# -*- coding: utf-8 -*-
"""
@file temporal.py
@brief provides functionality relating to searching the catalog temporally

@par History
     - Brian Helgans, Dec 02 2019, updated to add log name as input
"""
from typing import NamedTuple
from Sample_Execution.fileid import Catalog_File
from datetime import timedelta

class SearchResult(NamedTuple):
    '''
    A named tuple that can be accessed like searchresult.first to obtain items in the tuple. 
    It terms of appearance its similar to using a struct in C
    '''
    interval: timedelta
    first: Catalog_File
    middle: Catalog_File
    last: Catalog_File

def search_for_neighbors(file_middle, catalog, max_search_distance=9, epsilon_for_interval = timedelta(seconds=60)):
    '''
    Searches for Neighbors on each side within a given a search distance within the timestamp sorted catalog
    :param file_middle: middle file used for the timestamp of the search.
    :type file_middle: Sample_Execution.fileid.Catalog_File
    :param catalog: catalog for the search
    :type catalog: Sample_Execution.fileid.Catalog
    :param max_search_distance: max distance on either side of the timestamp sorted catalog
    :type max_search_distance: int
    :param epsilon_for_interval: timedelta to estimate when times are close enough to being equal.
    :type epsilon_for_interval: datetime.timedelta
    '''

    neighbors = []
    #we need to search some distance from the middle image for a match
    for search_distance in range(1,max_search_distance+1):

        #find it in the catalogue
        middle_index = catalog.time_index(file_middle.id.timestring)

        #attempt to find the first and last in the catalogue
        prior_index = middle_index - search_distance
        next_index = middle_index + search_distance
        if prior_index < 0:
            continue


        file_first = catalog.get_with_time_index(time_index=prior_index, catid=file_middle.id)
        file_last = catalog.get_with_time_index(time_index=next_index, catid=file_middle.id)
        if not file_first or not file_last:
            continue

        timedelta1 = file_middle.datetime - file_first.datetime
        timedelta2 = file_last.datetime - file_middle.datetime


        if (timedelta1 - timedelta2) > epsilon_for_interval :
            continue

        maxtimedelta = max(timedelta1,timedelta2)
        minutes_interval = round(maxtimedelta.total_seconds() / 60.0)

        neighbors.append( SearchResult(
              interval=minutes_interval,
              first=file_first,
              middle=file_middle,
              last=file_last))

    return neighbors