import streamlit as st
from fhir.resources.observation import Observation
from datetime import datetime
import requests
import json

# FHIR server endpoint
base_url = "https://<fhir_server_endpoint>/fhir/"

# Function to create an Observation resource
def create_observation_resource(activity, category, calories, duration, distance, heart_rate):
    observation = Observation()
    observation.status = "final"
    observation.category = [{"coding": [{"system": "http://terminology.hl7.org/CodeSystem/observation-category",
                                          "code": "activity"}]}]
    observation.code = {"coding": [{"system": "http://loinc.org", "code": "55409-7", "display": "Exercise tracking panel"}]}
    observation.effectiveDateTime = datetime.now().isoformat()
    observation.component = []
    if activity:
        observation.component.append({"code": {"coding": [{"system": "http://loinc.org", "code": "73985-4", "display": "Exercise activity"}]}, "valueString": activity})
    if category:
        observation.component.append({"code": {"coding": [{"system": "http://loinc.org", "code": "73986-2", "display": "Exercise aerobic category"}]}, "valueString": category})
    if calories:
        observation.component.append({"code": {"coding": [{"system": "http://loinc.org", "code": "55421-2", "display": "Calories burned Machine estimate"}]}, "valueQuantity": {"value": calories, "unit": "kcal"}})
    if duration:
        observation.component.append({"code": {"coding": [{"system": "http://loinc.org", "code": "55411-3", "display": "Exercise duration"}]}, "valueQuantity": {"value": duration, "unit": "min"}})
    if distance:
        observation.component.append({"code": {"coding": [{"system": "http://loinc.org", "code": "55412-1", "display": "Exercise distance unspecified time"}]}, "valueQuantity": {"value": distance, "unit": "[mi_us];km"}})
    if heart_rate:
        observation.component.append({"code": {"coding": [{"system": "http://loinc.org", "code": "55422-0", "display": "Heart rate Encounter maximum"}]}, "valueQuantity": {"value": heart_rate, "unit": "{beats}/min"}})
    return observation

# Function to create an Observation resource on the FHIR server
def create_observation(observation):
    headers = {"Content-Type": "application/fhir+json"}
    response = requests.post(base_url + "Observation", data=json.dumps(observation.as_json()), headers=headers)
    if response.status_code == 201:
        st.success("Observation created successfully!")
    else:
        st.error("Error creating Observation.")

# Streamlit user interface
def app():
    st.title("LOINC Exercise Tracking Panel")
    activity = st.text_input("Exercise activity")
    category = st.selectbox("Exercise aerobic category", ["", "Aerobic", "Anaerobic"])
    calories = st.number_input("Calories burned (Machine estimate)", min_value=0, step=1)
    duration = st.number_input("Exercise duration (minutes)", min_value=0, step=1)
    distance = st.number_input("Exercise distance unspecified time", min_value=0, step=0.01)
    heart_rate = st.number_input("Heart rate Encounter maximum", min_value=0, step=1)

if st.button("Record Exercise"):
    observation = create_observation_resource(activity, category, calories, duration, distance, heart_rate)
    create_observation(observation)