# -*- coding: utf-8 -*-

from datetime import date, timedelta
from dateutil.relativedelta import relativedelta
from odoo import models, fields, api
from odoo.exceptions import UserError


class HrTaxRemittance(models.Model):
    _name = 'hr.tax.remittance'
    _description = 'Payroll Tax Remittance'
    _order = 'period_start desc'
    _inherit = ['mail.thread', 'mail.activity.mixin']

    STATE_SELECTION = [
        ('draft', 'Draft'),
        ('pending', 'Pending'),
        ('due', 'Due Soon'),
        ('past_due', 'Past Due'),
        ('paid', 'Paid'),
    ]

    PERIOD_TYPE = [
        ('monthly', 'Monthly'),
        ('quarterly', 'Quarterly'),
    ]

    name = fields.Char(
        string='Reference',
        required=True,
        copy=False,
        default=lambda self: self.env['ir.sequence'].next_by_code('hr.tax.remittance') or 'New',
    )
    company_id = fields.Many2one(
        'res.company',
        string='Company',
        required=True,
        default=lambda self: self.env.company,
    )
    currency_id = fields.Many2one(
        related='company_id.currency_id',
        string='Currency',
    )
    state = fields.Selection(
        selection=STATE_SELECTION,
        string='Status',
        default='draft',
        tracking=True,
        compute='_compute_state',
        store=True,
    )

    # === Period Information ===
    period_type = fields.Selection(
        selection=PERIOD_TYPE,
        string='Period Type',
        default='monthly',
    )
    period_start = fields.Date(
        string='Period Start',
        required=True,
    )
    period_end = fields.Date(
        string='Period End',
        required=True,
    )
    due_date = fields.Date(
        string='Due Date',
        required=True,
        help='CRA remittance due date (15th of following month for regular remitters)',
    )

    # === CPP Amounts ===
    cpp_employee = fields.Monetary(
        string='CPP Employee',
        currency_field='currency_id',
        help='Total employee CPP contributions for period',
    )
    cpp_employer = fields.Monetary(
        string='CPP Employer',
        currency_field='currency_id',
        help='Total employer CPP contributions for period',
    )
    cpp2_employee = fields.Monetary(
        string='CPP2 Employee',
        currency_field='currency_id',
        help='Total employee CPP2 (second CPP) contributions for period',
    )
    cpp2_employer = fields.Monetary(
        string='CPP2 Employer',
        currency_field='currency_id',
        help='Total employer CPP2 contributions for period',
    )

    # === EI Amounts ===
    ei_employee = fields.Monetary(
        string='EI Employee',
        currency_field='currency_id',
        help='Total employee EI premiums for period',
    )
    ei_employer = fields.Monetary(
        string='EI Employer',
        currency_field='currency_id',
        help='Total employer EI premiums (1.4x employee) for period',
    )

    # === Tax Amounts ===
    income_tax = fields.Monetary(
        string='Income Tax',
        currency_field='currency_id',
        help='Total federal + provincial income tax withheld for period',
    )

    # === Totals ===
    total = fields.Monetary(
        string='Total Remittance',
        currency_field='currency_id',
        compute='_compute_total',
        store=True,
    )

    # === Payment Information ===
    payment_date = fields.Date(
        string='Payment Date',
        tracking=True,
    )
    payment_reference = fields.Char(
        string='Payment Reference',
        help='Bank reference or confirmation number',
    )
    payment_method = fields.Selection([
        ('cra_my_business', 'CRA My Business Account'),
        ('bank_payment', 'Bank Payment'),
        ('cheque', 'Cheque'),
    ], string='Payment Method')

    # === Linked Payslips ===
    payslip_ids = fields.Many2many(
        'hr.payslip',
        string='Related Payslips',
        help='Payslips included in this remittance period',
    )
    payslip_count = fields.Integer(
        string='Payslip Count',
        compute='_compute_payslip_count',
    )

    @api.depends('cpp_employee', 'cpp_employer', 'cpp2_employee', 'cpp2_employer',
                 'ei_employee', 'ei_employer', 'income_tax')
    def _compute_total(self):
        for rec in self:
            rec.total = (
                rec.cpp_employee + rec.cpp_employer +
                rec.cpp2_employee + rec.cpp2_employer +
                rec.ei_employee + rec.ei_employer +
                rec.income_tax
            )

