# /home/Autopartes/pos/blueprints/invoicing_bp.py
"""Invoicing blueprint: CFDI generation, queue management, cancellation.

All CFDI business logic lives in services (cfdi_builder, cfdi_queue).
This blueprint is the HTTP layer that validates input and returns JSON.
"""

import json
from flask import Blueprint, request, jsonify, g
from middleware import require_auth
from tenant_db import get_tenant_conn
from services.cfdi_builder import build_ingreso_xml, build_egreso_xml, build_pago_xml
from services.cfdi_queue import (
    enqueue_cfdi, process_queue, retry_failed,
    cancel_cfdi, get_queue_status,
)
from services.audit import log_action

invoicing_bp = Blueprint('invoicing', __name__, url_prefix='/pos/api/invoicing')


def _get_tenant_config(cur):
    """Load tenant CFDI configuration from tenant_config table.

    Falls back to sensible defaults if config is incomplete.
    """
    config = {}
    cur.execute("SELECT key, value FROM tenant_config WHERE key LIKE 'cfdi_%' OR key LIKE 'tenant_%'")
    for row in cur.fetchall():
        config[row[0]] = row[1]

    return {
        'rfc': config.get('tenant_rfc', ''),
        'razon_social': config.get('tenant_razon_social', ''),
        'regimen_fiscal': config.get('cfdi_regimen_fiscal', '601'),
        'cp': config.get('tenant_cp', '00000'),
        'serie': config.get('cfdi_serie', 'A'),
        'horux_api_url': config.get('cfdi_horux_api_url', ''),
        'horux_api_key': config.get('cfdi_horux_api_key', ''),
    }


def _get_sale_with_items(cur, sale_id):
    """Load a sale with its items for CFDI generation."""
    cur.execute("""
        SELECT id, branch_id, customer_id, employee_id, sale_type,
               payment_method, subtotal, discount_total, tax_total, total,
               metodo_pago_sat, forma_pago_sat, status, created_at
        FROM sales WHERE id = %s
    """, (sale_id,))
    row = cur.fetchone()
    if not row:
        return None

    sale = {
        'id': row[0], 'branch_id': row[1], 'customer_id': row[2],
        'employee_id': row[3], 'sale_type': row[4],
        'payment_method': row[5],
        'subtotal': float(row[6]) if row[6] else 0,
        'discount_total': float(row[7]) if row[7] else 0,
        'tax_total': float(row[8]) if row[8] else 0,
        'total': float(row[9]) if row[9] else 0,
        'metodo_pago_sat': row[10] or 'PUE',
        'forma_pago_sat': row[11] or '01',
        'status': row[12],
        'created_at': str(row[13]),
    }

    cur.execute("""
        SELECT id, inventory_id, part_number, name, quantity, unit_price,
               unit_cost, discount_pct, discount_amount, tax_rate, tax_amount,
               subtotal, clave_prod_serv, clave_unidad
        FROM sale_items WHERE sale_id = %s ORDER BY id
    """, (sale_id,))

    sale['items'] = []
    for r in cur.fetchall():
        sale['items'].append({
            'id': r[0], 'inventory_id': r[1], 'part_number': r[2],
            'name': r[3], 'quantity': r[4],
            'unit_price': float(r[5]) if r[5] else 0,
            'unit_cost': float(r[6]) if r[6] else 0,
            'discount_pct': float(r[7]) if r[7] else 0,
            'discount_amount': float(r[8]) if r[8] else 0,
            'tax_rate': float(r[9]) if r[9] else 0.16,
            'tax_amount': float(r[10]) if r[10] else 0,
            'subtotal': float(r[11]) if r[11] else 0,
            'clave_prod_serv': r[12] or '25174800',
            'clave_unidad': r[13] or 'H87',
        })

    return sale


def _get_customer(cur, customer_id):
    """Load customer data for CFDI receptor."""
    if not customer_id:
        return None
    cur.execute("""
        SELECT id, name, rfc, razon_social, regimen_fiscal, uso_cfdi, cp
        FROM customers WHERE id = %s
    """, (customer_id,))
    row = cur.fetchone()
    if not row:
        return None
    return {
        'id': row[0], 'name': row[1], 'rfc': row[2],
        'razon_social': row[3], 'regimen_fiscal': row[4],
        'uso_cfdi': row[5] or 'G03', 'cp': row[6],
    }


# ─── Generate CFDI ─────────────────────────────────

@invoicing_bp.route('/invoice', methods=['POST'])
@require_auth('invoicing.create')
def generate_invoice():
    """Generate a CFDI for a sale and enqueue for timbrado.

