'use client';

import { useRef, useState, useEffect } from 'react';

type ParsedItem = {
  rawName: string;
  quantity: number;
  unit: string;
  price?: number | null;
  matchedProductId?: number;
  matchedProductName?: string;
  suggestedProductId?: number;
  suggestedProductName?: string;
};

type Product = { id: number; name: string; canonicalName: string | null };

type RowState = {
  rawName: string;
  quantity: number;
  unit: string;
  price?: number | null;
  selectedProductId: number | '';
  selectedProductName: string;
  checked: boolean;
  saveAlias: boolean;
  editQty: string;
  editUnit: string;
  matchSource: 'alias' | 'suggestion' | 'manual' | 'none';
};

const UNITS = ['st', 'kg', 'g', 'l', 'dl', 'cl', 'ml', 'förp', 'pak', 'burk', 'flaska'];

export default function ReceiptImportClient() {
  const fileRef = useRef<HTMLInputElement>(null);
  const [preview, setPreview] = useState<string | null>(null);
  const [parsing, setParsing] = useState(false);
  const [saving, setSaving] = useState(false);
  const [rows, setRows] = useState<RowState[]>([]);
  const [allProducts, setAllProducts] = useState<Product[]>([]);
  const [error, setError] = useState<string | null>(null);
  const [savedCount, setSavedCount] = useState<number | null>(null);
  const [selectedFile, setSelectedFile] = useState<File | null>(null);

  useEffect(() => {
    fetch('/api/products')
      .then((r) => r.json())
      .then((data) => { if (Array.isArray(data)) setAllProducts(data); })
      .catch(() => {});
  }, []);

  const handleFileChange = (e: React.ChangeEvent<HTMLInputElement>) => {
    const file = e.target.files?.[0];
    if (!file) return;
    setSelectedFile(file);
    setPreview(file.type === 'application/pdf' ? 'pdf' : URL.createObjectURL(file));
    setRows([]);
    setError(null);
    setSavedCount(null);
  };

  const handleParse = async () => {
    if (!selectedFile) return;
    setParsing(true);
    setError(null);
    try {
      const fd = new FormData();
      fd.append('file', selectedFile);
      const res = await fetch('/api/receipt-import-proxy', { method: 'POST', body: fd });
      if (!res.ok) {
        const e = await res.json().catch(() => ({ message: 'Okänt fel' }));
        throw new Error(e.message ?? 'Servern svarade med fel');
      }
      const items: ParsedItem[] = await res.json();
      setRows(
        items.map((item): RowState => {
          if (item.matchedProductId) {
            return {
              rawName: item.rawName,
              quantity: item.quantity,
              unit: item.unit,
              price: item.price,
              selectedProductId: item.matchedProductId,
              selectedProductName: item.matchedProductName ?? '',
              checked: true,
              saveAlias: false,
              editQty: String(item.quantity),
              editUnit: item.unit,
              matchSource: 'alias',
            };
          }
          if (item.suggestedProductId) {
            return {
              rawName: item.rawName,
              quantity: item.quantity,
              unit: item.unit,
              price: item.price,
              selectedProductId: item.suggestedProductId,
              selectedProductName: item.suggestedProductName ?? '',
              checked: false,
              saveAlias: false,
              editQty: String(item.quantity),
              editUnit: item.unit,
              matchSource: 'suggestion',
            };
          }
          return {
            rawName: item.rawName,
            quantity: item.quantity,
            unit: item.unit,
            price: item.price,
            selectedProductId: '',
            selectedProductName: '',
            checked: false,
            saveAlias: false,
            editQty: String(item.quantity),
            editUnit: item.unit,
            matchSource: 'none',
          };
        }),
      );
    } catch (err) {
      setError(err instanceof Error ? err.message : 'Kunde inte tolka kvittot');
    } finally {
      setParsing(false);
    }
  };

  const updateRow = (i: number, patch: Partial<RowState>) => {
    setRows((prev) => prev.map((r, idx) => (idx === i ? { ...r, ...patch } : r)));
  };

  const handleProductSelect = (i: number, productId: string) => {
    if (!productId) {
      updateRow(i, { selectedProductId: '', selectedProductName: '', checked: false, matchSource: 'none' });
      return;
    }
    const prod = allProducts.find((p) => p.id === Number(productId));
    if (prod) {
      updateRow(i, {
        selectedProductId: prod.id,
        selectedProductName: prod.canonicalName ?? prod.name,
        checked: true,
        matchSource: 'manual',
        saveAlias: true,
      });
    }
  };

