# Copyright 2020 Tecnativa - Ernesto Tejeda
# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).

from datetime import date, datetime

from lxml import etree

from flectra import _, api, models
from flectra.exceptions import UserError
from flectra.tools.safe_eval import safe_eval


class ChainedSwapperWizard(models.TransientModel):
    _name = "chained.swapper.wizard"
    _description = "Wizard chained swapper"

    @api.model
    def default_get(self, fields):
        context = self.env.context
        if context.get("chained_swapper_id"):
            records = self.env[context.get("active_model")].browse(
                context.get("active_ids")
            )
            exp_dict = {
                "records": records,
                "env": self.env,
                "date": date,
                "datetime": datetime,
            }
            chained_swapper = self.env["chained.swapper"].browse(
                context.get("chained_swapper_id")
            )
            for constraint in chained_swapper.constraint_ids:
                if safe_eval(constraint.expression, exp_dict):
                    raise UserError(
                        _("Not possible to swap the field due to the constraint")
                        + ": "
                        + constraint.name
                    )
        return super().default_get(fields)

    @api.model
    def fields_view_get(
        self, view_id=None, view_type="form", toolbar=False, submenu=False
    ):
        """As we don't have any field in this model, result['fields']
        and result['arch'] are modified to add dynamically the
        corresponding field.
        """
        res = super().fields_view_get(
            view_id=view_id,
            view_type=view_type,
            toolbar=toolbar,
            submenu=submenu,
        )
        if not self.env.context.get("chained_swapper_id"):
            return res
        chained_swapper = self.env["chained.swapper"].browse(
            self.env.context.get("chained_swapper_id")
        )
        model_obj = self.env[self.env.context.get("active_model")]
        field_info = model_obj.fields_get()
        field = chained_swapper.field_id
        # Fields dict
        all_fields = {
            field.name: {
                "type": field.ttype,
                "string": field.field_description,
                "views": {},
            }
        }
        if field.ttype in ["many2many", "many2one"]:
            all_fields[field.name]["relation"] = field.relation
        elif field.ttype == "selection":
            field_selection = field_info[field.name]["selection"]
            all_fields[field.name]["selection"] = field_selection
        # XML view definition
        doc = etree.XML(res["arch"])
        group_node = doc.xpath("//group[@name='swap_field_group']")[0]
        etree.SubElement(group_node, "field", {"name": field.name, "colspan": "4"})
        if field.ttype in ["one2many", "many2many", "text"]:
            group_node.set("string", field.field_description)
            group_node.set("nolabel", "1")
        res.update(arch=etree.tostring(doc, encoding="unicode"), fields=all_fields)
        return res

    @api.model
    def create(self, vals):
        """As we don't have any field in this model, the key-value pair
        received in vals dict are only used to change the value in the active
        models.
        """
        model_obj = self.env[self.env.context.get("active_model")]
        context = self.env.context
        field_name, new_value = list(vals.items())[0]
        # write the active model
        model = model_obj.browse(self.env.context.get("active_ids"))
        original_values = {m.id: m[field_name] for m in model}
        model.write(vals)
        if hasattr(model, "message_post"):
            self.post_chained_swap(model, field_name, original_values, new_value)
        # write chained models
        chained_swapper_obj = self.env["chained.swapper"]
        chained_swapper = chained_swapper_obj.browse(context.get("chained_swapper_id"))
        for sub_field in chained_swapper.sub_field_ids:
            chain_fields = sub_field.sub_field_chain.split(".")
            field_name = chain_fields.pop()
            chain_model = model
            for chain_field in chain_fields:
                chain_model = chain_model.mapped(chain_field)
            original_values = {cm.id: cm[field_name] for cm in chain_model}
            chain_model.write({field_name: new_value})
            # post swap
            if hasattr(chain_model, "message_post"):
                self.post_chained_swap(
                    chain_model, field_name, original_values, new_value
                )
        return super().create({})

    def change_action(self):
        return {"type": "ir.actions.act_window_close"}

    @api.model
    def post_chained_swap(self, model, field_name, original_values, new_value):
        def human_readable_field(value):
            result = value
            field_def = model._fields[field_name]
            if field_def.type == "selection":
                if type(field_def.selection) == list:
                    selection = field_def.selection
                else:
                    selection = field_def.selection(self)
                for selection_item in selection:
                    if selection_item[0] == value:
                        result = selection_item[1]
                        break
            elif field_def.type == "many2one":
                if type(value) == int:
                    result = self.env[field_def.comodel_name].browse(value)
                result = result.display_name
            elif field_def.type == "many2many":
                if type(value) == list:
                    ids = value[0][2]
                    value = self.env[field_def.comodel_name].browse(ids)
                result = str(value.mapped("display_name"))
            return result

        field_desc = model._fields[field_name].string
        new_value = human_readable_field(new_value)
        for m in model:
            original_value = human_readable_field(original_values[m.id])
            m.message_post(
                body=_("<b>Chained swap done</b>:")
                + "<br/>{}: {} ⇒ {}".format(field_desc, original_value, new_value)
            )

    def read(self, fields, load="_classic_read"):
        """Without this call, dynamic fields build by fields_view_get()
        generate a crash and warning, i.e.: read() with unknown field 'myfield'
        """
        real_fields = set(fields) & set(self._fields)
        result = super().read(list(real_fields), load=load)
        result[0].update({x: False for x in set(fields) - real_fields})
        return result