"""Supplier Portal Blueprint — Demand insights for vendors.

Allows suppliers to view demand by zone, part type, and branch.
"""
from flask import Blueprint, request, jsonify, g
from functools import wraps
from datetime import datetime, timedelta
from decimal import Decimal
import json

supplier_portal_bp = Blueprint('supplier_portal', __name__, url_prefix='/pos/api/supplier-portal')


from middleware import require_auth


class DecimalEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, Decimal):
            return float(o)
        return super().default(o)


@supplier_portal_bp.route('/demand', methods=['GET'])
@require_auth()
def get_demand():
    """Aggregated demand by zone, part group, and time range."""
    days = request.args.get('days', 30, type=int)
    group_id = request.args.get('group_id', type=int)
    branch_id = request.args.get('branch_id', type=int)

    from tenant_db import get_tenant_db
    db = get_tenant_db()
    since = datetime.utcnow() - timedelta(days=days)

    params = [since]
    filters = "s.created_at >= %s"
    if group_id:
        filters += " AND p.group_id = %s"
        params.append(group_id)
    if branch_id:
        filters += " AND s.branch_id = %s"
        params.append(branch_id)

    rows = db.execute(
        f"""SELECT g.name as group_name, b.name as branch_name,
                   COUNT(DISTINCT s.id_sale) as orders,
                   SUM(si.quantity) as qty_requested,
                   COALESCE(SUM(si.total), 0) as revenue
            FROM sale_items si
            JOIN sales s ON si.sale_id = s.id_sale
            JOIN parts p ON si.part_id = p.id_part
            JOIN part_groups g ON p.group_id = g.id_group
            LEFT JOIN branches b ON s.branch_id = b.id_branch
            WHERE {filters}
            GROUP BY g.name, b.name
            ORDER BY revenue DESC
            LIMIT 100""", tuple(params)
    ).fetchall()

    return jsonify({
        'since': since.isoformat(),
        'days': days,
        'demand': [
            {'group': row['group_name'], 'branch': row['branch_name'],
             'orders': row['orders'], 'quantity': row['qty_requested'],
             'revenue': row['revenue']}
            for row in rows
        ]
    }, cls=DecimalEncoder)


@supplier_portal_bp.route('/top-parts', methods=['GET'])
@require_auth()
def get_top_parts():
    """Top moving parts for suppliers to restock."""
    days = request.args.get('days', 30, type=int)
    from tenant_db import get_tenant_db
    db = get_tenant_db()
    since = datetime.utcnow() - timedelta(days=days)

    rows = db.execute(
        """SELECT p.oem_part_number, p.name, g.name as group_name,
                  SUM(si.quantity) as sold, COALESCE(SUM(si.total), 0) as revenue,
                  COALESCE(SUM(wi.stock_quantity), 0) as current_stock
           FROM sale_items si
           JOIN sales s ON si.sale_id = s.id_sale
           JOIN parts p ON si.part_id = p.id_part
           JOIN part_groups g ON p.group_id = g.id_group
           LEFT JOIN warehouse_inventory wi ON p.id_part = wi.part_id
           WHERE s.created_at >= %s
           GROUP BY p.oem_part_number, p.name, g.name
           ORDER BY sold DESC
           LIMIT 50""", (since,)
    ).fetchall()

    return jsonify({
        'since': since.isoformat(),
        'parts': [
            {'oem': row['oem_part_number'], 'name': row['name'],
             'group': row['group_name'], 'sold': row['sold'],
             'revenue': row['revenue'], 'stock': row['current_stock']}
            for row in rows
        ]
    }, cls=DecimalEncoder)