# Fusion Accounting - Trial Balance Report Handler

from odoo import api, models, _, fields
from odoo.tools import float_compare
from odoo.tools.misc import DEFAULT_SERVER_DATE_FORMAT


# Sentinel key used for end-balance columns which are computed client-side
# and never generate their own SQL column group.
_END_COL_GROUP_SENTINEL = '_trial_balance_end_column_group'


class TrialBalanceCustomHandler(models.AbstractModel):
    """Wraps the General Ledger handler to produce a Trial Balance.

    The trial balance adds initial-balance and end-balance column groups
    around the regular period columns and collapses each account's detail
    into a single non-foldable row.
    """

    _name = 'account.trial.balance.report.handler'
    _inherit = 'account.report.custom.handler'
    _description = 'Trial Balance Custom Handler'

    # ------------------------------------------------------------------
    # Dynamic lines
    # ------------------------------------------------------------------

    def _dynamic_lines_generator(self, report, options, all_column_groups_expression_totals, warnings=None):
        """Delegate to the GL handler and then post-process rows to
        collapse debit/credit, compute end-balance columns, and remove
        expand functions."""

        def _set_cell(row, idx, amount):
            row['columns'][idx]['no_format'] = amount
            row['columns'][idx]['is_zero'] = self.env.company.currency_id.is_zero(amount)

        def _collapse_debit_credit(row, dr_idx, cr_idx, bal_idx=None):
            """Net debit and credit: whichever is larger keeps the difference;
            the other becomes zero.  Optionally write balance too."""
            dr_val = row['columns'][dr_idx]['no_format'] if dr_idx is not None else False
            cr_val = row['columns'][cr_idx]['no_format'] if cr_idx is not None else False

            if dr_val and cr_val:
                cmp = self.env.company.currency_id.compare_amounts(dr_val, cr_val)
                if cmp == 1:
                    _set_cell(row, dr_idx, dr_val - cr_val)
                    _set_cell(row, cr_idx, 0.0)
                else:
                    _set_cell(row, dr_idx, 0.0)
                    _set_cell(row, cr_idx, (dr_val - cr_val) * -1)

            if bal_idx is not None:
                _set_cell(row, bal_idx, dr_val - cr_val)

        # Obtain raw GL lines
        gl_handler = self.env['account.general.ledger.report.handler']
        raw = [
            row[1]
            for row in gl_handler._dynamic_lines_generator(
                report, options, all_column_groups_expression_totals, warnings=warnings,
            )
        ]

        # Locate column indices for initial / end balance
        col_defs = options['columns']
        init_dr = next((i for i, c in enumerate(col_defs) if c.get('expression_label') == 'debit'), None)
        init_cr = next((i for i, c in enumerate(col_defs) if c.get('expression_label') == 'credit'), None)

        end_dr = next((i for i, c in enumerate(col_defs)
                        if c.get('expression_label') == 'debit'
                        and c.get('column_group_key') == _END_COL_GROUP_SENTINEL), None)
        end_cr = next((i for i, c in enumerate(col_defs)
                        if c.get('expression_label') == 'credit'
                        and c.get('column_group_key') == _END_COL_GROUP_SENTINEL), None)
        end_bal = next((i for i, c in enumerate(col_defs)
                         if c.get('expression_label') == 'balance'
                         and c.get('column_group_key') == _END_COL_GROUP_SENTINEL), None)

        cur = self.env.company.currency_id

        # Process every account row (all except the last = total line)
        for row in raw[:-1]:
            _collapse_debit_credit(row, init_dr, init_cr)

            # End balance = sum of all debit columns except the end one itself
            if end_dr is not None:
                dr_sum = sum(
                    cur.round(cell['no_format'])
                    for idx, cell in enumerate(row['columns'])
                    if cell.get('expression_label') == 'debit'
                    and idx != end_dr
                    and cell['no_format'] is not None
                )
                _set_cell(row, end_dr, dr_sum)

            if end_cr is not None:
                cr_sum = sum(
                    cur.round(cell['no_format'])
                    for idx, cell in enumerate(row['columns'])
                    if cell.get('expression_label') == 'credit'
                    and idx != end_cr
                    and cell['no_format'] is not None
                )
                _set_cell(row, end_cr, cr_sum)

            _collapse_debit_credit(row, end_dr, end_cr, end_bal)

            # Remove GL expand-related keys
            row.pop('expand_function', None)
            row.pop('groupby', None)
            row['unfoldable'] = False
            row['unfolded'] = False

            mdl = report._get_model_info_from_id(row['id'])[0]
            if mdl == 'account.account':
                row['caret_options'] = 'trial_balance'

        # Recompute totals on the total line
        if raw:
            total_row = raw[-1]
            for idx in (init_dr, init_cr, end_dr, end_cr):
                if idx is not None:
                    total_row['columns'][idx]['no_format'] = sum(
                        cur.round(r['columns'][idx]['no_format'])
                        for r in raw[:-1]
                        if report._get_model_info_from_id(r['id'])[0] == 'account.account'
                    )

        return [(0, row) for row in raw]

