import { createSignal, Show, onMount, For, createMemo, createEffect } from "solid-js";
import { sessions, withSession, setActiveSession } from "@/stores/session-state";
import { instances } from "@/stores/instances";
import { sendMessage } from "@/stores/session-actions";
import { addTask, setActiveTask } from "@/stores/task-actions";
import { messageStoreBus } from "@/stores/message-v2/bus";
import MessageBlockList from "@/components/message-block-list";
import { formatTokenTotal } from "@/lib/formatters";
import { addToTaskQueue, getSoloState, setActiveTaskId, toggleAutonomous, toggleAutoApproval } from "@/stores/solo-store";
import { getLogger } from "@/lib/logger";
import {
  Command,
  Plus,
  CheckCircle2,
  PanelRight,
  ListTodo,
  AtSign,
  Hash,
  Mic,
  ArrowUp,
  Terminal,
  ChevronRight,
  Loader2,
  AlertCircle,
  X,
  Zap,
  Layers,
  Shield,
  Activity,
} from "lucide-solid";
import type { InstanceMessageStore } from "@/stores/message-v2/instance-store";
import type { Task } from "@/types/session";

const log = getLogger("multix-chat");

interface MultiTaskChatProps {
  instanceId: string;
  sessionId: string;
}

export default function MultiTaskChat(props: MultiTaskChatProps) {
  const selectedTaskId = () => session()?.activeTaskId || null;
  const setSelectedTaskId = (id: string | null) => setActiveTask(props.instanceId, props.sessionId, id || undefined);
  const [isSending, setIsSending] = createSignal(false);
  const [chatInput, setChatInput] = createSignal("");
  let scrollContainer: HTMLDivElement | undefined;
  const [bottomSentinel, setBottomSentinel] = createSignal<HTMLDivElement | null>(null);

  // Scroll to bottom helper
  const scrollToBottom = () => {
    if (scrollContainer) {
      scrollContainer.scrollTop = scrollContainer.scrollHeight;
    }
  };

  // Get current session and tasks
  const session = () => {
    const instanceSessions = sessions().get(props.instanceId);
    return instanceSessions?.get(props.sessionId);
  };

  const tasks = () => session()?.tasks || [];
  const selectedTask = () => tasks().find(t => t.id === selectedTaskId());

  // Message store integration
  const messageStore = () => messageStoreBus.getOrCreate(props.instanceId);
  const lastAssistantIndex = () => {
    const ids = filteredMessageIds();
    const store = messageStore();
    for (let i = ids.length - 1; i >= 0; i--) {
      const msg = store.getMessage(ids[i]);
      if (msg?.role === "assistant") return i;
    }
    return -1;
  };

  // Filter messages based on selected task - use store's session messages for the task session
  const filteredMessageIds = () => {
    const task = selectedTask();
    if (!task) return []; // Show no messages in Pipeline view

    // If task has a dedicated session, get messages from the store for that session
    if (task.taskSessionId) {
      const store = messageStore();
      return store.getSessionMessageIds(task.taskSessionId);
    }

    // Fallback to task.messageIds for backward compatibility
    return task.messageIds || [];
  };

  // Note: Auto-scroll is handled in two places:
  // 1. After sending a message (in handleSendMessage)
  // 2. During streaming (in the isAgentThinking effect below)
  // We intentionally don't scroll on message count change to let users scroll freely

  // Token and status tracking
  const sessionUsage = createMemo(() => {
    const store = messageStore();
    return store.getSessionUsage(props.sessionId);
  });

  const tokenStats = createMemo(() => {
    const usage = sessionUsage();
    return {
      used: usage?.actualUsageTokens ?? 0,
      total: usage?.totalCost ?? 0,
    };
  });

  const activeTaskSessionId = createMemo(() => {
    const task = selectedTask();
    return task?.taskSessionId || props.sessionId;
  });

  const solo = () => getSoloState(props.instanceId);

  const isAgentThinking = createMemo(() => {
    // Show thinking while we're actively sending
    if (isSending()) return true;

    const store = messageStore();

