import uuid
import os
import zipfile
import shutil
import sys
import urllib.request
import gzip

from flask import Flask
from flask import render_template
from flask import request

from terrain_gen import add_offset

# The output folder for all gzipped terrain requests
app = Flask(__name__, static_url_path='/terrain', static_folder='outputTer',)

# Directory of this file
this_path = os.path.dirname(os.path.realpath(__file__))

def clamp(n, smallest, largest):
    return max(smallest, min(n, largest))

def getDatFile(lat, lon):
    '''Get file'''
    if lat < 0:
        NS = 'S'
    else:
        NS = 'N'
    if lon < 0:
        EW = 'W'
    else:
        EW = 'E'
    return "%c%02u%c%03u.DAT.gz" % (NS, min(abs(int(lat)), 99), EW, min(abs(int(lon)), 999))

def compressFiles(fileList, uuidkey, outfolder):
    # create a zip file comprised of dat.gz tiles
    zipthis = os.path.join(this_path, outfolder, uuidkey + '.zip')
    foldertmp = os.path.join(this_path, outfolder + "-tmp", uuidkey)

    # create tmp and output dirs if needed
    os.makedirs(foldertmp)
    try:
        os.makedirs(os.path.join(this_path, outfolder))
    except OSError:
        pass

    try:
        with zipfile.ZipFile(zipthis, 'w') as terrain_zip:
            for fn in fileList:
                if not os.path.exists(fn):
                    #download if required
                    g = urllib.request.urlopen('https://firmware.ardupilot.org/terrain/terraingen/processedTerrain/' + os.path.basename(fn))
                    print("Downloaded " + os.path.basename(fn))
                    with open(fn, 'b+w') as f:
                        f.write(g.read())

                # need to decompress file
                datfile = os.path.join(foldertmp, os.path.basename(fn)[:-3])
                with gzip.open(fn, 'r') as f_in, open(datfile, 'wb') as f_out:
                    shutil.copyfileobj(f_in, f_out)
                    print("Decomp " + os.path.basename(fn))

                # and add file to zip
                terrain_zip.write(datfile, os.path.basename(datfile), compress_type = zipfile.ZIP_DEFLATED)

            # remove cache (decompressed files)
            shutil.rmtree(foldertmp)
    except Exception as ex:
        print("Unexpected error: {0}".format(ex))
        return False
        
     
    #terrain_zip.close()
    return True

@app.route('/')
def index():
    return render_template('index.html')

@app.route('/generate', methods=['GET', 'POST'])
def generate():
    if request.method == 'POST':
        # parse and sanitise the input
        try:
            # request.form['username']
            lat = float(request.form['lat'])
            lon = float(request.form['long'])
            radius = int(request.form['radius'])
            assert lat < 90
            assert lon < 180
            assert lat > -90
            assert lon > -180
            radius = clamp(radius, 1, 400)
        except:
            print("Bad data")
            return render_template('generate.html', error = "Error with input")

        # UUID for this terrain generation
        uuidkey = str(uuid.uuid1())

        # Flag for if user wanted a tile outside +-60deg latitude
        outsideLat = None

        # get a list of files required to cover area
        filelist = []
        done = set()
        for dx in range(-radius, radius):
            for dy in range(-radius, radius):
                (lat2, lon2) = add_offset(lat*1e7, lon*1e7, dx*1000.0, dy*1000.0)
                lat_int = int(round(lat2 * 1.0e-7))
                lon_int = int(round(lon2 * 1.0e-7))
                tag = (lat_int, lon_int)
                if tag in done:
                    continue
                done.add(tag)
                # make sure tile is inside the 60deg latitude limit
                if (abs(lat_int) < 60):
                    filelist.append(os.path.join(this_path, "processedTerrain", getDatFile(lat_int, lon_int)))
                else:
                    outsideLat = True

        # make sure tile is inside the 60deg latitude limit
        if (abs(lat_int) < 60):
            filelist.append(os.path.join(this_path, "processedTerrain", getDatFile(lat_int, lon_int)))
        else:
            outsideLat = True

        # remove duplicates
        filelist = list(dict.fromkeys(filelist))
        print(filelist)


        #compress
        success = compressFiles(filelist, uuidkey, 'outputTer')
        
        if success:
            print("Generated " + "/terrain/" + uuidkey + ".zip")
            return render_template('generate.html', urlkey="/terrain/" + uuidkey + ".zip", uuidkey=uuidkey, outsideLat=outsideLat)
        else:
            print("Failed " + "/terrain/" + uuidkey + ".zip")
            return render_template('generate.html', error="Cannot generate terrain", uuidkey=uuidkey)
    else:
        print("Bad get")
        return render_template('generate.html', error="Need to use POST, not GET")

if __name__ == "__main__":
    app.run()