'use client';

import { useEffect, useState, useCallback } from 'react';
import { SegmentedControl } from '@/components/ui/Primitives';
import {
  getRoadmapItems,
  getRoadmapStats,
  submitPublicItem,
  publicVote,
  type TrackerItem,
  type PublicRoadmapStats,
} from '@/lib/tracker-client';

// ── Status column config ────────────────────────────────────────────
const STATUS_COLUMNS = [
  {
    key: 'open',
    label: 'Planned',
    color: 'bg-blue-500',
    textColor: 'text-blue-700 dark:text-blue-300',
  },
  {
    key: 'in_progress',
    label: 'In Progress',
    color: 'bg-amber-500',
    textColor: 'text-amber-700 dark:text-amber-300',
  },
  {
    key: 'done',
    label: 'Complete',
    color: 'bg-emerald-500',
    textColor: 'text-emerald-700 dark:text-emerald-300',
  },
] as const;

const TYPE_BADGES: Record<string, { label: string; className: string }> = {
  feature: {
    label: 'Feature',
    className: 'bg-purple-100 text-purple-700 dark:bg-purple-900 dark:text-purple-300',
  },
  bug: { label: 'Bug', className: 'bg-red-100 text-red-700 dark:bg-red-900 dark:text-red-300' },
  task: {
    label: 'Task',
    className: 'bg-gray-100 text-gray-700 dark:bg-gray-900 dark:text-gray-300',
  },
};

const PRIORITY_BADGES: Record<string, { label: string; className: string }> = {
  critical: {
    label: 'Critical',
    className: 'bg-red-100 text-red-800 dark:bg-red-900 dark:text-red-200',
  },
  high: {
    label: 'High',
    className: 'bg-orange-100 text-orange-800 dark:bg-orange-900 dark:text-orange-200',
  },
  medium: {
    label: 'Medium',
    className: 'bg-yellow-100 text-yellow-800 dark:bg-yellow-900 dark:text-yellow-200',
  },
  low: {
    label: 'Low',
    className: 'bg-green-100 text-green-800 dark:bg-green-900 dark:text-green-200',
  },
};

export default function RoadmapPage() {
  const [items, setItems] = useState<TrackerItem[]>([]);
  const [stats, setStats] = useState<PublicRoadmapStats | null>(null);
  const [loading, setLoading] = useState(true);
  const [loadError, setLoadError] = useState('');
  const [search, setSearch] = useState('');
  const [typeFilter, setTypeFilter] = useState('');
  const [view, setView] = useState<'board' | 'list'>('board');

  // Submit form state
  const [showSubmit, setShowSubmit] = useState(false);
  const [submitForm, setSubmitForm] = useState({
    title: '',
    description: '',
    type: 'feature',
    email: '',
    name: '',
  });
  const [submitting, setSubmitting] = useState(false);
  const [submitSuccess, setSubmitSuccess] = useState('');

  // Vote email (persisted in localStorage)
  const [voteEmail, setVoteEmail] = useState('');
  const [showEmailPrompt, setShowEmailPrompt] = useState(false);
  const [pendingVoteId, setPendingVoteId] = useState<string | null>(null);
  const [votedItems, setVotedItems] = useState<Set<string>>(new Set());
  const [voteError, setVoteError] = useState('');

  useEffect(() => {
    if (typeof window !== 'undefined') {
      const saved = localStorage.getItem('roadmap_email');
      if (saved) setVoteEmail(saved);
      const voted = localStorage.getItem('roadmap_voted');
      if (voted) setVotedItems(new Set(JSON.parse(voted)));
    }
  }, []);

  const fetchData = useCallback(async () => {
    setLoading(true);
    setLoadError('');
    try {
      const params: Record<string, string> = {
        sortBy: 'voteCount',
        sortOrder: 'desc',
        limit: '100',
      };
      if (search) params.q = search;
      if (typeFilter) params.type = typeFilter;
      const [itemsRes, statsRes] = await Promise.all([getRoadmapItems(params), getRoadmapStats()]);
      setItems(itemsRes.items);
      setStats(statsRes);
    } catch (err) {
      setLoadError(err instanceof Error ? err.message : 'Failed to load roadmap');
    } finally {
      setLoading(false);
    }
  }, [search, typeFilter]);

