import json
import re

from bridge import AsyncBridge as Bridge
from browser import aio, console as log, document, timer, window
import dialog
import errors
from javascript import JSObject
import jid

log.warning = log.warn
profile = window.profile or ""
bridge = Bridge()


class WebRTC:
    def __init__(
        self,
        screen_sharing_cb=None,
        on_connection_established_cb=None,
        on_reconnect_cb=None,
        on_connection_lost_cb=None,
        on_video_devices=None,
        on_reset_cb=None,
    ):
        # reset
        self.on_reset_cb = on_reset_cb
        self.reset_instance()

        # ICE events
        bridge.register_signal("ice_candidates_new", self._on_ice_candidates_new)
        bridge.register_signal("ice_restart", self._on_ice_restart)

        # connection events callbacks
        self.on_connection_established_cb = on_connection_established_cb
        self.on_reconnect_cb = on_reconnect_cb
        self.on_connection_lost_cb = on_connection_lost_cb

        # video devices
        self.on_video_devices = on_video_devices
        self.video_devices = []
        self.has_multiple_cameras = False
        self.current_camera = None

        # Initially populate the video devices list
        aio.run(self._populate_video_devices())

        # muting
        self.is_audio_muted = None
        self.is_video_muted = None

        # screen sharing
        self._is_sharing_screen = False
        self.screen_sharing_cb = screen_sharing_cb

        # video elements
        self.local_video_elt = document["local_video"]
        self.remote_video_elt = document["remote_video"]

    @property
    def is_sharing_screen(self) -> bool:
        return self._is_sharing_screen

    @is_sharing_screen.setter
    def is_sharing_screen(self, sharing: bool) -> None:
        if sharing != self._is_sharing_screen:
            self._is_sharing_screen = sharing
            if self.screen_sharing_cb is not None:
                self.screen_sharing_cb(sharing)

    def reset_instance(self):
        """Inits or resets the instance variables to their default state."""
        self._peer_connection = None
        self._media_types = None
        self._media_types_inv = None
        self._callee = None
        self.ufrag = None
        self.pwd = None
        self.sid = None
        self.local_candidates = None
        self.remote_stream = None
        self.remote_candidates_buffer = {
            "audio": {"candidates": []},
            "video": {"candidates": []},
        }
        self.local_candidates_buffer = {}
        self.media_candidates = {}
        if self.on_reset_cb is not None:
            self.on_reset_cb()

    async def _populate_video_devices(self):
        devices = await window.navigator.mediaDevices.enumerateDevices()
        devices_ids = set()
        self.video_devices.clear()
        for device in devices:
            if device.kind != "videoinput":
                continue
            # we can have multiple devices with same IDs in some corner cases (e.g.
            # infrared camera)
            device_id = device.deviceId
            if device_id in devices_ids:
                continue
            devices_ids.add(device_id)
            self.video_devices.append(device)
        self.has_multiple_cameras = len(self.video_devices) > 1
        if self.on_video_devices is not None:
            self.on_video_devices(self.has_multiple_cameras)
        # Set the initial camera to the default (usually front on mobile)
        if self.video_devices:
            self.current_camera = self.video_devices[0].deviceId
        log.debug(
            f"devices populated: {self.video_devices=} {self.has_multiple_cameras=}"
        )

    @property
    def media_types(self):
        if self._media_types is None:
            raise Exception("self._media_types should not be None!")
        return self._media_types

    @media_types.setter
    def media_types(self, new_media_types: dict) -> None:
        self._media_types = new_media_types
        self._media_types_inv = {v: k for k, v in new_media_types.items()}

    @property
    def media_types_inv(self) -> dict:
        if self._media_types_inv is None:
            raise Exception("self._media_types_inv should not be None!")
        return self._media_types_inv

    def get_sdp_mline_index(self, media_type):
        """Gets the sdpMLineIndex for a given media type.

        @param media_type: The type of the media.
        """
        for index, m_type in self.media_types.items():
            if m_type == media_type:
                return index
        raise ValueError(f"Media type '{media_type}' not found")

    def extract_ufrag_pwd(self, sdp: str) -> tuple[str, str]:
        """Retrieves ICE password and user fragment for SDP offer.

