import {
  Alert,
  Badge,
  Button,
  Divider,
  Group,
  Loader,
  Modal,
  Paper,
  Stack,
  Table,
  Text,
} from '@mantine/core';
import { DateTimePicker } from '@mantine/dates';
import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
import { Receipt } from 'lucide-react';
import { useEffect, useState } from 'react';

import { QUERY_KEYS } from '@/constants/QUERY_KEYS';
import { useToast } from '@/hooks/use-toast';
import { isBackdated } from '@/lib/no-backdate';
import { lastMileService, type LastMileRecord } from '@/services/last-mile.service';

interface TruckDetentionModalProps {
  opened: boolean;
  onClose: () => void;
  record: LastMileRecord | null;
}

const money = (amount: number, currency: string) =>
  `${Number(amount).toLocaleString()} ${currency === 'ETB' ? 'Birr (ETB)' : currency}`;

function Stat({ label, value, strong }: { label: string; value: React.ReactNode; strong?: boolean }) {
  return (
    <Paper withBorder p="sm" radius="md" style={{ flex: 1, minWidth: 120 }}>
      <Text size="xs" c="dimmed" tt="uppercase" fw={600}>
        {label}
      </Text>
      <Text size={strong ? 'lg' : 'md'} fw={strong ? 800 : 600}>
        {value}
      </Text>
    </Paper>
  );
}

type TruckRow = {
  vehicleId: string;
  label: string;
  arrived: Date | null;
  returned: Date | null;
};

const plateOf = (a: NonNullable<LastMileRecord['vehicleAssignments']>[number]) =>
  [a.vehicle?.code, a.vehicle?.plateNumber].filter(Boolean).join(' · ') || a.vehicleId;

/**
 * Detention is PER TRUCK: every truck reaches the destination and is released at
 * its own time, so each row carries its own clock, days and amount. Legs with no
 * trucks assigned fall back to the single leg-level window.
 */
export function TruckDetentionModal({ opened, onClose, record }: TruckDetentionModalProps) {
  const { toast } = useToast();
  const qc = useQueryClient();
  const id = record?.id ?? null;
  const assignments = record?.vehicleAssignments ?? [];
  const perTruck = assignments.length > 0;

  const [rows, setRows] = useState<TruckRow[]>([]);
  // Leg-level fallback (no trucks assigned yet).
  const [arrived, setArrived] = useState<Date | null>(null);
  const [delivered, setDelivered] = useState<Date | null>(null);

  useEffect(() => {
    setRows(
      assignments.map((a) => ({
        vehicleId: a.vehicleId,
        label: plateOf(a),
        // Fall back to the leg-level pair so a truck without its own window
        // shows what it is actually being billed on today.
        arrived: a.destinationArrivedAt
          ? new Date(a.destinationArrivedAt)
          : record?.arrivedAt
            ? new Date(record.arrivedAt)
            : null,
        returned: a.returnedAt
          ? new Date(a.returnedAt)
          : record?.deliveredAt
            ? new Date(record.deliveredAt)
            : null,
      })),
    );
    setArrived(record?.arrivedAt ? new Date(record.arrivedAt) : null);
    setDelivered(record?.deliveredAt ? new Date(record.deliveredAt) : null);
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [record?.id, record?.arrivedAt, record?.deliveredAt, assignments.length, opened]);

  const previewQuery = useQuery({
    queryKey: ['truck-detention-preview', id],
    queryFn: async () => (await lastMileService.truckDetentionPreview(id as string)).data,
    enabled: opened && Boolean(id),
  });
  const preview = previewQuery.data;
  // With several trucks the header rule is null by design (each truck resolves
  // its own) — only warn when NO truck matched a rule.
  const hasAnyRule = Boolean(preview?.ruleId) || (preview?.groups ?? []).some((g) => g.ruleId);
  const byVehicle = new Map((preview?.groups ?? []).map((g) => [g.vehicleId ?? '', g]));

  const saveTimes = useMutation({
    mutationFn: () =>
      perTruck
        ? lastMileService.setDetentionTimes(
            id as string,
            rows.map((r) => ({
              vehicleId: r.vehicleId,
              destinationArrivedAt: r.arrived ? r.arrived.toISOString() : null,
              returnedAt: r.returned ? r.returned.toISOString() : null,
            })),
          )
        : lastMileService.update(id as string, {
            arrivedAt: arrived ? arrived.toISOString() : null,
            deliveredAt: delivered ? delivered.toISOString() : null,
          }),
    onSuccess: () => {
      void qc.invalidateQueries({ queryKey: QUERY_KEYS.LAST_MILE.ROOT });
      void previewQuery.refetch();
      toast({ title: 'Detention times saved' });
    },
    onError: (e: unknown) => {
      const description = (e as { response?: { data?: { message?: string } } })?.response?.data?.message;
      toast({ title: 'Save failed', description, variant: 'destructive' });
    },
  });

