import { useState, useMemo } from "react";
import { useNavigate } from "react-router-dom";
import { pluginRegistry } from "../core/plugins/plugin-registry";
import type { UnknownPlimiPlugin } from "../core/plugins/plugin-types";
import { useTheme } from "../app/useTheme";
import { PlimiSearch, CategoryChips, ToolTile, SectionHeader } from "../components/directory/DirectoryComponents";

const PLIMI_CATEGORIES = [
  { id: "all", label: "All tools" },
  { id: "developer", label: "Developer" },
  { id: "image", label: "Image" },
  { id: "text", label: "Text" },
  { id: "pdf", label: "PDF" },
  { id: "crypto", label: "Crypto" },
  { id: "privacy", label: "Privacy" },
];

export function ToolsPage() {
  const navigate = useNavigate();
  const { dark } = useTheme();
  
  const [q, setQ] = useState("");
  const [cat, setCat] = useState("all");
  const [focusedIndex, setFocusedIndex] = useState(0);

  const filtered = useMemo(() => {
    return pluginRegistry.filter(
      (p) => 
        (cat === "all" || p.manifest.category === cat) &&
        (p.manifest.name.toLowerCase().includes(q.toLowerCase()) || 
         p.manifest.description.toLowerCase().includes(q.toLowerCase()))
    );
  }, [q, cat]);

  const safeFocusedIndex =
    filtered.length === 0 ? -1 : Math.min(focusedIndex, filtered.length - 1);

  const counts = useMemo(() => {
    const out: Record<string, number> = { all: 0 };
    PLIMI_CATEGORIES.forEach((c) => { out[c.id] = 0; });
    
    pluginRegistry.forEach((p) => {
      const matchSearch = p.manifest.name.toLowerCase().includes(q.toLowerCase()) || 
                          p.manifest.description.toLowerCase().includes(q.toLowerCase());
      if (!matchSearch) return;
      
      out.all += 1;
      if (out[p.manifest.category] !== undefined) {
        out[p.manifest.category] += 1;
      } else {
        out[p.manifest.category] = 1;
      }
    });
    return out;
  }, [q]);

  const grouped = useMemo(() => {
    if (cat !== 'all' || q) return null;
    const map: Record<string, typeof pluginRegistry> = {};
    filtered.forEach((t) => {
      (map[t.manifest.category] = map[t.manifest.category] || []).push(t);
    });
    return PLIMI_CATEGORIES.filter((c) => c.id !== 'all' && map[c.id]?.length).map((c) => ({ cat: c, tools: map[c.id] }));
  }, [filtered, cat, q]);

  const handleOpenTool = (plugin: UnknownPlimiPlugin) => {
    navigate(`/tools/${plugin.manifest.id}`);
  };

  return (
    <div className="flex flex-col gap-7 max-w-[1200px] mx-auto pb-10">
      <div className="grid grid-cols-1 md:grid-cols-[1.1fr_1fr] gap-7 md:gap-12 items-end">
        <div className="flex flex-col gap-3.5">
          <span className="font-mono text-[11px] text-[var(--p-muted)] tracking-[0.12em] uppercase">
            your digital pencil case
          </span>
          <h1 className="m-0 font-sans text-4xl md:text-[56px] font-bold tracking-tight leading-[1.02] text-[var(--p-text)] text-balance">
            Small tools.<br />
            <span className="text-[var(--p-muted)]">Big trust.</span>
          </h1>
          <p className="m-0 max-w-[480px] text-base leading-relaxed text-[var(--p-muted)] text-pretty">
            {pluginRegistry.length} utilities for files, text and code — running entirely in your browser. No upload. No account. No server.
          </p>
        </div>
        
        <PlimiSearch
          value={q}
          onChange={(nextQuery) => {
            setQ(nextQuery);
            setFocusedIndex(0);
          }}
          count={filtered.length}
          total={pluginRegistry.length}
          onArrow={(dir) => {
            if (filtered.length === 0) return;
            setFocusedIndex((prev) => {
              const next = prev + dir;
              if (next < 0) return filtered.length - 1;
              if (next >= filtered.length) return 0;
              return next;
            });
          }}
          onEnter={() => {
            if (safeFocusedIndex >= 0 && safeFocusedIndex < filtered.length) {
              handleOpenTool(filtered[safeFocusedIndex]);
            }
          }}
        />
      </div>

      <CategoryChips
        active={cat}
        onPick={(nextCategory) => {
          setCat(nextCategory);
          setFocusedIndex(0);
        }}
        counts={counts}
        categories={PLIMI_CATEGORIES}
      />

      {grouped ? (
        <div className="flex flex-col gap-7 mt-4">
          {grouped.map(({ cat: c, tools }) => (
            <div key={c.id} className="flex flex-col gap-3.5">
              <SectionHeader catLabel={c.label} catId={c.id} n={tools.length} />
              <div className="grid grid-cols-1 sm:grid-cols-2 md:grid-cols-3 lg:grid-cols-4 gap-4">
                {tools.map((t) => {
                  const flatIdx = filtered.indexOf(t);
                  return (
                    <ToolTile key={t.manifest.id} plugin={t} onClick={handleOpenTool} focused={flatIdx === safeFocusedIndex} dark={dark} index={flatIdx} />
                  );
                })}
              </div>
            </div>
          ))}
        </div>
      ) : filtered.length === 0 ? (
        <div className="py-20 text-center text-[var(--p-muted)] font-sans">
          No tools found matching "{q}".
        </div>
      ) : (
        <div className="grid grid-cols-1 sm:grid-cols-2 md:grid-cols-3 lg:grid-cols-4 gap-4 mt-4">
          {filtered.map((t, flatIdx) => (
            <ToolTile key={t.manifest.id} plugin={t} onClick={handleOpenTool} focused={flatIdx === safeFocusedIndex} dark={dark} index={flatIdx} />
          ))}
        </div>
      )}
    </div>
  );
}