import { useRef, useEffect, useState } from "react";
import type { SearchAddon } from "@xterm/addon-search";
import "./SearchBar.css";

// ---------------------------------------------------------------------------
// SearchBar — per-pane find-in-scrollback overlay.
//
// Rendered as an absolutely-positioned sibling of the xterm canvas inside
// XtermPane's container div (position: relative).  The SearchAddon instance
// is owned by XtermPane and passed down as a prop; no IPC or Context needed.
//
// Toggle state (caseSensitive, regex) uses useState so aria-pressed reflects
// the live value on every render — refs alone don't trigger re-renders.
// ---------------------------------------------------------------------------

interface SearchBarProps {
  searchAddon: SearchAddon;
  onClose: () => void;
}

export default function SearchBar({ searchAddon, onClose }: SearchBarProps) {
  const inputRef = useRef<HTMLInputElement>(null);
  const queryRef = useRef("");
  const [caseSensitive, setCaseSensitive] = useState(false);
  const [useRegex, setUseRegex] = useState(false);

  // Keep stable refs to toggle values so findNext/findPrev closures always
  // see the current value without needing to be recreated on each state change.
  const caseSensitiveRef = useRef(caseSensitive);
  const useRegexRef = useRef(useRegex);
  useEffect(() => { caseSensitiveRef.current = caseSensitive; }, [caseSensitive]);
  useEffect(() => { useRegexRef.current = useRegex; }, [useRegex]);

  // Autofocus the input when the bar mounts.
  useEffect(() => {
    queueMicrotask(() => inputRef.current?.focus());
  }, []);

  function getOptions() {
    return {
      caseSensitive: caseSensitiveRef.current,
      regex: useRegexRef.current,
      // Highlight all matches and mark the active one distinctly.
      decorations: {
        matchBackground: "#3a3a00",
        matchBorder: "#888800",
        matchOverviewRuler: "#888800",
        activeMatchBackground: "#b5890080",
        activeMatchBorder: "#e6c000",
        activeMatchColorOverviewRuler: "#e6c000",
      },
    };
  }

  function findNext() {
    if (!queryRef.current) return;
    searchAddon.findNext(queryRef.current, getOptions());
  }

  function findPrev() {
    if (!queryRef.current) return;
    searchAddon.findPrevious(queryRef.current, getOptions());
  }

  function handleInput(e: React.ChangeEvent<HTMLInputElement>) {
    queryRef.current = e.target.value;
    // Live-search: jump to next match as you type.
    if (queryRef.current) {
      searchAddon.findNext(queryRef.current, getOptions());
    }
  }

  function handleKeyDown(e: React.KeyboardEvent<HTMLInputElement>) {
    if (e.key === "Escape") {
      e.preventDefault();
      onClose();
    } else if (e.key === "Enter") {
      e.preventDefault();
      if (e.shiftKey) {
        findPrev();
      } else {
        findNext();
      }
    }
  }

  function toggleCase() {
    setCaseSensitive((v) => {
      const next = !v;
      caseSensitiveRef.current = next;
      // Re-run with the new option so decorations update immediately.
      if (queryRef.current) {
        searchAddon.findNext(queryRef.current, {
          ...getOptions(),
          caseSensitive: next,
        });
      }
      return next;
    });
  }

  function toggleRegex() {
    setUseRegex((v) => {
      const next = !v;
      useRegexRef.current = next;
      if (queryRef.current) {
        searchAddon.findNext(queryRef.current, {
          ...getOptions(),
          regex: next,
        });
      }
      return next;
    });
  }

  return (
    <div className="search-bar" role="search" aria-label="Find in terminal">
      <input
        ref={inputRef}
        type="text"
        className="search-input"
        placeholder="Find…"
        onChange={handleInput}
        onKeyDown={handleKeyDown}
        aria-label="Search term"
        spellCheck={false}
      />

      <button
        className="search-toggle"
        title="Case-sensitive"
        aria-label="Toggle case-sensitive"
        aria-pressed={caseSensitive ? "true" : "false"}
        onClick={toggleCase}
      >
        Aa
      </button>

      <button
        className="search-toggle"
        title="Regular expression"
        aria-label="Toggle regular expression"
        aria-pressed={useRegex ? "true" : "false"}
        onClick={toggleRegex}
      >
        .*
      </button>

      <button
        className="search-nav"
        title="Previous match (Shift+Enter)"
        aria-label="Previous match"
        onClick={findPrev}
      >
        &#8593;
      </button>

      <button
        className="search-nav"
        title="Next match (Enter)"
        aria-label="Next match"
        onClick={findNext}
      >
        &#8595;
      </button>

      <button
        className="search-close"
        title="Close (Escape)"
        aria-label="Close search"
        onClick={onClose}
      >
        ×
      </button>
    </div>
  );
}