"use client";

import { useEffect, useRef, useState } from "react";
import type { LogLine } from "@/lib/types";

const LEVELS = ["DEBUG", "INFO", "WARN", "ERROR"] as const;

const levelColor: Record<string, string> = {
  DEBUG: "text-zinc-500",
  INFO: "text-zinc-300",
  WARN: "text-yellow-400",
  ERROR: "text-red-400",
};

interface ServerLogsPanelProps {
  lines: LogLine[];
  connected: boolean;
  onClear: () => void;
}

export function ServerLogsPanel({ lines, connected, onClear }: ServerLogsPanelProps) {
  const scrollRef = useRef<HTMLDivElement>(null);
  const [autoScroll, setAutoScroll] = useState(true);
  const [levelFilter, setLevelFilter] = useState<Set<string>>(
    new Set(["DEBUG", "INFO", "WARN", "ERROR"]),
  );

  const filtered = lines.filter((l) => levelFilter.has(l.level.toUpperCase()));

  useEffect(() => {
    if (!autoScroll) return;
    scrollRef.current?.scrollTo({ top: scrollRef.current.scrollHeight });
  }, [filtered.length, autoScroll]);

  const toggleLevel = (level: string) => {
    setLevelFilter((prev) => {
      const next = new Set(prev);
      if (next.has(level)) next.delete(level);
      else next.add(level);
      return next;
    });
  };

  const handleScroll = () => {
    const el = scrollRef.current;
    if (!el) return;
    const atBottom = el.scrollHeight - el.scrollTop - el.clientHeight < 40;
    setAutoScroll(atBottom);
  };

  const fmtTime = (ts: string) => {
    if (!ts) return "";
    try {
      return new Date(ts).toLocaleTimeString(undefined, { hour12: false });
    } catch {
      return ts;
    }
  };

  return (
    <div className="flex h-full flex-col">
      {/* Header */}
      <div className="flex items-center gap-2 border-b border-zinc-800 px-4 py-2.5">
        <span className="text-xs font-semibold uppercase tracking-widest text-violet-400">
          Server Logs
        </span>
        <span
          className={`rounded px-1.5 py-0.5 text-[10px] font-medium ${
            connected
              ? "bg-green-900/40 text-green-400"
              : "bg-zinc-800 text-zinc-500"
          }`}
        >
          {connected ? "● live" : "○ disconnected"}
        </span>

        <div className="ml-auto flex items-center gap-1">
          {LEVELS.map((lvl) => (
            <button
              key={lvl}
              onClick={() => toggleLevel(lvl)}
              className={`rounded px-2 py-0.5 text-[10px] font-medium transition-opacity ${
                levelFilter.has(lvl) ? "opacity-100" : "opacity-30"
              } ${levelColor[lvl] ?? "text-zinc-400"}`}
            >
              {lvl}
            </button>
          ))}
          <button
            onClick={() => {
              onClear();
              setAutoScroll(true);
            }}
            className="ml-2 rounded px-2 py-0.5 text-[10px] text-zinc-500 hover:text-zinc-300"
          >
            Clear
          </button>
        </div>
      </div>

      {/* Log lines */}
      <div
        ref={scrollRef}
        onScroll={handleScroll}
        className="flex-1 overflow-y-auto bg-zinc-950 px-4 py-2 font-mono text-[11px] leading-relaxed"
      >
        {filtered.length === 0 ? (
          <p className="mt-8 text-center text-zinc-600">
            {connected ? "Waiting for log events…" : "Connecting to server…"}
          </p>
        ) : (
          filtered.map((line, i) => (
            <div key={i} className="flex gap-3">
              <span className="shrink-0 text-zinc-600">{fmtTime(line.timestamp)}</span>
              <span
                className={`w-10 shrink-0 font-semibold ${levelColor[line.level?.toUpperCase()] ?? "text-zinc-400"}`}
              >
                {line.level?.toUpperCase()}
              </span>
              <span className="shrink-0 text-zinc-500">{line.target}</span>
              <span className="text-zinc-200">{line.message}</span>
            </div>
          ))
        )}
        <div className="text-violet-400">{connected && lines.length > 0 ? "▋" : ""}</div>
      </div>
    </div>
  );
}