    # ------------------------------------------------------------------
    # Caret options
    # ------------------------------------------------------------------

    def _caret_options_initializer(self):
        return {
            'trial_balance': [
                {'name': _("General Ledger"), 'action': 'caret_option_open_general_ledger'},
                {'name': _("Journal Items"), 'action': 'open_journal_items'},
            ],
        }

    # ------------------------------------------------------------------
    # Column group management
    # ------------------------------------------------------------------

    def _get_column_group_creation_data(self, report, options, previous_options=None):
        """Declare which extra column groups to add and on which side of
        the report they appear."""
        return (
            (self._build_initial_balance_col_group, 'left'),
            (self._build_end_balance_col_group, 'right'),
        )

    @api.model
    def _create_and_append_column_group(
        self, report, options, header_label, forced_opts, side,
        group_vals, exclude_initial_balance=False, append_col_groups=True,
    ):
        """Helper: generate a new column group and append it to *side*."""
        header_elem = [{'name': header_label, 'forced_options': forced_opts}]
        full_headers = [header_elem, *options['column_headers'][1:]]
        cg_vals = report._generate_columns_group_vals_recursively(full_headers, group_vals)

        if exclude_initial_balance:
            for cg in cg_vals:
                cg['forced_options']['general_ledger_strict_range'] = True

        cols, col_groups = report._build_columns_from_column_group_vals(forced_opts, cg_vals)

        side['column_headers'] += header_elem
        if append_col_groups:
            side['column_groups'] |= col_groups
        side['columns'] += cols

    # ------------------------------------------------------------------
    # Options
    # ------------------------------------------------------------------

    def _custom_options_initializer(self, report, options, previous_options):
        """Insert initial-balance and end-balance column groups around the
        standard period columns."""
        default_gv = {'horizontal_groupby_element': {}, 'forced_options': {}}
        lhs = {'column_headers': [], 'column_groups': {}, 'columns': []}
        rhs = {'column_headers': [], 'column_groups': {}, 'columns': []}

        # Mid-period columns should use strict range
        for cg in options['column_groups'].values():
            cg['forced_options']['general_ledger_strict_range'] = True

        if options.get('comparison') and not options['comparison'].get('periods'):
            options['comparison']['period_order'] = 'ascending'

        for factory_fn, side_label in self._get_column_group_creation_data(report, options, previous_options):
            target = lhs if side_label == 'left' else rhs
            factory_fn(report, options, previous_options, default_gv, target)

        options['column_headers'][0] = lhs['column_headers'] + options['column_headers'][0] + rhs['column_headers']
        options['column_groups'].update(lhs['column_groups'])
        options['column_groups'].update(rhs['column_groups'])
        options['columns'] = lhs['columns'] + options['columns'] + rhs['columns']
        options['ignore_totals_below_sections'] = True

        # Force a shared currency-table period for all middle columns
        shared_period_key = '_trial_balance_middle_periods'
        for cg in options['column_groups'].values():
            dt = cg['forced_options'].get('date')
            if dt:
                dt['currency_table_period_key'] = shared_period_key

        report._init_options_order_column(options, previous_options)

    def _custom_line_postprocessor(self, report, options, lines):
        """Add contrast styling to hierarchy group lines when hierarchy is
        enabled."""
        if options.get('hierarchy'):
            for ln in lines:
                mdl, _ = report._get_model_info_from_id(ln['id'])
                if mdl == 'account.group':
                    ln['class'] = ln.get('class', '') + ' o_account_coa_column_contrast_hierarchy'
        return lines

    # ------------------------------------------------------------------
    # Column group builders
    # ------------------------------------------------------------------

    def _build_initial_balance_col_group(self, report, options, previous_options, default_gv, side):
        """Create the Initial Balance column group on the left."""
        gl_handler = self.env['account.general.ledger.report.handler']
        init_opts = gl_handler._get_options_initial_balance(options)
        forced = {
            'date': init_opts['date'],
            'include_current_year_in_unaff_earnings': init_opts['include_current_year_in_unaff_earnings'],
            'no_impact_on_currency_table': True,
        }
        self._create_and_append_column_group(
            report, options, _("Initial Balance"), forced, side, default_gv,
        )

    def _build_end_balance_col_group(self, report, options, previous_options, default_gv, side):
        """Create the End Balance column group on the right.

        No actual SQL is run for this group; its values are computed by
        summing all other groups during line post-processing.
        """
        to_dt = options['date']['date_to']
        from_dt = (
            options['comparison']['periods'][-1]['date_from']
            if options.get('comparison', {}).get('periods')
            else options['date']['date_from']
        )
        forced = {
            'date': report._get_dates_period(
                fields.Date.from_string(from_dt),
                fields.Date.from_string(to_dt),
                'range',
            ),
        }
        self._create_and_append_column_group(
            report, options, _("End Balance"), forced, side, default_gv,
            append_col_groups=False,
        )

        # Mark end-balance columns with the sentinel key
        num_report_cols = len(report.column_ids)
        for col in side['columns'][-num_report_cols:]:
            col['column_group_key'] = _END_COL_GROUP_SENTINEL