from pydantic import BaseModel, Field, field_validator
from typing import Optional, List
from uuid import UUID
from datetime import datetime

VALID_STATUSES   = {"open", "waiting_on_customer", "waiting_on_staff", "resolved", "closed"}
VALID_PRIORITIES = {"low", "medium", "high", "urgent"}
VALID_OPENED_VIA = {"app", "email", "phone", "staff"}
VALID_SENDERS    = {"staff", "customer"}


class TicketCreate(BaseModel):
    customer_id:   str
    customer_name: Optional[str] = None
    subject:       str = Field(..., max_length=500)
    device_id:     Optional[str] = None
    device_serial: Optional[str] = None
    opened_via:    Optional[str] = None
    priority:      Optional[str] = None

    @field_validator("priority")
    @classmethod
    def check_priority(cls, v):
        if v is not None and v not in VALID_PRIORITIES:
            raise ValueError(f"priority must be one of {VALID_PRIORITIES}")
        return v


class TicketUpdate(BaseModel):
    status:        Optional[str] = None
    priority:      Optional[str] = None
    device_id:     Optional[str] = None
    device_serial: Optional[str] = None

    @field_validator("status")
    @classmethod
    def check_status(cls, v):
        if v is not None and v not in VALID_STATUSES:
            raise ValueError(f"status must be one of {VALID_STATUSES}")
        return v


class MessageCreate(BaseModel):
    sender_type: str
    sender_id:   str
    sender_name: Optional[str] = None
    body:        str
    is_internal: bool = False

    @field_validator("sender_type")
    @classmethod
    def check_sender_type(cls, v):
        if v not in VALID_SENDERS:
            raise ValueError(f"sender_type must be one of {VALID_SENDERS}")
        return v


class EscalateIn(BaseModel):
    entry_id: UUID


class MessageOut(BaseModel):
    id:          UUID
    sender_type: str
    sender_id:   str
    sender_name: Optional[str]
    body:        str
    is_internal: bool
    created_at:  datetime
    model_config = {"from_attributes": True}


class TicketOut(BaseModel):
    id:              UUID
    customer_id:     str
    customer_name:   Optional[str]
    device_id:       Optional[str]
    device_serial:   Optional[str]
    subject:         str
    status:          str
    priority:        Optional[str]
    opened_via:      Optional[str]
    linked_entry_id: Optional[UUID]
    created_at:      datetime
    updated_at:      datetime
    messages:        List[MessageOut] = []
    model_config = {"from_attributes": True}


class TicketListResponse(BaseModel):
    data: List[TicketOut]
    pagination: dict