"""Fusion Asset model.

Lifecycle: draft -> running -> (paused -> running)* -> disposed.
- draft: created, not yet running depreciation
- running: depreciation board active, periodic posts happen
- paused: depreciation suspended (e.g. asset out for repair)
- disposed: sold/scrapped/donated; no further depreciation
"""

import logging

from odoo import _, api, fields, models
from odoo.exceptions import ValidationError

_logger = logging.getLogger(__name__)


METHOD_SELECTION = [
    ('straight_line', 'Straight Line'),
    ('declining_balance', 'Declining Balance'),
    ('units_of_production', 'Units of Production'),
]

PRORATE_SELECTION = [
    ('full_month', 'Full Month'),
    ('days_365', 'Days / 365'),
    ('days_period', 'Days in Period'),
]

STATE_SELECTION = [
    ('draft', 'Draft'),
    ('running', 'Running'),
    ('paused', 'Paused'),
    ('disposed', 'Disposed'),
]


class FusionAsset(models.Model):
    _name = "fusion.asset"
    _description = "Fusion Fixed Asset"
    _order = "acquisition_date desc, id desc"
    _inherit = ['mail.thread', 'mail.activity.mixin']

    name = fields.Char(required=True, tracking=True)
    code = fields.Char(help="Internal asset code (e.g. tag number).")
    company_id = fields.Many2one(
        'res.company', required=True,
        default=lambda self: self.env.company,
    )
    category_id = fields.Many2one('fusion.asset.category', tracking=True)
    state = fields.Selection(
        STATE_SELECTION, default='draft', required=True, tracking=True,
    )

    cost = fields.Monetary(
        required=True, tracking=True,
        help="Original acquisition cost.",
    )
    salvage_value = fields.Monetary(
        default=0.0, tracking=True,
        help="Estimated end-of-life value.",
    )
    acquisition_date = fields.Date(
        required=True, default=fields.Date.today, tracking=True,
    )
    in_service_date = fields.Date(
        tracking=True,
        help="Date depreciation actually begins.",
    )
    disposed_date = fields.Date(readonly=True, tracking=True)
    currency_id = fields.Many2one(
        'res.currency', required=True,
        default=lambda self: self.env.company.currency_id,
    )

    method = fields.Selection(
        METHOD_SELECTION, required=True, default='straight_line', tracking=True,
    )
    useful_life_years = fields.Integer(
        default=5, tracking=True,
        help="For straight_line / declining_balance.",
    )
    declining_rate_pct = fields.Float(
        default=20.0,
        help="For declining_balance method, e.g. 20.0 = 20%/year.",
    )
    total_units_expected = fields.Float(
        help="For units_of_production method.",
    )
    units_used_to_date = fields.Float(
        default=0.0,
        help="For units_of_production: track usage.",
    )
    prorate_convention = fields.Selection(
        PRORATE_SELECTION, default='days_period', required=True,
    )

    source_invoice_line_id = fields.Many2one(
        'account.move.line', string='Source Invoice Line',
        help="The invoice line that originated this asset.",
    )
    parent_id = fields.Many2one(
        'fusion.asset', help='For partial-sale child assets.',
    )

    depreciation_line_ids = fields.One2many(
        'fusion.asset.depreciation.line', 'asset_id',
        string='Depreciation Lines',
    )
    book_value = fields.Monetary(compute='_compute_book_value', store=True)
    total_depreciated = fields.Monetary(compute='_compute_book_value', store=True)
    last_posted_date = fields.Date(compute='_compute_last_posted_date', store=True)

    @api.depends('cost', 'depreciation_line_ids.amount', 'depreciation_line_ids.is_posted')
    def _compute_book_value(self):
        for asset in self:
            posted = sum(l.amount for l in asset.depreciation_line_ids if l.is_posted)
            asset.total_depreciated = posted
            asset.book_value = asset.cost - posted

    @api.depends('depreciation_line_ids.is_posted', 'depreciation_line_ids.scheduled_date')
    def _compute_last_posted_date(self):
        for asset in self:
            posted_dates = [
                l.scheduled_date for l in asset.depreciation_line_ids if l.is_posted
            ]
            asset.last_posted_date = max(posted_dates) if posted_dates else False

    def action_set_running(self):
        for asset in self:
            if asset.state != 'draft':
                raise ValidationError(_("Only draft assets can be set running."))
            if not asset.in_service_date:
                asset.in_service_date = fields.Date.today()
            asset.state = 'running'

    def action_pause(self):
        for asset in self:
            if asset.state != 'running':
                raise ValidationError(_("Only running assets can be paused."))
            asset.state = 'paused'

    def action_resume(self):
        for asset in self:
            if asset.state != 'paused':
                raise ValidationError(_("Only paused assets can be resumed."))
            asset.state = 'running'

    def action_set_draft(self):
        for asset in self:
            if asset.state not in ('draft', 'paused'):
                raise ValidationError(
                    _("Cannot reset to draft from %s.") % asset.state,
                )
            asset.state = 'draft'

    _check_cost_positive = models.Constraint(
        'CHECK(cost >= 0)',
        'Asset cost must be non-negative.',
    )
    _check_salvage_lte_cost = models.Constraint(
        'CHECK(salvage_value >= 0 AND salvage_value <= cost)',
        'Salvage value must be between 0 and cost.',
    )