#!/usr/bin/env python3
# -*- coding:utf-8 -*-

from flexx import flx

from ipfsdocs.common import (
    URL,
    BootstrapDropdown,
)


class DownloadManager(flx.JsComponent):
    # cid, filename, mimetype
    current_download = flx.TupleProp(settable=True)
    download_queue = flx.ListProp(settable=True)
    progress = flx.FloatProp(settable=True)
    history = flx.DictProp(settable=True)
    prevented = flx.DictProp(settable=True)
    pause = flx.BoolProp(settable=True)

    def init(self):
        global window, JSON
        self.set_history(
            JSON.parse(
                window.localStorage.getItem("history")
                or "{}"
            )
        )

    @flx.reaction("history")
    def update_local_storage(self):
        global window, JSON
        window.localStorage.setItem(
            "history", JSON.stringify(self.history)
        )

    @flx.reaction("current_download")
    def trigger_download(self):
        if self.current_download != ():
            cid, filename, mimetype = self.current_download
            self._download(cid, filename, mimetype)

    @flx.reaction("download_queue", "current_download", "pause")
    def maybe_update_current_download(self, *events):
        if (
                self.current_download == ()
                and len(self.download_queue) > 0
                and not self.pause
        ):
            cid, filename, mimetype = self.pop_download()
            self.set_current_download((cid, filename, mimetype))

    def pop_download(self):
        self._pop_download()
        return self.download_queue[0]

    @flx.action
    def _pop_download(self):
        self._mutate_download_queue(1, "remove", 0)

    @flx.action
    def add_download(self, cid, filename, mimetype):
        if (
                cid in self.history
                or
                cid in [elem[0] for elem in self.download_queue]
                or cid == self.current_download[0]
        ):
            self._mutate_prevented({cid: True}, "insert",)
        else:
            self._mutate_download_queue(
                [(cid, filename, mimetype)],
                "insert",
                len(self.download_queue)
            )

    def onload(self, request, filename, mimetype):
        global download
        download(
            request.response,
            filename,
            mimetype,
        )

    @flx.action
    def push_to_history(self, cid):
        self._mutate_history({cid: True}, "insert")

    def _download(self, cid, filename, mimetype):
        self.push_to_history(cid)
        url = f"{URL}{cid}?filename={filename}"
        global XMLHttpRequest
        request = XMLHttpRequest()
        request.open(
            "GET",
            url,
            True
        )
        request.responseType = 'blob'
        request.onprogress = lambda event: self.set_progress(event.loaded / event.total)
        request.onload = lambda e: self.onload(request, filename, mimetype)
        request.onloadend = lambda: self.loadend()
        request.send()

    def loadend(self):
        # a download just finished, wait a bit to let the browser the time to
        # write on disk
        global window
        window.setTimeout(lambda: self.set_current_download(()), 5000)


class DownloadHandler(BootstrapDropdown):
    def init(self):
        self.set_text("\uf0ed")
        self.update_disabled()
        self.set_the_items()

    @flx.reaction("root.state.downloadmanager.pause")
    def set_the_items(self):
        self.set_items(
            [
                ("all", "\uf0ac"),
                ("selection", "\uf00c"),
                (None,),
                ("toggle_pause", ("\uf04b"
                                  if self.root.state.downloadmanager.pause
                                  else "\uf04c")),
                (None,),
                ("clean_queue", "\uf12d"),
                ("clean_history", "\uf0c7 \uf061 \uf12d"),
            ]
        )
        self.set_button_style(
            "SECONDARY"
            if self.root.state.downloadmanager.pause else
            "PRIMARY"
        )

    @flx.action
    def update_disabled(self):
        self._mutate_disabled_items(
            {
                "selection": not self.root.state.selection,
                "clean_history": not self.root.state.downloadmanager.history,
                "clean_queue": not self.root.state.downloadmanager.download_queue,
            },
            "insert"
        )

    @flx.reaction("root.state.downloadmanager.history", "root.state.selection", "root.state.downloadmanager.download_queue")
    def toggle_update_disabled(self):
        self.update_disabled()

    @flx.reaction("root.state.downloadmanager.prevented", "root.state.downloadmanager.download_queue")
    def update_on_prevented(self):
        text = '\uf0ed'
        if self.root.state.downloadmanager.download_queue:
            text += f" {len(self.root.state.downloadmanager.download_queue)}"
        if self.root.state.downloadmanager.prevented:
            text += f' ({len(self.root.state.downloadmanager.prevented.items())})'
        self.set_text(text)

    def download_url(self, url, filename, fast=False):
        global document
        a = document.createElement("a")
        a.download = filename
        if fast:
            base = URL
        else:
            base = ""
        url = base + url
        a.href = url
        a.target = "_blank"
        a.click()

    @flx.reaction("clicked")
    def on_clicked(self, *events):
        for event in events:
            if event.id == "all":
                for info_ in self.root.state.query_results:
                    self.root.state.downloadmanager.add_download(
                        info_["cid"], info_["filename"], info_["mimetype"]
                    )
            elif event.id == "selection":
                for info_ in [
                        self.root.state.get_info(cid)
                        for cid in self.root.state.selection
                ]:
                    self.root.state.downloadmanager.add_download(
                        info_["cid"], info_["filename"], info_["mimetype"]
                    )
            elif event.id == "clean_history":
                self.root.state.downloadmanager.set_history({})
                self.root.state.downloadmanager.set_prevented({})
            elif event.id == "toggle_pause":
                self.root.state.downloadmanager.set_pause(not self.root.state.downloadmanager.pause)
            elif event.id == "clean_queue":
                self.root.state.downloadmanager.set_download_queue([])