'use client';

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

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

const PROMISE_TAGS = ['commitment', 'promise', 'angajament', 'promisiune', 'obligatie', 'obligation'];

function isPromise(task: Task) {
  const tags = task.tags.map((t) => t.toLowerCase());
  const title = task.title.toLowerCase();
  return tags.some((t) => PROMISE_TAGS.includes(t)) ||
    title.includes('promit') || title.includes('ma angajez') || title.includes('commit');
}

function daysUntil(d: string) { return Math.ceil((new Date(d).getTime() - Date.now()) / 86400_000); }

const PRIORITY_CLS: Record<string, string> = {
  urgent: 'text-signal-danger',
  high: 'text-warn',
  medium: 'text-ink',
  low: 'text-ink-faint',
};

export default function PromisesPage() {
  const { activeTenant } = useSession();
  const tenantId = activeTenant?.tenantId ?? '';
  const qc = useQueryClient();
  const [showCreate, setShowCreate] = useState(false);
  const [statusFilter, setStatusFilter] = useState<'active' | 'kept' | 'all'>('active');
  const [form, setForm] = useState({ title: '', description: '', dueDate: '', priority: 'high' });

  const { data: allTasks = [], isLoading } = useQuery({
    queryKey: ['promises-tasks', tenantId],
    queryFn: () => apiFetch<Task[]>('/v1/tasks?limit=500', { tenantId }),
    enabled: Boolean(tenantId), staleTime: 30_000,
  });

  const promises = useMemo(() => allTasks.filter(isPromise), [allTasks]);

  const active = promises.filter((t) => t.status !== 'completed' && t.status !== 'cancelled');
  const kept = promises.filter((t) => t.status === 'completed');
  const overdue = active.filter((t) => t.dueDate && daysUntil(t.dueDate) < 0);

  const shown = statusFilter === 'active' ? active : statusFilter === 'kept' ? kept : promises;

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

  const createMut = useMutation({
    mutationFn: () => apiFetch('/v1/tasks', { tenantId, method: 'POST', body: {
      ...form, tags: ['commitment', 'promise'], dueDate: form.dueDate || null,
    }}),
    onSuccess: () => { qc.invalidateQueries({ queryKey: ['promises-tasks', tenantId] }); setShowCreate(false); setForm({ title: '', description: '', dueDate: '', priority: 'high' }); },
  });

  return (
    <div className="max-w-3xl space-y-6 p-6">
      <div className="flex items-start justify-between flex-wrap gap-3">
        <div>
          <h1 className="font-display text-2xl font-semibold text-ink">Angajamente & Promisiuni</h1>
          <p className="text-sm text-ink-faint mt-1">
            {isLoading ? 'Se încarcă…' : `${active.length} active · ${kept.length} onorate`}
            {overdue.length > 0 && <span className="ml-1 text-signal-danger font-semibold">· {overdue.length} depășite</span>}
          </p>
        </div>
        <button onClick={() => setShowCreate(true)}
          className="rounded-lg bg-primary px-4 py-2 text-sm font-medium text-white hover:bg-primary/90">
          + Angajament
        </button>
      </div>

      {overdue.length > 0 && (
        <div className="card p-4 border-signal-danger/30 bg-signal-danger/5 space-y-2">
          <p className="text-sm font-semibold text-signal-danger">⚠ Angajamente depășite ({overdue.length})</p>
          {overdue.map((t) => (
            <div key={t.id} className="flex items-center justify-between text-xs">
              <span className="text-ink">{t.title}</span>
              <span className="text-signal-danger">
                {t.dueDate ? `${Math.abs(daysUntil(t.dueDate))} zile întârziere` : ''}
              </span>
            </div>
          ))}
        </div>
      )}

