# -*- coding: utf-8 -*-
# Arihant AI - Industrial Security Gate Pass & Weighbridge Integration for Odoo 19

from odoo import models, fields, api, _
from odoo.exceptions import UserError, ValidationError
import hashlib
import logging

_logger = logging.getLogger(__name__)

class SecurityGatePass(models.Model):
    _name = 'security.gate.pass'
    _description = 'Security Gate Pass & Weighbridge Transaction'
    _inherit = ['mail.thread', 'mail.activity.mixin']
    _order = 'create_date desc, id desc'

    name = fields.Char(string='Gate Pass #', required=True, copy=False, readonly=True, index=True, default=lambda self: _('New'))
    gate_type = fields.Selection([
        ('inward', 'Inward (Raw Material / Purchase)'),
        ('outward', 'Outward (Finished Goods / Sale)')
    ], string='Transaction Type', required=True, default='inward', tracking=True)

    state = fields.Selection([
        ('draft', 'Gate Arrival'),
        ('inward_weighed', 'Gross Weighed'),
        ('unloading', 'In Yard / Unloading'),
        ('outward_weighed', 'Tare Weighed'),
        ('cleared', 'Cleared & Exited'),
        ('held', 'Held on Exception'),
        ('cancelled', 'Cancelled')
    ], string='Status', default='draft', tracking=True)

    # Transport & Driver KYC
    vehicle_number = fields.Char(string='Vehicle Plate', required=True, index=True, tracking=True)
    driver_name = fields.Char(string='Driver Full Name')
    driver_mobile = fields.Char(string='Driver Mobile Phone')
    driver_license_no = fields.Char(string='Driving License #')
    anpr_confidence = fields.Float(string='ANPR Match %', readonly=True)

    # Commercial Links
    purchase_order_id = fields.Many2one('purchase.order', string='Purchase Order', tracking=True)
    picking_id = fields.Many2one('stock.picking', string='Inventory Transfer (GRN)', readonly=True)
    partner_id = fields.Many2one('res.partner', string='Vendor / Customer', required=True)
    delivery_challan_no = fields.Char(string='Transporter Challan #')
    eway_bill_no = fields.Char(string='e-Way Bill Number')

    # Physical Weights (Cryptographically Locked to Hardware Stream)
    gross_weight = fields.Float(string='Gross Weight (KG)', digits=(12, 2), readonly=True, tracking=True)
    tare_weight = fields.Float(string='Tare Weight (KG)', digits=(12, 2), readonly=True, tracking=True)
    net_weight = fields.Float(string='Net Weight (KG)', compute='_compute_net_weight', store=True, digits=(12, 2))
    billed_weight = fields.Float(string='Vendor Billed Weight (KG)', digits=(12, 2))
    weight_variance = fields.Float(string='Weight Variance (KG)', compute='_compute_weight_variance', store=True)
    variance_percentage = fields.Float(string='Variance %', compute='_compute_weight_variance', store=True)

    # Hardware & Audit Evidence
    indicator_serial = fields.Char(string='Weighbridge Indicator Serial', readonly=True)
    scale_raw_stream = fields.Char(string='Raw Indicator Stream', readonly=True)
    integrity_hash = fields.Char(string='SHA-256 Security Hash', readonly=True)
    image_front_plate = fields.Binary(string='Front ANPR Snapshot', attachment=True)
    image_truck_bed = fields.Binary(string='Bed Snapshot', attachment=True)

    @api.depends('gross_weight', 'tare_weight', 'gate_type')
    def _compute_net_weight(self):
        for rec in self:
            if rec.gate_type == 'inward':
                rec.net_weight = max(0.0, rec.gross_weight - rec.tare_weight)
            else:
                rec.net_weight = max(0.0, rec.tare_weight - rec.gross_weight)

    @api.depends('net_weight', 'billed_weight')
    def _compute_weight_variance(self):
        for rec in self:
            if rec.billed_weight > 0:
                rec.weight_variance = rec.net_weight - rec.billed_weight
                rec.variance_percentage = (rec.weight_variance / rec.billed_weight) * 100.0
            else:
                rec.weight_variance = 0.0
                rec.variance_percentage = 0.0

    def action_lock_weighbridge_gross(self, raw_weight, raw_string, indicator_id):
        """Direct invocation by IoT Gateway edge daemon"""
        self.ensure_one()
        if self.gross_weight > 0 and not self.env.user.has_group('security_gate.group_gate_supervisor'):
            raise UserError(_('Gross weight is already locked. Supervisor token required to override.'))

        # Compute tamper-evident hash
        hash_payload = f'{self.vehicle_number}:{raw_weight}:{fields.Datetime.now()}:{indicator_id}'
        sec_hash = hashlib.sha256(hash_payload.encode('utf-8')).hexdigest()

        self.write({
            'gross_weight': raw_weight,
            'scale_raw_stream': raw_string,
            'indicator_serial': indicator_id,
            'integrity_hash': sec_hash,
            'state': 'inward_weighed'
        })
        _logger.info('Locked gross weight %s KG for %s', raw_weight, self.vehicle_number)
        return True

    def action_validate_grn_and_clear(self):
        """Auto-create and validate Odoo stock.picking when tare is locked"""
        self.ensure_one()
        if self.net_weight <= 0:
            raise ValidationError(_('Cannot clear vehicle without valid net weight.'))
        
        # Check tolerance threshold (e.g. 1.0%)
        if abs(self.variance_percentage) > 1.0 and self.state != 'held':
            self.state = 'held'
            return self._notify_variance_exception()

        # Create or update stock.picking receipt
        picking = self.env['stock.picking'].create({
            'picking_type_id': self.env.ref('stock.picking_type_in').id,
            'partner_id': self.partner_id.id,
            'origin': f'Gate Pass {self.name}',
            'move_ids_without_package': [(0, 0, {
                'name': f'Raw Material from {self.vehicle_number}',
                'product_id': self.purchase_order_id.order_line[0].product_id.id if self.purchase_order_id else self.env.ref('stock.product_product_raw').id,
                'product_uom_qty': self.net_weight,
                'product_uom': self.env.ref('uom.product_uom_kgm').id,
                'location_id': self.env.ref('stock.stock_location_suppliers').id,
                'location_dest_id': self.env.ref('stock.stock_location_stock').id,
            })]
        })
        picking.action_confirm()
        picking.action_assign()
        self.picking_id = picking.id
        self.state = 'cleared'
        return True