import os
import re

from sqlalchemy import inspect, text

from app import db
from app.models import User, UserGroup


def ensure_schema():
    inspector = inspect(db.engine)
    tables = inspector.get_table_names()

    if "photos" in tables:
        db.session.execute(
            text(
                "ALTER TABLE photos ADD COLUMN IF NOT EXISTS "
                "user_id INTEGER REFERENCES users(id)"
            )
        )
        db.session.commit()

    if "users" in tables and "user_groups" in tables:
        db.session.execute(
            text(
                "ALTER TABLE users ADD COLUMN IF NOT EXISTS "
                "group_id INTEGER REFERENCES user_groups(id)"
            )
        )
        db.session.commit()


def ensure_default_group(app):
    default_quota = int(os.getenv("DEFAULT_GROUP_QUOTA_MB", "100"))
    default_max_folders = int(os.getenv("DEFAULT_GROUP_MAX_FOLDERS", "10"))
    default_max_photos = int(os.getenv("DEFAULT_GROUP_MAX_PHOTOS", "500"))
    default_group = UserGroup.query.filter_by(is_default=True).first()

    if not default_group:
        default_group = UserGroup.query.filter_by(slug="users").first()
        if default_group:
            default_group.is_default = True
        else:
            default_group = UserGroup(
                name="Пользователи",
                slug="users",
                disk_quota_mb=default_quota,
                max_folders=default_max_folders,
                max_photos=default_max_photos,
                is_default=True,
            )
            db.session.add(default_group)
        db.session.commit()
        app.logger.info(
            "Default user group 'users' created (quota=%s MB, folders=%s, photos=%s)",
            default_quota,
            default_max_folders,
            default_max_photos,
        )

    User.query.filter(User.group_id.is_(None)).update({"group_id": default_group.id})
    db.session.commit()


def ensure_group_limit_columns():
    inspector = inspect(db.engine)
    if "user_groups" not in inspector.get_table_names():
        return

    db.session.execute(
        text(
            "ALTER TABLE user_groups ADD COLUMN IF NOT EXISTS "
            "max_folders INTEGER NOT NULL DEFAULT 10"
        )
    )
    db.session.execute(
        text(
            "ALTER TABLE user_groups ADD COLUMN IF NOT EXISTS "
            "max_photos INTEGER NOT NULL DEFAULT 500"
        )
    )
    db.session.commit()


def ensure_site_settings(app):
    from app.models import SiteSettings

    if SiteSettings.query.get(1) is None:
        db.session.add(SiteSettings(id=1))
        db.session.commit()
        app.logger.info("Site settings initialized")


def ensure_photo_storage_column():
    inspector = inspect(db.engine)
    if "photos" not in inspector.get_table_names():
        return
    db.session.execute(
        text(
            "ALTER TABLE photos ADD COLUMN IF NOT EXISTS "
            "storage_backend VARCHAR(20) DEFAULT 'local'"
        )
    )
    db.session.commit()


def run_schema_migrations():
    ensure_schema()
    ensure_group_limit_columns()
    from app.folders import ensure_folder_schema

    ensure_folder_schema()
    ensure_photo_storage_column()


def run_database_setup(app):
    run_schema_migrations()
    ensure_default_group(app)
    ensure_site_settings(app)
    create_first_admin(app)


def slugify(name):
    slug = re.sub(r"[^a-z0-9]+", "-", name.lower().strip())
    slug = slug.strip("-") or "group"
    return slug[:80]


def create_first_admin(app):
    username = os.getenv("ADMIN_USERNAME", "").strip()
    email = os.getenv("ADMIN_EMAIL", "").strip()
    password = os.getenv("ADMIN_PASSWORD", "").strip()

    if not username or not email or not password:
        app.logger.info("ADMIN_* env vars not set — first admin was not created automatically")
        return None

    if User.query.filter_by(is_admin=True).first():
        return None

    default_group = UserGroup.query.filter_by(is_default=True).first()

    if User.query.filter_by(username=username).first():
        user = User.query.filter_by(username=username).first()
        user.is_admin = True
        user.set_password(password)
        if default_group and not user.group_id:
            user.group_id = default_group.id
        db.session.commit()
        app.logger.info("Existing user '%s' promoted to admin", username)
        return user

    user = User(
        username=username,
        email=email,
        is_admin=True,
        group_id=default_group.id if default_group else None,
    )
    user.set_password(password)
    db.session.add(user)
    db.session.commit()
    app.logger.info("First admin '%s' created", username)
    return user