import sys
import sqlite3
import os
import json

# print help?
if len(sys.argv) == 1 or sys.argv[1] in ['-h', '--help', 'help', '/?']:
    print "Usage: python extract.py mbtiles_file_name"
    quit()

mbtiles_file = sys.argv[1]

# make sure file exist
try:
   with open(mbtiles_file) as f: pass
except IOError as e:
   print "File '%s' doesn't exists" % mbtiles_file
   quit()

# open sqlite3 database
conn = sqlite3.connect(mbtiles_file)

# get tile format from metadata table
format_row = conn.execute('SELECT value FROM metadata WHERE name = ?', ['format']).fetchone()
if format_row:
    format = format_row[0]
else:
    format = 'png'  # default is png

# get map name (root dir for extracted tiles)
dir_root = mbtiles_file[:mbtiles_file.rfind('.')]
if not os.path.exists(dir_root):
    os.makedirs(dir_root)

# dump all metadata as json
metadata_dict = { }
for row in conn.execute('SELECT name, value FROM metadata'):
    metadata_dict[row[0]] = row[1]
f = open(dir_root + '/metadata.json', 'w+')
json.dump(metadata_dict, f)

# fetch all tile rows
for row in conn.execute('SELECT zoom_level, tile_row, tile_column, tile_data FROM tiles ORDER BY zoom_level, tile_row, tile_column'):
    # create directory if it doesn't already exist
    dir_name = dir_root + '/' + str(row[0])
    if not os.path.exists(dir_name):
        os.makedirs(dir_name)

    # tile_name = str(row[1]) + '_' + str(row[2]) + 
    tile_name = '%d_%d.%s' % (row[1], row[2], format)

    # dump tile data (png or jpg image)
    f = open(dir_name + '/' + tile_name, 'w+')
    f.write(row[3])