  useEffect(() => {
    fetchData();
  }, [fetchData]);

  const handleVoteClick = (itemId: string) => {
    if (!voteEmail) {
      setPendingVoteId(itemId);
      setShowEmailPrompt(true);
      return;
    }
    doVote(itemId, voteEmail);
  };

  const doVote = async (itemId: string, email: string) => {
    setVoteError('');
    try {
      const res = await publicVote(itemId, email);
      setItems(prev => prev.map(i => (i.id === itemId ? { ...i, voteCount: res.voteCount } : i)));
      const newVoted = new Set(votedItems);
      if (res.voted) {
        newVoted.add(itemId);
      } else {
        newVoted.delete(itemId);
      }
      setVotedItems(newVoted);
      localStorage.setItem('roadmap_voted', JSON.stringify([...newVoted]));
    } catch (err) {
      setVoteError(err instanceof Error ? err.message : 'Vote failed');
    }
  };

  const handleEmailSubmit = () => {
    if (!voteEmail) return;
    localStorage.setItem('roadmap_email', voteEmail);
    setShowEmailPrompt(false);
    if (pendingVoteId) {
      doVote(pendingVoteId, voteEmail);
      setPendingVoteId(null);
    }
  };

  const handleSubmit = async (e: React.FormEvent) => {
    e.preventDefault();
    setSubmitting(true);
    setSubmitSuccess('');
    try {
      const res = await submitPublicItem(submitForm);
      setSubmitSuccess(
        `Thanks! Your ${submitForm.type} request "${res.title}" has been submitted for review.`
      );
      setSubmitForm({
        title: '',
        description: '',
        type: 'feature',
        email: submitForm.email,
        name: submitForm.name,
      });
      // Save email for voting
      if (submitForm.email) {
        setVoteEmail(submitForm.email);
        localStorage.setItem('roadmap_email', submitForm.email);
      }
      // Refresh data to show new item
      fetchData();
    } catch (err) {
      setSubmitSuccess(`Error: ${err instanceof Error ? err.message : 'Submission failed'}`);
    } finally {
      setSubmitting(false);
    }
  };

  const itemsByStatus = (status: string) => items.filter(i => i.status === status);

  return (
    <div className="min-h-screen bg-gradient-to-br from-slate-50 to-slate-100 dark:from-slate-950 dark:to-slate-900">
      {/* Header */}
      <header className="border-b border-slate-200 dark:border-slate-800 bg-white/80 dark:bg-slate-900/80 backdrop-blur-sm sticky top-0 z-20">
        <div className="max-w-7xl mx-auto px-4 sm:px-6 py-4 flex items-center justify-between">
          <div>
            <h1 className="text-2xl font-bold text-slate-900 dark:text-white">Product Roadmap</h1>
            <p className="text-sm text-slate-500 dark:text-slate-400 mt-0.5">
              Vote on features, report bugs, and shape what we build next
            </p>
          </div>
          <div className="flex items-center gap-3">
            <button
              onClick={() => setShowSubmit(true)}
              className="px-4 py-2 bg-blue-600 hover:bg-blue-700 text-white rounded-lg text-sm font-medium transition-colors"
            >
              + Submit Idea
            </button>
            <a
              href="/login"
              className="text-sm text-slate-500 hover:text-slate-700 dark:text-slate-400 dark:hover:text-slate-200"
            >
              Admin →
            </a>
          </div>
        </div>
      </header>

      <main className="max-w-7xl mx-auto px-4 sm:px-6 py-6">
        {loadError ? (
          <div className="mb-4 rounded-lg border border-red-200 bg-red-50 px-4 py-3 text-sm text-red-700 dark:border-red-900 dark:bg-red-900/20 dark:text-red-300">
            {loadError}
          </div>
        ) : null}
        {voteError ? (
          <div className="mb-4 rounded-lg border border-red-200 bg-red-50 px-4 py-3 text-sm text-red-700 dark:border-red-900 dark:bg-red-900/20 dark:text-red-300">
            {voteError}
          </div>
        ) : null}

