import datetime
import os
from flask import request

def parse_datetime_filter(value):
    if not value:
        return None

    try:
        return datetime.datetime.fromisoformat(value)
    except ValueError:
        try:
            return datetime.datetime.fromtimestamp(float(value))
        except ValueError as err:
            raise ValueError(
                "Date filters must be ISO-8601 strings or Unix timestamps"
            ) from err


def get_request_filters() -> dict:
    filters = {}

    search_query = request.args.get("search_query") or request.args.get("query")
    if search_query:
        filters["search_query"] = search_query

    start_date = parse_datetime_filter(
        request.args.get("start_date") or request.args.get("start")
    )
    if start_date:
        filters["start_date"] = start_date

    end_date = parse_datetime_filter(
        request.args.get("end_date") or request.args.get("end")
    )
    if end_date:
        filters["end_date"] = end_date

    data_sources = request.args.getlist("data_sources")
    if not data_sources:
        data_sources = request.args.getlist("sources")

    if len(data_sources) == 1 and "," in data_sources[0]:
        data_sources = [
            source.strip() for source in data_sources[0].split(",") if source.strip()
        ]

    if data_sources:
        filters["data_sources"] = data_sources

    return filters

def split_limit(limit: int, n: int) -> list[int]:
    base, remainder = divmod(limit, n)
    return [base + (1 if i < remainder else 0) for i in range(n)]

def get_env(name: str) -> str:
    value = os.getenv(name)
    if not value:
        raise RuntimeError(f"Missing required environment variable: {name}")
    return value