        @param sdp: The Session Description Protocol offer string.
        @return: ufrag and pwd
        @raise ValueError: Can't extract ufrag and password
        """
        ufrag_line = re.search(r"ice-ufrag:(\S+)", sdp)
        pwd_line = re.search(r"ice-pwd:(\S+)", sdp)

        if ufrag_line and pwd_line:
            ufrag = self.ufrag = ufrag_line.group(1)
            pwd = self.pwd = pwd_line.group(1)
            return ufrag, pwd
        else:
            log.error(f"SDP with missing ice-ufrag or ice-pwd:\n{sdp}")
            raise ValueError("Can't extract ice-ufrag and ice-pwd from SDP")

    def extract_fingerprint_data(self, sdp):
        """Retrieves fingerprint data from an SDP offer.

        @param sdp: The Session Description Protocol offer string.
        @return: A dictionary containing the fingerprint data.
        """
        fingerprint_line = re.search(r"a=fingerprint:(\S+)\s+(\S+)", sdp)
        if fingerprint_line:
            algorithm, fingerprint = fingerprint_line.groups()
            fingerprint_data = {"hash": algorithm, "fingerprint": fingerprint}

            setup_line = re.search(r"a=setup:(\S+)", sdp)
            if setup_line:
                setup = setup_line.group(1)
                fingerprint_data["setup"] = setup

            return fingerprint_data
        else:
            raise ValueError("fingerprint should not be missing")

    def parse_ice_candidate(self, candidate_string):
        """Parses the ice candidate string.

        @param candidate_string: The ice candidate string to be parsed.
        """
        pattern = re.compile(
            r"candidate:(?P<foundation>\S+) (?P<component_id>\d+) (?P<transport>\S+) "
            r"(?P<priority>\d+) (?P<address>\S+) (?P<port>\d+) typ "
            r"(?P<type>\S+)(?: raddr (?P<rel_addr>\S+) rport "
            r"(?P<rel_port>\d+))?(?: generation (?P<generation>\d+))?"
        )
        match = pattern.match(candidate_string)
        if match:
            candidate_dict = match.groupdict()

            # Apply the correct types to the dictionary values
            candidate_dict["component_id"] = int(candidate_dict["component_id"])
            candidate_dict["priority"] = int(candidate_dict["priority"])
            candidate_dict["port"] = int(candidate_dict["port"])

            if candidate_dict["rel_port"]:
                candidate_dict["rel_port"] = int(candidate_dict["rel_port"])

            if candidate_dict["generation"]:
                candidate_dict["generation"] = candidate_dict["generation"]

            # Remove None values
            return {k: v for k, v in candidate_dict.items() if v is not None}
        else:
            log.warning(f"can't parse candidate: {candidate_string!r}")
            return None

    def build_ice_candidate(self, parsed_candidate):
        """Builds ICE candidate

        @param parsed_candidate: Dictionary containing parsed ICE candidate
        """
        base_format = (
            "candidate:{foundation} {component_id} {transport} {priority} "
            "{address} {port} typ {type}"
        )

        if parsed_candidate.get("rel_addr") and parsed_candidate.get("rel_port"):
            base_format += " raddr {rel_addr} rport {rel_port}"

        if parsed_candidate.get("generation"):
            base_format += " generation {generation}"

        return base_format.format(**parsed_candidate)

    def on_ice_candidate(self, event):
        """Handles ICE candidate event

        @param event: Event containing the ICE candidate
        """
        log.debug(f"on ice candidate {event.candidate=}")
        if event.candidate and event.candidate.candidate:
            parsed_candidate = self.parse_ice_candidate(event.candidate.candidate)
            if parsed_candidate is None:
                return
            try:
                media_type = self.media_types[event.candidate.sdpMLineIndex]
            except (TypeError, IndexError):
                log.error(
                    f"Can't find media type.\n{event.candidate=}\n{self._media_types=}"
                )
                return
            self.media_candidates.setdefault(media_type, []).append(parsed_candidate)
            log.debug(f"ICE candidate [{media_type}]: {event.candidate.candidate}")
            if self.sid is None:
                log.debug("buffering candidate")
                self.local_candidates_buffer.setdefault(media_type, []).append(
                    parsed_candidate
                )
            else:
                ufrag, pwd = self.extract_ufrag_pwd(
                    self._peer_connection.localDescription.sdp
                )