        {/* Stats bar */}
        {stats && (
          <div className="grid grid-cols-2 sm:grid-cols-4 gap-4 mb-6">
            <StatCard label="Total Items" value={stats.total} />
            <StatCard label="Total Votes" value={stats.totalVotes} />
            <StatCard label="In Progress" value={stats.byStatus?.in_progress || 0} />
            <StatCard label="Completed" value={stats.byStatus?.done || 0} />
          </div>
        )}

        {/* Filters */}
        <div className="flex flex-col sm:flex-row gap-3 mb-6">
          <input
            type="text"
            placeholder="Search items..."
            value={search}
            onChange={e => setSearch(e.target.value)}
            className="flex-1 px-3 py-2 border border-slate-300 dark:border-slate-600 rounded-lg bg-white dark:bg-slate-800 text-sm focus:outline-none focus:ring-2 focus:ring-blue-500"
          />
          <select
            value={typeFilter}
            onChange={e => setTypeFilter(e.target.value)}
            aria-label="Filter by type"
            className="px-3 py-2 border border-slate-300 dark:border-slate-600 rounded-lg bg-white dark:bg-slate-800 text-sm"
          >
            <option value="">All Types</option>
            <option value="feature">Features</option>
            <option value="bug">Bugs</option>
            <option value="task">Tasks</option>
          </select>
          <SegmentedControl
            aria-label="Roadmap view"
            value={view}
            onValueChange={v => setView(v as 'board' | 'list')}
            options={[
              { value: 'board', label: 'Board' },
              { value: 'list', label: 'List' },
            ]}
          />
        </div>

        {loading ? (
          view === 'board' ? (
            <div className="grid grid-cols-1 md:grid-cols-3 gap-6">
              {STATUS_COLUMNS.map(col => (
                <div key={col.key} className="space-y-3">
                  <div className="flex items-center gap-2 mb-2">
                    <span className={`w-3 h-3 rounded-full ${col.color} animate-pulse`} />
                    <h2
                      className={`font-semibold ${col.textColor} h-5 w-24 bg-slate-200 dark:bg-slate-700 rounded animate-pulse`}
                    />
                  </div>
                  {[1, 2, 3].map(i => (
                    <div
                      key={i}
                      className="bg-white dark:bg-slate-800 rounded-xl border border-slate-200 dark:border-slate-700 p-4"
                    >
                      <div className="flex items-start gap-3">
                        <div className="flex flex-col items-center min-w-[44px] py-1.5 px-2">
                          <div className="h-4 w-4 bg-slate-200 dark:bg-slate-700 rounded animate-pulse" />
                          <div className="h-4 w-6 bg-slate-200 dark:bg-slate-700 rounded mt-1 animate-pulse" />
                        </div>
                        <div className="flex-1 min-w-0 space-y-2">
                          <div className="h-4 w-full bg-slate-200 dark:bg-slate-700 rounded animate-pulse" />
                          <div className="h-3 w-3/4 bg-slate-200 dark:bg-slate-700 rounded animate-pulse" />
                          <div className="flex gap-2 pt-2">
                            <div className="h-5 w-12 bg-slate-200 dark:bg-slate-700 rounded-full animate-pulse" />
                            <div className="h-5 w-12 bg-slate-200 dark:bg-slate-700 rounded-full animate-pulse" />
                          </div>
                        </div>
                      </div>
                    </div>
                  ))}
                </div>
              ))}
            </div>
          ) : (
            <div className="space-y-3">
              {[1, 2, 3, 4, 5].map(i => (
                <div
                  key={i}
                  className="bg-white dark:bg-slate-800 rounded-xl border border-slate-200 dark:border-slate-700 p-4 flex items-center gap-4"
                >
                  <div className="flex flex-col items-center min-w-[44px] py-1.5 px-2">
                    <div className="h-4 w-4 bg-slate-200 dark:bg-slate-700 rounded animate-pulse" />
                    <div className="h-4 w-6 bg-slate-200 dark:bg-slate-700 rounded mt-1 animate-pulse" />
                  </div>
                  <div className="flex-1 min-w-0 space-y-2">
                    <div className="h-4 w-full bg-slate-200 dark:bg-slate-700 rounded animate-pulse" />
                    <div className="h-3 w-1/2 bg-slate-200 dark:bg-slate-700 rounded animate-pulse" />
                  </div>
                  <div className="flex items-center gap-2 shrink-0">
                    <div className="h-5 w-12 bg-slate-200 dark:bg-slate-700 rounded-full animate-pulse" />
                    <div className="h-4 w-16 bg-slate-200 dark:bg-slate-700 rounded animate-pulse" />
                  </div>
                </div>
              ))}
            </div>
          )
        ) : view === 'board' ? (
          /* Board View */
          <div className="grid grid-cols-1 md:grid-cols-3 gap-6">
            {STATUS_COLUMNS.map(col => (
              <div key={col.key} className="space-y-3">
                <div className="flex items-center gap-2 mb-2">
                  <span className={`w-3 h-3 rounded-full ${col.color}`} />
                  <h2 className={`font-semibold ${col.textColor}`}>{col.label}</h2>
                  <span className="text-xs text-slate-400 ml-auto">
                    {itemsByStatus(col.key).length}
                  </span>
                </div>
                {itemsByStatus(col.key).length === 0 ? (
                  <p className="text-sm text-slate-400 italic py-4 text-center">No items</p>
                ) : (
                  itemsByStatus(col.key).map(item => (
                    <ItemCard
                      key={item.id}
                      item={item}
                      votedItems={votedItems}
                      onVote={handleVoteClick}
                    />
                  ))
                )}
              </div>
            ))}
          </div>
        ) : (
          /* List View */
          <div className="space-y-3">
            {items.length === 0 ? (
              <p className="text-center py-10 text-slate-400">No items found</p>
            ) : (
              items.map(item => (
                <ItemRow
                  key={item.id}
                  item={item}
                  votedItems={votedItems}
                  onVote={handleVoteClick}
                />
              ))
            )}
          </div>
        )}
      </main>

