import { useEffect, useState, useCallback } from 'react';
import { Plus, Wallet, TrendingUp, PiggyBank } from 'lucide-react';
import { useNavigate } from 'react-router-dom';
import { useStore } from '../store';
import { getBuckets, createBucket, updateBucket, deleteBucket } from '../appwrite/db';
import { bucketMonthlyAllocation } from '../lib/calculations';
import { formatCurrency, randomBucketColor, BUCKET_COLORS } from '../lib/utils';
import { Layout } from '../components/layout/Layout';
import { Header } from '../components/layout/Header';
import { Card, SectionHeader } from '../components/ui/Card';
import { Button } from '../components/ui/Button';
import { Input, Select } from '../components/ui/Input';
import { Modal, ConfirmModal } from '../components/ui/Modal';
import { Badge, ProgressBar } from '../components/ui/Badge';
import type { Bucket, BucketType } from '../types';

const TYPE_ICONS = {
  regular: Wallet,
  savings: PiggyBank,
  investment: TrendingUp,
};

const TYPE_LABELS: Record<BucketType, string> = {
  regular: 'Regular',
  savings: 'Savings',
  investment: 'Investment',
};

function BucketForm({
  initial,
  onSave,
  onCancel,
}: {
  initial?: Partial<Bucket>;
  onSave: (data: Omit<Bucket, '$id' | '$createdAt' | '$updatedAt'>) => void;
  onCancel: () => void;
}) {
  const [name, setName] = useState(initial?.name ?? '');
  const [description, setDescription] = useState(initial?.description ?? '');
  const [type, setType] = useState<BucketType>(initial?.type ?? 'regular');
  const [color, setColor] = useState(initial?.color ?? randomBucketColor());
  const [goalAmount, setGoalAmount] = useState(String(initial?.goal_amount ?? ''));
  const [goalType, setGoalType] = useState<'amount' | 'percent'>(initial?.goal_type ?? 'amount');
  const [goalFreq, setGoalFreq] = useState<'monthly' | 'yearly'>(initial?.goal_frequency ?? 'monthly');
  const [returnPct, setReturnPct] = useState(String(initial?.return_percent ?? ''));
  const [returnFreq, setReturnFreq] = useState<'monthly' | 'yearly'>(initial?.return_frequency ?? 'yearly');
  const { user } = useStore();

  function submit() {
    onSave({
      name,
      description,
      type,
      color,
      goal_amount: parseFloat(goalAmount) || 0,
      goal_type: goalType,
      goal_frequency: goalFreq,
      return_percent: parseFloat(returnPct) || 0,
      return_frequency: returnFreq,
      current_balance: initial?.current_balance ?? 0,
      sort_order: initial?.sort_order ?? 0,
      user_id: user?.$id ?? '',
    });
  }

  return (
    <div className="flex flex-col gap-4">
      <Input
        label="Bucket name"
        placeholder="Emergency Fund, Vacation..."
        value={name}
        onChange={(e) => setName(e.target.value)}
      />
      <Input
        label="Description (optional)"
        placeholder="What's this bucket for?"
        value={description}
        onChange={(e) => setDescription(e.target.value)}
      />
      <Select label="Type" value={type} onChange={(e) => setType(e.target.value as BucketType)}>
        <option value="regular">Regular</option>
        <option value="savings">Savings Goal</option>
        <option value="investment">Investment</option>
      </Select>

      {/* Color picker */}
      <div>
        <label className="text-sm font-medium text-slate-300 mb-2 block">Color</label>
        <div className="flex flex-wrap gap-2">
          {BUCKET_COLORS.map((c) => (
            <button
              key={c}
              onClick={() => setColor(c)}
              className="w-7 h-7 rounded-full transition-transform hover:scale-110"
              style={{
                backgroundColor: c,
                outline: color === c ? `2px solid ${c}` : 'none',
                outlineOffset: '2px',
              }}
            />
          ))}
        </div>
      </div>