                ice_data = {"ufrag": ufrag, "pwd": pwd, "candidates": [parsed_candidate]}
                aio.run(
                    bridge.ice_candidates_add(
                        self.sid, json.dumps({media_type: ice_data})
                    )
                )

        else:
            log.debug("All ICE candidates gathered")

    def on_ice_connection_state_change(self, event):
        """Log ICE connection change, mainly used for debugging"""
        state = self._peer_connection.iceConnectionState
        log.info(f"ICE Connection State changed to: {state}")

        if state == "connected":
            if self.on_connection_established_cb is not None:
                self.on_connection_established_cb()
        elif state == "failed":
            log.error(
                "ICE connection failed. Check network connectivity and ICE configurations."
            )
        elif state == "disconnected":
            log.warning("ICE connection was disconnected.")
            if self.on_connection_lost_cb is not None:
                self.on_connection_lost_cb()

    def on_ice_candidate_error(self, event):
        """Log ICE error, useful for debugging"""
        log.error(f"ICE Candidate Error: {event.errorText} (Code: {event.errorCode})")
        log.debug(
            f"URL: {event.url}, Host candidate: {event.hostCandidate}, Port: {event.port}"
        )

    def _set_media_types(self, offer):
        """Sets media types from offer SDP

        @param offer: RTC session description containing the offer
        """
        sdp_lines = offer.sdp.splitlines()
        media_types = {}
        mline_index = 0

        for line in sdp_lines:
            if line.startswith("m="):
                media_types[mline_index] = line[2 : line.find(" ")]
                mline_index += 1

        self.media_types = media_types

    def on_ice_gathering_state_change(self, event):
        """Handles ICE gathering state change

        @param event: Event containing the ICE gathering state change
        """
        connection = event.target
        log.debug(f"on_ice_gathering_state_change {connection.iceGatheringState=}")
        if connection.iceGatheringState == "complete":
            log.info("ICE candidates gathering done")

    async def _create_peer_connection(
        self,
    ):
        """Creates peer connection"""
        if self._peer_connection is not None:
            raise Exception("create_peer_connection can't be called twice!")

        external_disco = json.loads(await bridge.external_disco_get(""))
        ice_servers = []

        for server in external_disco:
            ice_server = {}
            if server["type"] == "stun":
                ice_server["urls"] = f"stun:{server['host']}:{server['port']}"
            elif server["type"] == "turn":
                ice_server[
                    "urls"
                ] = f"turn:{server['host']}:{server['port']}?transport={server['transport']}"
                ice_server["username"] = server["username"]
                ice_server["credential"] = server["password"]
            ice_servers.append(ice_server)

        rtc_configuration = {"iceServers": ice_servers}

        peer_connection = window.RTCPeerConnection.new(rtc_configuration)
        peer_connection.addEventListener("track", self.on_track)
        peer_connection.addEventListener("negotiationneeded", self.on_negotiation_needed)
        peer_connection.addEventListener(
            "iceconnectionstatechange", self.on_ice_connection_state_change
        )
        peer_connection.addEventListener("icecandidate", self.on_ice_candidate)
        peer_connection.addEventListener("icecandidateerror", self.on_ice_candidate_error)
        peer_connection.addEventListener(
            "icegatheringstatechange", self.on_ice_gathering_state_change
        )

        self._peer_connection = peer_connection
        window.pc = self._peer_connection

    async def _get_user_media(self, audio: bool = True, video: bool = True) -> None:
        """
        Gets user media (camera and microphone).

        @param audio: True if an audio flux is required.
        @param video: True if a video flux is required.
        """
        media_constraints = {"audio": audio, "video": video}
        local_stream = await window.navigator.mediaDevices.getUserMedia(media_constraints)

        if not local_stream:
            log.error("Failed to get the media stream.")
            return

        self.local_video_elt.srcObject = local_stream

        for track in local_stream.getTracks():
            self._peer_connection.addTrack(track)

    async def _replace_user_video(
        self,
        screen: bool = False,
    ) -> JSObject | None:
        """Replaces the user video track with either a camera or desktop sharing track.

