#!/usr/bin/python3

import aiohttp
import asyncio
import cv2
import io
import numpy as np
import os
import socket
import sys
from datetime import datetime
from kubernetes import client, config
from math import ceil
from prometheus_client import Counter, Gauge
from sanic import Sanic, response
from sanic.response import stream
from sanic_prometheus import monitor

SERVICE_NAMESPACE = os.getenv("SERVICE_NAMESPACE", "camtiler")
SERVICE_LABEL_SELECTOR = os.getenv("SERVICE_LABEL_SELECTOR", "component=camera-motion-detect")

targets = [(j,j) for j in sys.argv[1:]]
if not targets:
    # If no targets are specified, fall back to Kube API
    config.load_incluster_config()
    v1 = client.CoreV1Api()
    for i in v1.list_namespaced_service(SERVICE_NAMESPACE, label_selector=SERVICE_LABEL_SELETOR).items:
        url = "http://%s:%d/bypass" % (i.metadata.name, i.spec.ports[0].port)
        targets.append((i.metadata.name, url))

print("Running with following targets:")
for name, url in targets:
    print(url)

GIT_COMMIT = os.getenv("GIT_COMMIT", "null")
GIT_COMMIT_TIMESTAMP = os.getenv("GIT_COMMIT_TIMESTAMP", "null")

counter_dropped_bytes = Counter(
    "camtiler_client_dropped_bytes",
    "Bytes that were not not handled or part of actual JPEG frames")
counter_rx_bytes = Counter(
    "camtiler_client_rx_bytes",
    "Bytes received over HTTP stream")
counter_tx_bytes = Counter(
    "camtiler_client_tx_bytes",
    "Bytes transmitted over HTTP streams")
counter_rx_chunks = Counter(
    "camtiler_client_rx_chunks",
    "HTTP chunks received")
counter_rx_frames = Counter(
    "camtiler_client_rx_frames",
    "Frames received")
counter_tx_frames = Counter(
    "camtiler_client_tx_frames",
    "Frames transmitted")
counter_tx_events = Counter(
    "camtiler_client_tx_events",
    "Events emitted")
counter_errors =  Counter(
    "camtiler_errors",
    "Upstream connection errors",
    ["exception"])
gauge_build_info = Gauge(
    "docker_build_info",
    "Build info",
    ["git_commit", "git_commit_timestamp"])
gauge_build_info.labels(
    GIT_COMMIT,
    GIT_COMMIT_TIMESTAMP).set(1)

app = Sanic("camtiler")

STREAM_RESPONSE = \
b"""
--frame
Content-Type: image/jpeg

"""

MERGED_SUBSAMPLE=3

# Blank frame
BLANK = np.full((720, 1280, 3), 0)
GREEN = np.full((720, 1280, 3), (0, 135, 0))

def tilera(iterable):
    hstacking = ceil(len(iterable) ** 0.5)
    vstacking = ceil(len(iterable) / hstacking)
    rows = []
    for j in range(0, vstacking):
        row = []
        first_frame = True
        for i in range(0, hstacking):
            try:
                tile = iterable[i + hstacking * j]
            except IndexError:
                tile = None

            try:
                name, frame = tile
            except TypeError:
                frame = BLANK

            if frame is None:
                msg = "Signal lost"
                frame = GREEN
            else:
                msg = "Live"
            frame = frame[::MERGED_SUBSAMPLE, ::MERGED_SUBSAMPLE]
            footer = np.zeros((30, len(frame[0]), 3))

            if tile:
                cv2.putText(footer, msg, (10, 24), cv2.FONT_HERSHEY_PLAIN, 1, (255, 255, 255))
                cv2.putText(footer, name, (10, 12), cv2.FONT_HERSHEY_PLAIN, 1, (255, 255, 255))
            frame = np.vstack([frame, footer])
            if not first_frame:
                row.append(np.full((len(frame), 1, 3), 0))
            first_frame = False
            row.append(frame)
        stacked = np.hstack(row)
        rows.append(stacked)
    return np.vstack(rows)


async def client_connect(name, resp):
    buf = b""
    print("Upstream connection to %s opened with status: %d", (name, resp.status))
    async for data, end_of_http_chunk in resp.content.iter_chunks():
        if end_of_http_chunk:
            counter_rx_chunks.inc()

        if buf:
            # If we already have something in buffer, seek end in new data
            marker = data.find(b'\xff\xd9')
            if marker < 0:
                # If no end marker was found add it to buffer
                buf += data
                continue
            else:
                # If end marker was found, decode JPEG frame
                blob = np.frombuffer(buf + data[:marker+2], dtype=np.uint8)
                img = cv2.imdecode(blob, cv2.IMREAD_UNCHANGED)
                app.ctx.frames[name] = img
                data = data[marker+2:]
                buf = b""
                counter_rx_frames.inc()

        # Seek begin in newly received data
        marker = data.find(b'\xff\xd8')
        if marker >= 0:
            data, buf = data[:marker], data[marker:]

        # Remaining data is effectively dropped
        counter_dropped_bytes.inc(len(data))


async def client(name, url):
    print("Opening upstream connection to %s" % url)
    kwargs = dict(
        headers = {
            "User-Agent": "camtiler/%s" % GIT_COMMIT_TIMESTAMP
        },
        skip_auto_headers = True,
        timeout = aiohttp.ClientTimeout(connect=5, sock_read=2))
    while True:
        app.ctx.frames[name] = None
        async with aiohttp.ClientSession(**kwargs) as session:
            try:
                async with session.get(url) as resp:
                    await client_connect(name, resp)
            except (aiohttp.ClientError, asyncio.exceptions.TimeoutError) as e:
                    j = "%s.%s" % (e.__class__.__module__, e.__class__.__name__)
                    print("Caught exception %s for %s" % (j, name))
                    counter_errors.labels(exception=j).inc()
            await asyncio.sleep(1)


@app.route("/tiled")
async def stream_wrapper(request):
    async def stream_tiled(response):
        while True:
            img = tilera(sorted(app.ctx.frames.items()))
            _, jpeg = cv2.imencode(".jpg", img, (cv2.IMWRITE_JPEG_QUALITY, 80))
            data = STREAM_RESPONSE + jpeg.tobytes()
            await response.write(data)
            counter_tx_bytes.inc(len(data))
            counter_tx_frames.inc()
            await asyncio.sleep(0.1)

    return response.stream(
        stream_tiled,
        content_type='multipart/x-mixed-replace; boundary=frame'
    )

@app.listener('before_server_start')
async def setup_db(app, loop):
    app.ctx.event_frame = asyncio.Event()
    app.ctx.frames = {}
    app.ctx.avg = None
    app.ctx.motion_frames = 0
    app.ctx.motion_start = None
    app.ctx.motion_end = None
    for name, url in targets:
        app.ctx.frames[name] = None
        task = asyncio.create_task(client(name, url))

monitor(app).expose_endpoint()

try:
    app.run(host="0.0.0.0", port=5001)
except KeyboardInterrupt:
    asyncio.get_event_loop().close()