"use client";

import React, { useState, useEffect, useRef, useMemo } from "react";
import {
  Search, MessageSquare, Folder, Brain, Database,
  Sliders, Plus, Network, Volume2, VolumeX, ArrowRight,
  CornerDownLeft, Zap, Pin, Users
} from "lucide-react";
import type { Conversation, Project } from "@/types";
import { playClickSound, toggleSoundMute, isSoundMuted } from "@/lib/soundEffects";

interface QuickSwitcherProps {
  isOpen: boolean;
  onClose: () => void;
  conversations: Conversation[];
  projects: Project[];
  activeConvId: string;
  onSelectConversation: (id: string) => void;
  onSelectProject: (id: string | null) => void;
  onNewSession: () => void;
  onOpenKnowledge: () => void;
  onOpenSettings: () => void;
  onInsertCommand: (command: string) => void;
  enableReasoning: boolean;
  onToggleReasoning: () => void;
}

interface SearchItem {
  id: string;
  title: string;
  subtitle?: string;
  category: "session" | "project" | "command" | "action";
  icon: React.ReactNode;
  badge?: string;
  action: () => void;
}

export const QuickSwitcher: React.FC<QuickSwitcherProps> = ({
  isOpen,
  onClose,
  conversations,
  projects,
  activeConvId,
  onSelectConversation,
  onSelectProject,
  onNewSession,
  onOpenKnowledge,
  onOpenSettings,
  onInsertCommand,
  enableReasoning,
  onToggleReasoning,
}) => {
  const [query, setQuery] = useState("");
  const [selectedIndex, setSelectedIndex] = useState(0);
  const inputRef = useRef<HTMLInputElement>(null);
  const listRef = useRef<HTMLDivElement>(null);

  // Focus input when opened
  useEffect(() => {
    if (isOpen) {
      setQuery("");
      setSelectedIndex(0);
      setTimeout(() => inputRef.current?.focus(), 50);
    }
  }, [isOpen]);

  const items = useMemo<SearchItem[]>(() => {
    const list: SearchItem[] = [];

    // Core actions
    list.push({
      id: "action_new_session",
      title: "New Session",
      subtitle: "Start a fresh chat with Purcar",
      category: "action",
      icon: <Plus size={14} className="text-[#a0e4a0]" />,
      action: () => { onNewSession(); onClose(); },
    });

    list.push({
      id: "action_toggle_reasoning",
      title: enableReasoning ? "Disable Reasoning Mode" : "Enable Reasoning Mode",
      subtitle: enableReasoning ? "Switch to direct high-speed responses" : "Enable <think> cognitive chain",
      category: "action",
      icon: <Brain size={14} className={enableReasoning ? "text-[#a0e4a0]" : "text-zinc-400"} />,
      badge: enableReasoning ? "ON" : "OFF",
      action: () => { onToggleReasoning(); onClose(); },
    });

    list.push({
      id: "action_toggle_sound",
      title: isSoundMuted() ? "Unmute Audio Haptics" : "Mute Audio Haptics",
      subtitle: "Tactile Discord-inspired audio cues",
      category: "action",
      icon: isSoundMuted() ? <VolumeX size={14} className="text-zinc-400" /> : <Volume2 size={14} className="text-[#a0e4a0]" />,
      action: () => { toggleSoundMute(); onClose(); },
    });

    list.push({
      id: "action_knowledge",
      title: "Knowledge Base (RAG)",
      subtitle: "Manage private documents and embeddings",
      category: "action",
      icon: <Database size={14} className="text-cyan-400" />,
      action: () => { onOpenKnowledge(); onClose(); },
    });

    list.push({
      id: "action_settings",
      title: "Engine Hyperparameters",
      subtitle: "Temperature, Top-K, Repetition Penalty, Max Tokens",
      category: "action",
      icon: <Sliders size={14} className="text-amber-400" />,
      action: () => { onOpenSettings(); onClose(); },
    });

