import { useEffect, useState } from "react";
import { useParams, useNavigate } from "react-router-dom";
import {
  Title,
  Text,
  Group,
  Button,
  Stack,
  Paper,
  Alert,
  Loader,
  CopyButton,
  Tooltip,
  ActionIcon,
  Code,
} from "@mantine/core";
import { IconArrowLeft, IconCopy, IconCheck } from "@tabler/icons-react";
import { getRun } from "../api";
import { StatusBadge } from "../components/StatusBadge";
import { StepTimeline } from "../components/StepTimeline";
import type { RunDetail as RunDetailType, DagStepResult, DagRun } from "../types";

function buildLogText(run: DagRun, steps: DagStepResult[]): string {
  const lines: string[] = [];
  const started = run.StartedAt ? new Date(run.StartedAt) : null;
  const finished = run.FinishedAt ? new Date(run.FinishedAt) : null;
  const durationMs =
    started && finished ? finished.getTime() - started.getTime() : null;

  lines.push(`=== DAG run ${run.ID} ===`);
  lines.push(`dag:        ${run.DagName}`);
  lines.push(`path:       ${run.DagPath}`);
  lines.push(`status:     ${run.Status}`);
  lines.push(`trigger:    ${run.Trigger}`);
  lines.push(`started:    ${started ? started.toISOString() : "-"}`);
  lines.push(`finished:   ${finished ? finished.toISOString() : "-"}`);
  lines.push(
    `duration:   ${durationMs !== null ? `${durationMs} ms` : "running..."}`
  );
  if (run.Error) {
    lines.push("");
    lines.push("run error:");
    lines.push(run.Error);
  }
  lines.push("");
  lines.push(`--- steps (${steps.length}) ---`);
  for (const s of steps) {
    lines.push("");
    lines.push(
      `[${s.Status}] ${s.StepName}  exit=${s.ExitCode}  ${s.DurationMs}ms`
    );
    if (s.StartedAt) lines.push(`  started:  ${s.StartedAt}`);
    if (s.FinishedAt) lines.push(`  finished: ${s.FinishedAt}`);
    if (s.Error) {
      lines.push("  error:");
      lines.push(s.Error.split("\n").map((l) => "    " + l).join("\n"));
    }
    if (s.Stdout) {
      lines.push("  stdout:");
      lines.push(s.Stdout.split("\n").map((l) => "    " + l).join("\n"));
    }
    if (s.Stderr) {
      lines.push("  stderr:");
      lines.push(s.Stderr.split("\n").map((l) => "    " + l).join("\n"));
    }
  }
  return lines.join("\n");
}

export function RunDetail() {
  const { id } = useParams<{ id: string }>();
  const navigate = useNavigate();
  const [data, setData] = useState<RunDetailType | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

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

  useEffect(() => {
    load();
    // Auto-refresh while running.
    const interval = setInterval(() => {
      if (data?.run.Status === "running") {
        load();
      }
    }, 2000);
    return () => clearInterval(interval);
  }, [id, data?.run.Status]);

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

  const { run, steps } = data;
  const duration = run.FinishedAt
    ? `${Math.round((new Date(run.FinishedAt).getTime() - new Date(run.StartedAt).getTime()) / 1000)}s`
    : "running...";

  return (
    <Stack gap="md">
      <Group>
        <Button
          variant="subtle"
          size="xs"
          leftSection={<IconArrowLeft size={14} />}
          onClick={() => navigate(`/dags/${run.DagName}`)}
        >
          Back to {run.DagName}
        </Button>
      </Group>

      <Group justify="space-between">
        <div>
          <Title order={2}>Run {run.ID.substring(0, 16)}...</Title>
          <Text size="sm" c="dimmed">
            {run.DagName} &middot; {run.Trigger} &middot;{" "}
            {new Date(run.StartedAt).toLocaleString()}
          </Text>
        </div>
        <Group gap="xs">
          <StatusBadge status={run.Status} />
          <Text size="sm">{duration}</Text>
        </Group>
      </Group>

      {run.Error && (
        <Alert color="red" title="Error">
          {run.Error}
        </Alert>
      )}

      <Paper p="md" withBorder>
        <Title order={4} mb="md">
          Steps ({steps?.length || 0})
        </Title>
        {steps?.length ? (
          <StepTimeline steps={steps} />
        ) : (
          <Text size="sm" c="dimmed">
            No steps recorded
          </Text>
        )}
      </Paper>

      <Paper p="md" withBorder>
        <Group justify="space-between" mb="sm">
          <Title order={4}>Logs</Title>
          <CopyButton value={buildLogText(run, steps || [])} timeout={1500}>
            {({ copied, copy }) => (
              <Tooltip
                label={copied ? "Copiado" : "Copiar log completo"}
                withArrow
                position="left"
              >
                <ActionIcon
                  variant={copied ? "filled" : "light"}
                  color={copied ? "teal" : "blue"}
                  onClick={copy}
                  aria-label="Copiar logs"
                >
                  {copied ? <IconCheck size={16} /> : <IconCopy size={16} />}
                </ActionIcon>
              </Tooltip>
            )}
          </CopyButton>
        </Group>
        <Code
          block
          style={{
            maxHeight: 480,
            overflow: "auto",
            whiteSpace: "pre",
            fontSize: 12,
          }}
        >
          {buildLogText(run, steps || [])}
        </Code>
      </Paper>
    </Stack>
  );
}