#!/usr/bin/env python
#
# Copyright (C) 2026 GNS3 Technologies Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from sqlalchemy import Column, Boolean, ForeignKey, CheckConstraint, Index, Integer, String, text, JSON
from sqlalchemy.orm import relationship

from .base import BaseTable, generate_uuid, GUID

import logging

log = logging.getLogger(__name__)


class LLMModelConfig(BaseTable):
    """
    LLM model configuration for users and user groups.
    Supports inheritance: users can inherit configs from their groups.
    """

    __tablename__ = "llm_model_configs"

    config_id = Column(GUID, primary_key=True, default=generate_uuid)
    name = Column(String(100), nullable=False)  # Configuration name (table-level for indexing)
    model_type = Column(String(50), nullable=False)  # Model type: text, vision, stt, tts, multimodal, etc.
    config = Column(JSON, nullable=False)  # Config fields: provider, base_url, model, temperature, api_key, etc.
    user_id = Column(GUID, ForeignKey("users.user_id", ondelete="CASCADE"), nullable=True)
    group_id = Column(GUID, ForeignKey("user_groups.user_group_id", ondelete="CASCADE"), nullable=True)
    is_default = Column(Boolean, default=False, nullable=False)
    version = Column(Integer, default=0, nullable=False)  # Optimistic locking version

    # Relationships
    user = relationship("User", backref="llm_model_configs")
    group = relationship("UserGroup", backref="llm_model_configs")

    # Constraints
    __table_args__ = (
        # Ensure a config belongs to either a user or a group, not both
        CheckConstraint(
            "(user_id IS NOT NULL AND group_id IS NULL) OR "
            "(user_id IS NULL AND group_id IS NOT NULL)",
            name="single_owner_check"
        ),
        # Validate model_type values
        CheckConstraint(
            "model_type IN ('text', 'vision', 'stt', 'tts', 'multimodal', 'embedding', 'reranking', 'other')",
            name="valid_model_type_check"
        ),
        # Each user can have at most one default config (partial unique index, PostgreSQL only)
        Index("unique_user_default", "user_id", unique=True,
              postgresql_where=text("is_default = TRUE AND user_id IS NOT NULL")),
        # Each group can have at most one default config (partial unique index, PostgreSQL only)
        Index("unique_group_default", "group_id", unique=True,
              postgresql_where=text("is_default = TRUE AND group_id IS NOT NULL")),
        # Indexes for efficient queries
        Index("idx_llm_model_configs_user_id", "user_id"),
        Index("idx_llm_model_configs_group_id", "group_id"),
        Index("idx_llm_model_configs_model_type", "model_type"),
        # GIN index for JSON config (PostgreSQL only)
        Index("idx_llm_model_configs_config", "config", postgresql_using="gin"),
    )

    def __repr__(self):
        owner = f"user_{self.user_id}" if self.user_id else f"group_{self.group_id}"
        return f"<LLMModelConfig {self.name} ({self.model_type}) for {owner} (default={self.is_default}, version={self.version})>"