    // Commands
    [
      { name: "@web_search", desc: "Live web search & source citations", icon: <Network size={14} className="text-[#a0e4a0]" /> },
      { name: "@rag", desc: "Retrieve answers from knowledge base", icon: <Database size={14} className="text-cyan-400" /> },
      { name: "@reasoning", desc: "Force cognitive step-by-step thinking", icon: <Brain size={14} className="text-purple-400" /> },
      { name: "@raw", desc: "Bypass reasoning, RAG & web search", icon: <Zap size={14} className="text-amber-400" /> },
    ].forEach((cmd) => {
      list.push({
        id: `cmd_${cmd.name}`,
        title: cmd.name,
        subtitle: cmd.desc,
        category: "command",
        icon: cmd.icon,
        badge: "command",
        action: () => { onInsertCommand(`${cmd.name} `); onClose(); },
      });
    });

    // Projects
    projects.forEach((proj) => {
      list.push({
        id: `proj_${proj.id}`,
        title: proj.name,
        subtitle: "Filter workspace by this project",
        category: "project",
        icon: <Folder size={14} className="text-blue-400" />,
        badge: "project",
        action: () => { onSelectProject(proj.id); onClose(); },
      });
    });

    // Conversations
    conversations.forEach((conv) => {
      list.push({
        id: `conv_${conv.id}`,
        title: conv.title || "Untitled Session",
        subtitle: `${conv.messages?.length || 0} messages · ${new Date(conv.updatedAt || conv.createdAt).toLocaleDateString()}`,
        category: "session",
        icon: conv.isGroup ? <Users size={14} className="text-[#a0e4a0]" /> : <MessageSquare size={14} className="text-zinc-400" />,
        badge: conv.id === activeConvId ? "active" : conv.isPinned ? "pinned" : undefined,
        action: () => { onSelectConversation(conv.id); onClose(); },
      });
    });

    return list;
  }, [
    conversations,
    projects,
    activeConvId,
    enableReasoning,
    onNewSession,
    onToggleReasoning,
    onOpenKnowledge,
    onOpenSettings,
    onInsertCommand,
    onSelectProject,
    onSelectConversation,
    onClose,
  ]);

  // Filter items by query
  const filtered = useMemo(() => {
    const q = query.trim().toLowerCase();
    if (!q) return items;
    return items.filter(
      (item) =>
        item.title.toLowerCase().includes(q) ||
        (item.subtitle && item.subtitle.toLowerCase().includes(q)) ||
        item.category.includes(q)
    );
  }, [items, query]);

  // Handle keyboard navigation
  const handleKeyDown = (e: React.KeyboardEvent) => {
    if (e.key === "ArrowDown") {
      e.preventDefault();
      setSelectedIndex((prev) => (prev + 1) % (filtered.length || 1));
    } else if (e.key === "ArrowUp") {
      e.preventDefault();
      setSelectedIndex((prev) => (prev - 1 + filtered.length) % (filtered.length || 1));
    } else if (e.key === "Enter") {
      e.preventDefault();
      if (filtered[selectedIndex]) {
        playClickSound();
        filtered[selectedIndex].action();
      }
    } else if (e.key === "Escape") {
      e.preventDefault();
      onClose();
    }
  };

  // Keep selected element visible
  useEffect(() => {
    if (listRef.current) {
      const selectedEl = listRef.current.children[selectedIndex] as HTMLElement;
      if (selectedEl) {
        selectedEl.scrollIntoView({ block: "nearest" });
      }
    }
  }, [selectedIndex]);

  if (!isOpen) return null;