      {/* Email prompt modal */}
      {showEmailPrompt && (
        <Modal
          onClose={() => {
            setShowEmailPrompt(false);
            setPendingVoteId(null);
          }}
        >
          <h3 className="text-lg font-semibold mb-2">Enter your email to vote</h3>
          <p className="text-sm text-slate-500 mb-4">
            We use your email to track your votes. One vote per item.
          </p>
          <input
            type="email"
            placeholder="you@example.com"
            value={voteEmail}
            onChange={e => setVoteEmail(e.target.value)}
            className="w-full px-3 py-2 border border-slate-300 dark:border-slate-600 rounded-lg bg-white dark:bg-slate-800 text-sm mb-4"
            onKeyDown={e => e.key === 'Enter' && handleEmailSubmit()}
            autoFocus
          />
          <div className="flex justify-end gap-2">
            <button
              onClick={() => {
                setShowEmailPrompt(false);
                setPendingVoteId(null);
              }}
              className="px-4 py-2 text-sm text-slate-500 hover:text-slate-700"
            >
              Cancel
            </button>
            <button
              onClick={handleEmailSubmit}
              className="px-4 py-2 bg-blue-600 hover:bg-blue-700 text-white rounded-lg text-sm font-medium"
            >
              Vote
            </button>
          </div>
        </Modal>
      )}

