# Copyright 2018 Mike "KemoNine" Crosson
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#     http://www.apache.org/licenses/LICENSE-2.0
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Adapted from https://github.com/mapsforge/mapsforge-creator/blob/master/poly2bb.pl

import re, os

BOUND_BUFFER = 0.1
COORD_MATCHER = re.compile('^\s*([0-9.E+-]+)\s+([0-9.E+-]+)\s*$')

def calculate_total_bounds(maps_dir, map_lists):
	cached_maps_dir = os.path.abspath(maps_dir)
	x_min = 360.0
	x_max = -360.0
	y_min = 360.0
	y_max = -360.0
	for alist in map_lists:
		with open(alist, 'r') as maps:
			for line in maps:
				current_map = line.strip().split('/')[-1]
				bounds = calculate_bounds(os.path.join(cached_maps_dir, current_map + '.poly'))
				if bounds['bottom'] < y_min:
					y_min = bounds['bottom']
				if bounds['left'] < x_min:
					x_min = bounds['left']
				if bounds['top'] > y_max:
					y_max = bounds['top']
				if bounds['right'] > x_max:
					x_max = bounds['right']
	values = {}
	values['bottom'] = y_min
	values['left'] = x_min
	values['top'] = y_max
	values['right'] = x_max
	return values

def calculate_bounds(mappoly):
	# Opposite of max possible values so we find the right bounding box later
	x_min = 360.0
	x_max = -360.0
	y_min = 360.0
	y_max = -360.0

	with open(mappoly, 'r') as polyfile:
		for line in polyfile:
			if COORD_MATCHER.match(line.strip()):
				values = line.split()
				x = float(values[0])
				y = float(values[1])
				if x < x_min:
					x_min = x
				if x > x_max:
					x_max = x
				if y < y_min:
					y_min = y
				if y > y_max:
					y_max = y

	# Buffer bounds
	x_min = x_min - BOUND_BUFFER
	x_max = x_max + BOUND_BUFFER
	y_min = y_min - BOUND_BUFFER
	y_max = y_max + BOUND_BUFFER

	# Cleanup bounding (per original script)
	x_min = -180 if x_min < -180 else x_min
	x_max = 180 if x_max > 180 else x_max
	y_min = -90 if y_min < -90 else y_min
	y_max = 90 if y_max > 90 else y_max

	# Dict w/ useful values
	values = {}
	values['bottom'] = y_min
	values['left'] = x_min
	values['top'] = y_max
	values['right'] = x_max

	x_center = (x_min + x_max) / 2.0
	y_center = (y_min + y_max) / 2.0

	values['lat'] = y_center
	values['lon'] = x_center

	return values