import { html, useState, useEffect, useRef } from '../lib/preact.js';
import { getStatusMeta, getUserMessageBg } from '../utils/status.js';
import { formatDuration, formatTime } from '../utils/formatting.js';
import { MessageBubble, filterDisplayMessages } from './MessageBubble.js';

export function Modal({ session, conversations, conversationLoading, onClose, onSendMessage, onRefreshConversation }) {
  const [inputValue, setInputValue] = useState('');
  const [sending, setSending] = useState(false);
  const [inputFocused, setInputFocused] = useState(false);
  const inputRef = useRef(null);

  if (!session) return null;

  const conversation = conversations[session.session_id] || [];
  const hasPendingQuestions = session.pending_questions && session.pending_questions.length > 0;
  const optionCount = hasPendingQuestions ? session.pending_questions[0]?.options?.length || 0 : 0;
  const status = getStatusMeta(session.status);
  const agent = session.agent === 'codex' ? 'codex' : 'claude';
  const agentHeaderClass = agent === 'codex' ? 'agent-header-codex' : 'agent-header-claude';

  // Track if user has scrolled away from bottom
  const wasAtBottomRef = useRef(true);
  const prevConversationLenRef = useRef(0);
  const chatContainerRef = useRef(null);

  // Initialize scroll position to bottom on mount (no animation)
  useEffect(() => {
    if (chatContainerRef.current) {
      chatContainerRef.current.scrollTop = chatContainerRef.current.scrollHeight;
    }
  }, []);

  // Track scroll position
  useEffect(() => {
    const container = chatContainerRef.current;
    if (!container) return;

    const handleScroll = () => {
      const threshold = 50;
      wasAtBottomRef.current = container.scrollHeight - container.scrollTop - container.clientHeight < threshold;
    };

    container.addEventListener('scroll', handleScroll);
    return () => container.removeEventListener('scroll', handleScroll);
  }, []);

  // Only scroll to bottom on NEW messages, and only if user was already at bottom
  useEffect(() => {
    const container = chatContainerRef.current;
    if (!container || !conversation) return;

    const hasNewMessages = conversation.length > prevConversationLenRef.current;
    prevConversationLenRef.current = conversation.length;

    if (hasNewMessages && wasAtBottomRef.current) {
      container.scrollTop = container.scrollHeight;
    }
  }, [conversation]);

  // Focus input when modal opens
  useEffect(() => {
    if (inputRef.current) {
      inputRef.current.focus();
    }
  }, [session]);

  // Lock body scroll when modal is open
  useEffect(() => {
    document.body.style.overflow = 'hidden';
    return () => {
      document.body.style.overflow = '';
    };
  }, []);

  // Handle keyboard events
  useEffect(() => {
    const handleKeyDown = (e) => {
      // Escape closes modal
      if (e.key === 'Escape') {
        onClose();
      }
    };

    document.addEventListener('keydown', handleKeyDown);
    return () => document.removeEventListener('keydown', handleKeyDown);
  }, [onClose]);

  // Handle input key events
  const handleInputKeyDown = (e) => {
    // Enter sends message (unless Shift+Enter for newline)
    if (e.key === 'Enter' && !e.shiftKey) {
      e.preventDefault();
      handleSend();
    }
  };

  // Send message
  const handleSend = async () => {
    const text = inputValue.trim();
    if (!text || sending) return;

    setSending(true);
    try {
      if (onSendMessage) {
        await onSendMessage(session.session_id, text, true, optionCount);
      }
      setInputValue('');
      // Refresh conversation after sending
      if (onRefreshConversation) {
        await onRefreshConversation(session.session_id, session.project_dir, agent);
      }
    } catch (err) {
      console.error('Failed to send message:', err);
    } finally {
      setSending(false);
    }
  };

