import subprocess
import re
import sys
import requests
import json
import asyncio
from typing import List, Tuple

import aiohttp
from flask import current_app
from time import sleep
from os.path import join
from subprocess import run

from capsulflask.db_model import OnlineHost
from capsulflask.spoke_model import VirtualMachine
from capsulflask.spoke_model import validate_capsul_id
from capsulflask.db import get_model, my_exec_info_message

class HTTPResult:
  def __init__(self, status_code, body=None):
    self.status_code = status_code
    self.body = body

class HubInterface:
  def capacity_avaliable(self, additional_ram_bytes: int) -> bool:
    pass

  def get(self, id: str) -> VirtualMachine:
    pass

  def list_ids(self) -> list:
    pass

  def create(self, email: str, id: str, template_image_file_name: str, vcpus: int, memory: int, ssh_public_keys: list):
    pass

  def destroy(self, email: str, id: str):
    pass

class MockHub(HubInterface):
  def capacity_avaliable(self, additional_ram_bytes):
    return True

  def get(self, id):
    validate_capsul_id(id)
    return VirtualMachine(id, current_app.config["SPOKE_HOST_ID"], ipv4="1.1.1.1")

  def list_ids(self) -> list:
    return get_model().all_non_deleted_vm_ids()

  def create(self, email: str, id: str, template_image_file_name: str, vcpus: int, memory_mb: int, ssh_public_keys: list):
    validate_capsul_id(id)
    current_app.logger.info(f"mock create: {id} for {email}")
    sleep(1)

  def destroy(self, email: str, id: str):
    current_app.logger.info(f"mock destroy: {id} for {email}")


class CapsulFlaskHub(HubInterface):

  
  async def post_json(self, method: str, url: str,  body: str, session: aiohttp.ClientSession) -> HTTPResult:
      response = None
      try:
        response = await session.request(
          method=method, 
          url=url, 
          json=body, 
          auth=aiohttp.BasicAuth("hub", current_app.config['HUB_TOKEN']), 
          verify_ssl=True,
        )
      except:
        error_message = my_exec_info_message(sys.exc_info())
        response_body = json.dumps({"error_message": f"error contacting spoke: {error_message}"})
        current_app.logger.error(f"""
          error contacting spoke: post_json (HTTP {method} {url}) failed with: {error_message}"""
        )
        return HTTPResult(-1, response_body)

      response_body = None
      try:
        response_body = await response.text()
      except:
        error_message = my_exec_info_message(sys.exc_info())
        response_body = json.dumps({"error_message": f"error reading response from spoke: {error_message}"})
        current_app.logger.error(f"""
          error reading response from spoke: HTTP {method} {url} (status {response.status}) failed with: {error_message}"""
        )
        
      return HTTPResult(response.status, response_body)

  async def make_requests(self, online_hosts: List[OnlineHost], body: str) -> List(HTTPResult):
      timeout_seconds = 5
      async with aiohttp.ClientSession(timeout=aiohttp.ClientTimeout(total=timeout_seconds)) as session:
          tasks = []
          # append to tasks in the same order as online_hosts
          for host in online_hosts:
              tasks.append(
                  self.post_json(method="POST", url=host.url, body=body, session=session)
              )
          # gather is like Promise.all from javascript, it returns a future which resolves to an array of results 
          # in the same order as the tasks that we passed in -- which were in the same order as online_hosts
          results = await asyncio.gather(*tasks)

          return results
          

  async def generic_operation(self, hosts: List[OnlineHost], payload: str, immediate_mode: bool) -> Tuple[int, List[HTTPResult]]:
    operation_id = get_model().create_operation(hosts, payload)
    results = await self.make_requests(hosts, payload)
    for i in range(len(hosts)):
      host = hosts[i]
      result = results[i]
      task_result = None
      assignment_status = "pending"
      if result.status_code == -1:
        assignment_status = "no_response_from_host"
      if result.status_code != 200:
        assignment_status = "error_response_from_host"
      else:
        valid_statuses = {
          "assigned": True,
          "not_applicable": True,
          "assigned_to_other_host": True,
        }
        result_is_json = False
        result_is_dict = False
        result_has_status = False
        result_has_valid_status = False
        assignment_status = "invalid_response_from_host"
        try:
          if immediate_mode:
            task_result = result.body
          result_body = json.loads(result.body)
          result_is_json = True
          result_is_dict = isinstance(result_body, dict)
          result_has_status = result_is_dict and 'assignment_status' in result_body
          result_has_valid_status = result_has_status and result_body['assignment_status'] in valid_statuses
          if result_has_valid_status:
            assignment_status = result_body['assignment_status']
        except:
          pass

        if not result_has_valid_status: 
          current_app.logger.error(f"""error reading assignment_status for operation {operation_id} from host {host.id}: 
              result_is_json: {result_is_json}
              result_is_dict: {result_is_dict}
              result_has_status: {result_has_status}
              result_has_valid_status: {result_has_valid_status}
            """
          )

