"""
Peer API — public endpoints for inter-instance communication.

These endpoints do NOT require auth (they're called machine-to-machine by
other Nexus instances on the network). They expose read-only inventory data
so the marketplace can aggregate stock across the whole Nexus network.

Routes:
    GET /pos/api/peer/health        — instance status + inventory count
    GET /pos/api/peer/inventory     — search this instance's inventory
"""

from flask import Blueprint, request, jsonify, g
from tenant_db import get_tenant_conn
from services import peer_service

peer_bp = Blueprint('peer', __name__, url_prefix='/pos/api/peer')


# ─── Which tenant to use for the peer endpoint? ──────────────────────────
# In production each instance serves one tenant. For the demo, we hardcode
# tenant_id=11 (the demo refaccionaria). This will be read from a config
# file in the future when each instance has exactly 1 active tenant.

import os
import json

def _get_local_tenant_id():
    """Read the local tenant ID from peers.json or fall back to 11."""
    try:
        cfg_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), '..', 'peers.json')
        with open(cfg_path, 'r') as f:
            cfg = json.load(f)
        return cfg.get('tenant_id', 11)
    except Exception:
        return 11


@peer_bp.route('/health', methods=['GET'])
def peer_health():
    """Public health check — no auth. Returns instance name + basic stats."""
    tenant_id = _get_local_tenant_id()
    inventory_count = 0
    try:
        conn = get_tenant_conn(tenant_id)
        cur = conn.cursor()
        cur.execute("""
            SELECT COUNT(*) FROM inventory i
            WHERE i.is_active = TRUE
              AND COALESCE((SELECT SUM(quantity) FROM inventory_operations WHERE inventory_id = i.id), 0) > 0
        """)
        inventory_count = cur.fetchone()[0]
        cur.close()
        conn.close()
    except Exception as e:
        print(f'[peer] health check DB error: {e}')

    return jsonify({
        'status': 'ok',
        'instance_name': peer_service.get_instance_name(),
        'instance_id': peer_service.get_instance_id(),
        'inventory_count': inventory_count,
        'peer_count': len(peer_service.get_peers()),
    })


@peer_bp.route('/inventory', methods=['GET'])
def peer_inventory():
    """Public inventory search — no auth.

    Called by other Nexus instances to see what this refaccionaria has in stock.
    Returns minimal data: part number, name, brand, price, stock hint.
    Does NOT expose exact stock quantities (competitive info).

    Query params:
        q: search term (optional — without it, returns popular/all items)
        limit: max results (default 50, max 200)
    """
    q = request.args.get('q', '').strip() or None
    limit = min(request.args.get('limit', 50, type=int), 200)

    tenant_id = _get_local_tenant_id()
    try:
        conn = get_tenant_conn(tenant_id)
        data = peer_service.get_local_inventory(conn, query=q, limit=limit)
        conn.close()
    except Exception as e:
        print(f'[peer] inventory query error: {e}')
        data = []

    return jsonify({
        'instance_name': peer_service.get_instance_name(),
        'data': data,
        'count': len(data),
    })