from datetime import datetime
from typing import Optional, Any, Literal
from uuid import UUID
from pydantic import BaseModel, Field


class CategoryInfo(BaseModel):
    """Embedded category info for tree responses."""
    id: UUID
    name: str
    slug: str

    class Config:
        from_attributes = True


class TreeBase(BaseModel):
    name: str = Field(..., min_length=1, max_length=255)
    description: Optional[str] = None
    # Legacy category field - kept for backward compatibility
    category: Optional[str] = Field(None, max_length=100)


class TreeCreate(TreeBase):
    tree_structure: dict[str, Any] = Field(..., description="The decision tree structure in JSON format")
    is_public: bool = Field(False, description="Make tree visible to all users")
    is_default: bool = Field(False, description="Mark as a default/system tree (admin only)")
    status: Literal['draft', 'published'] = Field('published', description="Status: draft or published")
    category_id: Optional[UUID] = Field(None, description="Category ID from tree_categories table")
    tags: Optional[list[str]] = Field(None, max_length=10, description="List of tag names to assign")


class TreeUpdate(BaseModel):
    name: Optional[str] = Field(None, min_length=1, max_length=255)
    description: Optional[str] = None
    category: Optional[str] = Field(None, max_length=100)
    category_id: Optional[UUID] = None
    tree_structure: Optional[dict[str, Any]] = None
    is_public: Optional[bool] = None
    is_active: Optional[bool] = None
    status: Optional[Literal['draft', 'published']] = None
    tags: Optional[list[str]] = Field(None, max_length=10, description="List of tag names to assign (replaces existing)")


class ForkCreate(BaseModel):
    fork_reason: Optional[str] = Field(None, max_length=255, description="Brief reason for forking")
    name: Optional[str] = Field(None, min_length=1, max_length=255, description="Name for the fork (defaults to 'Fork of {original name}')")


class ForkInfo(BaseModel):
    """Fork metadata included in tree responses."""
    parent_tree_id: Optional[UUID] = None
    root_tree_id: Optional[UUID] = None
    fork_reason: Optional[str] = None
    fork_depth: int = 0
    parent_updated_at: Optional[datetime] = None
    has_parent_updates: bool = False

    class Config:
        from_attributes = True


class TreeResponse(TreeBase):
    id: UUID
    tree_structure: dict[str, Any]
    author_id: Optional[UUID] = None
    account_id: Optional[UUID] = None
    category_id: Optional[UUID] = None
    category_info: Optional[CategoryInfo] = None
    tags: list[str] = []  # List of tag names
    fork_info: Optional[ForkInfo] = None
    is_active: bool
    is_public: bool
    is_default: bool
    status: str  # draft or published
    version: int
    created_at: datetime
    updated_at: datetime
    usage_count: int

    class Config:
        from_attributes = True


class TreeListResponse(BaseModel):
    id: UUID
    name: str
    description: Optional[str] = None
    category: Optional[str] = None
    category_id: Optional[UUID] = None
    category_info: Optional[CategoryInfo] = None
    tags: list[str] = []  # List of tag names
    author_id: Optional[UUID] = None
    account_id: Optional[UUID] = None
    is_active: bool
    is_public: bool
    is_default: bool
    status: str  # draft or published
    version: int
    usage_count: int
    created_at: datetime
    updated_at: datetime

    class Config:
        from_attributes = True


# --- Tree Sharing Schemas ---

class TreeShareCreate(BaseModel):
    """Request to create a share token for a tree."""
    allow_forking: bool = Field(True, description="Whether recipients can fork this tree")
    expires_at: Optional[datetime] = Field(None, description="Optional expiration time for the share")


class TreeShareResponse(BaseModel):
    """Response containing share token and URL."""
    id: UUID
    tree_id: UUID
    share_token: str
    share_url: str
    allow_forking: bool
    created_by: UUID
    created_at: datetime
    expires_at: Optional[datetime] = None

    class Config:
        from_attributes = True


class TreeVisibilityUpdate(BaseModel):
    """Request to update tree visibility."""
    visibility: Literal['private', 'team', 'link', 'public'] = Field(..., description="Visibility level")


class SharedTreeResponse(TreeBase):
    """Public response for shared trees (minimal info)."""
    id: UUID
    tree_structure: dict[str, Any]
    category: Optional[str] = None
    tags: list[str] = []
    version: int
    allow_forking: bool  # From share token
    created_at: datetime
    updated_at: datetime

    class Config:
        from_attributes = True


# --- Tree Validation Schemas ---

class ValidationError(BaseModel):
    """Individual validation error."""
    field: str
    message: str


class TreeValidationResponse(BaseModel):
    """Response for tree validation endpoint."""
    can_publish: bool
    errors: list[ValidationError] = []