'use client';

import { useState } from 'react';
import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
import { apiFetch } from '../../../lib/api';
import { useSession } from '../../../components/session-provider';

interface Task {
  id: string; title: string; status: string; priority: string;
  dueDate: string | null; tags: string[]; assignedTo: string | null;
  description: string | null; createdAt: string;
}

const PRIORITY_DOT: Record<string, string> = {
  critical: 'bg-signal-danger', high: 'bg-warn',
  medium: 'bg-primary', low: 'bg-muted-foreground',
};

const ROUTINE_TAGS = ['routine', 'daily', 'weekly', 'monthly', 'recurring', 'habit'];

function isRoutine(task: Task) {
  return task.tags.some((t) => ROUTINE_TAGS.includes(t.toLowerCase()));
}

const TODAY_LABEL: Record<string, string> = {
  Mon: 'Lu', Tue: 'Ma', Wed: 'Mi', Thu: 'Jo', Fri: 'Vi', Sat: 'Sâ', Sun: 'Du',
};

export default function RoutinesPage() {
  const { activeTenant } = useSession();
  const tenantId = activeTenant?.tenantId ?? '';
  const qc = useQueryClient();

  const [tab, setTab] = useState<'routines' | 'all'>('routines');
  const [showCreate, setShowCreate] = useState(false);
  const [form, setForm] = useState({ title: '', priority: 'medium', dueDate: '', tags: 'routine,daily', description: '' });

  const { data: tasks = [], isLoading } = useQuery({
    queryKey: ['tasks-routines', tenantId],
    queryFn: () => apiFetch<Task[]>('/v1/tasks?limit=200', { tenantId }),
    enabled: Boolean(tenantId), staleTime: 30_000,
  });

  const completeMut = useMutation({
    mutationFn: (id: string) =>
      apiFetch<Task>(`/v1/tasks/${id}`, { tenantId, method: 'PATCH', body: { status: 'completed' } }),
    onSuccess: () => qc.invalidateQueries({ queryKey: ['tasks-routines', tenantId] }),
  });

  const createMut = useMutation({
    mutationFn: (body: Record<string, string | string[]>) =>
      apiFetch<Task>('/v1/tasks', { tenantId, method: 'POST', body }),
    onSuccess: () => {
      qc.invalidateQueries({ queryKey: ['tasks-routines', tenantId] });
      setShowCreate(false);
      setForm({ title: '', priority: 'medium', dueDate: '', tags: 'routine,daily', description: '' });
    },
  });

  const routines = tasks.filter(isRoutine);
  const active = routines.filter((t) => t.status !== 'completed' && t.status !== 'cancelled');
  const completed = routines.filter((t) => t.status === 'completed');

  const today = new Date().toLocaleDateString('en-US', { weekday: 'short' });
  const todayLabel = TODAY_LABEL[today] ?? today;

  // All active tasks for the "all tasks" view
  const allActive = tasks.filter((t) => t.status !== 'completed' && t.status !== 'cancelled');
  const overdueAll = allActive.filter((t) => t.dueDate && new Date(t.dueDate) < new Date());

  return (
    <div className="max-w-3xl space-y-6 p-6">
      <div className="flex items-center justify-between flex-wrap gap-3">
        <div>
          <h1 className="font-display text-2xl font-semibold text-ink">Tasks & Rutine</h1>
          <p className="text-sm text-ink-faint mt-1">
            {active.length} rutine active · {todayLabel} · {allActive.length} taskuri totale
            {overdueAll.length > 0 && <span className="ml-1 text-signal-danger font-semibold">{overdueAll.length} depășite</span>}
          </p>
        </div>
        <button onClick={() => setShowCreate(!showCreate)}
          className="btn btn-primary px-4 py-2 text-sm rounded-lg">
          + Task nou
        </button>
      </div>