        @param screen: True if desktop sharing is required. False will use the camera.
        @return: The local media stream or None if failed.
        """
        if screen:
            media_constraints = {"video": {"cursor": "always"}}
            new_stream = await window.navigator.mediaDevices.getDisplayMedia(
                media_constraints
            )
        else:
            if self.local_video_elt.srcObject:
                for track in self.local_video_elt.srcObject.getTracks():
                    if track.kind == "video":
                        track.stop()

            media_constraints = {
                "video": {"deviceId": self.current_camera}
                if self.current_camera
                else True
            }

            new_stream = await window.navigator.mediaDevices.getUserMedia(
                media_constraints
            )

        if not new_stream:
            log.error("Failed to get the media stream.")
            return None

        new_video_tracks = [
            track for track in new_stream.getTracks() if track.kind == "video"
        ]

        if not new_video_tracks:
            log.error("Failed to retrieve the video track from the new stream.")
            return None

        # Retrieve the current local stream's video track.
        local_stream = self.local_video_elt.srcObject
        if local_stream:
            local_video_tracks = [
                track for track in local_stream.getTracks() if track.kind == "video"
            ]
            if local_video_tracks:
                # Remove the old video track and add the new one to the local stream.
                local_stream.removeTrack(local_video_tracks[0])
                local_stream.addTrack(new_video_tracks[0])

        video_sender = next(
            (
                sender
                for sender in self._peer_connection.getSenders()
                if sender.track and sender.track.kind == "video"
            ),
            None,
        )
        if video_sender:
            await video_sender.replaceTrack(new_video_tracks[0])

            if screen:
                # For screen sharing, we track the end event to properly stop the sharing when
                # the user clicks on the browser's stop sharing dialog.
                def on_track_ended(event):
                    aio.run(self.toggle_screen_sharing())

                new_video_tracks[0].bind("ended", on_track_ended)

        self.is_sharing_screen = screen

        return local_stream

    async def switch_camera(self) -> None:
        """Switches to the next available camera.

        This method cycles through the list of available video devices, replaces the
        current video track with the next one in the user's local video element, and then
        updates the sender's track in the peer connection. If there's only one camera or
        if an error occurs while switching, the method logs the error and does nothing.
        """
        log.info("switching camera")
        if not self.has_multiple_cameras:
            log.error("No multiple cameras to switch.")
            return

        current_camera_index = -1
        for i, device_info in enumerate(self.video_devices):
            if device_info.deviceId == self.current_camera:
                current_camera_index = i
                break

        if current_camera_index == -1:
            log.error("Current camera not found in available devices.")
            return

        # Switch to the next camera in the list
        next_camera_index = (current_camera_index + 1) % len(self.video_devices)
        self.current_camera = self.video_devices[next_camera_index].deviceId
        log.debug(f"{next_camera_index=} {self.current_camera=}")

        new_stream = await window.navigator.mediaDevices.getUserMedia(
            {"video": {"deviceId": self.current_camera}}
        )

        new_video_tracks = [
            track for track in new_stream.getTracks() if track.kind == "video"
        ]

        if not new_video_tracks:
            log.error("Failed to retrieve the video track from the new stream.")
            return

        # Update local video element's stream
        local_stream = self.local_video_elt.srcObject
        if local_stream:
            local_video_tracks = [
                track for track in local_stream.getTracks() if track.kind == "video"
            ]
            if local_video_tracks:
                local_video_tracks[0].stop()
                local_stream.removeTrack(local_video_tracks[0])
                local_stream.addTrack(new_video_tracks[0])
            self.local_video_elt.srcObject = local_stream

        # update remove video stream
        video_sender = next(
            (
                sender
                for sender in self._peer_connection.getSenders()
                if sender.track and sender.track.kind == "video"
            ),
            None,
        )

        if video_sender:
            await video_sender.replaceTrack(new_video_tracks[0])

    async def _gather_ice_candidates(self, is_initiator: bool, remote_candidates=None):
        """Get ICE candidates and wait to have them all before returning them