    Body: {
        sale_id: int,
        type: 'ingreso' (default) | 'egreso',
        original_uuid: str (required for egreso)
    }
    """
    data = request.get_json() or {}
    sale_id = data.get('sale_id')
    cfdi_type = data.get('type', 'ingreso')

    if not sale_id:
        return jsonify({'error': 'sale_id is required'}), 400

    conn = get_tenant_conn(g.tenant_id)
    cur = conn.cursor()

    try:
        tenant_config = _get_tenant_config(cur)
        if not tenant_config['rfc']:
            return jsonify({'error': 'Tenant RFC not configured. Set tenant_rfc in config.'}), 400

        sale = _get_sale_with_items(cur, sale_id)
        if not sale:
            return jsonify({'error': 'Sale not found'}), 404

        if sale['status'] == 'cancelled':
            return jsonify({'error': 'Cannot invoice a cancelled sale'}), 400

        customer = _get_customer(cur, sale.get('customer_id'))

        # Check if this sale already has a stamped CFDI
        cur.execute("""
            SELECT id, status FROM cfdi_queue
            WHERE sale_id = %s AND type = %s AND status NOT IN ('cancelled', 'failed')
        """, (sale_id, cfdi_type))
        existing = cur.fetchone()
        if existing:
            return jsonify({
                'error': f'Sale #{sale_id} already has a {cfdi_type} CFDI (queue #{existing[0]}, status: {existing[1]})'
            }), 409

        # Build XML
        if cfdi_type == 'ingreso':
            xml = build_ingreso_xml(sale, tenant_config, customer)
        elif cfdi_type == 'egreso':
            original_uuid = data.get('original_uuid')
            if not original_uuid:
                return jsonify({'error': 'original_uuid required for egreso'}), 400
            xml = build_egreso_xml(sale, tenant_config, customer, original_uuid)
        else:
            return jsonify({'error': f'Invalid CFDI type: {cfdi_type}'}), 400

        # Enqueue
        result = enqueue_cfdi(conn, sale_id, cfdi_type, xml)

        log_action(conn, 'CFDI_GENERATED', 'cfdi_queue', result['id'],
                   new_value={'sale_id': sale_id, 'type': cfdi_type,
                              'folio': result['provisional_folio']})

        conn.commit()
        cur.close()
        conn.close()
        return jsonify(result), 201

    except ValueError as e:
        conn.rollback()
        cur.close()
        conn.close()
        return jsonify({'error': str(e)}), 400
    except Exception as e:
        conn.rollback()
        cur.close()
        conn.close()
        return jsonify({'error': str(e)}), 500


# ─── Queue Management ──────────────────────────────

@invoicing_bp.route('/queue', methods=['GET'])
@require_auth('invoicing.view')
def list_queue():
    """List CFDI queue items.

    Query params: status, sale_id, type, page, per_page
    """
    conn = get_tenant_conn(g.tenant_id)

    filters = {
        'status': request.args.get('status'),
        'sale_id': request.args.get('sale_id'),
        'type': request.args.get('type'),
        'page': request.args.get('page', 1),
        'per_page': request.args.get('per_page', 50),
    }

    result = get_queue_status(conn, filters)
    conn.close()
    return jsonify(result)


@invoicing_bp.route('/queue/<int:cfdi_id>', methods=['GET'])
@require_auth('invoicing.view')
def get_queue_item(cfdi_id):
    """Get CFDI queue item detail (includes XML)."""
    conn = get_tenant_conn(g.tenant_id)
    cur = conn.cursor()

    cur.execute("""
        SELECT q.id, q.sale_id, q.type, q.xml_unsigned, q.xml_signed,
               q.uuid_fiscal, q.status, q.retry_count, q.provisional_folio,
               q.error_message, q.cancel_motive, q.cancel_replacement_uuid,
               q.created_at, q.stamped_at
        FROM cfdi_queue q WHERE q.id = %s
    """, (cfdi_id,))
    row = cur.fetchone()

    if not row:
        cur.close(); conn.close()
        return jsonify({'error': 'CFDI queue item not found'}), 404

    item = {
        'id': row[0], 'sale_id': row[1], 'type': row[2],
        'xml_unsigned': row[3], 'xml_signed': row[4],
        'uuid_fiscal': row[5], 'status': row[6],
        'retry_count': row[7], 'provisional_folio': row[8],
        'error_message': row[9], 'cancel_motive': row[10],
        'cancel_replacement_uuid': row[11],
        'created_at': str(row[12]) if row[12] else None,
        'stamped_at': str(row[13]) if row[13] else None,
    }

    cur.close()
    conn.close()
    return jsonify(item)


@invoicing_bp.route('/queue/process', methods=['POST'])
@require_auth('invoicing.create')
def trigger_process_queue():
    """Manually trigger processing of pending CFDI queue items."""
    conn = get_tenant_conn(g.tenant_id)
    cur = conn.cursor()

    try:
        tenant_config = _get_tenant_config(cur)
        horux_url = tenant_config.get('horux_api_url')
        horux_key = tenant_config.get('horux_api_key')

        if not horux_url or not horux_key:
            cur.close()
            conn.close()
            return jsonify({'error': 'Horux API not configured'}), 400

        # Reset eligible failed items first
        reset_count = retry_failed(conn)

        # Process the queue
        result = process_queue(conn, horux_url, horux_key)
        result['retries_reset'] = reset_count

        cur.close()
        conn.close()
        return jsonify(result)

    except Exception as e:
        conn.rollback()
        cur.close()
        conn.close()
        return jsonify({'error': str(e)}), 500


# ─── Cancel CFDI ────────────────────────────────────

@invoicing_bp.route('/cancel/<int:cfdi_id>', methods=['POST'])
@require_auth('invoicing.delete')
def cancel_invoice(cfdi_id):
    """Cancel a CFDI with SAT motive code.