      {/* Goal settings */}
      <div className="border-t border-slate-700 pt-4">
        <p className="text-sm font-medium text-slate-300 mb-3">Goal / Allocation</p>
        <div className="flex gap-2 mb-3">
          {(['amount', 'percent'] as const).map((t) => (
            <button
              key={t}
              onClick={() => setGoalType(t)}
              className={`flex-1 py-1.5 text-xs rounded-lg transition-colors font-medium ${
                goalType === t ? 'bg-accent text-white' : 'bg-surface-raised text-slate-400'
              }`}
            >
              {t === 'amount' ? 'Fixed $' : '% of Income'}
            </button>
          ))}
        </div>
        <div className="flex gap-2">
          <Input
            label={goalType === 'amount' ? 'Goal amount' : 'Percent of income'}
            type="number"
            placeholder="0"
            value={goalAmount}
            onChange={(e) => setGoalAmount(e.target.value)}
            prefix={goalType === 'amount' ? '$' : undefined}
            suffix={goalType === 'percent' ? '%' : undefined}
            inputMode="decimal"
          />
          <Select
            label="Frequency"
            value={goalFreq}
            onChange={(e) => setGoalFreq(e.target.value as 'monthly' | 'yearly')}
          >
            <option value="monthly">Monthly</option>
            <option value="yearly">Yearly</option>
          </Select>
        </div>
      </div>

      {/* Investment settings */}
      {type === 'investment' && (
        <div className="border-t border-slate-700 pt-4">
          <p className="text-sm font-medium text-slate-300 mb-3">Returns</p>
          <div className="flex gap-2">
            <Input
              label="Return %"
              type="number"
              placeholder="8"
              value={returnPct}
              onChange={(e) => setReturnPct(e.target.value)}
              suffix="%"
              inputMode="decimal"
            />
            <Select
              label="Period"
              value={returnFreq}
              onChange={(e) => setReturnFreq(e.target.value as 'monthly' | 'yearly')}
            >
              <option value="monthly">Monthly</option>
              <option value="yearly">Yearly</option>
            </Select>
          </div>
        </div>
      )}

      <div className="flex gap-3 mt-2">
        <Button variant="secondary" fullWidth onClick={onCancel}>
          Cancel
        </Button>
        <Button fullWidth onClick={submit} disabled={!name}>
          Save Bucket
        </Button>
      </div>
    </div>
  );
}

export function Buckets() {
  const navigate = useNavigate();
  const { user, buckets, setBuckets, addBucket, updateBucketItem, removeBucket } = useStore();
  const totalMonthlyIncome = useStore((s) =>
    s.incomes.reduce(
      (sum, i) => sum + (i.frequency === 'yearly' ? i.amount / 12 : i.amount),
      0,
    ),
  );

  const [showModal, setShowModal] = useState(false);
  const [editingBucket, setEditingBucket] = useState<Bucket | null>(null);
  const [deletingBucket, setDeletingBucket] = useState<Bucket | null>(null);
  const [loading, setLoading] = useState(false);

  const loadBuckets = useCallback(async () => {
    if (!user) return;
    setLoading(true);
    try {
      const bkts = await getBuckets(user.$id);
      setBuckets(bkts);
    } finally {
      setLoading(false);
    }
  }, [user, setBuckets]);

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

  async function handleCreate(data: Omit<Bucket, '$id' | '$createdAt' | '$updatedAt'>) {
    const b = await createBucket({ ...data, sort_order: buckets.length });
    addBucket(b);
    setShowModal(false);
  }

  async function handleUpdate(data: Omit<Bucket, '$id' | '$createdAt' | '$updatedAt'>) {
    if (!editingBucket) return;
    const b = await updateBucket(editingBucket.$id, data);
    updateBucketItem(editingBucket.$id, b);
    setEditingBucket(null);
  }

  async function handleDelete() {
    if (!deletingBucket) return;
    await deleteBucket(deletingBucket.$id);
    removeBucket(deletingBucket.$id);
    setDeletingBucket(null);
  }

  const totalAllocation = buckets.reduce(
    (sum, b) => sum + bucketMonthlyAllocation(b, totalMonthlyIncome),
    0,
  );

  const groupedBuckets = {
    regular: buckets.filter((b) => b.type === 'regular'),
    savings: buckets.filter((b) => b.type === 'savings'),
    investment: buckets.filter((b) => b.type === 'investment'),
  };

  function BucketList({ type }: { type: BucketType }) {
    const list = groupedBuckets[type];
    if (list.length === 0) return null;
    const Icon = TYPE_ICONS[type];

