# Generated by Django 5.2.4 on 2026-08-05 05:23

from django.conf import settings
from django.db import migrations, models


def populate_task_participants(apps, schema_editor):
    Task = apps.get_model("tasks", "Task")
    TaskActivity = apps.get_model("tasks", "TaskActivity")
    TaskAttachment = apps.get_model("tasks", "TaskAttachment")
    TaskChecklistItem = apps.get_model("tasks", "TaskChecklistItem")
    TaskExternalLink = apps.get_model("tasks", "TaskExternalLink")
    TaskLinkedObject = apps.get_model("tasks", "TaskLinkedObject")
    through = Task.participants.through
    task_field = next(
        field
        for field in through._meta.fields
        if field.is_relation and field.related_model == Task
    )
    employee_field = next(
        field
        for field in through._meta.fields
        if field.is_relation and field.related_model != Task
    )

    pairs = set()
    for task_id, created_by_id, assignee_id in Task.objects.values_list(
        "id",
        "created_by_id",
        "assignee_id",
    ):
        pairs.add((task_id, created_by_id))
        if assignee_id:
            pairs.add((task_id, assignee_id))

    contributor_fields = [
        (TaskActivity, "actor_id"),
        (TaskAttachment, "uploaded_by_id"),
        (TaskChecklistItem, "created_by_id"),
        (TaskChecklistItem, "completed_by_id"),
        (TaskExternalLink, "created_by_id"),
        (TaskLinkedObject, "created_by_id"),
    ]
    for model, employee_id_field in contributor_fields:
        pairs.update(
            (task_id, employee_id)
            for task_id, employee_id in model.objects.exclude(
                **{f"{employee_id_field}__isnull": True}
            ).values_list("task_id", employee_id_field)
        )

    through.objects.bulk_create(
        [
            through(
                **{
                    task_field.attname: task_id,
                    employee_field.attname: employee_id,
                }
            )
            for task_id, employee_id in pairs
            if task_id and employee_id
        ],
        ignore_conflicts=True,
    )


class Migration(migrations.Migration):
    dependencies = [
        ("tasks", "0018_task_claim_activity"),
        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
    ]

    operations = [
        migrations.AddField(
            model_name="task",
            name="participants",
            field=models.ManyToManyField(
                blank=True,
                related_name="participating_tasks",
                to=settings.AUTH_USER_MODEL,
                verbose_name="Участники",
            ),
        ),
        migrations.RunPython(
            populate_task_participants,
            migrations.RunPython.noop,
        ),
    ]