import AddIcon from "@mui/icons-material/Add";
import DeleteIcon from "@mui/icons-material/Delete";
import EditIcon from "@mui/icons-material/Edit";
import {
  Box,
  Button,
  Chip,
  Dialog,
  DialogActions,
  DialogContent,
  DialogContentText,
  DialogTitle,
  IconButton,
  InputAdornment,
  MenuItem,
  Paper,
  Table,
  TableBody,
  TableCell,
  TableHead,
  TableRow,
  TextField,
  Tooltip,
  Typography
} from "@mui/material";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { useMemo, useState } from "react";
import { useTranslation } from "react-i18next";
import { useNavigate } from "react-router-dom";

import { fetchContracts, removeContract } from "../api/contracts";
import PageHeader from "../components/PageHeader";
import { useSnackbar } from "../hooks/useSnackbar";
import { Contract } from "../types";
import { formatCurrency, formatDate } from "../utils/date";

export default function ContractsList() {
  const navigate = useNavigate();
  const queryClient = useQueryClient();
  const { showMessage } = useSnackbar();
  const { t } = useTranslation();
  const [contractToDelete, setContractToDelete] = useState<Contract | null>(null);

  const {
    data: contracts,
    isLoading,
    isError
  } = useQuery({
    queryKey: ["contracts", "list"],
    queryFn: () => fetchContracts({ limit: 500 })
  });

  const [search, setSearch] = useState("");
  const [category, setCategory] = useState<string>("all");

  const categories = useMemo(() => {
    const values = new Set<string>();
    contracts?.forEach((contract) => {
      if (contract.category) values.add(contract.category);
    });
    return Array.from(values).sort();
  }, [contracts]);

  const normalizedContracts = useMemo(() => {
    if (!contracts) return [] as Contract[];
    if (Array.isArray(contracts)) return contracts as Contract[];
    if (typeof (contracts as any).results === "object" && Array.isArray((contracts as any).results)) {
      return (contracts as any).results as Contract[];
    }
    return [] as Contract[];
  }, [contracts]);

  const filtered = useMemo(() => {
    return normalizedContracts.filter((contract) => {
      const searchMatch =
        !search ||
        [contract.title, contract.provider, contract.notes, contract.category]
          .filter(Boolean)
          .some((field) => field!.toLowerCase().includes(search.toLowerCase()));

      const categoryMatch = category === "all" || contract.category === category;
      return searchMatch && categoryMatch;
    });
  }, [contracts, search, category]);

  const deleteMutation = useMutation({
    mutationFn: (contractId: number) => removeContract(contractId),
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["contracts"] });
      showMessage(t("contracts.deleted"), "success");
    },
    onError: (error: Error) => showMessage(error.message ?? t("contracts.deleteError"), "error")
  });

  const handleDeleteConfirm = () => {
    if (!contractToDelete) return;
    deleteMutation.mutate(contractToDelete.id);
    setContractToDelete(null);
  };

  return (
    <>
      <PageHeader
        title={t("contracts.title")}
        subtitle={t("contracts.subtitle")}
        action={
          <Button variant="contained" startIcon={<AddIcon />} onClick={() => navigate("/contracts/new")}>
            {t("contracts.new")}
          </Button>
        }
      />

      <Paper variant="outlined" sx={{ p: 2.5, borderRadius: 3 }}>
        <Box display="flex" flexWrap="wrap" gap={2} mb={2}>
          <TextField
            label={t("contracts.searchLabel")}
            placeholder={t("contracts.searchPlaceholder")}
            value={search}
            onChange={(event) => setSearch(event.target.value)}
            sx={{ flex: { xs: "1 1 100%", md: "1 1 320px" } }}
            InputProps={{
              startAdornment: <InputAdornment position="start">🔍</InputAdornment>
            }}
          />
          <TextField
            select
            label={t("contracts.columns.category")}
            value={category}
            onChange={(event) => setCategory(event.target.value)}
            sx={{ width: 200 }}
          >
            <MenuItem value="all">{t("contracts.filterAll")}</MenuItem>
            {categories.map((item) => (
              <MenuItem key={item} value={item}>
                {item}
              </MenuItem>
            ))}
          </TextField>
        </Box>

