import csv
import math
import operator
import os
import re
from collections import deque

import matplotlib.pyplot as plot


def load(directory):
	def _read(iterable):
		for x, y in iterable:
			yield float(x), float(y)

	def _load(filename):
		with open(filename) as fd:
			reader = csv.reader(fd)
			return list(_read(reader))

	def _files(directory):
		for file in os.listdir(directory):
			match = re.match(r"SWI_(-?\d+)\.csv", file)
			if match:
				yield int(match.group(1)), os.path.join(directory, file)

	return [(x, _load(y)) for x, y in sorted(_files(directory), key=lambda x: x[0])]


def look_downwards(data, x, start):
	for i in range(start, 0, -1):
		if data[i - 1][0] < x:
			break
	else:
		raise IndexError
	return i - 1


def look_upwards(data, x, start):
	for i in range(start, len(data)):
		if data[i + 1][0] > x:
			break
	else:
		raise IndexError
	return i


def find_segment(data, x):
	width = data[-1][0] - data[0][0]
	relative = x - data[0][0]
	candidate = math.floor(relative / width * len(data))
	look = look_downwards if data[candidate][0] > x else look_upwards  # May raise IndexError
	candidate = look(data, x, candidate)
	return candidate, candidate + 1


def find_boundary_curves(swis, x, y):
	segments = deque()
	for index, data in swis:
		i, j = find_segment(data, x)
		if data[i][1] > y and data[j][1] > y:
			segments.append((index, data, i, j))
			break
		if data[i][1] < y and data[j][1] < y:
			if segments:
				segments.popleft()
		segments.append((index, data, i, j))
	return segments


swis = load("dataset")


def onclick(event):
	if event.button != 1:
		return
	plot.clf()
	segments = find_boundary_curves(swis, event.xdata, event.ydata)
	plot.plot([event.xdata], [event.ydata], "rx")
	for index, data, i, j in segments:
		plot.plot([x[0] for x in data], [x[1] for x in data], ".", label=index)
	plot.show()

fig, _ = plot.subplots()
fig.canvas.mpl_connect('button_press_event', onclick)
plot.show()