import json
import logging
from flask import Blueprint, render_template, request, jsonify
from flask_login import login_required
from app.models.account import Account
from app.models.category import Category
from app.services.bank_import_service import parse_file, do_import

bank_import_bp = Blueprint('bank_import', __name__, url_prefix='/bank-import')
log = logging.getLogger(__name__)

ALLOWED_EXTENSIONS = {'csv', 'ofx', 'qfx', 'txt', 'pdf'}


@bank_import_bp.route('/')
@login_required
def index():
    accounts   = Account.query.filter_by(is_active=True).order_by(Account.name).all()
    categories = Category.query.filter_by(is_active=True).order_by(Category.name).all()
    return render_template('bank_import/index.html',
                           accounts=accounts,
                           categories=categories)


@bank_import_bp.route('/parse', methods=['POST'])
@login_required
def parse():
    """
    Accepts a multipart/form-data POST with:
      file      — the bank statement file
      col_map   — JSON string (optional); user-supplied column mapping

    Returns JSON with parsed rows, detected format, errors, or needs_mapping flag.
    """
    f = request.files.get('file')
    if not f or not f.filename:
        return jsonify({'error': 'No file uploaded'}), 400

    ext = f.filename.rsplit('.', 1)[-1].lower() if '.' in f.filename else ''
    if ext not in ALLOWED_EXTENSIONS:
        return jsonify({'error': f'Unsupported file type: .{ext}. Use CSV, OFX, or QFX.'}), 400

    col_map = None
    raw_map = request.form.get('col_map', '')
    if raw_map:
        try:
            col_map = json.loads(raw_map)
        except (ValueError, TypeError):
            return jsonify({'error': 'Invalid col_map JSON'}), 400

    file_bytes = f.read()
    log.info('[bank_import] parse request: filename=%s size=%d bytes', f.filename, len(file_bytes))

    try:
        result = parse_file(file_bytes, f.filename, col_map=col_map)
    except Exception as e:
        log.error('[bank_import] parse failed: %s', e, exc_info=True)
        return jsonify({'error': f'Failed to parse file: {e}'}), 500

    return jsonify(result)


@bank_import_bp.route('/import', methods=['POST'])
@login_required
def confirm_import():
    """
    Accepts JSON:
      {
        "account_id": int,
        "skip_dupes": bool,
        "rows": [
          {"date": "YYYY-MM-DD", "transaction_type": "expense|income",
           "amount": float, "description": str, "category_id": int|null,
           "notes": str, "source_id": str|null},
          ...
        ]
      }
    Returns {"imported": N, "skipped": N}.
    """
    data = request.get_json()
    if not data:
        return jsonify({'error': 'No JSON payload'}), 400

    rows       = data.get('rows', [])
    account_id = data.get('account_id')
    skip_dupes = data.get('skip_dupes', True)

    if not rows:
        return jsonify({'error': 'No rows provided'}), 400
    if not account_id:
        return jsonify({'error': 'account_id is required'}), 400

    # Validate account exists
    acct = Account.query.get(int(account_id))
    if not acct:
        return jsonify({'error': f'Account {account_id} not found'}), 400

    log.info('[bank_import] importing %d rows into account_id=%s skip_dupes=%s',
             len(rows), account_id, skip_dupes)
    try:
        imported, skipped = do_import(rows, int(account_id), skip_dupes=skip_dupes)
    except Exception as e:
        log.error('[bank_import] import failed: %s', e, exc_info=True)
        return jsonify({'error': f'Import failed: {e}'}), 500

    return jsonify({'imported': imported, 'skipped': skipped})