  return html`
    <div
      class="fixed inset-0 z-50 flex items-center justify-center bg-[#02050d]/84 p-4 backdrop-blur-sm"
      onClick=${(e) => e.target === e.currentTarget && onClose()}
    >
      <div
        class="glass-panel flex max-h-[90vh] w-full max-w-5xl flex-col overflow-hidden rounded-2xl border border-selection/80"
        style=${{ borderLeftWidth: '3px', borderLeftColor: status.borderColor }}
        onClick=${(e) => e.stopPropagation()}
      >
        <!-- Modal Header -->
        <div class="flex items-center justify-between border-b px-5 py-4 ${agentHeaderClass}">
          <div class="flex-1 min-w-0">
            <div class="mb-1 flex items-center gap-3">
              <h2 class="truncate font-display text-xl font-semibold text-bright">${session.project || session.name || session.session_id}</h2>
              <div class="flex items-center gap-2 rounded-full border px-2.5 py-1 text-xs ${status.badge}">
                <span class="h-2 w-2 rounded-full ${status.dot}"></span>
                <span class="font-mono uppercase tracking-[0.14em]">${status.label}</span>
              </div>
              <span class="rounded-full border px-2.5 py-1 font-mono text-micro uppercase tracking-[0.14em] ${agent === 'codex' ? 'border-emerald-400/45 bg-emerald-500/14 text-emerald-300' : 'border-violet-400/45 bg-violet-500/14 text-violet-300'}">
                ${agent}
              </span>
            </div>
            <div class="flex items-center gap-4 text-sm text-dim">
              <span class="truncate font-mono">${session.cwd || 'No working directory'}</span>
              ${session.started_at && html`
                <span class="flex-shrink-0 font-mono">Running ${formatDuration(session.started_at)}</span>
              `}
            </div>
          </div>
          <button
            class="ml-4 flex h-9 w-9 flex-shrink-0 items-center justify-center rounded-xl border border-selection/70 text-dim transition-colors hover:border-done/35 hover:bg-done/10 hover:text-bright"
            onClick=${onClose}
          >
            <svg class="h-5 w-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
              <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M6 18L18 6M6 6l12 12"/>
            </svg>
          </button>
        </div>

        <!-- Modal Content -->
        <div ref=${chatContainerRef} class="flex-1 overflow-y-auto overflow-x-hidden bg-surface p-5">
          ${conversationLoading ? html`
            <div class="flex items-center justify-center py-12">
              <div class="font-mono text-dim">Loading conversation...</div>
            </div>
          ` : conversation.length > 0 ? html`
            <div class="space-y-4">
              ${filterDisplayMessages(conversation).map((msg, i) => html`
                <${MessageBubble}
                  key=${i}
                  msg=${msg}
                  userBg=${getUserMessageBg(session.status)}
                  compact=${false}
                  formatTime=${formatTime}
                />
              `)}
            </div>
          ` : html`
            <p class="text-dim text-center py-12">No conversation messages</p>
          `}
        </div>

        <!-- Modal Footer -->
        <div class="border-t border-selection/70 bg-bg/55 p-4">
          ${hasPendingQuestions && html`
            <div class="mb-3 rounded-xl border border-attention/40 bg-attention/12 px-3 py-2 text-sm text-attention">
              Agent is waiting for a response
            </div>
          `}
          <div class="flex items-end gap-2.5">
            <textarea
              ref=${inputRef}
              value=${inputValue}
              onInput=${(e) => {
                setInputValue(e.target.value);
                e.target.style.height = 'auto';
                e.target.style.height = Math.min(e.target.scrollHeight, 150) + 'px';
              }}
              onKeyDown=${handleInputKeyDown}
              onFocus=${() => setInputFocused(true)}
              onBlur=${() => setInputFocused(false)}
              placeholder=${hasPendingQuestions ? "Type your response..." : "Send a message..."}
              rows="1"
              class="flex-1 resize-none overflow-hidden rounded-xl border border-selection/75 bg-bg/70 px-4 py-2 text-sm text-fg placeholder:text-dim focus:outline-none"
              style=${{ minHeight: '42px', maxHeight: '150px', borderColor: inputFocused ? status.borderColor : undefined }}
              disabled=${sending}
            />
            <button
              class="rounded-xl px-4 py-2 font-medium transition-all hover:-translate-y-0.5 hover:brightness-110 disabled:cursor-not-allowed disabled:opacity-50"
              style=${{ backgroundColor: status.borderColor, color: '#0a0f18' }}
              onClick=${handleSend}
              disabled=${sending || !inputValue.trim()}
            >
              ${sending ? 'Sending...' : 'Send'}
            </button>
          </div>
          <div class="mt-2 font-mono text-label text-dim">
            Press Enter to send, Shift+Enter for new line, Escape to close
          </div>
        </div>
      </div>
    </div>
  `;
}