import { Card, Group, Loader, SimpleGrid, Stack, Text, ThemeIcon } from '@mantine/core';
import { Gauge } from 'lucide-react';
import {
  Bar,
  BarChart,
  CartesianGrid,
  ResponsiveContainer,
  Tooltip,
  XAxis,
  YAxis,
} from 'recharts';

import { useOnTimeDispatch, useWarehouseCycleStats } from '@/hooks/useWarehouses';
import { formatDays } from './options';

function onTimeColor(pct: number | null | undefined): string {
  if (pct == null) return 'edr-text';
  if (pct >= 80) return 'teal';
  if (pct >= 50) return 'orange';
  return 'red';
}

/**
 * Warehouse performance: on-time dispatch rate (items that left before their
 * storage free-days expired), average dock-to-dispatch, and the per-stage
 * cycle times that make it up.
 */
export function CycleTimeCard() {
  const { data: cycle, isLoading: cycleLoading } = useWarehouseCycleStats();
  const { data: onTime, isLoading: onTimeLoading } = useOnTimeDispatch();
  const isLoading = cycleLoading || onTimeLoading;

  const hasStages = (cycle?.sampleSize ?? 0) > 0;
  const stages = cycle?.stages ?? [];

  return (
    <Card withBorder radius="lg" padding="lg" h="100%">
      <Group gap="sm" mb="md">
        <ThemeIcon size="lg" radius="md" color="teal" variant="light">
          <Gauge size={20} />
        </ThemeIcon>
        <div>
          <Text fw={700}>Cycle time &amp; on-time</Text>
          <Text size="xs" c="dimmed">
            Dispatch performance over the last 90 days
          </Text>
        </div>
      </Group>

      {isLoading ? (
        <Group justify="center" h={220}>
          <Loader />
        </Group>
      ) : (
        <Stack gap="md">
          <SimpleGrid cols={2} spacing="sm">
            <Stack gap={2}>
              <Text size="xs" c="dimmed" tt="uppercase" fw={700}>
                On-time dispatch
              </Text>
              <Text fw={800} fz={30} lh={1.1} c={onTimeColor(onTime?.onTimePct)}>
                {onTime?.onTimePct == null ? 'N/A' : `${onTime.onTimePct}%`}
              </Text>
              <Text size="xs" c="dimmed">
                {onTime?.onTimePct == null
                  ? 'No storage rule / sample'
                  : `${onTime.onTimeCount}/${onTime.sampleSize} left before free-days`}
              </Text>
            </Stack>
            <Stack gap={2}>
              <Text size="xs" c="dimmed" tt="uppercase" fw={700}>
                Dock → dispatch
              </Text>
              <Text fw={800} fz={30} lh={1.1}>
                {hasStages ? formatDays(cycle?.avgDockToDispatchDays) : '—'}
              </Text>
              <Text size="xs" c="dimmed">
                avg over {cycle?.sampleSize ?? 0} dispatched
              </Text>
            </Stack>
          </SimpleGrid>

          {hasStages ? (
            <ResponsiveContainer width="100%" height={170}>
              <BarChart
                data={stages}
                layout="vertical"
                margin={{ top: 4, right: 16, left: 8, bottom: 0 }}
              >
                <CartesianGrid strokeDasharray="3 3" horizontal={false} stroke="var(--mantine-color-gray-2)" />
                <XAxis type="number" tick={{ fontSize: 12 }} unit="d" />
                <YAxis type="category" dataKey="label" width={130} tick={{ fontSize: 11 }} />
                <Tooltip
                  cursor={{ fill: 'var(--mantine-color-gray-1)' }}
                  formatter={(value) => [`${value} days`, 'Avg'] as [string, string]}
                />
                <Bar dataKey="avgDays" name="Avg days" fill="#12b886" radius={[0, 6, 6, 0]} />
              </BarChart>
            </ResponsiveContainer>
          ) : (
            <Group justify="center" align="center" h={170}>
              <Text c="dimmed" size="sm">
                Not enough dispatched items yet to chart stage times.
              </Text>
            </Group>
          )}
        </Stack>
      )}
    </Card>
  );
}