/**
 * 带环境变量自动补全的输入框：
 * 输入 "{{" 后弹出当前环境变量浮层，↑↓ 选择、Enter/Tab 插入 {{变量名}}。
 */
import { useWorkspace } from "../workspaceStore";
import { useEffect, useLayoutEffect, useMemo, useRef, useState, type KeyboardEvent } from "react";
import { EnvBadge } from "./EnvBadge";

type Candidate = { name: string; value: string; description?: string };

export function VarHintInput({
  value,
  onChange,
  placeholder,
  className,
  onKeyDown,
  autoFocus,
  spellCheck = false,
  ariaLabel,
}: {
  value: string;
  onChange: (v: string) => void;
  placeholder?: string;
  className?: string;
  onKeyDown?: (e: KeyboardEvent<HTMLInputElement>) => void;
  autoFocus?: boolean;
  spellCheck?: boolean;
  ariaLabel?: string;
}) {
  const inputRef = useRef<HTMLInputElement | null>(null);
  const [query, setQuery] = useState<{ prefix: string; caret: number } | null>(null);
  const [active, setActive] = useState(0);

  const candidates = useMemo<Candidate[]>(() => {
    const state = useWorkspace.getState();
    const env = state.environments.find((e) => e.id === state.activeEnvironmentId);
    return (env?.variables ?? [])
      .filter((v) => v.enabled && v.key.trim())
      .map((v) => ({ name: v.key.trim(), value: v.value, description: v.description }));
  }, [query]); // query 变化时重查（环境可能被改）

  const filtered = useMemo(() => {
    if (!query) return [];
    const q = query.prefix.toLowerCase();
    const list = candidates.filter((c) => c.name.toLowerCase().includes(q));
    return list.slice(0, 8);
  }, [candidates, query]);

  // 光标前未闭合的 {{ 即触发
  const detect = (v: string, caret: number) => {
    const before = v.slice(0, caret);
    const idx = before.lastIndexOf("{{");
    if (idx < 0) return null;
    const frag = before.slice(idx + 2);
    if (frag.includes("}") || frag.includes("{") || frag.includes(" ") || frag.length > 40) return null;
    return { prefix: frag, caret };
  };

  const sync = () => {
    const el = inputRef.current;
    if (!el) return;
    const q = detect(el.value, el.selectionStart ?? 0);
    setQuery(q);
    setActive(0);
  };

  const insert = (name: string) => {
    const el = inputRef.current;
    if (!el || !query) return;
    const idx = el.value.slice(0, query.caret).lastIndexOf("{{");
    if (idx < 0) return;
    const next = `${el.value.slice(0, idx)}{{${name}}}` + el.value.slice(query.caret);
    onChange(next);
    setQuery(null);
    const caretTarget = idx + name.length + 4;
    requestAnimationFrame(() => {
      el.focus();
      el.setSelectionRange(caretTarget, caretTarget);
    });
  };

  // 过滤结果为空时收起
  useEffect(() => {
    if (query && filtered.length === 0) setQuery(null);
  }, [filtered.length, query]);

  // 外部清空时重置
  useLayoutEffect(() => {
    if (!value) setQuery(null);
  }, [value]);

  const handleKeyDown = (e: KeyboardEvent<HTMLInputElement>) => {
    if (query && filtered.length > 0) {
      if (e.key === "ArrowDown") {
        e.preventDefault();
        e.stopPropagation();
        setActive((a) => Math.min(a + 1, filtered.length - 1));
        return;
      }
      if (e.key === "ArrowUp") {
        e.preventDefault();
        e.stopPropagation();
        setActive((a) => Math.max(a - 1, 0));
        return;
      }
      if (e.key === "Enter" || e.key === "Tab") {
        e.preventDefault();
        e.stopPropagation();
        insert(filtered[active].name);
        return;
      }
      if (e.key === "Escape") {
        e.stopPropagation();
        setQuery(null);
        return;
      }
    }
    onKeyDown?.(e);
  };

  const envName = useWorkspace(
    (s) => s.environments.find((e) => e.id === s.activeEnvironmentId)?.name ?? "",
  );
  const envId = useWorkspace((s) => s.activeEnvironmentId);

  return (
    <div className="var-hint-wrap">
      <input
        ref={inputRef}
        className={className}
        placeholder={placeholder}
        value={value}
        aria-label={ariaLabel}
        spellCheck={spellCheck}
        autoFocus={autoFocus}
        onChange={(e) => {
          const el = e.currentTarget;
          onChange(el.value);
          // 同步阶段探测（input 事件时 DOM 已更新，避免 React 并发提交的竞态）
          setQuery(detect(el.value, el.selectionStart ?? el.value.length));
          setActive(0);
        }}
        onKeyUp={sync}
        onClick={sync}
        onBlur={() => setTimeout(() => setQuery(null), 120)}
        onKeyDown={handleKeyDown}
      />
      {query && filtered.length > 0 && (
        <div className="var-hint-panel" onMouseDown={(e) => e.preventDefault()}>
          <div className="var-hint-head">
            {envId ? (
              <>
                <EnvBadge envId={envId} name={envName} size={16} />
                <span>{envName || "当前环境"}</span>
              </>
            ) : (
              <span>未选择环境</span>
            )}
            <span className="ops-faint">{"输入 {{变量名}} 引用 · Enter 插入"}</span>
          </div>
          {filtered.map((c, i) => (
            <button
              key={c.name}
              className={i === active ? "var-hint-item sel" : "var-hint-item"}
              onMouseEnter={() => setActive(i)}
              onMouseDown={(e) => {
                e.preventDefault();
                insert(c.name);
              }}
            >
              <span className="var-hint-name">{"{{"}{c.name}{"}}"}</span>
              <span className="var-hint-value">{c.value || "（空）"}</span>
            </button>
          ))}
        </div>
      )}
    </div>
  );
}