    // Check for streaming in the specific task session
    const taskSessionId = activeTaskSessionId();
    const sessionRecord = store.state.sessions[taskSessionId];
    const sessionMessages = sessionRecord ? sessionRecord.messageIds : [];
    const isAnyStreaming = sessionMessages.some((id: string) => {
      const m = store.getMessage(id);
      return m?.role === "assistant" && (m.status === "streaming" || m.status === "sending");
    });

    if (isAnyStreaming) return true;

    // Also check the filtered message IDs (for tasks)
    const ids = filteredMessageIds();
    if (ids.length === 0) return false;
    const lastMsg = store.getMessage(ids[ids.length - 1]);
    return lastMsg?.role === "assistant" && (lastMsg.status === "streaming" || lastMsg.status === "sending");
  });

  // Auto-scroll during streaming - must be after isAgentThinking is defined
  createEffect(() => {
    const streaming = isAgentThinking();
    if (!streaming) return;

    // During streaming, scroll periodically to keep up with content
    const interval = setInterval(scrollToBottom, 300);
    return () => clearInterval(interval);
  });

  const handleSendMessage = async () => {
    const message = chatInput().trim();
    if (!message || isSending()) return;

    setIsSending(true);
    log.info("handleSendMessage started", {
      instanceId: props.instanceId,
      sessionId: props.sessionId,
      selectedTaskId: selectedTaskId(),
      messageLength: message.length
    });
    try {
      let taskId = selectedTaskId();
      let targetSessionId = props.sessionId;

      // If no task selected, create one automatically
      if (!taskId) {
        log.info("No task selected, creating new task");
        const title = message.length > 30 ? message.substring(0, 27) + "..." : message;
        const result = await addTask(props.instanceId, props.sessionId, title);
        taskId = result.id;
        targetSessionId = result.taskSessionId || props.sessionId;

        log.info("New task created", { taskId, targetSessionId });
        setSelectedTaskId(taskId);

        // If autonomous mode is on, we might want to queue it or set it as active
        const s = solo();
        if (s.isAutonomous) {
          log.info("Autonomous mode active, setting active task or queuing");
          if (!s.activeTaskId) {
            setActiveTaskId(props.instanceId, taskId);
          } else {
            addToTaskQueue(props.instanceId, taskId);
          }
        }
      } else {
        const task = selectedTask();
        targetSessionId = task?.taskSessionId || props.sessionId;
      }

      log.info("Target session identified", { targetSessionId, taskId });

      const store = messageStore();
      log.info("Message store check before sending", {
        instanceId: props.instanceId,
        storeExists: !!store,
        messageCount: store?.getSessionMessageIds(targetSessionId).length
      });

      await sendMessage(
        props.instanceId,
        targetSessionId,
        message,
        [],
        taskId || undefined
      );

      log.info("sendMessage call completed");
      setChatInput("");

      // Auto-scroll to bottom after sending
      setTimeout(scrollToBottom, 100);
    } catch (error) {
      log.error("handleSendMessage failed", error);
      console.error("[MultiTaskChat] Send failed:", error);
    } finally {
      setIsSending(false);
      log.info("handleSendMessage finished");
    }
  };

  const handleKeyDown = (e: KeyboardEvent) => {
    // Enter to submit, Shift+Enter for new line
    if (e.key === "Enter" && !e.shiftKey) {
      e.preventDefault();
      handleSendMessage();
    }
  };

  return (
    <main class="h-full flex flex-col bg-[#0a0a0b] text-zinc-300 font-sans selection:bg-indigo-500/30">
      {/* Header */}
      <header class="h-14 px-4 flex items-center justify-between bg-zinc-900/60 backdrop-blur-xl border-b border-white/5 relative z-30 shrink-0">
        <div class="flex items-center space-x-3">
          <div class="flex items-center bg-indigo-500/10 border border-indigo-500/20 rounded-lg px-2.5 py-1.5 shadow-[0_0_20px_rgba(99,102,241,0.1)]">
            <span class="text-[10px] font-black text-indigo-400 mr-2.5 tracking-tighter uppercase">MULTIX</span>
            <div class="bg-indigo-500 rounded-md w-4 h-4 flex items-center justify-center shadow-lg shadow-indigo-500/40">
              <Zap size={10} class="text-white fill-current" />
            </div>
          </div>