      {showCreate && (
        <div className="card p-5 space-y-3">
          <p className="text-sm font-semibold text-ink">Angajament nou</p>
          <input placeholder="Ce ai promis / la ce te-ai angajat?" value={form.title}
            onChange={(e) => setForm((p) => ({ ...p, title: e.target.value }))}
            className="w-full rounded-lg border bg-background px-3 py-2 text-sm text-ink focus:outline-none focus:ring-2 focus:ring-ring" />
          <textarea placeholder="Față de cine? Context?" value={form.description}
            onChange={(e) => setForm((p) => ({ ...p, description: e.target.value }))} rows={2}
            className="w-full rounded-lg border bg-background px-3 py-2 text-sm text-ink focus:outline-none focus:ring-2 focus:ring-ring" />
          <div className="grid gap-3 sm:grid-cols-2">
            <input type="date" value={form.dueDate} onChange={(e) => setForm((p) => ({ ...p, dueDate: e.target.value }))}
              className="rounded-lg border bg-background px-3 py-2 text-sm text-ink focus:outline-none focus:ring-2 focus:ring-ring" />
            <select value={form.priority} onChange={(e) => setForm((p) => ({ ...p, priority: e.target.value }))}
              className="rounded-lg border bg-background px-3 py-2 text-sm text-ink focus:outline-none focus:ring-2 focus:ring-ring">
              <option value="urgent">Urgent</option>
              <option value="high">Ridicat</option>
              <option value="medium">Mediu</option>
              <option value="low">Scăzut</option>
            </select>
          </div>
          <div className="flex gap-2">
            <button onClick={() => createMut.mutate()} disabled={!form.title || createMut.isPending}
              className="rounded-lg bg-primary px-4 py-2 text-sm font-medium text-white disabled:opacity-50">
              {createMut.isPending ? 'Se salvează…' : 'Salvează'}
            </button>
            <button onClick={() => setShowCreate(false)} className="rounded-lg border px-4 py-2 text-sm text-ink hover:bg-muted/50">Anulează</button>
          </div>
        </div>
      )}

      {/* Filter tabs */}
      <div className="flex gap-1 border-b border-border/50">
        {([['active', `Active (${active.length})`], ['kept', `Onorate (${kept.length})`], ['all', `Toate (${promises.length})`]] as const).map(([key, label]) => (
          <button key={key} onClick={() => setStatusFilter(key as typeof statusFilter)}
            className={`pb-2 px-3 text-sm font-medium border-b-2 transition-colors ${statusFilter === key ? 'border-primary text-ink' : 'border-transparent text-ink-faint hover:text-ink'}`}>
            {label}
          </button>
        ))}
      </div>

      {isLoading ? (
        <div className="text-center text-sm text-ink-faint py-8">Se încarcă…</div>
      ) : shown.length === 0 ? (
        <div className="card p-8 text-center space-y-2">
          <p className="text-2xl">🤝</p>
          <p className="text-sm text-ink-faint">
            {promises.length === 0
              ? 'Niciun angajament. Taskurile cu tagul "commitment" sau "promise" apar aici.'
              : 'Niciun angajament în această categorie.'}
          </p>
        </div>
      ) : (
        <div className="card divide-y divide-border/50">
          {shown.map((task) => {
            const days = task.dueDate ? daysUntil(task.dueDate) : null;
            const isOverdue = days !== null && days < 0;
            const isToday = days === 0;
            return (
              <div key={task.id} className="flex items-start gap-3 p-4">
                <button
                  onClick={() => completeMut.mutate(task.id)}
                  disabled={task.status === 'completed' || completeMut.isPending}
                  className={`mt-0.5 w-5 h-5 rounded-full border-2 shrink-0 flex items-center justify-center transition-colors ${task.status === 'completed' ? 'bg-signal-ok border-signal-ok text-white' : 'border-border hover:border-primary'}`}>
                  {task.status === 'completed' && <span className="text-[10px]">✓</span>}
                </button>
                <div className="flex-1 min-w-0">
                  <p className={`text-sm font-medium ${task.status === 'completed' ? 'line-through text-ink-faint' : 'text-ink'}`}>
                    {task.title}
                  </p>
                  {task.description && <p className="text-xs text-ink-faint mt-0.5 line-clamp-1">{task.description}</p>}
                  <div className="flex flex-wrap gap-2 mt-1">
                    {task.priority && (
                      <span className={`text-[10px] font-semibold ${PRIORITY_CLS[task.priority] ?? 'text-ink-faint'}`}>
                        {task.priority.toUpperCase()}
                      </span>
                    )}
                    {task.dueDate && (
                      <span className={`text-[10px] ${isOverdue ? 'text-signal-danger font-semibold' : isToday ? 'text-warn font-semibold' : 'text-ink-faint'}`}>
                        {isOverdue ? `${Math.abs(days!)} zile depășit` : isToday ? 'azi' : `${days} zile`}
                      </span>
                    )}
                  </div>
                </div>
              </div>
            );
          })}
        </div>
      )}
    </div>
  );
}