[REF] mail: improve and refactor mail template preview

PURPOSE

Improve mail template preview wizard by improve its views and displaying
more rendered fields. It helps users knowing what will be sent to customers.

SPECIFICATIONS

Rename template model to mail_template_preview to better match the mail
template namespace.

Remove _inherit on mail.template and instead choose fields to compute
and display. Indeed lot of fields are unnecessary or badly computed.
Instead just add fields on the wizard that depends on mail template
and will be computed based on mail_template_id field of wizard.

Improve error management.

LINKS

Task 2085912
PR #38708

Signed-off-by: Thibault Delavallee (tde) <tde@openerp.com>

1 files changed, 86 insertions, 0 deletions

diff --git a/addons/mail/wizard/mail_template_preview.py b/addons/mail/wizard/mail_template_preview.py
new file mode 100644
index 00000000000..7cedde9b5e5
--- /dev/null
+++ b/addons/mail/wizard/mail_template_preview.py
@@ -0,0 +1,86 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import api, fields, models
+from odoo.exceptions import UserError
+
+
+class MailTemplatePreview(models.TransientModel):
+    _name = 'mail.template.preview'
+    _description = 'Email Template Preview'
+    _MAIL_TEMPLATE_FIELDS = ['subject', 'body_html', 'email_from', 'email_to',
+                             'email_cc', 'reply_to', 'scheduled_date', 'attachment_ids']
+
+    @api.model
+    def _selection_target_model(self):
+        return [(model.model, model.name) for model in self.env['ir.model'].search([])]
+
+    @api.model
+    def _selection_languages(self):
+        return self.env['res.lang'].get_installed()
+
+    @api.model
+    def default_get(self, fields):
+        result = super(MailTemplatePreview, self).default_get(fields)
+        if not result.get('mail_template_id') or 'resource_ref' not in fields:
+            return result
+        mail_template = self.env['mail.template'].browse(result['mail_template_id'])
+        res = self.env[mail_template.model_id.model].search([], limit=1)
+        if res:
+            result['resource_ref'] = '%s,%s' % (mail_template.model_id.model, res.id)
+        return result
+
+    mail_template_id = fields.Many2one('mail.template', string='Related Mail Template', required=True)
+    model_id = fields.Many2one('ir.model', string='Targeted model', related="mail_template_id.model_id")
+    resource_ref = fields.Reference(string='Record', selection='_selection_target_model')
+    lang = fields.Selection(_selection_languages, string='Template Preview Language')
+    no_record = fields.Boolean('No Record', compute='_compute_no_record')
+    error_msg = fields.Char('Error Message', readonly=True)
+    # Fields same than the mail.template model, computed with resource_ref and lang
+    subject = fields.Char('Subject', compute='_compute_mail_template_fields')
+    email_from = fields.Char('From', compute='_compute_mail_template_fields', help="Sender address")
+    email_to = fields.Char('To', compute='_compute_mail_template_fields',
+                           help="Comma-separated recipient addresses")
+    email_cc = fields.Char('Cc', compute='_compute_mail_template_fields', help="Carbon copy recipients")
+    reply_to = fields.Char('Reply-To', compute='_compute_mail_template_fields', help="Preferred response address")
+    scheduled_date = fields.Char('Scheduled Date', compute='_compute_mail_template_fields',
+                                 help="The queue manager will send the email after the date")
+    body_html = fields.Html('Body', compute='_compute_mail_template_fields', sanitize=False)
+    attachment_ids = fields.Many2many('ir.attachment', 'Attachments', compute='_compute_mail_template_fields')
+    # Extra fields info generated by generate_email
+    partner_ids = fields.Many2many('res.partner', string='Recipients', compute='_compute_mail_template_fields')
+
+    @api.depends('model_id')
+    def _compute_no_record(self):
+        for preview in self:
+            preview.no_record = (self.env[preview.model_id.model].search_count([]) == 0) if preview.model_id else True
+
+    @api.depends('lang', 'resource_ref')
+    def _compute_mail_template_fields(self):
+        """ Preview the mail template (body, subject, ...) depending of the language and
+        the record reference, more precisely the record id for the defined model of the mail template.
+        If no record id is selectable/set, the jinja placeholders won't be replace in the display information. """
+        copy_depends_values = {'lang': self.lang}
+        mail_template = self.mail_template_id.with_context(lang=self.lang)
+        try:
+            if not self.resource_ref:
+                self._set_mail_attributes()
+            else:
+                copy_depends_values['resource_ref'] = '%s,%s' % (self.resource_ref._name, self.resource_ref.id)
+                mail_values = mail_template.with_context(template_preview_lang=self.lang).generate_email(
+                    self.resource_ref.id, self._MAIL_TEMPLATE_FIELDS)
+                self._set_mail_attributes(values=mail_values)
+            self.error_msg = False
+        except UserError as user_error:
+            self._set_mail_attributes()
+            self.error_msg = user_error.name
+        finally:
+            # Avoid to be change by a invalidate_cache call (in generate_mail), e.g. Quotation / Order report
+            for key, value in copy_depends_values.items():
+                self[key] = value
+
+    def _set_mail_attributes(self, values=None):
+        for field in self._MAIL_TEMPLATE_FIELDS:
+            field_value = values.get(field, False) if values else self.mail_template_id[field]
+            self[field] = field_value
+        self.partner_ids = values.get('partner_ids', False) if values else False