          <Show when={selectedTaskId()}>
            <div class="flex items-center space-x-2 animate-in fade-in slide-in-from-left-2 duration-300">
              <ChevronRight size={14} class="text-zinc-600" />
              <div class="flex items-center space-x-2 px-2.5 py-1 bg-white/5 rounded-lg border border-white/5">
                <ListTodo size={14} class="text-indigo-400" />
                <span class="text-[11px] font-bold text-zinc-100 truncate max-w-[120px]">
                  {selectedTask()?.title || "Active Task"}
                </span>
                <button
                  onClick={() => setSelectedTaskId(null)}
                  class="ml-1 p-0.5 hover:bg-white/10 rounded-md transition-colors text-zinc-500 hover:text-white"
                >
                  <X size={12} />
                </button>
              </div>
            </div>
          </Show>
        </div>

        <div class="flex items-center space-x-2">
          <button class="p-2 text-zinc-500 hover:text-white transition-all hover:bg-white/5 rounded-xl active:scale-90">
            <Command size={18} strokeWidth={2} />
          </button>
          <button class="p-2 text-zinc-500 hover:text-white transition-all hover:bg-white/5 rounded-xl active:scale-90">
            <PanelRight size={18} strokeWidth={2} />
          </button>
        </div>
      </header>

      {/* Task Tabs (Horizontal Scroll) */}
      <Show when={tasks().length > 0}>
        <div class="flex items-center bg-[#0a0a0b] border-b border-white/5 px-2 py-2 space-x-1.5 overflow-x-auto custom-scrollbar-hidden no-scrollbar shrink-0">
          <button
            onClick={() => setSelectedTaskId(null)}
            class={`flex items-center space-x-2 px-3.5 py-2 rounded-xl text-[10px] font-black uppercase tracking-widest transition-all shrink-0 border ${!selectedTaskId()
              ? "bg-indigo-500/15 text-indigo-400 border-indigo-500/30 shadow-[0_0_15px_rgba(99,102,241,0.1)]"
              : "text-zinc-500 hover:text-zinc-300 hover:bg-white/5 border-transparent"
              }`}
          >
            <Layers size={12} class={!selectedTaskId() ? "text-indigo-400" : "text-zinc-600"} />
            <span>Pipeline</span>
          </button>

          <div class="w-px h-4 bg-white/10 shrink-0 mx-0.5" />

          <div class="flex items-center space-x-1.5 overflow-x-auto no-scrollbar">
            <For each={tasks()}>
              {(task) => (
                <button
                  onClick={() => setSelectedTaskId(task.id)}
                  class={`flex items-center space-x-2 px-3.5 py-2 rounded-xl text-[10px] font-bold transition-all shrink-0 max-w-[160px] border group ${selectedTaskId() === task.id
                    ? "bg-white/10 text-zinc-100 border-white/20 shadow-xl shadow-black/20"
                    : "text-zinc-500 hover:text-zinc-300 hover:bg-white/5 border-transparent"
                    }`}
                >
                  <div class={`w-2 h-2 rounded-full transition-all duration-500 ${task.status === "completed" ? "bg-emerald-500 shadow-[0_0_8px_rgba(16,185,129,0.4)]" :
                    task.status === "interrupted" ? "bg-rose-500 shadow-[0_0_8px_rgba(244,63,94,0.4)]" :
                      "bg-indigo-500 shadow-[0_0_8px_rgba(99,102,241,0.4)] animate-pulse"
                    }`} />
                  <span class="truncate">{task.title}</span>
                  <Show when={selectedTaskId() === task.id}>
                    <div class="ml-1 w-1 h-1 bg-indigo-400 rounded-full animate-ping" />
                  </Show>
                </button>
              )}
            </For>
          </div>

          <button
            onClick={() => {
              setChatInput("");
              setSelectedTaskId(null);
            }}
            class="flex items-center justify-center w-8 h-8 rounded-xl text-zinc-500 hover:text-indigo-400 hover:bg-indigo-500/10 transition-all shrink-0 ml-1 border border-transparent hover:border-indigo-500/20"
            title="New Task"
          >
            <Plus size={16} strokeWidth={3} />
          </button>
        </div>
      </Show>

