"""
Copyright 2024-2026 ChatterMate

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
"""

from sqlalchemy import Column, Integer, String, JSON, ForeignKey, TIMESTAMP, func, UUID, Interval, Float, Index, text
from sqlalchemy.orm import relationship
from app.core.encryption import EncryptedText
from app.database import Base


class ChatHistory(Base):
    __tablename__ = "chat_history"
    __table_args__ = (
        # Every read of a conversation filters by session_id and orders by
        # (created_at, id) — the inbox previews, get_session_history, the AI's
        # context window. Declared here as well as in the migration so autogenerate
        # never proposes dropping it and the sqlite test schema matches Postgres.
        Index('ix_chat_history_session_created', 'session_id',
              text('created_at DESC'), text('id DESC')),
        # Delivery receipts look their message up by platform id
        Index('ix_chat_history_org_external_message', 'organization_id', 'external_message_id',
              postgresql_where=text('external_message_id IS NOT NULL'),
              sqlite_where=text('external_message_id IS NOT NULL')),
    )

    id = Column(Integer, primary_key=True, index=True)
    organization_id = Column(UUID(as_uuid=True), ForeignKey(
        "organizations.id", ondelete="SET NULL"), nullable=True)
    user_id = Column(UUID(as_uuid=True), ForeignKey(
        "users.id", ondelete="SET NULL"), nullable=True)
    customer_id = Column(UUID(as_uuid=True), ForeignKey(
        "customers.id", ondelete="SET NULL"), nullable=True)
    agent_id = Column(UUID(as_uuid=True), ForeignKey(
        "agents.id", ondelete="SET NULL"), nullable=True)
    session_id = Column(UUID(as_uuid=True), ForeignKey("session_to_agents.session_id"), nullable=True)
    # Encrypted at rest — see app.core.encryption. Storage stays text, so rows
    # written before the change read back as plaintext until the backfill lands.
    message = Column(EncryptedText, nullable=False)
    # 'user', 'bot', or 'agent'
    message_type = Column(String, nullable=False)
    attributes = Column(JSON, default={})
    sentiment_label = Column(String, nullable=True)  # 'positive', 'neutral', 'negative'
    sentiment_score = Column(Float, nullable=True)  # -1.0 to 1.0
    # Channel messages only: the platform's id for this message (WhatsApp wamid)
    # and its latest delivery receipt — app.channels.base.DeliveryState values.
    external_message_id = Column(String, nullable=True)
    channel_status = Column(String(16), nullable=True)
    channel_status_at = Column(TIMESTAMP(timezone=True), nullable=True)
    created_at = Column(TIMESTAMP(timezone=True), server_default=func.now())
    updated_at = Column(TIMESTAMP(timezone=True), server_default=func.now(),
                        onupdate=func.now())

    # Relationships
    user = relationship("User", back_populates="chat_histories")
    customer = relationship("Customer", back_populates="chat_histories")
    agent = relationship("Agent", back_populates="chat_histories")
    organization = relationship("Organization", back_populates="chat_histories")
    session_assignment = relationship("SessionToAgent")