadow">
        <div className="px-6 py-4 border-b border-gray-200">
          <div className="flex items-center justify-between">
            <h3 className="text-lg font-medium text-gray-900">Transactions</h3>
            <div className="flex items-center space-x-2">
              {hasActiveFilters && (
                <button
                  onClick={clearFilters}
                  className="inline-flex items-center px-3 py-1 text-sm bg-gray-100 text-gray-700 rounded-full hover:bg-gray-200 transition-colors"
                >
                  <X className="h-3 w-3 mr-1" />
                  Clear filters
                </button>
              )}
              <button
                onClick={() => setShowFilters(!showFilters)}
                className="inline-flex items-center px-3 py-2 bg-blue-100 text-blue-700 rounded-md hover:bg-blue-200 transition-colors"
              >
                <Filter className="h-4 w-4 mr-2" />
                Filters
              </button>
            </div>
          </div>
        </div>

        {showFilters && (
          <div className="px-6 py-4 border-b border-gray-200 bg-gray-50">
            <div className="grid grid-cols-1 md:grid-cols-4 gap-4">
              {/* Search */}
              <div>
                <label className="block text-sm font-medium text-gray-700 mb-1">
                  Search
                </label>
                <div className="relative">
                  <Search className="absolute left-3 top-1/2 transform -translate-y-1/2 h-4 w-4 text-gray-400" />
                  <input
                    type="text"
                    value={searchTerm}
                    onChange={(e) => setSearchTerm(e.target.value)}
                    placeholder="Description, name, reference..."
                    className="pl-10 pr-3 py-2 w-full border border-gray-300 rounded-md focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                  />
                </div>
              </div>

              {/* Account Filter */}
              <div>
                <label className="block text-sm font-medium text-gray-700 mb-1">
                  Account
                </label>
                <select
                  value={selectedAccount}
                  onChange={(e) => setSelectedAccount(e.target.value)}
                  className="w-full border border-gray-300 rounded-md px-3 py-2 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                >
                  <option value="">All accounts</option>
                  {accounts?.map((account) => (
                    <option key={account.id} value={account.id}>
                      {account.name || "Unnamed Account"} (
                      {account.institution_id})
                    </option>
                  ))}
                </select>
              </div>

              {/* Start Date */}
              <div>
                <label className="block text-sm font-medium text-gray-700 mb-1">
                  Start Date
                </label>
                <div className="relative">
                  <Calendar className="absolute left-3 top-1/2 transform -translate-y-1/2 h-4 w-4 text-gray-400" />
                  <input
                    type="date"
                    value={startDate}
                    onChange={(e) => setStartDate(e.target.value)}
                    className="pl-10 pr-3 py-2 w-full border border-gray-300 rounded-md focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                  />
                </div>
              </div>

              {/* End Date */}
              <div>
                <label className="block text-sm font-medium text-gray-700 mb-1">
                  End Date
                </label>
                <div className="relative">
                  <Calendar className="absolute left-3 top-1/2 transform -translate-y-1/2 h-4 w-4 text-gray-400" />
                  <input
                    type="date"
                    value={endDate}
                    onChange={(e) => setEndDate(e.target.value)}
                    className="pl-10 pr-3 py-2 w-full border border-gray-300 rounded-md focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-blue-500"
                  />
                </div>
              </div>
            </div>
          </div>
        )}

        {/* Results Summary */}
        <div className="px-6 py-3 bg-gray-50 border-b border-gray-200">
          <p className="text-sm text-gray-600">
            Showing {filteredTransactions.length} transaction
            {filteredTransactions.length !== 1 ? "s" : ""}
            {selectedAccount && accounts && (
              <span className="ml-1">
                for {accounts.find((acc) => acc.id === selectedAccount)?.name}
              </span>
            )}
          </p>
        </div>
      </div>

      {/* Transactions List */}
      {filteredTransactions.length === 0 ? (
        <div className="bg-white rounded-lg shadow p-6 text-center">
          <div className="text-gray-400 mb-4">
            <TrendingUp className="h-12 w-12 mx-auto" />
          </div>
          <h3 className="text-lg font-medium text-gray-900 mb-2">
            No transactions found
          </h3>
          <p className="text-gray-600">
            {hasActiveFilters
              ? "Try adjusting your filters to see more results."
              : "No transactions are available for the selected criteria."}
          </p>
        </div>
      ) : (
        <div className="bg-white rounded-lg shadow divide-y divide-gray-200">
          {filteredTransactions.map((transaction) => {
            const account = accounts?.find(
              (acc) => acc.id === transaction.account_id,
            );
            const isPositive = transaction.amount > 0;

            return (
              <div
                key={
                  transaction.internal_transaction_id ||
                  `${transaction.account_id}-${transaction.date}-${transaction.amount}`
                }
                className="p-6 hover:bg-gray-50 transition-colors"
              >
                <div className="flex items-start justify-between">
                  <div className="flex-1">
                    <div className="flex items-start space-x-3">
                      <div
                        className={`p-2 rounded-full ${
                          isPositive ? "bg-green-100" : "bg-red-100"
                        }`}
                      >
                        {isPositive ? (
                          <TrendingUp className="h-4 w-4 text-green-600" />
                        ) : (
                          <TrendingDown className="h-4 w-4 text-red-600" />
                        )}
                      </div>

                      <div className="flex-1">
                        <h4 className="text-sm font-medium text-gray-900 mb-1">
                          {transaction.description}
                        </h4>

                        <div className="text-xs text-gray-500 space-y-1">
                          {account && (
                            <p>
                              {account.name || "Unnamed Account"} •{" "}
                              {account.institution_id}
                            </p>
                          )}

                          {(transaction.creditor_name ||
                            transaction.debtor_name) && (
                            <p>
                              {isPositive ? "From: " : "To: "}
                              {transaction.creditor_name ||
                                transaction.debtor_name}
                            </p>
                          )}

                          {transaction.reference && (
                            <p>Ref: {transaction.reference}</p>
                          )}

                          {transaction.internal_transaction_id && (
                            <p>ID: {transaction.internal_transaction_id}</p>
                          )}
                        </div>
                      </div>
                    </div>
                  </div>

                  <div className="text-right ml-4">
                    <p
                      className={`text-lg font-semibold ${
                        isPositive ? "text-green-600" : "text-red-600"
                      }`}
                    >
                      {isPositive ? "+" : ""}
                      {formatCurrency(transaction.amount, transaction.currency)}
                    </p>
                    <p className="text-sm text-gray-500">
                      {transaction.date
                        ? formatDate(transaction.date)
                        : "No date"}
                    </p>
                    {transaction.booking_date &&
                      transaction.booking_date !== transaction.date && (
                        <p className="text-xs text-gray-400">
                          Booked: {formatDate(transaction.booking_date)}
                        </p>
                      )}
                  </div>
                </div>
              </div>
            );
          })}
        </div>
      )}
    </div>
  );
}