        @param is_initiator: Boolean indicating if the user is the initiator of the connection
        @param remote_candidates: Remote ICE candidates, if any
        """
        if self._peer_connection is None:
            raise Exception(
                "The peer connection must be created before gathering ICE candidates!"
            )

        self.media_candidates.clear()

        if is_initiator:
            offer = await self._peer_connection.createOffer()
            self._set_media_types(offer)
            await self._peer_connection.setLocalDescription(offer)
        else:
            answer = await self._peer_connection.createAnswer()
            self._set_media_types(answer)
            await self._peer_connection.setLocalDescription(answer)

        if not is_initiator:
            log.debug(self._peer_connection.localDescription.sdp)
        log.debug(self._peer_connection.localDescription.sdp)
        ufrag, pwd = self.extract_ufrag_pwd(self._peer_connection.localDescription.sdp)
        return {
            "ufrag": ufrag,
            "pwd": pwd,
            "candidates": self.media_candidates,
        }

    async def accept_call(self, session_id: str, sdp: str, profile: str) -> None:
        """Call has been accepted, connection can be established

        @param session_id: Session identifier
        @param sdp: Session Description Protocol data
        @param profile: Profile associated
        """
        await self._peer_connection.setRemoteDescription({"type": "answer", "sdp": sdp})
        await self.on_ice_candidates_new(self.remote_candidates_buffer)
        self.remote_candidates_buffer.clear()

    def _on_ice_candidates_new(self, sid: str, candidates_s: str, profile: str) -> None:
        """Called when new ICE candidates are received

        @param sid: Session identifier
        @param candidates_s: ICE candidates serialized
        @param profile: Profile associated with the action
        """
        if sid != self.sid:
            log.debug(f"ignoring peer ice candidates for {sid=} ({self.sid=}).")
            return
        candidates = json.loads(candidates_s)
        aio.run(self.on_ice_candidates_new(candidates))

    def _on_ice_restart(self, sid: str, side: str, profile: str):
        if sid != self.sid:
            log.debug(f"ignoring peer ice candidates for {sid=} ({self.sid=}).")
            return
        log.debug("ICE has been restarted")
        if self.on_reconnect_cb is not None:
            self.on_reconnect_cb()

    async def on_ice_candidates_new(self, candidates: dict) -> None:
        """Called when new ICE canidates are received from peer

        @param candidates: Dictionary containing new ICE candidates
        """
        log.debug(f"new peer candidates received: {candidates}")
        # FIXME: workaround for https://github.com/brython-dev/brython/issues/2227, the
        #  following test raise a JS exception
        try:
            remoteDescription_is_none = self._peer_connection.remoteDescription is None
        except Exception as e:
            log.debug("Workaround for Brython bug activated.")
            remoteDescription_is_none = True

        if (
            self._peer_connection is None
            # or self._peer_connection.remoteDescription is None
            or remoteDescription_is_none
        ):
            for media_type in ("audio", "video"):
                media_candidates = candidates.get(media_type)
                if media_candidates:
                    buffer = self.remote_candidates_buffer[media_type]
                    buffer["candidates"].extend(media_candidates["candidates"])
            return
        for media_type, ice_data in candidates.items():
            for candidate in ice_data["candidates"]:
                candidate_sdp = self.build_ice_candidate(candidate)
                try:
                    sdp_mline_index = self.get_sdp_mline_index(media_type)
                except Exception as e:
                    log.warning(e)
                    continue
                ice_candidate = window.RTCIceCandidate.new(
                    {"candidate": candidate_sdp, "sdpMLineIndex": sdp_mline_index}
                )
                await self._peer_connection.addIceCandidate(ice_candidate)

    def on_track(self, event):
        """New track has been received from peer

        @param event: Event associated with the new track
        """
        if event.streams and event.streams[0]:
            remote_stream = event.streams[0]
            self.remote_video_elt.srcObject = remote_stream
        else:
            if self.remote_stream is None:
                self.remote_stream = window.MediaStream.new()
                self.remote_video_elt.srcObject = self.remote_stream
            self.remote_stream.addTrack(event.track)

    def on_negotiation_needed(self, event) -> None:
        log.debug(f"on_negotiation_needed {event=}")
        # TODO

    async def answer_call(self, sid: str, offer_sdp: str, profile: str):
        """We respond to the call"""
        log.debug("answering call")
        if sid != self.sid:
            raise Exception(f"Internal Error: unexpected sid: {sid=} {self.sid=}")
        await self._create_peer_connection()

        await self._peer_connection.setRemoteDescription(
            {"type": "offer", "sdp": offer_sdp}
        )
        await self.on_ice_candidates_new(self.remote_candidates_buffer)
        self.remote_candidates_buffer.clear()
        await self._get_user_media()

