from jsonschema import Draft202012Validator, FormatChecker
from pydantic import ValidationError

from app.domain.schemas import PlannerDecision, ValidationResult
from app.ai.tool_registry import ToolRegistry


class ActionValidator:
    def __init__(self, registry: ToolRegistry) -> None:
        self.registry = registry

    def validate(self, decision: PlannerDecision) -> ValidationResult:
        if decision.intent == "no_action":
            return ValidationResult(valid=False, errors=["No actionable intent detected."])
        if not decision.tool:
            return ValidationResult(valid=False, errors=["Planner did not select a tool."])
        tool = self.registry.get(decision.tool)
        if not tool:
            return ValidationResult(valid=False, errors=[f"Unknown tool: {decision.tool}"])
        try:
            Draft202012Validator(tool.schema, format_checker=FormatChecker()).validate(decision.arguments)
        except Exception as exc:
            return ValidationResult(valid=False, errors=[str(exc)])
        extra = set(decision.arguments) - set(tool.schema.get("properties", {}))
        if extra:
            return ValidationResult(valid=False, errors=[f"Hallucinated parameters: {sorted(extra)}"])
        try:
            self._validate_dates(decision.arguments)
        except ValidationError as exc:
            return ValidationResult(valid=False, errors=[str(exc)])
        return ValidationResult(valid=True)

    def _validate_dates(self, args: dict) -> None:
        # JSON Schema catches shape; FastAPI/Pydantic validates API models at execution time.
        return None