import { useCallback, useEffect, useState } from "react";
import { Link } from "react-router-dom";
import { listRuns } from "../api";
import type { RunSummary } from "../types";
import { useSse } from "../hooks/useSse";

function formatDuration(milliseconds?: number): string {
  if (!milliseconds) {
    return "-";
  }
  if (milliseconds < 1000) {
    return `${milliseconds}ms`;
  }
  const seconds = milliseconds / 1000;
  if (seconds < 60) {
    return `${seconds.toFixed(1)}s`;
  }
  const minutes = Math.floor(seconds / 60);
  const remainingSeconds = Math.round(seconds - minutes * 60);
  return `${minutes}m${remainingSeconds}s`;
}

function formatStartedAt(value: string): string {
  const date = new Date(value);
  if (Number.isNaN(date.getTime())) {
    return value;
  }
  return date.toLocaleString();
}

function basename(specPath: string): string {
  const index = specPath.lastIndexOf("/");
  return index >= 0 ? specPath.slice(index + 1) : specPath;
}

export default function RunList() {
  const [runs, setRuns] = useState<RunSummary[] | null>(null);
  const [error, setError] = useState<string | null>(null);

  const refresh = useCallback(() => {
    listRuns()
      .then(setRuns)
      .catch((failure: unknown) => {
        setError(failure instanceof Error ? failure.message : String(failure));
      });
  }, []);

  useEffect(() => {
    refresh();
  }, [refresh]);

  useSse("runs.changed", refresh);

  if (error) {
    return <div className="status-block status-error">failed to load runs: {error}</div>;
  }
  if (!runs) {
    return <div className="status-block">loading runs...</div>;
  }
  if (runs.length === 0) {
    return <div className="status-block">no runs yet. run `sanderling test` to produce some.</div>;
  }

  return (
    <table className="run-table">
      <thead>
        <tr>
          <th>started</th>
          <th>spec</th>
          <th>seed</th>
          <th>platform</th>
          <th>duration</th>
          <th>steps</th>
          <th>violations</th>
          <th></th>
        </tr>
      </thead>
      <tbody>
        {runs.map((run) => (
          <tr key={run.id}>
            <td>
              <Link to={`/runs/${run.id}`}>{formatStartedAt(run.started_at)}</Link>
            </td>
            <td title={run.spec_path}>{basename(run.spec_path)}</td>
            <td>{run.seed}</td>
            <td>{run.platform}</td>
            <td>{formatDuration(run.duration_millis)}</td>
            <td>{run.step_count}</td>
            <td>
              {run.violation_count > 0 ? (
                <span className="chip chip-violation">{run.violation_count}</span>
              ) : (
                "0"
              )}
            </td>
            <td>{run.in_progress ? <span className="chip chip-progress">in progress</span> : null}</td>
          </tr>
        ))}
      </tbody>
    </table>
  );
}