        <Table>
          <TableHead>
            <TableRow>
              <TableCell>{t("contracts.columns.title")}</TableCell>
              <TableCell>{t("contracts.columns.provider")}</TableCell>
              <TableCell>{t("contracts.columns.category")}</TableCell>
              <TableCell>{t("contracts.columns.price")}</TableCell>
              <TableCell>{t("contracts.columns.end")}</TableCell>
              <TableCell>{t("contracts.columns.tags")}</TableCell>
              <TableCell align="right">{t("contracts.columns.actions")}</TableCell>
            </TableRow>
          </TableHead>
          <TableBody>
            {isLoading && (
              <TableRow>
                <TableCell colSpan={7}>
                  <Typography variant="body2" color="text.secondary">
                    {t("contracts.loading")}
                  </Typography>
                </TableCell>
              </TableRow>
            )}
            {isError && (
              <TableRow>
                <TableCell colSpan={7}>
                  <Typography variant="body2" color="error">
                    {t("dashboard.contractsError")}
                  </Typography>
                </TableCell>
              </TableRow>
            )}
            {!isLoading && !isError && filtered.length === 0 && (
              <TableRow>
                <TableCell colSpan={7}>
                  <Typography variant="body2" color="text.secondary">
                    {t("contracts.empty")}
                  </Typography>
                </TableCell>
              </TableRow>
            )}
            {filtered.map((contract) => (
              <TableRow
                key={contract.id}
                hover
                sx={{ cursor: "pointer" }}
                onClick={() => navigate(`/contracts/${contract.id}`)}
              >
                <TableCell>
                  <Typography fontWeight={600}>{contract.title}</Typography>
                  <Typography variant="caption" color="text.secondary">
                    #{contract.id}
                  </Typography>
                </TableCell>
                <TableCell>{contract.provider ?? "–"}</TableCell>
                <TableCell>{contract.category ?? "–"}</TableCell>
                <TableCell>{formatCurrency(contract.price, contract.currency ?? "EUR")}</TableCell>
                <TableCell>{formatDate(contract.contractEndDate)}</TableCell>
                <TableCell>
                  <Box display="flex" flexWrap="wrap" gap={1}>
                    {(contract.tags ?? []).map((tag) => (
                      <Chip key={tag} label={tag} size="small" />
                    ))}
                  </Box>
                </TableCell>
                <TableCell align="right">
                  <Tooltip title={t("contracts.edit")}>
                    <IconButton
                      onClick={(event) => {
                        event.stopPropagation();
                        navigate(`/contracts/${contract.id}/edit`);
                      }}
                    >
                      <EditIcon />
                    </IconButton>
                  </Tooltip>
                  <Tooltip title={t("actions.delete")}>
                    <IconButton
                      color="error"
                      onClick={(event) => {
                        event.stopPropagation();
                        setContractToDelete(contract);
                      }}
                    >
                      <DeleteIcon />
                    </IconButton>
                  </Tooltip>
                </TableCell>
              </TableRow>
            ))}
          </TableBody>
        </Table>
      </Paper>

      <Dialog
        open={Boolean(contractToDelete)}
        onClose={() => setContractToDelete(null)}
        aria-labelledby="delete-contract-title"
      >
        <DialogTitle id="delete-contract-title">{t("contracts.deleteTitle")}</DialogTitle>
        <DialogContent>
          <DialogContentText>
            {t("contracts.deleteConfirm", { title: contractToDelete?.title ?? "" })}
          </DialogContentText>
        </DialogContent>
        <DialogActions>
          <Button onClick={() => setContractToDelete(null)}>{t("actions.cancel")}</Button>
          <Button
            color="error"
            variant="contained"
            onClick={handleDeleteConfirm}
            disabled={deleteMutation.isPending}
          >
            {t("actions.delete")}
          </Button>
        </DialogActions>
      </Dialog>
    </>
  );
}