from cherrypy.process import plugins
import cherrypy

from queue import Queue, Empty
import threading
from collections import Counter, defaultdict

from imap_tools.errors import MailboxFolderSelectError

from .imapplugin import ImapPlugin
from .types import Site
from .db import DBPoolManager

from . import html

class Generator(plugins.SimplePlugin):
	def __init__(self,bus,imap:ImapPlugin,site:Site,dbpool:DBPoolManager):
		plugins.SimplePlugin.__init__(self,bus)

		self.imap=imap
		self.site=site
		self.dbpool=dbpool

		self.queue=Queue()
		self.stopping=threading.Event()
		self.thread=None

		cherrypy.engine.subscribe("regen",self.enqueue_update)
		cherrypy.engine.subscribe("generate::projectpage",self.generate_project_page_dynamically)

		self.statcache:dict[str,Counter]=defaultdict(lambda:Counter())

	def enqueue_update(self,project,bugid):
		self.queue.put((project,bugid),block=True)

	def start(self):
		self.mlog("Starting...")
		self.thread=threading.Thread(target=self.worker)
		self.thread.start()
	
	
	def worker(self):
		"""
		Listens to a queue and calls the page regenerator when requested via the queue.
		Use by putting a tuple `(project,bugid)` in :attr:`queue`
		"""
		threading.current_thread().setName("PageGenerator")
		dolog=True
		while not self.stopping.is_set():
			if dolog and self.queue.empty():
				self.mlog("Ready, waiting for items to enter queue...")
			try:
				proj,bug=self.queue.get(timeout=1)
			except Empty:
				dolog=False
				continue

			#self.mlog("Starting regen for %s/%s"%(proj or "",bug or ""))
			self.generate_page(project=proj,bug=bug)
			dolog=True


	def generate_page(self,project=None,bug=None):
		"Responsible for regenerating pages. Only generates bug pages, forwards any request to generate project pages to that function."
		if not bug and not project:
			return
		if project and not bug:
			return self.generate_project_page(project)

		try:
			bugobj=self.site.getbug(tracker=project,bugid=bug)
			with self.imap.get_MailBox() as mailbox:
				# cd into mailbox folder
				mailbox.folder.set(self.imap.get_bug_folder(mailbox,project,bug))
				pagelimit=25 # confusingly sets the limit on how many emails per page.
				currentpage=""
				pagenr=1
				emailsonpage=0

				from .util import (
					lookahead, # this allows us to detect when we reached the last message in the mailbox
					email2html
					)

				totalemails=mailbox.folder.status()["MESSAGES"] # only used for displaying to user and providing a `last page` link
				#totalemails=30*totalemails # again, for testing purposes
				totalpages=totalemails//pagelimit + min(totalemails%pagelimit,1)
				self.mlog("Generating %d pages from %d emails for %s/%d"%(totalpages,totalemails,project,bug))

				#mails=[i for i in mailbox.fetch()]*30 # DON'T UNCOMMENT, for testing purposes.
				# when using above line, change ``mailbox.fetch()`` below for ``mails``

				for msg, last in lookahead(mailbox.fetch()):
					# block: allow showing bug description
					# show an expandable thing with the original thing at the top of every page
					if emailsonpage==0:
						currentpage+='<details class="bugdesc"'
						if pagenr==1:
							currentpage+=' open'
						currentpage+='><summary>Click to expand bug description</summary>'
						currentpage+=email2html(bugobj.description)
						currentpage+='</details>'
					# end block

					# block: page generation
					currentpage+='<div class="emailheader" id="{n}"><a href="#{n}">#{n}</a> On {date}, {from_} wrote,<br>'.format(
						n=(pagenr-1)*25 +emailsonpage,
						date=msg.date_str,
						from_=msg.from_)
					currentpage+='with Subject: <i>%s</i></div>'%msg.subject
					currentpage+=email2html(msg.text, ispatch=msg.subject.startswith("[PATCH"))
					# end block
					emailsonpage+=1

					pageswitcher=''
					if pagenr>=2:
						pageswitcher+='<a href="/%s/%d/1">&lt;&lt;first</a> | '%(project,bug)
					if pagenr>=3:
						pageswitcher+='<a href="/%s/%d/%d">&lt;prev</a> | '%(project,bug,pagenr-1)
					pageswitcher+="[page %d/%d]"%(pagenr,totalpages)
					if totalpages-pagenr>1: # if more than 2 pages left
						pageswitcher+=' | <a href="/%s/%d/%d">next&gt;</a>'%(project,bug,pagenr+1)
					if totalpages-pagenr>0: # if more than 1 pages left
						pageswitcher+=' | <a href="/%s/%d/%d">last&gt;&gt;</a>'%(project,bug,totalpages)

					# block: complete page formatting, register page
					if emailsonpage>=pagelimit or last:

						#first=(pagenr-1)*25
						#jumptos="| jump: "+", ".join([
						#	'<a href="#%d">#%d</a>'%(i,i) for i in range(first, first+emailsonpage+1)
						#	])


						resultingpage=html.mailpage.format(
								emailaddr=self.imap.format_emailaddr(project,bug,subject="RE: "+bugobj.subject),
								subscribe=self.imap.format_emailaddr(project,bug,subject="SUBSCRIBE"),
								status=bugobj.status,
								bugtype=bugobj.type,
								project=project,
								bug=bug,
								subject=bugobj.subject,
								content=currentpage,
								pagenr=pagenr,
								pageswitcher=pageswitcher,
								jumptos=""
								)

