import inspect
import logging
import sys
import os
from logging.config import fileConfig

from flask import current_app

from alembic import context
from sqlalchemy import NullPool, engine_from_config, text
import sqlalchemy as sa
from sqlalchemy.sql import schema
import pgvector
from pgvector.sqlalchemy import Vector

from common.models import document, interaction, user

# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config

# Interpret the config file for Python logging.
# This line sets up loggers basically.
# fileConfig(config.config_file_name)
# logger = logging.getLogger('alembic.env')

logging.basicConfig(
    stream=sys.stdout,
    level=logging.INFO,
    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
)

logger = logging.getLogger()

# Reset handlers to avoid issues with Alembic overriding them
for handler in logger.handlers:
    logger.removeHandler(handler)

# Add a stream handler to output logs to the console
console_handler = logging.StreamHandler(sys.stdout)
console_handler.setFormatter(logging.Formatter('%(asctime)s - %(name)s - %(levelname)s - %(message)s'))
logger.addHandler(console_handler)
logger.setLevel(logging.INFO)


def get_engine():
    try:
        # this works with Flask-SQLAlchemy<3 and Alchemical
        return current_app.extensions['migrate'].db.get_engine()
    except (TypeError, AttributeError):
        # this works with Flask-SQLAlchemy>=3
        return current_app.extensions['migrate'].db.engine


def get_engine_url():
    try:
        return get_engine().url.render_as_string(hide_password=False).replace(
            '%', '%%')
    except AttributeError:
        return str(get_engine().url).replace('%', '%%')


# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
config.set_main_option('sqlalchemy.url', get_engine_url())
target_db = current_app.extensions['migrate'].db


def get_public_table_names():
    # TODO: This function should include the necessary functionality to automatically retrieve table names
    return ['role', 'roles_users', 'tenant', 'user', 'tenant_domain','license_tier', 'license', 'license_usage',
            'business_event_log', 'tenant_project']


PUBLIC_TABLES = get_public_table_names()
logger.info(f"Public tables: {PUBLIC_TABLES}")


def include_object(object, name, type_, reflected, compare_to):
    if type_ == "table" and name in PUBLIC_TABLES:
        logger.info(f"Excluding public table: {name}")
        return False
    logger.info(f"Including object: {type_} {name}")
    return True


# List of Tenants
def get_tenant_ids():
    from common.models.user import Tenant

    tenants_ = Tenant.query.all()
    if tenants_:
        tenants = [tenant.id for tenant in tenants_]
    else:
        tenants = []
    return tenants


def get_metadata():
    if hasattr(target_db, 'metadatas'):
        return target_db.metadatas[None]
    return target_db.metadata


def run_migrations_offline():
    """Run migrations in 'offline' mode.

    This configures the context with just a URL
    and not an Engine, though an Engine is acceptable
    here as well.  By skipping the Engine creation
    we don't even need a DBAPI to be available.

    Calls to context.execute() here emit the given string to the
    script output.

    """
    url = config.get_main_option("sqlalchemy.url")
    context.configure(
        url=url,
        target_metadata=get_metadata(),
        # literal_binds=True,
        include_object=include_object,
    )

    with context.begin_transaction():
        context.run_migrations()


def run_migrations_online():
    """Updated migration script for handling schema based multi-tenancy

    ref:
     - https://alembic.sqlalchemy.org/en/latest/cookbook.html#rudimental-schema-level-multi-tenancy-for-postgresql-databases # noqa
    """

    connectable = engine_from_config(
        config.get_section(config.config_ini_section),
        prefix="sqlalchemy.",
        poolclass=NullPool,
    )

    with connectable.connect() as connection:
        tenants = get_tenant_ids()
        for tenant in tenants:
            try:
                os.environ['TENANT_ID'] = str(tenant)
                logger.info(f"Migrating tenant: {tenant}")
                # set search path on the connection, which ensures that
                # PostgreSQL will emit all CREATE / ALTER / DROP statements
                # in terms of this schema by default
                connection.execute(text(f'SET search_path TO "{tenant}", public'))
                # in SQLAlchemy v2+ the search path change needs to be committed
                connection.commit()

                # make use of non-supported SQLAlchemy attribute to ensure
                # the dialect reflects tables in terms of the current tenant name
                connection.dialect.default_schema_name = str(tenant)

                context.configure(
                    connection=connection,
                    target_metadata=get_metadata(),
                    # literal_binds=True,
                    include_object=include_object,
                )

                with context.begin_transaction():
                    context.run_migrations()

                # for checking migrate or upgrade is running
                if getattr(config.cmd_opts, "autogenerate", False):
                    break
            except Exception as e:
                continue


if context.is_offline_mode():
    raise Exception("Offline migrations are not supported")
else:
    run_migrations_online()