      {/* Tabs */}
      <div className="flex gap-1 border-b border-border/50">
        <button onClick={() => setTab('routines')}
          className={`pb-2 px-3 text-sm font-medium border-b-2 transition-colors ${tab === 'routines' ? 'border-primary text-ink' : 'border-transparent text-ink-faint hover:text-ink'}`}>
          Rutine ({routines.length})
        </button>
        <button onClick={() => setTab('all')}
          className={`pb-2 px-3 text-sm font-medium border-b-2 transition-colors ${tab === 'all' ? 'border-primary text-ink' : 'border-transparent text-ink-faint hover:text-ink'}`}>
          Toate ({tasks.length})
        </button>
      </div>

      {/* Create form */}
      {showCreate && (
        <div className="card p-5 space-y-3">
          <h2 className="text-sm font-semibold text-ink">Task / rutină nouă</h2>
          <input placeholder="Titlu *" value={form.title}
            onChange={(e) => setForm({ ...form, title: e.target.value })}
            className="w-full rounded-lg border bg-card px-3 py-2 text-sm text-ink focus:outline-none focus:ring-2 focus:ring-ring" />
          <div className="grid grid-cols-2 gap-3">
            <select value={form.priority} onChange={(e) => setForm({ ...form, priority: e.target.value })}
              className="rounded-lg border bg-card px-3 py-2 text-sm text-ink focus:outline-none focus:ring-2 focus:ring-ring">
              {['low','medium','high','critical'].map((p) => <option key={p}>{p}</option>)}
            </select>
            <input type="date" value={form.dueDate}
              onChange={(e) => setForm({ ...form, dueDate: e.target.value })}
              className="rounded-lg border bg-card px-3 py-2 text-sm text-ink focus:outline-none focus:ring-2 focus:ring-ring" />
          </div>
          <input placeholder="Taguri (virgulă) — ex: routine,daily" value={form.tags}
            onChange={(e) => setForm({ ...form, tags: e.target.value })}
            className="w-full rounded-lg border bg-card px-3 py-2 text-sm text-ink focus:outline-none focus:ring-2 focus:ring-ring" />
          <input placeholder="Descriere (opțional)" value={form.description}
            onChange={(e) => setForm({ ...form, description: e.target.value })}
            className="w-full rounded-lg border bg-card px-3 py-2 text-sm text-ink focus:outline-none focus:ring-2 focus:ring-ring" />
          <div className="flex gap-2">
            <button
              onClick={() => createMut.mutate({ title: form.title, priority: form.priority, dueDate: form.dueDate || undefined, tags: form.tags.split(',').map(t => t.trim()).filter(Boolean), description: form.description || undefined } as Record<string,string|string[]>)}
              disabled={!form.title || createMut.isPending}
              className="btn btn-primary px-4 py-1.5 text-sm rounded-lg disabled:opacity-50">
              {createMut.isPending ? 'Se creează…' : 'Salvează'}
            </button>
            <button onClick={() => setShowCreate(false)} className="text-sm text-ink-faint hover:text-ink px-2">Anulează</button>
          </div>
        </div>
      )}