  const handleSave = async () => {
    const toSave = rows.filter((r) => r.checked && r.selectedProductId !== '');
    if (toSave.length === 0) return;
    setSaving(true);
    setError(null);
    try {
      await Promise.all([
        ...toSave.map((r) =>
          fetch('/api/inventory', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
              productId: r.selectedProductId,
              quantity: parseFloat(r.editQty) || r.quantity,
              unit: r.editUnit,
              brand: r.rawName,
            }),
          }),
        ),
        ...toSave
          .filter((r) => r.saveAlias && r.selectedProductId !== '')
          .map((r) =>
            fetch('/api/receipt-alias-proxy', {
              method: 'POST',
              headers: { 'Content-Type': 'application/json' },
              body: JSON.stringify({
                receiptName: r.rawName,
                productId: r.selectedProductId,
              }),
            }),
          ),
      ]);
      setSavedCount(toSave.length);
      setRows([]);
      setPreview(null);
      setSelectedFile(null);
      if (fileRef.current) fileRef.current.value = '';
    } catch {
      setError('Något gick fel vid sparning. Försök igen.');
    } finally {
      setSaving(false);
    }
  };

  const checkedCount = rows.filter((r) => r.checked && r.selectedProductId !== '').length;

  const sourceLabel = (src: RowState['matchSource']) => {
    if (src === 'alias') return { text: 'Känd vara', color: '#27ae60' };
    if (src === 'suggestion') return { text: 'Förslag', color: '#e67e22' };
    if (src === 'manual') return { text: 'Manuellt vald', color: '#0070f3' };
    return null;
  };

  return (
    <div>
      <div
        style={{ border: '2px dashed #ced4da', borderRadius: '10px', padding: '1.5rem', textAlign: 'center', background: '#fafafa', marginBottom: '1rem', cursor: 'pointer' }}
        onClick={() => fileRef.current?.click()}
      >
        <input ref={fileRef} type="file" accept="image/*,application/pdf" capture="environment" onChange={handleFileChange} style={{ display: 'none' }} />
        {preview === 'pdf' ? (
          <div style={{ padding: '1rem' }}>
            <div style={{ fontSize: '2.5rem', marginBottom: '0.5rem' }}>📄</div>
            <div style={{ fontWeight: 600 }}>{selectedFile?.name}</div>
            <div style={{ fontSize: '0.85rem', color: '#888', marginTop: '0.25rem' }}>PDF-kvitto valt</div>
          </div>
        ) : preview ? (
          // eslint-disable-next-line @next/next/no-img-element
          <img src={preview} alt="Kvittoförhandsgranskning" style={{ maxHeight: '300px', maxWidth: '100%', borderRadius: '6px' }} />
        ) : (
          <div style={{ color: '#888' }}>
            <div style={{ fontSize: '2.5rem', marginBottom: '0.5rem' }}>📷</div>
            <div style={{ fontWeight: 600 }}>Fotografera eller välj kvitto</div>
            <div style={{ fontSize: '0.85rem', marginTop: '0.25rem' }}>Klicka för att välja bild (JPEG, PNG, WebP) eller PDF</div>
          </div>
        )}
      </div>

      {preview && rows.length === 0 && (
        <button onClick={handleParse} disabled={parsing} style={primaryBtn(parsing)}>
          {parsing ? '⏳ Läser kvitto...' : '🔍 Läs kvitto'}
        </button>
      )}

      {error && (
        <p style={{ color: '#c0392b', background: '#fdf0ef', padding: '0.75rem 1rem', borderRadius: '6px', marginTop: '0.75rem' }}>{error}</p>
      )}

      {savedCount !== null && (
        <p style={{ color: '#27ae60', background: '#edfdf4', padding: '0.75rem 1rem', borderRadius: '6px', marginTop: '0.75rem', fontWeight: 600 }}>
          ✓ {savedCount} {savedCount === 1 ? 'vara lades till' : 'varor lades till'} i inventariet.
        </p>
      )}

      {rows.length > 0 && (
        <div style={{ marginTop: '1.25rem' }}>
          <div style={{ marginBottom: '0.75rem', display: 'flex', gap: '1rem', alignItems: 'baseline', flexWrap: 'wrap' }}>
            <h2 style={{ margin: 0, fontSize: '1.05rem' }}>Identifierade varor ({rows.length})</h2>
            <span style={{ fontSize: '0.8rem', color: '#888' }}>Grön = känd koppling · Orange = förslag · Välj manuellt om inget förslag</span>
          </div>