    return (
      <div>
        <SectionHeader title={TYPE_LABELS[type]} />
        <div className="space-y-2">
          {list.map((b) => {
            const allocation = bucketMonthlyAllocation(b, totalMonthlyIncome);
            const progress =
              b.goal_amount > 0 ? (b.current_balance / b.goal_amount) * 100 : 0;

            return (
              <Card key={b.$id} onClick={() => navigate(`/buckets/${b.$id}`)}>
                <div className="flex items-start justify-between mb-2">
                  <div className="flex items-center gap-2">
                    <div
                      className="w-8 h-8 rounded-xl flex items-center justify-center shrink-0"
                      style={{ backgroundColor: b.color + '33', border: `1px solid ${b.color}55` }}
                    >
                      <Icon size={16} style={{ color: b.color }} />
                    </div>
                    <div>
                      <p className="text-sm font-medium text-white">{b.name}</p>
                      {b.description && (
                        <p className="text-xs text-slate-500 truncate max-w-[160px]">{b.description}</p>
                      )}
                    </div>
                  </div>
                  <div className="text-right">
                    <p className="text-sm font-mono font-semibold text-white">
                      {formatCurrency(b.current_balance)}
                    </p>
                    {allocation > 0 && (
                      <p className="text-xs text-slate-500">+{formatCurrency(allocation)}/mo</p>
                    )}
                  </div>
                </div>
                {b.goal_amount > 0 && (
                  <ProgressBar value={progress} color={b.color} showPercent />
                )}
                {type === 'investment' && b.return_percent > 0 && (
                  <p className="text-xs text-success mt-1">
                    {b.return_percent}% / {b.return_frequency}
                  </p>
                )}
                <div className="flex gap-2 mt-2">
                  <button
                    onClick={(e) => {
                      e.stopPropagation();
                      setEditingBucket(b);
                    }}
                    className="text-xs text-slate-400 hover:text-white transition-colors px-2"
                  >
                    Edit
                  </button>
                  <button
                    onClick={(e) => {
                      e.stopPropagation();
                      setDeletingBucket(b);
                    }}
                    className="text-xs text-slate-500 hover:text-danger transition-colors px-2"
                  >
                    Delete
                  </button>
                </div>
              </Card>
            );
          })}
        </div>
      </div>
    );
  }

  return (
    <Layout>
      <Header
        title="Buckets"
        action={
          <Button size="sm" onClick={() => setShowModal(true)}>
            <Plus size={14} /> New
          </Button>
        }
      />
      <div className="px-4 py-4 space-y-5">
        {totalAllocation > 0 && (
          <div className="bg-surface rounded-2xl px-4 py-3 flex justify-between items-center">
            <span className="text-sm text-slate-400">Total monthly allocation</span>
            <span className="text-sm font-semibold font-mono text-white">
              {formatCurrency(totalAllocation)}
            </span>
          </div>
        )}

        {loading ? (
          <div className="flex justify-center py-12">
            <div className="w-8 h-8 border-2 border-accent border-t-transparent rounded-full animate-spin" />
          </div>
        ) : buckets.length === 0 ? (
          <Card>
            <div className="text-center py-6">
              <Wallet size={32} className="text-slate-600 mx-auto mb-3" />
              <p className="text-slate-400 mb-2">No buckets yet.</p>
              <p className="text-xs text-slate-500">
                Create buckets for savings goals, investments, or expense categories.
              </p>
            </div>
          </Card>
        ) : (
          <>
            <BucketList type="regular" />
            <BucketList type="savings" />
            <BucketList type="investment" />
          </>
        )}
      </div>

      <Modal open={showModal} onClose={() => setShowModal(false)} title="New Bucket" size="lg">
        <BucketForm onSave={handleCreate} onCancel={() => setShowModal(false)} />
      </Modal>

      <Modal
        open={!!editingBucket}
        onClose={() => setEditingBucket(null)}
        title="Edit Bucket"
        size="lg"
      >
        <BucketForm
          initial={editingBucket ?? undefined}
          onSave={handleUpdate}
          onCancel={() => setEditingBucket(null)}
        />
      </Modal>

      <ConfirmModal
        open={!!deletingBucket}
        onClose={() => setDeletingBucket(null)}
        onConfirm={handleDelete}
        title="Delete bucket?"
        message={`"${deletingBucket?.name}" and all its transactions will be deleted. This cannot be undone.`}
        confirmLabel="Delete"
        danger
      />
    </Layout>
  );
}