    @api.depends('due_date', 'payment_date')
    def _compute_state(self):
        today = date.today()
        for rec in self:
            if rec.payment_date:
                rec.state = 'paid'
            elif not rec.due_date:
                rec.state = 'draft'
            elif rec.due_date < today:
                rec.state = 'past_due'
            elif rec.due_date <= today + timedelta(days=7):
                rec.state = 'due'
            else:
                rec.state = 'pending'

    def _compute_payslip_count(self):
        for rec in self:
            rec.payslip_count = len(rec.payslip_ids)

    def action_calculate_amounts(self):
        """Calculate remittance amounts from payslips in the period"""
        self.ensure_one()

        # Find all confirmed payslips in the period
        payslips = self.env['hr.payslip'].search([
            ('company_id', '=', self.company_id.id),
            ('state', 'in', ['validated', 'paid']),
            ('date_from', '>=', self.period_start),
            ('date_to', '<=', self.period_end),
        ])

        if not payslips:
            raise UserError('No confirmed payslips found for this period.')

        # Sum up amounts by rule code
        cpp_ee = cpp_er = cpp2_ee = cpp2_er = 0
        ei_ee = ei_er = 0
        income_tax = 0

        for payslip in payslips:
            for line in payslip.line_ids:
                code = line.code
                amount = abs(line.total)
                
                if code == 'CPP_EE':
                    cpp_ee += amount
                elif code == 'CPP_ER':
                    cpp_er += amount
                elif code == 'CPP2_EE':
                    cpp2_ee += amount
                elif code == 'CPP2_ER':
                    cpp2_er += amount
                elif code == 'EI_EE':
                    ei_ee += amount
                elif code == 'EI_ER':
                    ei_er += amount
                elif code in ('FED_TAX', 'PROV_TAX'):
                    income_tax += amount

        self.write({
            'cpp_employee': cpp_ee,
            'cpp_employer': cpp_er,
            'cpp2_employee': cpp2_ee,
            'cpp2_employer': cpp2_er,
            'ei_employee': ei_ee,
            'ei_employer': ei_er,
            'income_tax': income_tax,
            'payslip_ids': [(6, 0, payslips.ids)],
        })

        return {
            'type': 'ir.actions.client',
            'tag': 'display_notification',
            'params': {
                'title': 'Amounts Calculated',
                'message': f'Calculated from {len(payslips)} payslips. Total: ${self.total:,.2f}',
                'type': 'success',
            }
        }

    def action_mark_paid(self):
        """Mark remittance as paid"""
        self.ensure_one()
        if not self.payment_date:
            self.payment_date = date.today()
        self.state = 'paid'

    def action_view_payslips(self):
        """View related payslips"""
        self.ensure_one()
        return {
            'type': 'ir.actions.act_window',
            'name': 'Payslips',
            'res_model': 'hr.payslip',
            'view_mode': 'list,form',
            'domain': [('id', 'in', self.payslip_ids.ids)],
        }

    @api.model
    def _get_payment_frequency_from_settings(self, company_id=None):
        """Get payment frequency from payroll settings."""
        if not company_id:
            company_id = self.env.company.id
        settings = self.env['payroll.config.settings'].get_settings(company_id)
        return settings.federal_tax_payment_frequency or 'monthly'

    def create_monthly_remittance(self, year, month, company_id=None):
        """Create a monthly remittance record"""
        if not company_id:
            company_id = self.env.company.id

        # Get settings for payment frequency and CRA info
        settings = self.env['payroll.config.settings'].get_settings(company_id)
        payment_freq = settings.federal_tax_payment_frequency or 'monthly'

        # Calculate period dates
        period_start = date(year, month, 1)
        if month == 12:
            period_end = date(year + 1, 1, 1) - timedelta(days=1)
            due_date = date(year + 1, 1, 15)
        else:
            period_end = date(year, month + 1, 1) - timedelta(days=1)
            due_date = date(year, month + 1, 15)

        # Create the remittance
        remittance = self.create({
            'company_id': company_id,
            'period_type': payment_freq if payment_freq in ['monthly', 'quarterly'] else 'monthly',
            'period_start': period_start,
            'period_end': period_end,
            'due_date': due_date,
        })

        # Calculate amounts
        remittance.action_calculate_amounts()
        
        return remittance


class HrTaxRemittanceSequence(models.Model):
    """Create sequence for tax remittance"""
    _name = 'hr.tax.remittance.sequence'
    _description = 'Tax Remittance Sequence Setup'
    _auto = False

    def init(self):
        # This will be handled by ir.sequence data instead
        pass