"""

 (c) Copyright Ascensio System SIA 2020
 *
 The MIT License (MIT)

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.

"""

import os
import io
import json
import config

from . import users, fileUtils
from datetime import datetime
from src import settings
from src.utils import docManager
from src.utils import jwtManager
    
def getHistoryDir(storagePath):
    return f'{storagePath}-hist'

def getVersionDir(histDir, version):
    return os.path.join(histDir, str(version))

def getFileVersion(histDir):
    if not os.path.exists(histDir):
        return 0

    cnt = 1

    for f in os.listdir(histDir):
        if not os.path.isfile(os.path.join(histDir, f)):
            cnt += 1
    
    return cnt

def getNextVersionDir(histDir):
    v = getFileVersion(histDir)
    path = getVersionDir(histDir, v)

    if not os.path.exists(path):
        os.makedirs(path)
    return path

def getChangesZipPath(verDir):
    return os.path.join(verDir, 'diff.zip')

def getChangesHistoryPath(verDir):
    return os.path.join(verDir, 'changes.json')

def getPrevFilePath(verDir, ext):
    return os.path.join(verDir, f'prev{ext}')

def getKeyPath(verDir):
    return os.path.join(verDir, 'key.txt')

def getMetaPath(histDir):
    return os.path.join(histDir, 'createdInfo.json')

def createMeta(storagePath, req):
    histDir = getHistoryDir(storagePath)
    path = getMetaPath(histDir)

    if not os.path.exists(histDir):
        os.makedirs(histDir)

    user = users.getUserFromReq(req)

    obj = {
        'created': datetime.today().strftime('%Y-%m-%d %H:%M:%S'),
        'uid': user['uid'],
        'uname': user['uname']
    }

    writeFile(path, json.dumps(obj))
    
    return

def writeFile(path, content):
    with io.open(path, 'w') as out:
        out.write(content)
    return

def readFile(path):
    with io.open(path, 'r') as stream:
        return stream.read()

def getPrevUri(filename, ver, ext, req):
    host = docManager.getServerUrl(True, req)
    curAdr = req.META['REMOTE_ADDR']
    return f'{host}{settings.STATIC_URL}{curAdr}/{filename}-hist/{ver}/prev{ext}'

def getZipUri(filename, ver, req):
    host = docManager.getServerUrl(True, req)
    curAdr = req.META['REMOTE_ADDR']
    return f'{host}{settings.STATIC_URL}{curAdr}/{filename}-hist/{ver}/diff.zip'

def getMeta(storagePath):
    histDir = getHistoryDir(storagePath)
    path = getMetaPath(histDir)

    if os.path.exists(path):
        with io.open(path, 'r') as stream:
            return json.loads(stream.read())
    
    return None

def getHistoryObject(storagePath, filename, docKey, docUrl, req):
    histDir = getHistoryDir(storagePath)
    version = getFileVersion(histDir)
    if version > 0:
        hist = []
        histData = {}
        
        for i in range(1, version + 1):
            obj = {}
            dataObj = {}
            prevVerDir = getVersionDir(histDir, i - 1)
            verDir = getVersionDir(histDir, i)

            try:
                key = docKey if i == version else readFile(getKeyPath(verDir))

                obj['key'] = key
                obj['version'] = i
                dataObj['key'] = key
                dataObj['version'] = i

                if i == 1:
                    meta = getMeta(storagePath)
                    if meta:
                        obj['created'] = meta['created']
                        obj['user'] = {
                            'id': meta['uid'],
                            'name': meta['uname']
                        }
                    
                dataObj['url'] = docUrl if i == version else getPrevUri(filename, i, fileUtils.getFileExt(filename), req)

                if i > 1:
                    changes = json.loads(readFile(getChangesHistoryPath(prevVerDir)))
                    change = changes['changes'][0]
                    
                    obj['changes'] = changes['changes']
                    obj['serverVersion'] = changes['serverVersion']
                    obj['created'] = change['created']
                    obj['user'] = change['user']

                    prev = histData[str(i - 2)]
                    prevInfo = {
                        'key': prev['key'],
                        'url': prev['url']
                    }
                    dataObj['previous'] = prevInfo
                    dataObj['changesUrl'] = getZipUri(filename, i - 1, req)

                if jwtManager.isEnabled():
                    dataObj['token'] = jwtManager.encode(dataObj) 

                hist.append(obj)
                histData[str(i - 1)] = dataObj
            except Exception:
                return {}
        
        histObj = {
            'currentVersion': version,
            'history': hist
        }

        return { 'history': histObj, 'historyData': histData }
    return {}


class CorsHeaderMiddleware:
    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        resp = self.get_response(request)
        if request.path.endswith('.zip'):
            resp['Access-Control-Allow-Origin'] = '*'
        return resp