"""One-shot collection/backfill and monthly report orchestration."""

from datetime import UTC, datetime, timedelta
from pathlib import Path
from .config import PowerMeterConfig
from .gateway import PowerMeterGateway
from .repository import PostgresPowerMeterRepository
from .report import write_pdf


class PowerMeterCollector:
    def __init__(self, config: PowerMeterConfig, gateway: PowerMeterGateway,
                 repository: PostgresPowerMeterRepository) -> None:
        self.config, self.gateway, self.repository = config, gateway, repository

    def backfill(self, start: datetime, end: datetime) -> int:
        readings = self.gateway.read(self.config, start, end)
        for reading in readings:
            self.repository.write(self.config.name, reading)
        return len(readings)

    def poll_once(self, now: datetime | None = None) -> int:
        now = now or datetime.now(UTC)
        start = now - timedelta(seconds=self.config.poll_interval_seconds * 2)
        return self.backfill(start, now)


def monthly_report(config: PowerMeterConfig, repository: PostgresPowerMeterRepository,
                   month: str) -> Path:
    start = datetime.fromisoformat(month + "-01").replace(tzinfo=UTC)
    end = datetime.fromisoformat(month + "-01").replace(tzinfo=UTC)
    if start.month == 12:
        end = end.replace(year=start.year + 1, month=1)
    else:
        end = end.replace(month=start.month + 1)
    summary = repository.monthly(config.name, start, end, month)
    output = Path(config.report_mount_path) / config.name / month[:4] / f"{config.name}_Powermeter_{month}.pdf"
    write_pdf(summary, output)
    repository.save_report_metadata(summary, str(output))
    return output