# Part of Odoo. See LICENSE file for full copyright and licensing details.

from odoo import api, models, _
from odoo.tools import SQL


class KpiProvider(models.AbstractModel):
    _inherit = 'kpi.provider'

    @api.model
    def get_documents_kpi_summary(self):
        return get_kpi_summary(self.env.cr, self.env.uid)

    @api.model
    def get_kpi_summary(self):
        result = super().get_kpi_summary()
        result.extend(self.get_documents_kpi_summary())
        return result


def get_kpi_summary(cr, uid):
    """
    Retrieve the number of active documents currently present in the Inbox folder.

    Only active non-folder documents located in the configured Inbox hierarchy
    are counted.

    This function intentionally bypasses the ORM so KPI summaries can be retrieved
    without loading a registry, allowing multi-database servers to serve them faster.
    """
    expected_columns = {
        'documents_document.id',
        'documents_document.folder_id',
        'documents_document.type',
        'documents_document.active',
    }

    cr.execute(SQL("""
        SELECT table_name || '.' || column_name
          FROM information_schema.columns
         WHERE table_name || '.' || column_name IN %(columns)s
    """, columns=tuple(expected_columns)))
    existing_columns = {x[0] for x in cr.fetchall()}
    if expected_columns - existing_columns:
        # Needed columns are not present -> module is not installed
        return []

    cr.execute(SQL("""
        SELECT document.parent_path
          FROM documents_document document
          JOIN ir_model_data imd ON imd.model = 'documents.document'
                                AND imd.res_id = document.id
         WHERE imd.module = 'documents'
           AND imd.name = 'document_inbox_folder'
           AND document.active
    """))
    row = cr.fetchone()
    if not row:
        return []
    inbox_path, = row

    cr.execute(SQL("""
        SELECT COUNT(*)
          FROM documents_document document
         WHERE document.type != 'folder'
           AND document.parent_path LIKE (%(inbox_path)s || '%%')
           AND document.active
    """,
        inbox_path=inbox_path))
    count, = cr.fetchone()

    cr.execute(SQL("""
        SELECT partner.lang
          FROM res_users u
          JOIN res_partner partner ON u.partner_id = partner.id
         WHERE u.id = %(uid)s
         LIMIT 1
    """, uid=uid))
    row = cr.fetchone()
    context = {  # noqa: F841 "unused" `context` is actually used by `_` frame inspection
        'lang': row[0] if row else 'en_US',
    }

    return [{
        'id': 'documents.inbox',
        'name': _('Inbox'),
        'type': 'integer',
        'value': count,
    }]