						# subblock: register page
						path="%s/%d/%d"%(project,bug,pagenr)
						cherrypy.engine.publish(
							"newpage",
							path=path,
							content=resultingpage
							)
						# also register without page number if first page
						if pagenr==1:
							cherrypy.engine.publish(
								"newpage",
								path="%s/%d"%(project,bug),
								content=resultingpage
								)
						# end subblock

						# reset page-specific trackers
						currentpage=""
						emailsonpage=0
						pagenr+=1
					# end block

		except Exception:
			self.mlog("Error occured generating bug page for %s/%d"%(project,bug),traceback=True)
	
	def generate_project_page_dynamically(self,path='',**kwargs):
		if not path:
			return
		return self.generate_project_page(mailbox=None,proj=path,register=False,**kwargs)

	def generate_project_page(self,proj,register=True,**kwargs):
		from .html import projectpage
		from datetime import datetime, timedelta

		statc=self.statcache[proj]
		if register:
			statc.clear()

		self.mlog("Generating projectpage %s"%proj)
		
		if register:
			with self.imap.get_MailBox() as mailbox:
				self.mlog("Updating statcounter for %s"%proj)
				for folder in mailbox.folder.list(self.imap.get_bug_folder(mailbox,proj)):
					try:
						mailbox.folder.set(folder.name)
						for email in mailbox.fetch():
							statc["total"]+=1
							if email.date>datetime.now(tz=email.date.tzinfo)-timedelta(hours=24):
								statc["today"]+=1
							#self.mlog("%d: %s"%(statc["today"],email.subject))
					except MailboxFolderSelectError:
						pass

		with self.dbpool.get_connection() as conn, conn.cursor() as cur:
			args=[proj]
			extraquery=''
			if kwargs and not register:

				for bugtype in ["bug","patch","discus"]:
					if bugtype in kwargs:
						kwargs.setdefault("types",[]).append(bugtype.upper())
				for status in ["open","closed","reject","upstrm","unconf"]:
					if status in kwargs:
						kwargs.setdefault("status",[]).append(status.upper())

				if 'subject' in kwargs:
					extraquery+="AND LOWER(subject) LIKE LOWER(?)"
					args.append("%"+kwargs["subject"]+"%")
				if 'types' in kwargs:
					extraquery+="AND type IN ("+",".join("?"*len(kwargs["types"]))+")"
					args.extend(kwargs["types"])
				if 'status' in kwargs:
					extraquery+="AND status IN ("+",".join("?"*len(kwargs["status"]))+")"
					args.extend(kwargs["status"])

			filter_subject=kwargs.get("subject","")
			filter_by=kwargs.get("by","")
				
			def default_kws(*keys):
				for key in keys:
					if key in kwargs:
						break
				else:
					for key in keys:
						kwargs[key]="true"

			default_kws("bug","patch","discus")
			filter_bug=kwargs.get("bug")
			filter_patch=kwargs.get("patch")
			filter_discus=kwargs.get("discus")

			default_kws("open","closed","reject","upstrm","unconf")
			filter_open=kwargs.get("open")
			filter_closed=kwargs.get("closed")
			filter_reject=kwargs.get("reject")
			filter_upstrm=kwargs.get("upstrm")
			filter_unconf=kwargs.get("unconf")


			sql="SELECT bugid,subject,status,type FROM bugs WHERE tracker=? "+\
				extraquery+\
				" ORDER BY FIELD(status,'OPEN') DESC"
			#self.mlog(sql,args)

			cur.execute(sql,args)

			tabledata=""

			for id,subject,status,bugtype in cur:
				if register:
					statc[bugtype+status]+=1
					statc[bugtype]+=1

				tabledata+='<tr>'
				tabledata+='<td class="bugnr" id="bugid">%d</td>'%id
				tabledata+='<td id="subject"><a href="/%s/%d">%s</a></td>'%(proj,id,subject)
				tabledata+='<td id="status" class="status-{status}">{status}</td>'.format(status=status)
				tabledata+='<td id="type">%s</td>'%bugtype
				tabledata+='</tr>'



		result=projectpage.format(
			project=proj,
			emailaddr=self.imap.format_emailaddr(project=proj),
			readme="TODO",

			mailtoday=statc["today"],mailtotal=statc["total"],

			bugstotal=statc["BUG"],
			bugsopen=statc["BUGOPEN"],
			bugsclosed=statc["BUGCLOSED"],

			patchestotal=statc["PATCH"],
			patchesopen=statc["PATCHOPEN"],
			patchesclosed=statc["PATCHCLOSED"],
			patchesrejected=statc["PATCHREJECT"],

			filter_subject=filter_subject,
			filter_by=filter_by,

			filter_bug="checked" if filter_bug else "",
			filter_patch="checked" if filter_patch else "",
			filter_discus="checked" if filter_discus else "",

			filter_open="checked" if filter_open else "",
			filter_closed="checked" if filter_closed else "",
			filter_reject="checked" if filter_reject else "",
			filter_upstrm="checked" if filter_upstrm else "",
			filter_unconf="checked" if filter_unconf else "",

			maillist=tabledata
			)
		if register:
			cherrypy.engine.publish(
				"newpage",
				path=proj,
				content=result,
				regentoken="projectpage"
				)
		else:
			return result
	
	def stop(self):
		if not self.thread or not self.thread.is_alive():
			return
		self.mlog("Signalling stop to page generator")
		self.stopping.set()
		self.thread.join()
		self.mlog("Stopped")

	
	def mlog(self,*msg,**kwargs):
		import traceback
		function=traceback.extract_stack(limit=2)[0].name
		cherrypy.log(context="%s>>REGEN:%s"%(threading.current_thread().name, function), msg=" ".join([str(i) for i in msg]),**kwargs)