  const generate = useMutation({
    mutationFn: () => lastMileService.generateTruckDetentionInvoice(id as string),
    onSuccess: () => {
      void qc.invalidateQueries({ queryKey: QUERY_KEYS.LAST_MILE.ROOT });
      toast({ title: 'Truck detention invoice generated' });
      onClose();
    },
    onError: (e: unknown) => {
      const description = (e as { response?: { data?: { message?: string } } })?.response?.data?.message;
      toast({ title: 'Detention invoice failed', description, variant: 'destructive' });
    },
  });

  const handleSave = () => {
    const values = perTruck
      ? rows.flatMap((r) => [r.arrived, r.returned])
      : [arrived, delivered];
    // No backdating: detention times are recorded as they happen.
    if (values.some((v) => isBackdated(v))) {
      toast({ variant: 'destructive', title: 'Detention times cannot be in the past' });
      return;
    }
    const reversed = perTruck
      ? rows.find((r) => r.arrived && r.returned && r.returned < r.arrived)
      : arrived && delivered && delivered < arrived
        ? { label: 'this delivery' }
        : undefined;
    if (reversed) {
      toast({
        variant: 'destructive',
        title: 'Return time is before arrival',
        description: `Check the times for ${reversed.label}.`,
      });
      return;
    }
    saveTimes.mutate();
  };

  const patchRow = (vehicleId: string, patch: Partial<TruckRow>) =>
    setRows((prev) => prev.map((r) => (r.vehicleId === vehicleId ? { ...r, ...patch } : r)));

  return (
    <Modal
      opened={opened}
      onClose={onClose}
      centered
      size="xl"
      title={
        <Text fw={700}>
          Truck detention{record?.booking?.reference ? ` · ${record.booking.reference}` : ''}
        </Text>
      }
    >
      <Stack gap="md">
        {perTruck ? (
          <Stack gap="xs">
            <Text size="sm" c="dimmed">
              Each truck has its own detention clock — record when it reached the destination and
              when it was released. Days and charges are calculated per truck.
            </Text>
            {rows.map((r) => {
              const g = byVehicle.get(r.vehicleId);
              return (
                <Paper key={r.vehicleId} withBorder p="sm" radius="md">
                  <Group justify="space-between" mb={6} wrap="nowrap">
                    <Group gap={8}>
                      <Text size="sm" fw={600}>
                        {r.label}
                      </Text>
                      {g?.vehicleType && (
                        <Badge size="xs" variant="light" color="gray">
                          {g.vehicleType}
                        </Badge>
                      )}
                    </Group>
                    {g && (
                      <Group gap={10} wrap="nowrap">
                        <Text size="xs" c={g.endIsOpen ? 'orange' : 'dimmed'}>
                          {g.chargeableDays} day{g.chargeableDays === 1 ? '' : 's'}
                          {g.endIsOpen ? ' · still out' : ''}
                        </Text>
                        <Text size="sm" fw={700}>
                          {money(g.amount, preview?.currency ?? 'USD')}
                        </Text>
                      </Group>
                    )}
                  </Group>
                  <Group grow align="flex-start">
                    <DateTimePicker
                      label="Arrived at destination"
                      description="Detention clock start"
                      value={r.arrived}
                      onChange={(v) => patchRow(r.vehicleId, { arrived: v ? new Date(v) : null })}
                      minDate={new Date()}
                      clearable
                    />
                    <DateTimePicker
                      label="Released / returned at"
                      description="Clock end (blank = still out)"
                      value={r.returned}
                      onChange={(v) => patchRow(r.vehicleId, { returned: v ? new Date(v) : null })}
                      minDate={new Date()}
                      clearable
                    />
                  </Group>
                  {g && !g.ruleId && (
                    <Text size="xs" c="red" mt={4}>
                      No detention rule matches this truck type — it will not be billed.
                    </Text>
                  )}
                </Paper>
              );
            })}
          </Stack>
        ) : (
          <>
            <Text size="sm" c="dimmed">
              No trucks assigned yet — this records the delivery-level detention window. Assign
              trucks to track each one separately.
            </Text>
            <Group grow align="flex-start">
              <DateTimePicker
                label="Arrived at"
                description="Detention clock start"
                value={arrived}
                onChange={(v) => setArrived(v ? new Date(v) : null)}
                minDate={new Date()}
                clearable
              />
              <DateTimePicker
                label="Delivered / returned at"
                description="Clock end (blank = still out)"
                value={delivered}
                onChange={(v) => setDelivered(v ? new Date(v) : null)}
                minDate={new Date()}
                clearable
              />
            </Group>
          </>
        )}
        <Group justify="flex-end">
          <Button variant="light" loading={saveTimes.isPending} onClick={handleSave}>
            Save times
          </Button>
        </Group>

