import { useEffect, useRef, useState } from "react";
import { useNavigate } from "@tanstack/react-router";
import { Search, Briefcase, Users, UserPlus, FileText, Loader2 } from "lucide-react";
import { supabase } from "@/integrations/supabase/client";
import { cn } from "@/lib/utils";

type SearchResult = {
  id: string;
  label: string;
  sublabel?: string;
  kind: "case" | "client" | "contact" | "document";
  to: string;
};

const KIND_ICON = {
  case: Briefcase,
  client: Users,
  contact: UserPlus,
  document: FileText,
} as const;

const KIND_LABEL = {
  case: "Case",
  client: "Client",
  contact: "Contact",
  document: "Document",
} as const;

export function GlobalSearch() {
  const navigate = useNavigate();
  const [query, setQuery] = useState("");
  const [results, setResults] = useState<SearchResult[]>([]);
  const [loading, setLoading] = useState(false);
  const [open, setOpen] = useState(false);
  const [activeIdx, setActiveIdx] = useState(0);
  const containerRef = useRef<HTMLDivElement>(null);

  // Close on outside click
  useEffect(() => {
    const onClick = (e: MouseEvent) => {
      if (containerRef.current && !containerRef.current.contains(e.target as Node)) {
        setOpen(false);
      }
    };
    document.addEventListener("mousedown", onClick);
    return () => document.removeEventListener("mousedown", onClick);
  }, []);

  // Debounced search
  useEffect(() => {
    const q = query.trim();
    if (q.length < 2) {
      setResults([]);
      setLoading(false);
      return;
    }
    setLoading(true);
    const handle = setTimeout(async () => {
      const like = `%${q}%`;
      const [casesRes, clientsRes, contactsRes, docsRes] = await Promise.all([
        supabase
          .from("cases")
          .select("id,title,case_number")
          .or(`title.ilike.${like},case_number.ilike.${like}`)
          .is("archived_at", null)
          .limit(6),
        supabase
          .from("clients")
          .select("id,name")
          .ilike("name", like)
          .is("archived_at", null)
          .limit(6),
        supabase
          .from("contacts")
          .select("id,name,company,email")
          .or(`name.ilike.${like},company.ilike.${like},email.ilike.${like}`)
          .is("archived_at", null)
          .limit(6),
        supabase
          .from("documents")
          .select("id,name,case_id")
          .ilike("name", like)
          .limit(6),
      ]);

      const out: SearchResult[] = [];
      casesRes.data?.forEach((c) =>
        out.push({
          id: c.id,
          label: c.title,
          sublabel: c.case_number,
          kind: "case",
          to: `/cases/${c.id}`,
        }),
      );
      clientsRes.data?.forEach((c) =>
        out.push({ id: c.id, label: c.name, kind: "client", to: `/clients/${c.id}` }),
      );
      contactsRes.data?.forEach((c) =>
        out.push({
          id: c.id,
          label: c.name,
          sublabel: c.company || c.email || undefined,
          kind: "contact",
          to: `/contacts/${c.id}`,
        }),
      );
      docsRes.data?.forEach((d) =>
        out.push({
          id: d.id,
          label: d.name,
          sublabel: "Document",
          kind: "document",
          to: d.case_id ? `/cases/${d.case_id}` : `/files`,
        }),
      );

      setResults(out);
      setActiveIdx(0);
      setLoading(false);
    }, 250);
    return () => clearTimeout(handle);
  }, [query]);

  const select = (r: SearchResult) => {
    setOpen(false);
    setQuery("");
    setResults([]);
    navigate({ to: r.to });
  };

  const onKeyDown = (e: React.KeyboardEvent<HTMLInputElement>) => {
    if (e.key === "ArrowDown") {
      e.preventDefault();
      setActiveIdx((i) => Math.min(i + 1, results.length - 1));
    } else if (e.key === "ArrowUp") {
      e.preventDefault();
      setActiveIdx((i) => Math.max(i - 1, 0));
    } else if (e.key === "Enter" && results[activeIdx]) {
      e.preventDefault();
      select(results[activeIdx]);
    } else if (e.key === "Escape") {
      setOpen(false);
    }
  };

  return (
    <div ref={containerRef} className="relative px-3 pt-3">
      <div className="relative">
        <Search className="absolute left-2.5 top-1/2 -translate-y-1/2 h-3.5 w-3.5 text-sidebar-foreground/50" />
        <input
          type="text"
          value={query}
          onChange={(e) => {
            setQuery(e.target.value);
            setOpen(true);
          }}
          onFocus={() => setOpen(true)}
          onKeyDown={onKeyDown}
          placeholder="Search…"
          className="w-full h-8 pl-8 pr-2 text-sm rounded-md bg-sidebar-accent/40 text-sidebar-foreground placeholder:text-sidebar-foreground/50 border border-sidebar-border focus:outline-none focus:ring-1 focus:ring-sidebar-primary"
        />
        {loading && (
          <Loader2 className="absolute right-2 top-1/2 -translate-y-1/2 h-3.5 w-3.5 animate-spin text-sidebar-foreground/50" />
        )}
      </div>

      {open && query.trim().length >= 2 && (
        <div className="absolute left-3 right-3 top-full mt-1 z-50 max-h-96 overflow-y-auto rounded-md border bg-popover text-popover-foreground shadow-lg">
          {results.length === 0 && !loading ? (
            <div className="px-3 py-4 text-xs text-muted-foreground text-center">
              No results
            </div>
          ) : (
            <ul className="py-1">
              {results.map((r, idx) => {
                const Icon = KIND_ICON[r.kind];
                return (
                  <li key={`${r.kind}-${r.id}`}>
                    <button
                      type="button"
                      onMouseEnter={() => setActiveIdx(idx)}
                      onClick={() => select(r)}
                      className={cn(
                        "w-full flex items-center gap-2 px-3 py-1.5 text-left text-sm",
                        idx === activeIdx ? "bg-accent text-accent-foreground" : "",
                      )}
                    >
                      <Icon className="h-3.5 w-3.5 shrink-0 text-muted-foreground" />
                      <div className="min-w-0 flex-1">
                        <div className="truncate">{r.label}</div>
                        {r.sublabel && (
                          <div className="truncate text-[11px] text-muted-foreground">
                            {r.sublabel}
                          </div>
                        )}
                      </div>
                      <span className="text-[10px] uppercase tracking-wider text-muted-foreground">
                        {KIND_LABEL[r.kind]}
                      </span>
                    </button>
                  </li>
                );
              })}
            </ul>
          )}
        </div>
      )}
    </div>
  );
}