    Body: {
        motive: '01' | '02' | '03' | '04',
        replacement_uuid: str (required if motive == '01')
    }

    Only owner and admin can cancel CFDIs.
    """
    if g.employee_role not in ('owner', 'admin'):
        return jsonify({'error': 'Only owner or admin can cancel CFDIs'}), 403

    data = request.get_json() or {}
    motive = data.get('motive')
    replacement_uuid = data.get('replacement_uuid')

    if not motive:
        return jsonify({'error': 'motive is required'}), 400

    conn = get_tenant_conn(g.tenant_id)
    cur = conn.cursor()

    try:
        tenant_config = _get_tenant_config(cur)
        result = cancel_cfdi(
            conn, cfdi_id, motive, replacement_uuid,
            tenant_config.get('horux_api_url'),
            tenant_config.get('horux_api_key'),
        )

        log_action(conn, 'CFDI_CANCELLED', 'cfdi_queue', cfdi_id,
                   new_value={'motive': motive, 'replacement_uuid': replacement_uuid})

        conn.commit()
        cur.close()
        conn.close()
        return jsonify(result)

    except ValueError as e:
        conn.rollback()
        cur.close()
        conn.close()
        return jsonify({'error': str(e)}), 400
    except Exception as e:
        conn.rollback()
        cur.close()
        conn.close()
        return jsonify({'error': str(e)}), 500


# ─── PDF Generation ─────────────────────────────────

@invoicing_bp.route('/<int:sale_id>/pdf', methods=['GET'])
@require_auth('invoicing.view')
def get_sale_pdf(sale_id):
    """Generate a PDF representation of the sale/CFDI.

    Returns an HTML page styled for print/PDF generation.
    For actual PDF file generation, the frontend uses window.print() or
    a headless browser. This endpoint returns the formatted HTML.
    """
    conn = get_tenant_conn(g.tenant_id)
    cur = conn.cursor()

    sale = _get_sale_with_items(cur, sale_id)
    if not sale:
        cur.close(); conn.close()
        return jsonify({'error': 'Sale not found'}), 404

    tenant_config = _get_tenant_config(cur)
    customer = _get_customer(cur, sale.get('customer_id'))

    # Check if there's a stamped CFDI
    cur.execute("""
        SELECT uuid_fiscal, provisional_folio, status, stamped_at
        FROM cfdi_queue
        WHERE sale_id = %s AND type = 'ingreso' AND status = 'stamped'
        ORDER BY stamped_at DESC LIMIT 1
    """, (sale_id,))
    cfdi_row = cur.fetchone()

    cfdi_info = None
    if cfdi_row:
        cfdi_info = {
            'uuid_fiscal': cfdi_row[0],
            'provisional_folio': cfdi_row[1],
            'status': cfdi_row[2],
            'stamped_at': str(cfdi_row[3]) if cfdi_row[3] else None,
        }

    cur.close()
    conn.close()

    return jsonify({
        'sale': sale,
        'tenant': {
            'rfc': tenant_config.get('rfc', ''),
            'razon_social': tenant_config.get('razon_social', ''),
            'regimen_fiscal': tenant_config.get('regimen_fiscal', ''),
            'cp': tenant_config.get('cp', ''),
        },
        'customer': customer,
        'cfdi': cfdi_info,
    })


@invoicing_bp.route('/stats', methods=['GET'])
@require_auth('invoicing.read')
def api_invoicing_stats():
    """Return counts for tab badges: invoices, credit notes, payment complements, cancellations."""
    conn = get_tenant_conn(g.tenant_id)
    cur = conn.cursor()

    cur.execute("""
        SELECT
            COUNT(*) FILTER (WHERE type = 'ingreso' AND status IN ('pending', 'stamped', 'retry')) as facturas,
            COUNT(*) FILTER (WHERE type = 'egreso' AND status IN ('pending', 'stamped', 'retry')) as notas_credito,
            COUNT(*) FILTER (WHERE type = 'pago' AND status IN ('pending', 'stamped', 'retry')) as complementos,
            COUNT(*) FILTER (WHERE status = 'cancelled') as cancelaciones
        FROM cfdi_queue
    """)
    row = cur.fetchone()
    cur.close()
    conn.close()

    return jsonify({
        'facturas': row[0] or 0,
        'notas_credito': row[1] or 0,
        'complementos': row[2] or 0,
        'cancelaciones': row[3] or 0,
    })