from dataclasses import dataclass, field
from typing import List


@dataclass
class Evidence:
    claim: str
    source_url: str
    excerpt: str
    supports_claim: bool | None = None


@dataclass
class ResearchState:
    question: str
    claims: List[str] = field(default_factory=list)
    evidence: List[Evidence] = field(default_factory=list)

    def add_claim(self, claim: str):
        if claim not in self.claims:
            self.claims.append(claim)

    def add_evidence(
        self,
        claim: str,
        source_url: str,
        excerpt: str,
        supports_claim: bool | None = None,
    ):
        self.evidence.append(
            Evidence(
                claim=claim,
                source_url=source_url,
                excerpt=excerpt,
                supports_claim=supports_claim,
            )
        )

    def evidence_for_claim(self, claim: str) -> List[Evidence]:
        return [
            evidence
            for evidence in self.evidence
            if evidence.claim == claim
        ]