#!/usr/bin/env python

from dash.dependencies import Input, Output
import dash
import dash_core_components as dcc
import dash_html_components as html

import pandas as pd
from functools import lru_cache

import argparse
import sqlite3
import time
import sys
import datetime


app = dash.Dash(__name__)

def get_topics(db):
    cursor = db.cursor()
    query = 'SELECT name FROM sqlite_master WHERE type="table"'
    q = cursor.execute(query)
    topics = [t[0] for t in q.fetchall()]
    return topics


# Since we're adding callbacks to elements that don't exist in the app.layout,
# Dash will raise an exception to warn us that we might be
# doing something wrong.
# In this case, we're adding the elements through a callback, so we can ignore
# the exception.
app.config.suppress_callback_exceptions = True

app.layout = html.Div([
    dcc.Location(id='url', refresh=False),
    html.Div(id='page-content')
])


@lru_cache(maxsize=10)
def get_data(topic, timerange, ts):
    start = time.time()
    conn = sqlite3.connect(db)
    table = topic

    earliest = datetime.datetime.now() - timerange
    query = f"SELECT * FROM \"{table}\" WHERE timestamp > '{earliest}'"

    df = pd.read_sql(query, conn, parse_dates=[
                     'timestamp'], index_col='timestamp')
    print(f"Obtained data in {time.time()-start}")
    return df




plot_page = html.Div([
    dcc.Interval(
        id='interval-component',
        interval=4*1000,  # in milliseconds
        n_intervals=0),
    html.Div(id='range-controls', children=[
        dcc.Input(id="range_count",
              type="number",
                  value=1,
                  debounce=True,
                  min=1),
        dcc.Dropdown(
            id='timerange',
            options=[
                {'label': 'hours', 'value': 'h'},
                {'label': 'days', 'value': 'd'},
                {'label': 'weeks', 'value': 'w'},
                {'label': 'all', 'value': 'all'}
            ],
            value='d'
        ),
    ]),
    dcc.Graph(id='graph', animate=False, responsive=True),
    dcc.Checklist(id='topic-checklist', className="checklist-container",
                  inputClassName="checklist-input"),
    dcc.Link('Back', href='/')
])

def get_timedelta(range_str, count):
    range_to_delta = {
        'h': datetime.timedelta(hours=count),
        'd': datetime.timedelta(days=count),
        'w': datetime.timedelta(weeks=count),
        'all': datetime.timedelta(weeks=10000),
    }
    return range_to_delta[range_str]


@app.callback([Output('topic-checklist', 'options'),
               Output('topic-checklist', 'value')],
              [Input('url', 'pathname')])
def update_topic_checklist(pathname):
    pathname = pathname.strip('/')
    if pathname:
        topics = pathname.strip('/').split('+')
        selected = topics
    else:
        topics = all_topics
        selected = []

    return [{"label":topic, "value":topic, "disabled":False} for topic in sorted(topics)], selected

@app.callback(Output('graph', 'figure'),
              [
               Input('timerange', 'value'),
               Input('range_count', 'value'),
               Input('topic-checklist', 'value')])
def update_graph(timerange, range_count, topics):
    if topics:
        print(f"topics: {topics}")

        delta = get_timedelta(timerange, range_count)
        now = int(time.time())
        def make_data(df, name):
            return {
                'x': df.index,
                'y': df['value'],
                'type': 'scatter',
                'mode': 'lines',
                'name': name
            }

        return {
            'data': [make_data(get_data(topic, delta, now), topic) for topic in topics]}

    else:
        return {}, []

# Update the index
@app.callback(dash.dependencies.Output('page-content', 'children'),
              [dash.dependencies.Input('url', 'pathname')])
def display_page(pathname):
    return plot_page
    # You could also return a 404 "URL not found" page here


if __name__ == '__main__':

    options = argparse.ArgumentParser()
    options.add_argument('--debug', '-d', action='store_true')
    options.add_argument('db')

    args = options.parse_args()

    db = args.db

    conn = sqlite3.connect(db)
    all_topics = get_topics(conn)

    index_page = html.Div(sum([[
        dcc.Link(f'Go to {page}', href=f'/{page}'),
        html.Br()] for page in all_topics], []))

    app.run_server(debug=args.debug, host='0.0.0.0')