from odoo import models, fields, api, _
from odoo.exceptions import UserError
from odoo.tools import float_compare, float_is_zero

class StockInventoryRevaluation(models.Model):
    _name = 'stock.inventory.revaluation'
    _description = 'Stock Inventory Revaluation'
    _inherit = ['mail.thread', 'mail.activity.mixin']

    name = fields.Char(string='Reference', required=True, copy=False, readonly=True, default=lambda self: _('New'))
    date = fields.Datetime(string='Date', required=True, default=fields.Datetime.now)
    product_id = fields.Many2one('product.product', string='Product', required=True, domain=[('type', '=', 'product')])
    account_journal_id = fields.Many2one('account.journal', string='Journal', required=True)
    account_id = fields.Many2one('account.account', string='Account', help="Counterpart account for the revaluation")
    
    current_value = fields.Float(string='Current Value', compute='_compute_current_value', store=True)
    quantity = fields.Float(string='Quantity', compute='_compute_current_value', store=True)
    
    extra_cost = fields.Float(string='Extra Cost', help="Amount to add to the stock value")
    
    state = fields.Selection([
        ('draft', 'Draft'),
        ('done', 'Done'),
        ('cancel', 'Cancelled')
    ], string='Status', default='draft', tracking=True)
    
    company_id = fields.Many2one('res.company', string='Company', required=True, default=lambda self: self.env.company)

    @api.depends('product_id', 'date')
    def _compute_current_value(self):
        for record in self:
            if record.product_id and record.date:
                # Calculate quantity and value at the specific date
                layers = self.env['stock.valuation.layer'].search([
                    ('product_id', '=', record.product_id.id),
                    ('create_date', '<=', record.date),
                    ('company_id', '=', record.company_id.id)
                ])
                record.quantity = sum(layers.mapped('quantity'))
                record.current_value = sum(layers.mapped('value'))
            elif record.product_id:
                record.quantity = record.product_id.quantity_svl
                record.current_value = record.product_id.value_svl
            else:
                record.quantity = 0.0
                record.current_value = 0.0

    @api.model_create_multi
    def create(self, vals_list):
        for vals in vals_list:
            if vals.get('name', _('New')) == _('New'):
                vals['name'] = self.env['ir.sequence'].next_by_code('stock.inventory.revaluation') or _('New')
        return super().create(vals_list)

    def action_validate(self):
        self.ensure_one()
        if float_is_zero(self.extra_cost, precision_rounding=self.currency_id.rounding):
            raise UserError(_("The Extra Cost cannot be zero."))
            
        # Create Accounting Entry
        move_vals = self._prepare_account_move_vals()
        move = self.env['account.move'].create(move_vals)
        move.action_post()
        
        # Create Stock Valuation Layer
        self._create_valuation_layer(move)
        
        self.state = 'done'

    def _prepare_account_move_vals(self):
        self.ensure_one()
        debit_account_id = self.product_id.categ_id.property_stock_valuation_account_id.id
        
        # Auto-detect counterpart account if not set
        credit_account_id = self.account_id.id
        if not credit_account_id:
            if self.extra_cost > 0:
                credit_account_id = self.product_id.categ_id.property_stock_account_input_categ_id.id
            else:
                credit_account_id = self.product_id.categ_id.property_stock_account_output_categ_id.id
                
        if not debit_account_id:
             raise UserError(_("Please define the Stock Valuation Account for product category: %s") % self.product_id.categ_id.name)
        if not credit_account_id:
             raise UserError(_("Please define the Stock Input/Output Account for product category: %s, or select an Account manually.") % self.product_id.categ_id.name)

        amount = self.extra_cost
        name = _('%s - Revaluation') % self.name
        
        # If amount is negative, swap accounts/logic or just let debits be negative?
        # Usually easier to swap or just have positive/negative balance.
        # Standard: Debit Stock, Credit Counterpart for increase.
        
        lines = [
            (0, 0, {
                'name': name,
                'account_id': debit_account_id,
                'debit': amount if amount > 0 else 0,
                'credit': -amount if amount < 0 else 0,
                'product_id': self.product_id.id,
            }),
            (0, 0, {
                'name': name,
                'account_id': credit_account_id,
                'debit': -amount if amount < 0 else 0,
                'credit': amount if amount > 0 else 0,
            }),
        ]
        
        return {
            'ref': self.name,
            'date': self.date.date(), # BACKDATE HERE
            'journal_id': self.account_journal_id.id,
            'line_ids': lines,
            'move_type': 'entry',
        }

    def _create_valuation_layer(self, move):
        self.ensure_one()
        layer_vals = {
            'product_id': self.product_id.id,
            'value': self.extra_cost,
            'unit_cost': 0, # Not adjusting unit cost directly, just total value
            'quantity': 0,
            'remaining_qty': 0,
            'description': _('Revaluation: %s') % self.name,
            'account_move_id': move.id,
            'company_id': self.company_id.id,
            # We try to force the date if the model allows it, but stock.valuation.layer usually takes create_date.
            # However, for reporting, Odoo joins with account_move.
        }
        # Note: stock.valuation.layer 'create_date' is automatic. 
        # But we can try to override it or rely on the account move date for reports.
        # Standard Odoo valuation reports often rely on the move date.
        
        layer = self.env['stock.valuation.layer'].create(layer_vals)
        
        # Force backdate the validation layer's create_date to match the revaluation date
        # This is critical for "Inventory Valuation at Date" reports.
        self.env.cr.execute('UPDATE stock_valuation_layer SET create_date = %s WHERE id = %s', (self.date, layer.id))


    @property
    def currency_id(self):
        return self.company_id.currency_id