"""
Pydantic models for The Scheduler API.
"""
from pydantic import BaseModel, Field
from typing import Optional, Dict, Any
from datetime import datetime
from enum import Enum


class SchedulePattern(str, Enum):
    """Common schedule patterns."""
    EVERY_MINUTE = "every_minute"
    HOURLY = "hourly"
    DAILY = "daily"
    WEEKLY = "weekly"
    MONTHLY = "monthly"


class TaskExecutor(str, Enum):
    """Available task executors."""
    REST_API = "rest_api"
    SHELL = "shell"
    PYTHON = "python"


class TaskPriorityLevel(str, Enum):
    """Task priority levels."""
    EMERGENCY = "emergency"  # 1-5: Critical system tasks
    SYSTEM = "system"        # 5-10: System maintenance
    USER = "user"            # 10-30: User-initiated tasks
    MAINTENANCE = "maintenance"  # 40-70: Background maintenance
    LOW = "low"             # 70+: Low priority cleanup


class TaskBase(BaseModel):
    """Base task fields."""
    task_name: str = Field(
        ...,
        description="Unique task identifier (e.g., 'librarian_consolidation')",
        example="librarian_consolidation"
    )
    service: str = Field(
        ...,
        description="Service that owns this task (e.g., 'library-desk', 'core-api')",
        example="library-desk"
    )
    executor: str = Field(
        ...,
        description="Executor type: 'rest_api', 'shell', or 'python'",
        example="rest_api"
    )
    priority: int = Field(
        ...,
        ge=1,
        le=100,
        description="Priority level (1-5: emergency, 10-30: user, 40-70: maintenance, 70+: low)",
        example=25
    )
    description: Optional[str] = Field(
        None,
        description="Human-readable task description",
        example="Processes unprocessed search queries and consolidates knowledge into wiki pages"
    )


class TaskSchedule(BaseModel):
    """Cron-style schedule fields."""
    minute: int = Field(
        -1,
        ge=-1,
        le=59,
        description="Minute to run (-1 = every minute, 0-59 = specific minute)",
        example=-1
    )
    hour: int = Field(
        -1,
        ge=-1,
        le=23,
        description="Hour to run (-1 = every hour, 0-23 = specific hour)",
        example=-1
    )
    day_of_month: int = Field(
        -1,
        ge=-1,
        le=31,
        description="Day of month to run (-1 = every day, 1-31 = specific day)",
        example=-1
    )
    month: int = Field(
        -1,
        ge=-1,
        le=12,
        description="Month to run (-1 = every month, 1-12 = specific month)",
        example=-1
    )
    day_of_week: int = Field(
        -1,
        ge=-1,
        le=6,
        description="Day of week to run (-1 = every day, 0-6 = Monday-Sunday)",
        example=-1
    )


class TaskConfig(BaseModel):
    """Task execution configuration."""
    enabled: bool = Field(
        True,
        description="Whether task is enabled",
        example=True
    )
    max_retries: int = Field(
        3,
        ge=0,
        le=10,
        description="Maximum retry attempts on failure",
        example=3
    )
    timeout_seconds: int = Field(
        3600,
        ge=1,
        description="Execution timeout in seconds",
        example=3600
    )
    config: Optional[Dict[str, Any]] = Field(
        None,
        description="Executor-specific configuration (varies by executor type)",
        example={
            "method": "POST",
            "url": "http://library-desk:8089/consolidation/run",
            "headers": {
                "Authorization": "Bearer ${LIBRARY_DESK_API_KEY}",
                "Content-Type": "application/json"
            },
            "body": {
                "dry_run": False,
                "process_limit": 10,
                "lookback_days": 7,
                "min_web_results": 2
            }
        }
    )


class TaskCreate(TaskBase, TaskSchedule, TaskConfig):
    """Request model for creating a new scheduled task."""
    created_by: Optional[str] = Field(
        "api",
        description="User or system that created this task",
        example="api"
    )

    class Config:
        json_schema_extra = {
            "example": {
                "task_name": "librarian_consolidation",
                "service": "library-desk",
                "executor": "rest_api",
                "priority": 25,
                "description": "Processes unprocessed search queries and consolidates knowledge",
                "minute": 0,
                "hour": -1,
                "day_of_month": -1,
                "month": -1,
                "day_of_week": -1,
                "enabled": True,
                "max_retries": 3,
                "timeout_seconds": 3600,
                "config": {
                    "method": "POST",
                    "url": "http://library-desk:8089/consolidation/run",
                    "headers": {
                        "Authorization": "Bearer ${LIBRARY_DESK_API_KEY}",
                        "Content-Type": "application/json"
                    },
                    "body": {
                        "dry_run": False,
                        "process_limit": 10,
                        "lookback_days": 7,
                        "min_web_results": 2
                    }
                },
                "created_by": "api"
            }
        }


class TaskUpdate(BaseModel):
    """Request model for updating a scheduled task."""
    service: Optional[str] = None
    executor: Optional[str] = None
    priority: Optional[int] = Field(None, ge=1, le=100)
    minute: Optional[int] = Field(None, ge=-1, le=59)
    hour: Optional[int] = Field(None, ge=-1, le=23)
    day_of_month: Optional[int] = Field(None, ge=-1, le=31)
    month: Optional[int] = Field(None, ge=-1, le=12)
    day_of_week: Optional[int] = Field(None, ge=-1, le=6)
    enabled: Optional[bool] = None
    description: Optional[str] = None
    config: Optional[Dict[str, Any]] = None
    max_retries: Optional[int] = Field(None, ge=0, le=10)
    timeout_seconds: Optional[int] = Field(None, ge=1)


class TaskResponse(TaskCreate):
    """Response model for task operations."""
    # These are `timestamp` columns, so psycopg2 hands back datetime objects.
    # Declaring them as `str` made Pydantic reject every create response, which
    # 500'd the endpoint *after* the row had already been inserted and committed.
    # FastAPI serialises datetime to an ISO 8601 string, so the JSON on the wire
    # is unchanged — and now matches what GET /tasks/{name} already returned.
    created_at: datetime
    updated_at: Optional[datetime] = None

    class Config:
        from_attributes = True