from pydantic import BaseModel, Field, HttpUrl, validator, root_validator
from typing import List, Literal, Union, Optional
from datetime import datetime
from enum import Enum


class VerdictEnum(str, Enum):
    TRUE = "True"
    FALSE = "False"
    PARTIALLY_TRUE = "Partially True"
    UNVERIFIED = "Unverified"


class ConfidenceEnum(str, Enum):
    HIGH = "High"
    MEDIUM = "Medium"
    LOW = "Low"


class FactCheckRequest(BaseModel):
    query: Optional[str] = Field(
        None,
        min_length=3,
        max_length=500,
        description="The claim or statement to be fact-checked",
        example="Did NASA confirm finding alien structures on Mars in 2024?",
    )
    url: Optional[str] = Field(
        None,
        description="URL to be fact-checked",
        example="https://example.com/article",
    )

    @root_validator(pre=True)
    def validate_at_least_one(cls, values):
        """Validate that at least one of query or url is provided."""
        query = values.get('query')
        url = values.get('url')
        if not query and not url:
            raise ValueError("At least one of 'query' or 'url' must be provided")
        return values

    @validator('url')
    def validate_url(cls, v):
        """Validate URL format if provided."""
        if v is not None and len(v) < 3:
            raise ValueError("URL must be at least 3 characters")
        return v


class Source(BaseModel):
    url: str
    name: str = ""

    @validator("url")
    def validate_url(cls, v):
        if not v or len(v) < 3:
            raise ValueError("URL must not be empty and must be at least 3 characters")
        return v


class UnverifiedFactCheckResponse(BaseModel):
    claim: str = Field(
        ...,
        min_length=10,
        max_length=1000,
        description="The exact claim being verified",
    )
    verdict: VerdictEnum = Field(..., description="The verification verdict")
    confidence: ConfidenceEnum = Field(..., description="Confidence level in the verdict")
    sources: List[Source] = Field(
        default=[],
        description="List of sources used in verification"
    )
    evidence: str = Field(
        ...,
        min_length=20,
        max_length=500,
        description="Concise summary of key evidence",
    )
    explanation: str = Field(
        ...,
        min_length=50,
        max_length=1000,
        description="Detailed explanation of verification findings",
    )
    additional_context: str = Field(
        ...,
        min_length=20,
        max_length=500,
        description="Important context about the verification",
    )


class FactCheckResponse(BaseModel):
    claim: str = Field(
        ...,
        min_length=10,
        max_length=1000,
        description="The exact claim being verified",
    )
    verdict: VerdictEnum = Field(..., description="The verification verdict")
    confidence: ConfidenceEnum = Field(..., description="Confidence level in the verdict")
    sources: List[Source] = Field(
        ...,
        min_items=1,
        description="List of sources used in verification"
    )
    evidence: str = Field(
        ...,
        min_length=20,
        max_length=500,
        description="Concise summary of key evidence",
    )
    explanation: str = Field(
        ...,
        min_length=50,
        max_length=1000,
        description="Detailed explanation of verification findings",
    )
    additional_context: str = Field(
        ...,
        min_length=20,
        max_length=500,
        description="Important context about the verification",
    )

    class Config:
        json_schema_extra = {
            "example": {
                "claim": "NASA confirmed finding alien structures on Mars in 2024",
                "verdict": "False",
                "confidence": "High",
                "sources": [
                    {
                        "url": "https://www.nasa.gov/mars-exploration",
                        "name": "NASA Mars Exploration",
                    }
                ],
                "evidence": "NASA has made no such announcement. Recent Mars rover images show natural rock formations.",
                "explanation": "Multiple fact-checking organizations investigated this claim. NASA's official communications and Mars mission reports from 2024 contain no mention of alien structures.",
                "additional_context": "Similar false claims about alien structures on Mars have circulated periodically.",
            }
        }


class ErrorResponse(BaseModel):
    detail: str
    error_code: str = Field(..., example="VALIDATION_ERROR")
    path: str = Field(..., example="/check-facts")