"""Per-period depreciation board lines for an asset."""

from odoo import fields, models


class FusionAssetDepreciationLine(models.Model):
    _name = "fusion.asset.depreciation.line"
    _description = "Asset Depreciation Board Line"
    _order = "asset_id, scheduled_date"

    asset_id = fields.Many2one('fusion.asset', required=True, ondelete='cascade')
    company_id = fields.Many2one(related='asset_id.company_id', store=True)
    currency_id = fields.Many2one(related='asset_id.currency_id', store=True)

    period_index = fields.Integer(required=True)
    scheduled_date = fields.Date(required=True)
    amount = fields.Monetary(required=True)
    accumulated = fields.Monetary()
    book_value_at_end = fields.Monetary()

    is_posted = fields.Boolean(default=False, copy=False)
    posted_date = fields.Date(copy=False)
    move_id = fields.Many2one(
        'account.move', copy=False,
        help="Journal entry created when this line was posted.",
    )

    def action_post(self):
        """Mark this line as posted (without creating the journal entry yet —
        engine method post_depreciation_entry handles the actual entry creation)."""
        for line in self:
            if line.is_posted:
                continue
            line.write({
                'is_posted': True,
                'posted_date': fields.Date.today(),
            })

    _unique_period_per_asset = models.Constraint(
        'UNIQUE(asset_id, period_index)',
        'A depreciation line for that period already exists.',
    )