  return (
    <div
      className="fixed inset-0 z-50 flex items-start justify-center pt-24 px-4 bg-black/75 backdrop-blur-sm"
      onClick={onClose}
    >
      <div
        className="w-full max-w-xl rounded-lg border border-white/15 bg-[#171414] shadow-2xl overflow-hidden font-mono text-xs text-[#f5f0eb]"
        onClick={(e) => e.stopPropagation()}
        onKeyDown={handleKeyDown}
      >
        {/* Search Input Bar */}
        <div className="flex items-center gap-3 px-4 py-3 border-b border-white/[0.09] bg-[#1a1717]">
          <Search size={15} className="text-zinc-400 shrink-0" />
          <input
            ref={inputRef}
            type="text"
            value={query}
            onChange={(e) => {
              setQuery(e.target.value);
              setSelectedIndex(0);
            }}
            placeholder="Search sessions, commands (@), projects, or actions..."
            className="flex-1 bg-transparent text-[#f5f0eb] placeholder-zinc-500 text-xs outline-none border-none"
          />
          <kbd className="px-1.5 py-0.5 rounded bg-white/[0.08] text-[10px] text-zinc-400 border border-white/10">
            ESC
          </kbd>
        </div>

        {/* Results List */}
        <div
          ref={listRef}
          className="max-h-80 overflow-y-auto p-1.5 space-y-0.5 divide-y divide-transparent"
        >
          {filtered.length === 0 ? (
            <div className="p-8 text-center text-zinc-500 text-xs">
              No matching sessions, commands, or actions found for "{query}"
            </div>
          ) : (
            filtered.map((item, index) => {
              const isSelected = index === selectedIndex;
              return (
                <div
                  key={item.id}
                  onClick={() => {
                    playClickSound();
                    item.action();
                  }}
                  onMouseEnter={() => setSelectedIndex(index)}
                  className={`flex items-center justify-between px-3 py-2 rounded-md cursor-pointer transition-colors ${
                    isSelected
                      ? "bg-white/[0.08] text-[#f5f0eb] border border-white/10"
                      : "text-zinc-300 hover:bg-white/[0.04] border border-transparent"
                  }`}
                >
                  <div className="flex items-center gap-2.5 overflow-hidden">
                    <div className="shrink-0">{item.icon}</div>
                    <div className="overflow-hidden">
                      <div className="font-medium truncate flex items-center gap-2">
                        <span>{item.title}</span>
                        {item.badge && (
                          <span
                            className={`px-1.5 py-0.2 rounded text-[9px] uppercase tracking-wider ${
                              item.badge === "active"
                                ? "bg-[#a0e4a0]/15 text-[#a0e4a0] border border-[#a0e4a0]/30"
                                : item.badge === "pinned"
                                ? "bg-amber-500/15 text-amber-300 border border-amber-500/30"
                                : "bg-white/[0.06] text-zinc-400 border border-white/10"
                            }`}
                          >
                            {item.badge}
                          </span>
                        )}
                      </div>
                      {item.subtitle && (
                        <div className="text-[10px] text-zinc-500 truncate">
                          {item.subtitle}
                        </div>
                      )}
                    </div>
                  </div>

                  <div className="flex items-center gap-1.5 text-zinc-500 shrink-0 text-[10px]">
                    {isSelected && (
                      <span className="flex items-center gap-1 text-[#a0e4a0]">
                        <span>Select</span>
                        <CornerDownLeft size={10} />
                      </span>
                    )}
                  </div>
                </div>
              );
            })
          )}
        </div>

        {/* Footer info */}
        <div className="flex items-center justify-between px-3 py-2 bg-[#141212] border-t border-white/[0.07] text-[10px] text-zinc-500">
          <div className="flex items-center gap-3">
            <span className="flex items-center gap-1">
              <kbd className="px-1 py-0.2 rounded bg-white/[0.06] border border-white/10">↑</kbd>
              <kbd className="px-1 py-0.2 rounded bg-white/[0.06] border border-white/10">↓</kbd>
              <span>navigate</span>
            </span>
            <span className="flex items-center gap-1">
              <kbd className="px-1 py-0.2 rounded bg-white/[0.06] border border-white/10">↵</kbd>
              <span>select</span>
            </span>
          </div>
          <div>Discord Quick Switcher · <span className="text-[#a0e4a0]">Ctrl+K</span></div>
        </div>
      </div>
    </div>
  );
};