      get_model().update_host_operation(host.id, operation_id, assignment_status, task_result)
    
    return results

  async def capacity_avaliable(self, additional_ram_bytes):
    online_hosts = get_model().get_online_hosts()
    payload = json.dumps(dict(type="capacity_avaliable", additional_ram_bytes=additional_ram_bytes))
    op = await self.generic_operation(online_hosts, payload, True)
    results = op[1]
    for result in results:
      try:
        result_body = json.loads(result.body)
        if isinstance(result_body, dict) and 'capacity_avaliable' in result_body and result_body['capacity_avaliable'] == True:
          return True
      except: 
        pass

    return False
    

  async def get(self, id) -> VirtualMachine:
    validate_capsul_id(id)
    host = get_model().host_of_capsul(id)
    if host is not None:
      payload = json.dumps(dict(type="get", id=id))
      op = await self.generic_operation([host], payload, True)
      results = op[1]
      for result in results:
        try:
          result_body = json.loads(result.body)
          if isinstance(result_body, dict) and ('ipv4' in result_body or 'ipv6' in result_body):
            return VirtualMachine(id, host=host, ipv4=result_body['ipv4'], ipv6=result_body['ipv6'])
        except: 
          pass

    return None

  def list_ids(self) -> list:
    online_hosts = get_model().get_online_hosts()
    payload = json.dumps(dict(type="list_ids"))
    op = await self.generic_operation(online_hosts, payload, False)
    operation_id = op[0]
    results = op[1]
    to_return = []
    for i in range(len(results)):
      host = online_hosts[i]
      result = results[i]
      try:
        result_body = json.loads(result.body)
        if isinstance(result_body, dict) and 'ids' in result_body and isinstance(result_body['ids'], list):
          all_valid = True
          for id in result_body['ids']:
            try:
              validate_capsul_id(id)
              to_return.append(id)
            except:
              all_valid = False
          if all_valid:
            get_model().update_host_operation(host.id, operation_id, None, result.body)
          else:
            result_json_string = json.dumps({"error_message": "invalid capsul id returned"})
            get_model().update_host_operation(host.id, operation_id, None, result_json_string)
            current_app.logger.error(f"""error reading ids for list_ids operation {operation_id}, host {host.id}""")
        else:
            result_json_string = json.dumps({"error_message": "invalid response, missing 'ids' list"})
            get_model().update_host_operation(host.id, operation_id, "invalid_response_from_host", result_json_string)
            current_app.logger.error(f"""missing 'ids' list for list_ids operation {operation_id}, host {host.id}""")
      except:
        # no need to do anything here since if it cant be parsed then generic_operation will handle it.
        pass

    return to_return

  def create(self, email: str, id: str, template_image_file_name: str, vcpus: int, memory_mb: int, ssh_public_keys: list):
    validate_capsul_id(id)
    online_hosts = get_model().get_online_hosts()
    payload = json.dumps(dict(
      type="create", 
      email=email, 
      id=id, 
      template_image_file_name=template_image_file_name, 
      vcpus=vcpus,
      memory_mb=memory_mb,
      ssh_public_keys=ssh_public_keys,
    ))
    op = await self.generic_operation(online_hosts, payload, False)
    operation_id = op[0]
    results = op[1]
    number_of_assigned = 0
    error_message = ""
    assigned_hosts = []
    for i in range(len(results)):
      host = online_hosts[i]
      result = results[i]
      try:
        result_body = json.loads(result.body)
        if isinstance(result_body, dict) and 'assignment_status' in result_body and result_body['assignment_status'] == "assigned":
          number_of_assigned += 1
          assigned_hosts.append(host.id)
        if isinstance(result_body, dict) and 'error_message' in result_body:
          error_message = result_body['error_message']
      except:
        # no need to do anything here since if it cant be parsed then generic_operation will handle it.
        pass
      
    if number_of_assigned != 1:
      assigned_hosts_string = ", ".join(assigned_hosts)
      raise ValueError(f"expected create capsul operation {operation_id} to be assigned to one host, it was assigned to {number_of_assigned} ({assigned_hosts_string})")
    if error_message != "":
      raise ValueError(f"create capsul operation {operation_id} on {assigned_hosts_string} failed with {error_message}")
      

  def destroy(self, email: str, id: str):
    validate_capsul_id(id)
    result_status = None
    host = get_model().host_of_capsul(id)
    if host is not None:
      payload = json.dumps(dict(type="destroy", id=id))
      op = await self.generic_operation([host], payload, True)
      results = op[1]
      result_json_string = "<no response from host>"
      for result in results:
        try:
          result_json_string = result.body
          result_body = json.loads(result_json_string)
          if isinstance(result_body, dict) and 'status' in result_body:
            result_status = result_body['status']
        except: 
          pass

    if not result_status == "success":
      raise ValueError(f"""failed to destroy vm "{id}" on host "{host}" for {email}: {result_json_string}""")