          <div style={{ display: 'grid', gap: '0.5rem', marginBottom: '1rem' }}>
            {rows.map((row, i) => {
              const label = sourceLabel(row.matchSource);
              return (
                <div key={i} style={{ padding: '0.75rem 1rem', border: `1px solid ${row.matchSource === 'alias' ? '#a8d5b5' : row.matchSource === 'suggestion' ? '#f5cba7' : '#dee2e6'}`, borderRadius: '8px', background: row.matchSource === 'alias' ? '#f0faf4' : row.matchSource === 'suggestion' ? '#fef9f5' : '#fff' }}>
                  <div style={{ display: 'flex', alignItems: 'center', gap: '0.6rem', marginBottom: '0.5rem', flexWrap: 'wrap' }}>
                    <input type="checkbox" checked={row.checked} disabled={row.selectedProductId === ''} onChange={(e) => updateRow(i, { checked: e.target.checked })} style={{ width: '18px', height: '18px', cursor: row.selectedProductId !== '' ? 'pointer' : 'not-allowed' }} />
                    <span style={{ fontWeight: 500 }}>{row.rawName}</span>
                    {label && (
                      <span style={{ fontSize: '0.75rem', color: label.color, border: `1px solid ${label.color}`, borderRadius: '4px', padding: '1px 6px' }}>{label.text}</span>
                    )}
                  </div>
                  <div style={{ display: 'grid', gridTemplateColumns: '1fr 80px 90px', gap: '0.5rem', alignItems: 'center' }}>
                    <select value={row.selectedProductId} onChange={(e) => handleProductSelect(i, e.target.value)} style={{ padding: '0.35rem 0.5rem', border: '1px solid #ced4da', borderRadius: '6px', fontSize: '0.9rem' }}>
                      <option value="">— Välj produkt —</option>
                      {allProducts.map((p) => (
                        <option key={p.id} value={p.id}>{p.canonicalName ?? p.name}</option>
                      ))}
                    </select>
                    <input type="number" min="0" step="0.01" value={row.editQty} onChange={(e) => updateRow(i, { editQty: e.target.value })} style={{ padding: '0.35rem 0.5rem', border: '1px solid #ced4da', borderRadius: '6px', fontSize: '0.9rem' }} />
                    <select value={row.editUnit} onChange={(e) => updateRow(i, { editUnit: e.target.value })} style={{ padding: '0.35rem 0.5rem', border: '1px solid #ced4da', borderRadius: '6px', fontSize: '0.9rem' }}>
                      {UNITS.map((u) => <option key={u} value={u}>{u}</option>)}
                    </select>
                  </div>
                  {row.selectedProductId !== '' && row.matchSource !== 'alias' && (
                    <label style={{ display: 'flex', alignItems: 'center', gap: '0.4rem', marginTop: '0.5rem', fontSize: '0.82rem', color: '#555', cursor: 'pointer' }}>
                      <input type="checkbox" checked={row.saveAlias} onChange={(e) => updateRow(i, { saveAlias: e.target.checked })} />
                      Kom ihåg kopplingen — nästa gång matchas &quot;{row.rawName}&quot; automatiskt
                    </label>
                  )}
                </div>
              );
            })}
          </div>

          <div style={{ display: 'flex', gap: '0.75rem', alignItems: 'center' }}>
            <button onClick={handleSave} disabled={saving || checkedCount === 0} style={primaryBtn(saving || checkedCount === 0)}>
              {saving ? 'Sparar...' : `Lägg till ${checkedCount} ${checkedCount === 1 ? 'vara' : 'varor'} i inventariet`}
            </button>
            <button onClick={() => { setRows([]); setPreview(null); setSelectedFile(null); if (fileRef.current) fileRef.current.value = ''; }} style={{ padding: '0.5rem 1rem', background: '#f0f0f0', border: '1px solid #ccc', borderRadius: '6px', cursor: 'pointer', fontSize: '0.9rem' }}>
              Börja om
            </button>
          </div>
        </div>
      )}
    </div>
  );
}

function primaryBtn(disabled: boolean): React.CSSProperties {
  return { padding: '0.6rem 1.25rem', background: disabled ? '#aaa' : '#0070f3', color: '#fff', border: 'none', borderRadius: '6px', cursor: disabled ? 'not-allowed' : 'pointer', fontWeight: 600, fontSize: '0.95rem' };
}