import { useEffect, useState } from "react";
import { useParams, useNavigate } from "react-router-dom";
import {
  Title,
  Text,
  Group,
  Button,
  Badge,
  Stack,
  Paper,
  Table,
  Alert,
  Loader,
  Code,
} from "@mantine/core";
import { IconPlayerPlay, IconArrowLeft } from "@tabler/icons-react";
import { getDag, triggerDag } from "../api";
import { StatusBadge } from "../components/StatusBadge";
import type { DagDetail as DagDetailType } from "../types";

export function DagDetail() {
  const { name } = useParams<{ name: string }>();
  const navigate = useNavigate();
  const [data, setData] = useState<DagDetailType | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [triggering, setTriggering] = useState(false);

  const load = async () => {
    if (!name) return;
    setLoading(true);
    try {
      setData(await getDag(name));
      setError(null);
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    load();
  }, [name]);

  const handleRun = async () => {
    if (!name) return;
    setTriggering(true);
    try {
      await triggerDag(name);
      setTimeout(load, 1000);
    } catch (e) {
      setError((e as Error).message);
    } finally {
      setTriggering(false);
    }
  };

  if (loading) return <Loader />;
  if (error) return <Alert color="red">{error}</Alert>;
  if (!data) return <Text>Not found</Text>;

  const { dag, validation, runs } = data;

  return (
    <Stack gap="md">
      <Group>
        <Button
          variant="subtle"
          size="xs"
          leftSection={<IconArrowLeft size={14} />}
          onClick={() => navigate("/")}
        >
          Back
        </Button>
      </Group>

      <Group justify="space-between">
        <div>
          <Title order={2}>{dag.Name}</Title>
          {dag.Description && (
            <Text size="sm" c="dimmed">
              {dag.Description}
            </Text>
          )}
        </div>
        <Button
          leftSection={<IconPlayerPlay size={16} />}
          onClick={handleRun}
          loading={triggering}
        >
          Run Now
        </Button>
      </Group>

      <Group gap="xs">
        {dag.Schedule?.map((s: string) => (
          <Badge key={s} variant="light" ff="monospace">
            {s}
          </Badge>
        ))}
        <Badge variant="light">{dag.Type || "chain"}</Badge>
        {dag.Tags?.map((t: string) => (
          <Badge key={t} variant="dot">
            {t}
          </Badge>
        ))}
      </Group>

      {!validation.Valid && (
        <Alert color="red" title="Validation errors">
          {validation.Errors.map((e: string, i: number) => (
            <Text key={i} size="sm">
              {e}
            </Text>
          ))}
        </Alert>
      )}

      <Paper p="md" withBorder>
        <Title order={4} mb="sm">
          Steps ({dag.Steps?.length || 0})
        </Title>
        {validation.Levels?.map((level: string[], i: number) => (
          <Group key={i} gap="xs" mb="xs">
            <Text size="xs" c="dimmed" w={60}>
              Level {i}:
            </Text>
            {level.map((name: string) => {
              const step = dag.Steps?.find(
                (s) => s.Name === name || s.ID === name
              );
              return (
                <Badge key={name} variant="outline" size="sm">
                  {name}
                  {step?.Depends?.length
                    ? ` (after ${step.Depends.join(",")})`
                    : ""}
                </Badge>
              );
            })}
          </Group>
        ))}

        {dag.Env && Object.keys(dag.Env).length > 0 && (
          <>
            <Title order={5} mt="md" mb="xs">
              Environment
            </Title>
            <Code block>
              {Object.entries(dag.Env)
                .map(([k, v]) => `${k}=${v}`)
                .join("\n")}
            </Code>
          </>
        )}
      </Paper>

      <Paper p="md" withBorder>
        <Title order={4} mb="sm">
          Run History
        </Title>
        {runs?.length ? (
          <Table striped>
            <Table.Thead>
              <Table.Tr>
                <Table.Th>Status</Table.Th>
                <Table.Th>Trigger</Table.Th>
                <Table.Th>Started</Table.Th>
                <Table.Th>Duration</Table.Th>
              </Table.Tr>
            </Table.Thead>
            <Table.Tbody>
              {runs.map((r) => (
                <Table.Tr
                  key={r.ID}
                  style={{ cursor: "pointer" }}
                  onClick={() => navigate(`/runs/${r.ID}`)}
                >
                  <Table.Td>
                    <StatusBadge status={r.Status} />
                  </Table.Td>
                  <Table.Td>{r.Trigger}</Table.Td>
                  <Table.Td>
                    {new Date(r.StartedAt).toLocaleString()}
                  </Table.Td>
                  <Table.Td>
                    {r.FinishedAt
                      ? `${Math.round((new Date(r.FinishedAt).getTime() - new Date(r.StartedAt).getTime()) / 1000)}s`
                      : "running..."}
                  </Table.Td>
                </Table.Tr>
              ))}
            </Table.Tbody>
          </Table>
        ) : (
          <Text size="sm" c="dimmed">
            No runs yet
          </Text>
        )}
      </Paper>
    </Stack>
  );
}