"""
Ticket Model - ServiceManagerWeb
Tickets de soporte - Core del negocio
"""
from sqlalchemy import String, ForeignKey, Text, Integer, CheckConstraint, UniqueConstraint, Enum as SAEnum
from sqlalchemy.orm import Mapped, mapped_column, relationship, synonym
from sqlalchemy.dialects.postgresql import ENUM as PG_ENUM
from typing import Optional
from datetime import datetime
import enum
import uuid

from app.core.database import Base, GUID


def _generate_fallback_ticket_number() -> str:
    # Matches helper format "TK-000001" and stays within VARCHAR(20)
    return f"TK-{(uuid.uuid4().int % 1_000_000):06d}"

class TicketStatus(str, enum.Enum):
    """Estados posibles de un ticket"""
    NEW = "NEW"
    TRIAGE = "TRIAGE"
    IN_PROGRESS = "IN_PROGRESS"
    WAITING_CUSTOMER = "WAITING_CUSTOMER"  # ✅ CORREGIDO: nombre según schema.sql
    RESOLVED = "RESOLVED"
    CLOSED = "CLOSED"
    REOPENED = "REOPENED"

class TicketPriority(str, enum.Enum):
    """Prioridades posibles de un ticket"""
    LOW = "LOW"
    MEDIUM = "MEDIUM"
    HIGH = "HIGH"
    URGENT = "URGENT"

class Ticket(Base):
    """Modelo de tickets de soporte"""
    __tablename__ = "tickets"
    
    # Multi-tenancy
    tenant_id: Mapped[uuid.UUID] = mapped_column(
        GUID(),
        ForeignKey("tenants.id", ondelete="CASCADE"), 
        nullable=False
    )
    
    # Campos básicos
    ticket_number: Mapped[str] = mapped_column(
        String(20),
        nullable=False,
        default=_generate_fallback_ticket_number,
    )
    subject: Mapped[str] = mapped_column(String(255), nullable=False)
    description: Mapped[str] = mapped_column(Text, nullable=False)

    # Compatibility aliases (API/UI/tests often use these names)
    title = synonym("subject")
    system_id = synonym("affected_system_id")
    
    # Estado y Prioridad
    status: Mapped[TicketStatus] = mapped_column(
        SAEnum(TicketStatus, name="ticket_status_enum", native_enum=False).with_variant(
            PG_ENUM(TicketStatus, name="ticket_status_enum", create_type=True),
            "postgresql",
        ),
        default=TicketStatus.NEW,
        nullable=False
    )
    priority: Mapped[TicketPriority] = mapped_column(
        SAEnum(TicketPriority, name="ticket_priority_enum", native_enum=False).with_variant(
            PG_ENUM(TicketPriority, name="ticket_priority_enum", create_type=True),
            "postgresql",
        ),
        default=TicketPriority.MEDIUM,
        nullable=False
    )
    
    # ✅ CORREGIDO: Foreign Keys apuntan a tablas correctas
    created_by: Mapped[uuid.UUID] = mapped_column(
        GUID(),
        ForeignKey("users.id"), 
        nullable=False
    )
    assigned_to: Mapped[Optional[uuid.UUID]] = mapped_column(
        GUID(),
        ForeignKey("users.id"), 
        nullable=True
    )
    
    # ✅ CORREGIDO: Renombrado de system_id a affected_system_id
    affected_system_id: Mapped[Optional[uuid.UUID]] = mapped_column(
        GUID(),
        ForeignKey("affected_systems.id"),  # ✅ Tabla correcta
        nullable=True
    )
    
    # ✅ CORREGIDO: Foreign key a tabla correcta
    category_id: Mapped[Optional[uuid.UUID]] = mapped_column(
        GUID(),
        ForeignKey("ticket_categories.id"),  # ✅ Tabla correcta
        nullable=True
    )
    
    # ✅ AÑADIDOS: Campos de SLA según schema.sql
    sla_response_due: Mapped[Optional[datetime]] = mapped_column(nullable=True)
    sla_resolution_due: Mapped[Optional[datetime]] = mapped_column(nullable=True)
    first_response_at: Mapped[Optional[datetime]] = mapped_column(nullable=True)
    resolved_at: Mapped[Optional[datetime]] = mapped_column(nullable=True)
    
    # ✅ AÑADIDOS: Campos de CSAT (Customer Satisfaction) según schema.sql
    rating: Mapped[Optional[int]] = mapped_column(Integer, nullable=True)
    rating_comment: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
    rated_at: Mapped[Optional[datetime]] = mapped_column(nullable=True)

    # Relationships
    tenant: Mapped["Tenant"] = relationship("Tenant", back_populates="tickets")
    
    # ✅ ACTUALIZADO: Nombre de relación y optional
    affected_system: Mapped[Optional["System"]] = relationship(
        "System", 
        back_populates="tickets"
    )
    
    category: Mapped[Optional["Category"]] = relationship(
        "Category", 
        back_populates="tickets"
    )
    
    created_by_user: Mapped["User"] = relationship(
        "User", 
        foreign_keys=[created_by], 
        back_populates="created_tickets"
    )
    
    assigned_to_user: Mapped[Optional["User"]] = relationship(
        "User", 
        foreign_keys=[assigned_to], 
        back_populates="assigned_tickets"
    )

    comments: Mapped[list["TicketComment"]] = relationship(
        "TicketComment",
        back_populates="ticket",
        cascade="all, delete-orphan"
    )
    
    attachments: Mapped[list["TicketAttachment"]] = relationship(
        "TicketAttachment",
        back_populates="ticket",
        cascade="all, delete-orphan"
    )
    
    # ✅ AÑADIDOS: Constraints según schema.sql
    __table_args__ = (
        UniqueConstraint('tenant_id', 'ticket_number', name='uq_tickets_tenant_number'),
        CheckConstraint('rating >= 1 AND rating <= 5', name='check_rating_range'),
    )

    participants: Mapped[list["TicketParticipant"]] = relationship(
        "TicketParticipant",
        back_populates="ticket",
        cascade="all, delete-orphan"
    )

    def __repr__(self) -> str:
        return f"<Ticket(id={self.id}, number='{self.ticket_number}', status={self.status})>"

class TicketParticipant(Base):
    """Participantes asignados a un ticket"""
    __tablename__ = "ticket_participants"

    ticket_id: Mapped[uuid.UUID] = mapped_column(
        GUID(),
        ForeignKey("tickets.id", ondelete="CASCADE"),
        nullable=False
    )
    user_id: Mapped[uuid.UUID] = mapped_column(
        GUID(),
        ForeignKey("users.id", ondelete="CASCADE"),
        nullable=False
    )
    role: Mapped[str] = mapped_column(String(50), nullable=False, default="participant")

    ticket: Mapped["Ticket"] = relationship("Ticket", back_populates="participants")
    user: Mapped["User"] = relationship("User")

    __table_args__ = (
        UniqueConstraint("ticket_id", "user_id", name="uq_ticket_participant"),
    )

    def __repr__(self):
        return f"<TicketParticipant(ticket={self.ticket_id}, user={self.user_id})>"