from datetime import datetime
from typing import Optional


class ScanState:
    def __init__(self):
        self.status: str = "idle"  # idle, scanning, done, error
        self.last_scan: Optional[datetime] = None
        self.progress: int = 0
        self.total: int = 0
        self.error: str = ""

    def start(self):
        self.status = "scanning"
        self.progress = 0
        self.total = 0
        self.error = ""

    def finish(self, count: int):
        self.status = "done"
        self.progress = count
        self.total = count
        self.last_scan = datetime.utcnow()

    def fail(self, error: str):
        self.status = "error"
        self.error = error

    def to_dict(self) -> dict:
        return {
            "scan_status": self.status,
            "last_scan": self.last_scan.isoformat() if self.last_scan else None,
            "progress": self.progress,
            "total": self.total,
            "error": self.error,
        }


scan_state = ScanState()