from collections import defaultdict

from odoo import api, fields, models


class EsgEmissionFactorLine(models.Model):
    _name = 'esg.emission.factor.line'
    _description = 'Emission Factor Line'
    _inherit = ['mail.thread']

    esg_emission_factor_id = fields.Many2one('esg.emission.factor', string='Emission Factor', index=True)
    activity_type_id = fields.Many2one('esg.activity.type', string='Activity Type', tracking=True)
    gas_id = fields.Many2one('esg.gas', required=True, tracking=True)
    quantity = fields.Float(string='kg', default=1.0, required=True, tracking=True, digits=(16, 8))  # Fixing the digits for a correct display in tracking values.
    esg_emissions_value = fields.Float(string='Emissions (kgCO₂e)', compute='_compute_esg_emissions_value', store=True, tracking=True)

    @api.depends('quantity', 'gas_id.global_warming_potential')
    def _compute_esg_emissions_value(self):
        for emission in self:
            emission.esg_emissions_value = emission.quantity * emission.gas_id.global_warming_potential

    @api.depends('gas_id')
    def _compute_display_name(self):
        for gas_line in self:
            gas_line.display_name = self.env._(
                '%(gas_name)s (%(quantity)s kg)',
                gas_name=gas_line.gas_id.name,
                quantity=gas_line.quantity,
            )

    def write(self, vals):
        """Track field changes and log them to the linked emission factor."""
        # Get all tracked fields to be updated.
        tracked_field_names = {fname for fname in self._track_get_fields() if fname in vals}
        tracked_fields = self.fields_get(tracked_field_names)

        # Get initial values for each gas line.
        gas_line_initial_values = defaultdict(dict)
        for gas_line in self:
            for fname in tracked_field_names:
                gas_line_initial_values[gas_line][fname] = gas_line[fname]
            gas_line_initial_values[gas_line].update({
                'gas_name': gas_line.gas_id.name,
                'activity_type_name': gas_line.activity_type_id.name,
            })

        # Write the new values to trigger the tracking values to be created.
        res = super().write(vals)

        # Log changes to gas lines on the emission factor.
        for gas_line, initial_values in gas_line_initial_values.items():
            tracking_value_ids = gas_line._mail_track(tracked_fields, initial_values)[1]
            if tracking_value_ids:
                gas_line.esg_emission_factor_id._message_log(
                    body=self.env._(
                        "Updated values for %(gas_name)s (%(activity_type_name)s)",
                        gas_name=initial_values['gas_name'],
                        activity_type_name=initial_values['activity_type_name'],
                    ),
                    tracking_value_ids=tracking_value_ids,
                )

        return res