# Generated by Django 5.2.9 on 2025-12-13 07:00

from django.db import migrations


def fix_task_shares_table(apps, schema_editor):
    """
    Fix the task_shares table to reference the correct 'tags' table
    instead of the old 'task_groups' table.
    """
    db_alias = schema_editor.connection.alias

    # Check database type
    is_postgres = schema_editor.connection.vendor == 'postgresql'
    is_mysql = schema_editor.connection.vendor == 'mysql'

    # Drop and recreate the task_shares table with correct foreign keys
    schema_editor.execute(
        "DROP TABLE IF EXISTS task_shares CASCADE;" if is_postgres else "DROP TABLE IF EXISTS task_shares;"
    )

    if is_postgres:
        # PostgreSQL syntax
        schema_editor.execute(
            """
            CREATE TABLE task_shares (
                id UUID NOT NULL PRIMARY KEY,
                permission VARCHAR(20) NOT NULL,
                sync_id UUID NOT NULL UNIQUE,
                created_at TIMESTAMP NOT NULL,
                updated_at TIMESTAMP NOT NULL,
                owner_id UUID NOT NULL REFERENCES users(id) DEFERRABLE INITIALLY DEFERRED,
                shared_with_id UUID NOT NULL REFERENCES users(id) DEFERRABLE INITIALLY DEFERRED,
                task_id UUID NULL REFERENCES tasks(id) ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED,
                tag_id UUID NULL REFERENCES tags(id) ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED,
                CONSTRAINT share_task_or_tag_not_both CHECK (
                    (tag_id IS NULL AND task_id IS NOT NULL) OR
                    (tag_id IS NOT NULL AND task_id IS NULL)
                )
            );
            """
        )
    elif is_mysql:
        # MySQL/MariaDB syntax
        schema_editor.execute(
            """
            CREATE TABLE task_shares (
                id CHAR(32) NOT NULL PRIMARY KEY,
                permission VARCHAR(20) NOT NULL,
                sync_id CHAR(32) NOT NULL UNIQUE,
                created_at DATETIME NOT NULL,
                updated_at DATETIME NOT NULL,
                owner_id CHAR(32) NOT NULL,
                shared_with_id CHAR(32) NOT NULL,
                task_id CHAR(32) NULL,
                tag_id CHAR(32) NULL,
                CONSTRAINT share_task_or_tag_not_both CHECK (
                    (tag_id IS NULL AND task_id IS NOT NULL) OR
                    (tag_id IS NOT NULL AND task_id IS NULL)
                ),
                FOREIGN KEY (owner_id) REFERENCES users(id),
                FOREIGN KEY (shared_with_id) REFERENCES users(id),
                FOREIGN KEY (task_id) REFERENCES tasks(id) ON DELETE CASCADE,
                FOREIGN KEY (tag_id) REFERENCES tags(id) ON DELETE CASCADE
            );
            """
        )
    else:
        # SQLite syntax (default)
        schema_editor.execute(
            """
            CREATE TABLE task_shares (
                id CHAR(32) NOT NULL PRIMARY KEY,
                permission VARCHAR(20) NOT NULL,
                sync_id CHAR(32) NOT NULL UNIQUE,
                created_at DATETIME NOT NULL,
                updated_at DATETIME NOT NULL,
                owner_id CHAR(32) NOT NULL REFERENCES users(id) DEFERRABLE INITIALLY DEFERRED,
                shared_with_id CHAR(32) NOT NULL REFERENCES users(id) DEFERRABLE INITIALLY DEFERRED,
                task_id CHAR(32) NULL REFERENCES tasks(id) ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED,
                tag_id CHAR(32) NULL REFERENCES tags(id) ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED,
                CONSTRAINT share_task_or_tag_not_both CHECK (
                    (tag_id IS NULL AND task_id IS NOT NULL) OR
                    (tag_id IS NOT NULL AND task_id IS NULL)
                )
            );
            """
        )

    # Create indexes for foreign keys
    schema_editor.execute(
        "CREATE INDEX task_shares_owner_id_idx ON task_shares(owner_id);"
    )
    schema_editor.execute(
        "CREATE INDEX task_shares_shared_with_id_idx ON task_shares(shared_with_id);"
    )
    schema_editor.execute(
        "CREATE INDEX task_shares_task_id_idx ON task_shares(task_id);"
    )
    schema_editor.execute(
        "CREATE INDEX task_shares_tag_id_idx ON task_shares(tag_id);"
    )


class Migration(migrations.Migration):

    dependencies = [
        ('tasks', '0005_fix_tasks_tags_table'),
    ]

    operations = [
        migrations.RunPython(fix_task_shares_table, migrations.RunPython.noop),
    ]