        # Gather local ICE candidates
        local_ice_data = await self._gather_ice_candidates(False)
        self.local_candidates = local_ice_data["candidates"]

        await bridge.call_answer_sdp(sid, self._peer_connection.localDescription.sdp)

    async def make_call(
        self, callee_jid: jid.JID, audio: bool = True, video: bool = True
    ) -> None:
        """Start a WebRTC call

        @param audio: True if an audio flux is required
        @param video: True if a video flux is required
        """
        await self._create_peer_connection()
        await self._get_user_media(audio, video)
        await self._gather_ice_candidates(True)

        call_data = {"sdp": self._peer_connection.localDescription.sdp}
        log.info(f"calling {callee_jid!r}")
        self.sid = await bridge.call_start(str(callee_jid), json.dumps(call_data))
        log.debug(f"Call SID: {self.sid}")

        if self.local_candidates_buffer:
            log.debug(
                f"sending buffered local ICE candidates: {self.local_candidates_buffer}"
            )
            assert self.pwd is not None
            ice_data = {}
            for media_type, candidates in self.local_candidates_buffer.items():
                ice_data[media_type] = {
                    "ufrag": self.ufrag,
                    "pwd": self.pwd,
                    "candidates": candidates
                }
            aio.run(
                bridge.ice_candidates_add(
                    self.sid,
                    json.dumps(
                        ice_data
                    ),
                )
            )
            self.local_candidates_buffer.clear()

    async def end_call(self) -> None:
        """Stop streaming and clean instance"""
        if self._peer_connection is None:
            log.debug("There is currently no call to end.")
        else:
            self._peer_connection.removeEventListener("track", self.on_track)
            self._peer_connection.removeEventListener(
                "negotiationneeded", self.on_negotiation_needed
            )
            self._peer_connection.removeEventListener(
                "icecandidate", self.on_ice_candidate
            )
            self._peer_connection.removeEventListener(
                "icegatheringstatechange", self.on_ice_gathering_state_change
            )

            # Base64 encoded 1x1 black pixel image
            # this is a trick to reset the image displayed, so we don't see last image of
            # last stream
            black_image_data = (
                "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0"
                "lEQVR42mP8/wcAAwAB/uzNq7sAAAAASUVORK5CYII="
            )

            local_video = self.local_video_elt
            remote_video = self.remote_video_elt
            if local_video.srcObject:
                for track in local_video.srcObject.getTracks():
                    track.stop()
            local_video.src = black_image_data

            if remote_video.srcObject:
                for track in remote_video.srcObject.getTracks():
                    track.stop()
            remote_video.src = black_image_data

            self._peer_connection.close()
        self.reset_instance()

    def toggle_media_mute(self, media_type: str) -> bool:
        """Toggle mute/unmute for media tracks.

        @param media_type: "audio" or "video". Determines which media tracks
            to process.
        """
        assert media_type in ("audio", "video"), "Invalid media type"

        local_video = self.local_video_elt
        is_muted_attr = f"is_{media_type}_muted"

        if local_video.srcObject:
            track_getter = getattr(
                local_video.srcObject, f"get{media_type.capitalize()}Tracks"
            )
            for track in track_getter():
                track.enabled = not track.enabled
                setattr(self, is_muted_attr, not track.enabled)

        media_name = self.media_types_inv.get(media_type)
        if media_name is not None:
            extra = {"name": str(media_name)}
            aio.run(
                bridge.call_info(
                    self.sid,
                    "mute" if getattr(self, is_muted_attr) else "unmute",
                    json.dumps(extra),
                )
            )

        return getattr(self, is_muted_attr)

    def toggle_audio_mute(self) -> bool:
        """Toggle mute/unmute for audio tracks."""
        return self.toggle_media_mute("audio")

    def toggle_video_mute(self) -> bool:
        """Toggle mute/unmute for video tracks."""
        return self.toggle_media_mute("video")

    async def toggle_screen_sharing(self):
        log.debug(f"toggle_screen_sharing {self._is_sharing_screen=}")

        if self._is_sharing_screen:
            await self._replace_user_video(screen=False)
        else:
            await self._replace_user_video(screen=True)