from datetime import datetime
from typing import Optional, List, Dict, Any, Union
from pydantic import BaseModel, Field


class FieldChangeCondition(BaseModel):
    """Condition for field_change triggers."""
    field: str = Field(..., description="Field to check: status_id, assignee_id, priority, start_date, due_date, custom_fields")
    operator: str = Field(..., description="Operator: equals, not_equals, changed_to, changed_from, before, after, in")
    value: Any = Field(..., description="Value to compare against")
    field_id: Optional[str] = Field(None, description="Custom field ID when field is custom_fields")


class TriggerRule(BaseModel):
    """Rule for composite field_change triggers."""
    field: str = Field(..., description="Field to check: status_id, assignee_id, priority, start_date, due_date, custom_fields")
    operator: str = Field(..., description="Operator: equals, not_equals, changed_to, changed_from, before, after, in")
    value: Any = Field(..., description="Value to compare against")
    field_id: Optional[str] = Field(None, description="Custom field ID when field is custom_fields")


class ScheduleCondition(BaseModel):
    """Condition for schedule triggers."""
    cron_expression: Optional[str] = Field(None, description="Cron expression (e.g., '0 9 * * 1' for Monday 9am)")
    deadline_reminder_days: Optional[int] = Field(None, ge=1, le=365, description="Days before due date to send reminder")


class TriggerCondition(BaseModel):
    """Union condition that supports both field_change and schedule triggers."""
    # Field change conditions
    field: Optional[str] = Field(None, description="Field to check: status_id, assignee_id, priority, start_date, due_date, custom_fields")
    operator: Optional[str] = Field(None, description="Operator: equals, not_equals, changed_to, changed_from, before, after, in")
    value: Optional[Any] = Field(None, description="Value to compare against")
    field_id: Optional[str] = Field(None, description="Custom field ID when field is custom_fields")
    logic: Optional[str] = Field(None, description="Composite logic: and")
    rules: Optional[List[TriggerRule]] = None
    # Schedule conditions
    cron_expression: Optional[str] = Field(None, description="Cron expression for schedule triggers")
    deadline_reminder_days: Optional[int] = Field(None, ge=1, le=365, description="Days before due date to send reminder")


class TriggerAction(BaseModel):
    """Action configuration for triggers.

    Supported action types:
    - notify: Send notification (requires target, optional template)
    - update_field: Update task field (requires field, value)
    - auto_assign: Auto-assign task (requires strategy, optional user_id for specific_user)
    """
    type: str = Field(..., description="Action type: notify, update_field, auto_assign")
    # Notify action fields
    target: Optional[str] = Field(None, description="Target: assignee, creator, project_owner, project_members, department:<id>, role:<name>, user:<id>")
    template: Optional[str] = Field(None, description="Message template with variables")
    # update_field action fields (FEAT-014)
    field: Optional[str] = Field(None, description="Field to update: priority, status_id, due_date")
    value: Optional[Any] = Field(None, description="New value for the field")
    # auto_assign action fields (FEAT-015)
    strategy: Optional[str] = Field(None, description="Strategy: round_robin, least_loaded, specific_user")
    user_id: Optional[str] = Field(None, description="User ID for specific_user strategy")


class TriggerCreate(BaseModel):
    name: str = Field(..., min_length=1, max_length=200)
    description: Optional[str] = Field(None, max_length=2000)
    trigger_type: str = Field(default="field_change")
    conditions: TriggerCondition
    actions: List[TriggerAction]
    is_active: bool = Field(default=True)


class TriggerUpdate(BaseModel):
    name: Optional[str] = Field(None, min_length=1, max_length=200)
    description: Optional[str] = Field(None, max_length=2000)
    conditions: Optional[TriggerCondition] = None
    actions: Optional[List[TriggerAction]] = None
    is_active: Optional[bool] = None


class TriggerUserInfo(BaseModel):
    id: str
    name: str
    email: str

    class Config:
        from_attributes = True


class TriggerResponse(BaseModel):
    id: str
    project_id: str
    name: str
    description: Optional[str]
    trigger_type: str
    conditions: Dict[str, Any]
    actions: List[Dict[str, Any]]
    is_active: bool
    created_by: Optional[str]
    created_at: datetime
    updated_at: datetime
    creator: Optional[TriggerUserInfo] = None

    class Config:
        from_attributes = True


class TriggerListResponse(BaseModel):
    triggers: List[TriggerResponse]
    total: int


class TriggerLogResponse(BaseModel):
    id: str
    trigger_id: str
    task_id: Optional[str]
    executed_at: datetime
    status: str
    details: Optional[Dict[str, Any]]
    error_message: Optional[str]

    class Config:
        from_attributes = True


class TriggerLogListResponse(BaseModel):
    logs: List[TriggerLogResponse]
    total: int