        <Divider label="Detention preview" labelPosition="left" />

        {previewQuery.isLoading ? (
          <Group justify="center" py="md">
            <Loader />
          </Group>
        ) : !preview ? (
          <Alert color="gray" variant="light">
            No preview available.
          </Alert>
        ) : !hasAnyRule ? (
          <Alert color="orange" variant="light">
            No active Truck Detention rule matches this booking. Create one under Warehouse → Fee rules
            (rule type "Truck Detention Cost").
          </Alert>
        ) : (
          <Stack gap="sm">
            <Group grow>
              <Stat label="Longest detention" value={`${preview.chargeableDays} day(s)`} />
              <Stat label="Trucks" value={preview.containerCount} />
              <Stat label="Total amount" value={money(preview.amount, preview.currency)} strong />
            </Group>
            {preview.endIsOpen && (
              <Text size="xs" c="orange">
                Still accruing — at least one truck has no release time yet. The amount grows until
                every truck is returned.
              </Text>
            )}
            {preview.groups && preview.groups.length > 0 ? (
              <Table withTableBorder withColumnBorders verticalSpacing="xs" fz="xs">
                <Table.Thead>
                  <Table.Tr>
                    <Table.Th>Truck</Table.Th>
                    <Table.Th>Type</Table.Th>
                    <Table.Th>Days</Table.Th>
                    <Table.Th ta="right">Rate / day</Table.Th>
                    <Table.Th ta="right">Amount</Table.Th>
                  </Table.Tr>
                </Table.Thead>
                <Table.Tbody>
                  {preview.groups.map((g, i) => (
                    <Table.Tr key={g.assignmentId ?? i}>
                      <Table.Td>
                        {g.plateNumber ?? 'Unassigned'}
                        {!g.ruleId && (
                          <Text span size="xs" c="red">
                            {' '}· no rule
                          </Text>
                        )}
                      </Table.Td>
                      <Table.Td>{g.vehicleType ?? 'Unknown'}</Table.Td>
                      <Table.Td>
                        {g.chargeableDays}
                        {g.endIsOpen && (
                          <Text span size="xs" c="orange">
                            {' '}· open
                          </Text>
                        )}
                      </Table.Td>
                      <Table.Td ta="right">{money(g.ratePerDay, preview.currency)}</Table.Td>
                      <Table.Td ta="right">{money(g.amount, preview.currency)}</Table.Td>
                    </Table.Tr>
                  ))}
                </Table.Tbody>
              </Table>
            ) : preview.tiers && preview.tiers.length > 0 ? (
              <Table withTableBorder withColumnBorders verticalSpacing="xs" fz="xs">
                <Table.Thead>
                  <Table.Tr>
                    <Table.Th>From day</Table.Th>
                    <Table.Th>To day</Table.Th>
                    <Table.Th>Days</Table.Th>
                    <Table.Th ta="right">Rate / truck / day</Table.Th>
                    <Table.Th ta="right">Amount</Table.Th>
                  </Table.Tr>
                </Table.Thead>
                <Table.Tbody>
                  {preview.tiers.map((t, i) => (
                    <Table.Tr key={i}>
                      <Table.Td>{t.appliedFromDay}</Table.Td>
                      <Table.Td>{t.appliedToDay}</Table.Td>
                      <Table.Td>{t.days}</Table.Td>
                      <Table.Td ta="right">{money(t.ratePerDay, preview.currency)}</Table.Td>
                      <Table.Td ta="right">{money(t.amount, preview.currency)}</Table.Td>
                    </Table.Tr>
                  ))}
                </Table.Tbody>
              </Table>
            ) : (
              <Text size="sm" c="dimmed">
                Flat {money(preview.ratePerDay, preview.currency)} per truck per day after the grace window.
              </Text>
            )}
            <Group gap="xs">
              <Badge variant="light" color="gray">
                {preview.ruleName ?? 'Detention rule'}
              </Badge>
              {preview.billableUnits > 0 && (
                <Text size="xs" c="dimmed">
                  {preview.billableUnits} billable truck-day(s)
                </Text>
              )}
            </Group>
          </Stack>
        )}

        <Group justify="flex-end" mt="sm">
          <Button variant="default" onClick={onClose}>
            Close
          </Button>
          <Button
            color="edr-green"
            leftSection={<Receipt size={16} />}
            disabled={!preview || preview.amount <= 0}
            loading={generate.isPending}
            onClick={() => generate.mutate()}
          >
            Generate invoice
          </Button>
        </Group>
      </Stack>
    </Modal>
  );
}