      {/* Main Content Area - min-h-0 is critical for flex containers with overflow */}
      <div class="flex-1 min-h-0 relative overflow-hidden flex flex-col">
        <div
          ref={scrollContainer}
          class="flex-1 min-h-0 overflow-y-auto overflow-x-hidden custom-scrollbar"
        >
          <Show when={!selectedTaskId()} fallback={
            <div class="p-3 pb-4 overflow-x-hidden">
              <MessageBlockList
                instanceId={props.instanceId}
                sessionId={activeTaskSessionId()}
                store={messageStore}
                messageIds={filteredMessageIds}
                lastAssistantIndex={lastAssistantIndex}
                showThinking={() => true}
                thinkingDefaultExpanded={() => true}
                showUsageMetrics={() => true}
                scrollContainer={() => scrollContainer}
                setBottomSentinel={setBottomSentinel}
              />
            </div>
          }>
            {/* Pipeline View */}
            <div class="p-4 space-y-8 animate-in fade-in slide-in-from-bottom-4 duration-500">
              <div class="space-y-2">
                <h2 class="text-2xl font-black text-white tracking-tight leading-none">Pipeline</h2>
                <p class="text-xs font-medium text-zinc-500 uppercase tracking-[0.2em]">Agentic Orchestration</p>
              </div>

              <div class="space-y-4">
                <div class="flex items-center justify-between">
                  <span class="text-[10px] font-bold text-zinc-600 uppercase tracking-widest">Active Threads</span>
                  <div class="h-px flex-1 bg-white/5 mx-4" />
                  <span class="text-[10px] font-black text-indigo-400 bg-indigo-500/10 px-2 py-0.5 rounded border border-indigo-500/20">
                    {tasks().length}
                  </span>
                </div>

                <div class="grid gap-3">
                  <For each={tasks()} fallback={
                    <div class="group relative p-8 rounded-3xl border border-dashed border-white/5 bg-zinc-900/20 flex flex-col items-center justify-center text-center space-y-4 transition-all hover:bg-zinc-900/40 hover:border-white/10">
                      <div class="w-12 h-12 rounded-2xl bg-white/5 flex items-center justify-center text-zinc-600 group-hover:text-indigo-400 group-hover:scale-110 transition-all duration-500">
                        <Plus size={24} strokeWidth={1.5} />
                      </div>
                      <div class="space-y-1">
                        <p class="text-sm font-bold text-zinc-400">No active tasks</p>
                        <p class="text-[11px] text-zinc-600">Send a message below to start a new thread</p>
                      </div>
                    </div>
                  }>
                    {(task) => (
                      <button
                        onClick={() => setSelectedTaskId(task.id)}
                        class="group relative p-4 rounded-2xl border border-white/5 bg-zinc-900/40 hover:bg-zinc-800/60 hover:border-indigo-500/30 transition-all duration-300 text-left flex items-start space-x-4 active:scale-[0.98]"
                      >
                        <div class={`mt-1 w-2 h-2 rounded-full shadow-[0_0_10px_rgba(var(--color),0.5)] ${task.status === "completed" ? "bg-emerald-500 shadow-emerald-500/40" :
                          task.status === "in-progress" ? "bg-indigo-500 shadow-indigo-500/40 animate-pulse" :
                            "bg-zinc-600 shadow-zinc-600/20"
                          }`} />
                        <div class="flex-1 min-w-0 space-y-1">
                          <p class="text-sm font-bold text-zinc-100 truncate group-hover:text-white transition-colors">
                            {task.title}
                          </p>
                          <div class="flex items-center space-x-3 text-[10px] font-bold text-zinc-500 uppercase tracking-tight">
                            <span>{new Date(task.timestamp).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })}</span>
                            <span class="w-1 h-1 rounded-full bg-zinc-800" />
                            <span>{task.messageIds?.length || 0} messages</span>
                          </div>
                        </div>
                        <ChevronRight size={16} class="text-zinc-700 group-hover:text-indigo-400 group-hover:translate-x-1 transition-all" />
                      </button>
                    )}
                  </For>
                </div>
              </div>
            </div>
          </Show>
        </div>