      {isLoading ? (
        <div className="text-center text-sm text-ink-faint py-8">Se încarcă…</div>
      ) : tab === 'routines' ? (
        <>
          {active.length === 0 && (
            <div className="card p-8 text-center space-y-2">
              <p className="text-2xl">🔄</p>
              <p className="text-sm text-ink-faint">Nicio rutină activă. Adaugă un task cu tag-ul &quot;routine&quot; sau &quot;daily&quot;.</p>
            </div>
          )}
          {active.length > 0 && (
            <div className="space-y-2">
              <p className="text-[10px] font-semibold uppercase tracking-wider text-ink-faint">Active ({active.length})</p>
              <div className="card divide-y divide-border/50">
                {active.map((t) => {
                  const overdue = t.dueDate && new Date(t.dueDate) < new Date();
                  return (
                    <div key={t.id} className="flex items-center gap-3 px-4 py-3">
                      <button onClick={() => completeMut.mutate(t.id)}
                        className="w-5 h-5 shrink-0 rounded-full border-2 border-border hover:border-signal-ok hover:bg-signal-ok/10 transition-colors" />
                      <div className={`w-1.5 h-1.5 rounded-full shrink-0 ${PRIORITY_DOT[t.priority] ?? 'bg-muted'}`} />
                      <div className="flex-1 min-w-0">
                        <p className="text-sm text-ink">{t.title}</p>
                        <div className="flex items-center gap-2 flex-wrap">
                          {t.tags.map((tag) => (
                            <span key={tag} className="text-[9px] rounded-full bg-primary/10 px-1.5 py-0.5 text-ink">{tag}</span>
                          ))}
                        </div>
                      </div>
                      {t.dueDate && (
                        <span className={`text-[10px] shrink-0 ${overdue ? 'text-signal-danger font-semibold' : 'text-ink-faint'}`}>
                          {new Date(t.dueDate).toLocaleDateString('ro-RO', { day: '2-digit', month: 'short' })}
                        </span>
                      )}
                    </div>
                  );
                })}
              </div>
            </div>
          )}
          {completed.length > 0 && (
            <div className="space-y-2 opacity-60">
              <p className="text-[10px] font-semibold uppercase tracking-wider text-ink-faint">Completate recent ({completed.length})</p>
              <div className="card divide-y divide-border/50">
                {completed.slice(0, 5).map((t) => (
                  <div key={t.id} className="flex items-center gap-3 px-4 py-2.5">
                    <div className="w-5 h-5 shrink-0 rounded-full bg-signal-ok/20 flex items-center justify-center text-[10px] text-signal-ok">✓</div>
                    <p className="text-sm text-ink-faint line-through">{t.title}</p>
                  </div>
                ))}
              </div>
            </div>
          )}
        </>
      ) : (
        /* All tasks view */
        <div className="space-y-3">
          {overdueAll.length > 0 && (
            <div className="space-y-1">
              <p className="text-[10px] font-semibold uppercase tracking-wider text-signal-danger">Depășite ({overdueAll.length})</p>
              <div className="card divide-y divide-border/50 border-signal-danger/20">
                {overdueAll.map((t) => (
                  <div key={t.id} className="flex items-center gap-3 px-4 py-3">
                    <button onClick={() => completeMut.mutate(t.id)}
                      className="w-5 h-5 shrink-0 rounded-full border-2 border-signal-danger/50 hover:bg-signal-ok/10 transition-colors" />
                    <div className={`w-1.5 h-1.5 rounded-full shrink-0 ${PRIORITY_DOT[t.priority] ?? 'bg-muted'}`} />
                    <p className="flex-1 text-sm text-ink">{t.title}</p>
                    <span className="text-[10px] text-signal-danger font-semibold shrink-0">
                      {new Date(t.dueDate!).toLocaleDateString('ro-RO', { day: '2-digit', month: 'short' })}
                    </span>
                  </div>
                ))}
              </div>
            </div>
          )}
          <div className="card divide-y divide-border/50">
            {allActive.filter((t) => !overdueAll.includes(t)).map((t) => (
              <div key={t.id} className="flex items-center gap-3 px-4 py-3">
                <button onClick={() => completeMut.mutate(t.id)}
                  className="w-5 h-5 shrink-0 rounded-full border-2 border-border hover:border-signal-ok hover:bg-signal-ok/10 transition-colors" />
                <div className={`w-1.5 h-1.5 rounded-full shrink-0 ${PRIORITY_DOT[t.priority] ?? 'bg-muted'}`} />
                <p className="flex-1 text-sm text-ink">{t.title}</p>
                {t.dueDate && (
                  <span className="text-[10px] text-ink-faint shrink-0">
                    {new Date(t.dueDate).toLocaleDateString('ro-RO', { day: '2-digit', month: 'short' })}
                  </span>
                )}
              </div>
            ))}
          </div>
        </div>
      )}
    </div>
  );
}