      {/* Submit modal */}
      {showSubmit && (
        <Modal
          onClose={() => {
            setShowSubmit(false);
            setSubmitSuccess('');
          }}
        >
          <h3 className="text-lg font-semibold mb-4">Submit an Idea</h3>
          {submitSuccess ? (
            <div
              className={`p-3 rounded-lg text-sm mb-4 ${submitSuccess.startsWith('Error') ? 'bg-red-50 text-red-700 dark:bg-red-900/20 dark:text-red-300' : 'bg-green-50 text-green-700 dark:bg-green-900/20 dark:text-green-300'}`}
            >
              {submitSuccess}
            </div>
          ) : null}
          <form onSubmit={handleSubmit} className="space-y-3">
            <div className="grid grid-cols-2 gap-3">
              <input
                type="text"
                placeholder="Your name"
                value={submitForm.name}
                onChange={e => setSubmitForm({ ...submitForm, name: e.target.value })}
                required
                className="px-3 py-2 border border-slate-300 dark:border-slate-600 rounded-lg bg-white dark:bg-slate-800 text-sm"
              />
              <input
                type="email"
                placeholder="Your email"
                value={submitForm.email}
                onChange={e => setSubmitForm({ ...submitForm, email: e.target.value })}
                required
                className="px-3 py-2 border border-slate-300 dark:border-slate-600 rounded-lg bg-white dark:bg-slate-800 text-sm"
              />
            </div>
            <select
              value={submitForm.type}
              onChange={e => setSubmitForm({ ...submitForm, type: e.target.value })}
              aria-label="Request type"
              className="w-full px-3 py-2 border border-slate-300 dark:border-slate-600 rounded-lg bg-white dark:bg-slate-800 text-sm"
            >
              <option value="feature">Feature Request</option>
              <option value="bug">Bug Report</option>
              <option value="task">Task</option>
            </select>
            <input
              type="text"
              placeholder="Title — what would you like to see?"
              value={submitForm.title}
              onChange={e => setSubmitForm({ ...submitForm, title: e.target.value })}
              required
              maxLength={500}
              className="w-full px-3 py-2 border border-slate-300 dark:border-slate-600 rounded-lg bg-white dark:bg-slate-800 text-sm"
            />
            <textarea
              placeholder="Describe your idea or issue in detail (optional)"
              value={submitForm.description}
              onChange={e => setSubmitForm({ ...submitForm, description: e.target.value })}
              rows={4}
              maxLength={5000}
              className="w-full px-3 py-2 border border-slate-300 dark:border-slate-600 rounded-lg bg-white dark:bg-slate-800 text-sm resize-none"
            />
            <div className="flex justify-end gap-2 pt-2">
              <button
                type="button"
                onClick={() => setShowSubmit(false)}
                className="px-4 py-2 text-sm text-slate-500 hover:text-slate-700"
              >
                Cancel
              </button>
              <button
                type="submit"
                disabled={submitting}
                className="px-4 py-2 bg-blue-600 hover:bg-blue-700 disabled:opacity-50 text-white rounded-lg text-sm font-medium"
              >
                {submitting ? 'Submitting...' : 'Submit'}
              </button>
            </div>
          </form>
        </Modal>
      )}
    </div>
  );
}

// ── Sub-components ──────────────────────────────────────────────────

function StatCard({ label, value }: { label: string; value: number }) {
  return (
    <div className="bg-white dark:bg-slate-800 rounded-xl border border-slate-200 dark:border-slate-700 p-4">
      <p className="text-2xl font-bold text-slate-900 dark:text-white">{value}</p>
      <p className="text-xs text-slate-500 dark:text-slate-400">{label}</p>
    </div>
  );
}

function ItemCard({
  item,
  votedItems,
  onVote,
}: {
  item: TrackerItem;
  votedItems: Set<string>;
  onVote: (id: string) => void;
}) {
  const typeBadge = TYPE_BADGES[item.type] || TYPE_BADGES.task;
  const priorityBadge = PRIORITY_BADGES[item.priority] || PRIORITY_BADGES.medium;
  const hasVoted = votedItems.has(item.id);