        {/* Chat Input Area - Fixed at bottom */}
        <div class="p-3 bg-[#0a0a0b] border-t border-white/5 shrink-0">
          <div class="w-full bg-zinc-900/80 border border-white/10 rounded-2xl shadow-lg p-3">
            {/* Header Row */}
            <div class="flex items-center justify-between mb-2">
              <div class="flex items-center space-x-2">
                <div class="w-5 h-5 rounded-lg bg-gradient-to-br from-indigo-500 to-violet-600 flex items-center justify-center">
                  <AtSign size={10} class="text-white" strokeWidth={3} />
                </div>
                <div class="flex flex-col">
                  <span class="text-[10px] font-bold text-zinc-100 uppercase tracking-wide">
                    {selectedTaskId() ? "Task Context" : "Global Pipeline"}
                  </span>
                  <span class="text-[9px] text-zinc-500 uppercase">
                    {selectedTaskId() ? "MultiX Threaded" : "Auto-Task"}
                  </span>
                </div>
              </div>

              <div class="flex items-center space-x-2">
                <button
                  onClick={() => toggleAutonomous(props.instanceId)}
                  class={`px-2 py-0.5 rounded text-[9px] font-bold uppercase border ${solo().isAutonomous
                    ? "bg-indigo-500/20 border-indigo-500/40 text-indigo-400"
                    : "bg-white/5 border-white/10 text-zinc-500"
                    }`}
                >
                  Auto
                </button>
                <button
                  onClick={() => toggleAutoApproval(props.instanceId)}
                  class={`px-2 py-0.5 rounded text-[9px] font-bold uppercase border ${solo().autoApproval
                    ? "bg-emerald-500/20 border-emerald-500/40 text-emerald-400"
                    : "bg-white/5 border-white/10 text-zinc-500"
                    }`}
                >
                  Shield
                </button>
                <Show when={tokenStats().used > 0}>
                  <div class="px-2 py-0.5 bg-emerald-500/10 rounded border border-emerald-500/20 text-[9px] font-bold text-emerald-400">
                    {formatTokenTotal(tokenStats().used)}
                  </div>
                </Show>
                <Show when={isSending() || isAgentThinking()}>
                  <div class="flex items-center space-x-1 px-2 py-0.5 bg-indigo-500/10 rounded border border-indigo-500/20">
                    <Loader2 size={10} class="text-indigo-400 animate-spin" />
                    <span class="text-[9px] font-bold text-indigo-400">{isAgentThinking() ? "Thinking" : "Sending"}</span>
                  </div>
                </Show>
              </div>
            </div>

            {/* Text Input */}
            <textarea
              value={chatInput()}
              onInput={(e) => setChatInput(e.currentTarget.value)}
              placeholder={selectedTaskId() ? "Send instruction to this task..." : "Type to create a new task and begin..."}
              class="w-full bg-transparent border-none focus:ring-0 focus:outline-none text-[13px] text-zinc-100 placeholder-zinc-600 resize-none min-h-[40px] max-h-32 leading-relaxed disabled:opacity-50"
              onKeyDown={handleKeyDown}
              disabled={isSending()}
              rows={1}
            />

            {/* Footer Row */}
            <div class="flex items-center justify-between pt-2 border-t border-white/5 mt-2">
              <div class="flex items-center space-x-3">
                <button class="text-zinc-600 hover:text-zinc-400 transition-colors p-1">
                  <Hash size={14} />
                </button>
                <button class="text-zinc-600 hover:text-zinc-400 transition-colors p-1">
                  <Mic size={14} />
                </button>
                <div class="w-px h-3 bg-zinc-800" />
                <div class="flex items-center space-x-1 text-zinc-600">
                  <kbd class="px-1.5 py-0.5 bg-zinc-800 rounded text-[9px] font-bold border border-white/5">ENTER</kbd>
                  <span class="text-[9px]">to send</span>
                </div>
              </div>

              <button
                onClick={handleSendMessage}
                disabled={!chatInput().trim() || isSending()}
                class="px-4 py-1.5 bg-indigo-500 hover:bg-indigo-400 text-white rounded-lg text-[11px] font-bold uppercase tracking-wide transition-all disabled:opacity-30 disabled:cursor-not-allowed flex items-center space-x-1.5"
              >
                <Show when={isSending()} fallback={
                  <>
                    <span>{selectedTaskId() ? "Update Task" : "Launch Task"}</span>
                    <ArrowUp size={12} strokeWidth={3} />
                  </>
                }>
                  <Loader2 size={12} class="animate-spin" />
                </Show>
              </button>
            </div>
          </div>
        </div>
      </div>
    </main>
  );
}