from pydantic import BaseModel, Field, validator
from typing import List, Optional
import re


class CustomTaskStatus(BaseModel):
    """Schema for a custom task status"""
    id: str = Field(..., description="Unique identifier for the status")
    name: str = Field(..., min_length=1, max_length=50, description="Display name")
    color: str = Field(..., pattern=r'^#[0-9A-Fa-f]{6}$', description="Hex color code")
    order: int = Field(..., ge=0, description="Display order")
    is_default: bool = Field(default=False, description="Whether this is the default status")

    class Config:
        from_attributes = True


class CustomTaskStatusCreate(BaseModel):
    """Schema for creating a new custom task status"""
    name: str = Field(..., min_length=1, max_length=50, description="Status name")
    color: Optional[str] = Field(None, description="Hex color code (e.g., #FF5733)")
    
    @validator('name')
    def validate_name(cls, v):
        """Validate and normalize status name"""
        # Trim whitespace
        v = v.strip()
        if not v:
            raise ValueError('Status name cannot be empty')
        if len(v) > 50:
            raise ValueError('Status name cannot exceed 50 characters')
        return v
    
    @validator('color')
    def validate_color(cls, v):
        """Validate color format if provided"""
        if v is None:
            return v
        # Trim whitespace
        v = v.strip()
        # Check hex color format
        if not re.match(r'^#[0-9A-Fa-f]{6}$', v):
            raise ValueError('Color must be a valid hex code (e.g., #FF5733)')
        return v.upper()  # Normalize to uppercase


class CustomTaskStatusUpdate(BaseModel):
    """Schema for updating a custom task status"""
    name: Optional[str] = Field(None, min_length=1, max_length=50, description="Status name")
    color: Optional[str] = Field(None, description="Hex color code (e.g., #FF5733)")
    is_default: Optional[bool] = Field(None, description="Set as default status")
    
    @validator('name')
    def validate_name(cls, v):
        """Validate and normalize status name"""
        if v is None:
            return v
        # Trim whitespace
        v = v.strip()
        if not v:
            raise ValueError('Status name cannot be empty')
        if len(v) > 50:
            raise ValueError('Status name cannot exceed 50 characters')
        return v
    
    @validator('color')
    def validate_color(cls, v):
        """Validate color format if provided"""
        if v is None:
            return v
        # Trim whitespace
        v = v.strip()
        # Check hex color format
        if not re.match(r'^#[0-9A-Fa-f]{6}$', v):
            raise ValueError('Color must be a valid hex code (e.g., #FF5733)')
        return v.upper()  # Normalize to uppercase


class CustomTaskStatusReorder(BaseModel):
    """Schema for reordering statuses"""
    status_ids: List[str] = Field(..., min_items=1, description="Ordered list of status IDs")
    
    @validator('status_ids')
    def validate_status_ids(cls, v):
        """Validate status IDs list"""
        if not v:
            raise ValueError('Status IDs list cannot be empty')
        # Check for duplicates
        if len(v) != len(set(v)):
            raise ValueError('Status IDs list contains duplicates')
        return v


class CustomTaskStatusDelete(BaseModel):
    """Schema for deleting a status with optional reassignment"""
    reassign_to_status_id: Optional[str] = Field(
        None, 
        description="Status ID to reassign tasks to (required if status is in use)"
    )


class SystemTaskStatus(BaseModel):
    """Schema for system (built-in) task statuses"""
    id: str = Field(..., description="System status identifier")
    name: str = Field(..., description="Display name")
    color: str = Field(..., description="Hex color code")
    is_system: bool = Field(default=True, description="Indicates this is a system status")

    class Config:
        from_attributes = True


class AllTaskStatusesResponse(BaseModel):
    """Schema for response containing all task statuses (system + custom)"""
    statuses: List[CustomTaskStatus] = Field(
        default_factory=list,
        description="Custom task statuses defined for the project"
    )
    system_statuses: List[SystemTaskStatus] = Field(
        default_factory=list,
        description="Built-in system task statuses"
    )
    default_status_id: str = Field(
        ...,
        description="ID of the default status for new tasks"
    )

    class Config:
        from_attributes = True


class TaskStatusInUseError(BaseModel):
    """Schema for error when trying to delete a status that is in use"""
    error: str = Field(..., description="Error message")
    status_id: str = Field(..., description="ID of the status that cannot be deleted")
    status_name: str = Field(..., description="Name of the status that cannot be deleted")
    task_count: int = Field(..., ge=0, description="Number of tasks using this status")
    task_ids: List[int] = Field(
        default_factory=list,
        description="IDs of tasks using this status"
    )

    class Config:
        from_attributes = True


class CustomTaskStatusResponse(BaseModel):
    """Schema for successful custom task status operation response"""
    message: str = Field(..., description="Success message")
    status: Optional[CustomTaskStatus] = Field(None, description="The created or updated status")
    all_statuses: Optional[AllTaskStatusesResponse] = Field(
        None,
        description="All statuses after the operation"
    )

    class Config:
        from_attributes = True