  return (
    <div className="bg-white dark:bg-slate-800 rounded-xl border border-slate-200 dark:border-slate-700 p-4 hover:shadow-md transition-shadow">
      <div className="flex items-start gap-3">
        <button
          onClick={() => onVote(item.id)}
          type="button"
          aria-pressed={hasVoted}
          aria-label={hasVoted ? `Remove vote from ${item.title}` : `Upvote ${item.title}`}
          className={`flex flex-col items-center min-w-[44px] py-1.5 px-2 rounded-lg border text-sm font-semibold transition-colors ${
            hasVoted
              ? 'bg-blue-50 border-blue-300 text-blue-700 dark:bg-blue-900/30 dark:border-blue-700 dark:text-blue-300'
              : 'bg-slate-50 border-slate-200 text-slate-500 hover:border-blue-300 hover:text-blue-600 dark:bg-slate-700 dark:border-slate-600 dark:text-slate-300'
          }`}
          title={hasVoted ? 'Remove vote' : 'Upvote'}
        >
          <span className="text-xs">▲</span>
          <span>{item.voteCount}</span>
        </button>
        <div className="flex-1 min-w-0">
          <h3 className="font-medium text-slate-900 dark:text-white text-sm leading-snug">
            {item.title}
          </h3>
          {item.description && (
            <p className="text-xs text-slate-500 dark:text-slate-400 mt-1 line-clamp-2">
              {item.description}
            </p>
          )}
          <div className="flex flex-wrap gap-1.5 mt-2">
            <span
              className={`text-[10px] font-medium px-1.5 py-0.5 rounded-full ${typeBadge.className}`}
            >
              {typeBadge.label}
            </span>
            <span
              className={`text-[10px] font-medium px-1.5 py-0.5 rounded-full ${priorityBadge.className}`}
            >
              {priorityBadge.label}
            </span>
            {item.commentCount > 0 && (
              <span className="text-[10px] text-slate-400">💬 {item.commentCount}</span>
            )}
          </div>
        </div>
      </div>
    </div>
  );
}

function ItemRow({
  item,
  votedItems,
  onVote,
}: {
  item: TrackerItem;
  votedItems: Set<string>;
  onVote: (id: string) => void;
}) {
  const typeBadge = TYPE_BADGES[item.type] || TYPE_BADGES.task;
  const statusCol = STATUS_COLUMNS.find(c => c.key === item.status);
  const hasVoted = votedItems.has(item.id);

  return (
    <div className="bg-white dark:bg-slate-800 rounded-xl border border-slate-200 dark:border-slate-700 p-4 flex items-center gap-4 hover:shadow-md transition-shadow">
      <button
        onClick={() => onVote(item.id)}
        type="button"
        aria-pressed={hasVoted}
        aria-label={hasVoted ? `Remove vote from ${item.title}` : `Upvote ${item.title}`}
        title={hasVoted ? 'Remove vote' : 'Upvote'}
        className={`flex flex-col items-center min-w-[44px] py-1.5 px-2 rounded-lg border text-sm font-semibold transition-colors ${
          hasVoted
            ? 'bg-blue-50 border-blue-300 text-blue-700 dark:bg-blue-900/30 dark:border-blue-700 dark:text-blue-300'
            : 'bg-slate-50 border-slate-200 text-slate-500 hover:border-blue-300 hover:text-blue-600 dark:bg-slate-700 dark:border-slate-600 dark:text-slate-300'
        }`}
      >
        <span className="text-xs">▲</span>
        <span>{item.voteCount}</span>
      </button>
      <div className="flex-1 min-w-0">
        <h3 className="font-medium text-slate-900 dark:text-white text-sm">{item.title}</h3>
        {item.description && (
          <p className="text-xs text-slate-500 dark:text-slate-400 mt-0.5 line-clamp-1">
            {item.description}
          </p>
        )}
      </div>
      <div className="flex items-center gap-2 shrink-0">
        <span
          className={`text-[10px] font-medium px-1.5 py-0.5 rounded-full ${typeBadge.className}`}
        >
          {typeBadge.label}
        </span>
        {statusCol && (
          <span className="flex items-center gap-1 text-xs text-slate-500">
            <span className={`w-2 h-2 rounded-full ${statusCol.color}`} />
            {statusCol.label}
          </span>
        )}
        {item.commentCount > 0 && (
          <span className="text-xs text-slate-400">💬 {item.commentCount}</span>
        )}
      </div>
    </div>
  );
}

function Modal({ children, onClose }: { children: React.ReactNode; onClose: () => void }) {
  return (
    <div className="fixed inset-0 z-50 flex items-center justify-center p-4">
      <div className="absolute inset-0 bg-black/40 backdrop-blur-sm" onClick={onClose} />
      <div className="relative bg-white dark:bg-slate-800 rounded-2xl shadow-2xl border border-slate-200 dark:border-slate-700 p-6 w-full max-w-md">
        {children}
      </div>
    </div>
  );
}