#!/bin/bash

# Grafana Auto-Configuration Script for Prometheus Datasource
# This script ensures Grafana is properly configured to connect to Prometheus

set -e

# Default values
GRAFANA_URL="http://localhost:3000"
GRAFANA_USER="admin"
GRAFANA_PASSWORD="${GRAFANA_ADMIN_PASSWORD:-admin}"
PROMETHEUS_URL="http://prometheus:9090"
PROMETHEUS_USER="${PROMETHEUS_USERNAME:-prometheus_user}"
PROMETHEUS_PASSWORD="${PROMETHEUS_PASSWORD:-prometheus_password}"

# Wait for Grafana to be ready
echo "Waiting for Grafana to be ready..."
until curl -s "${GRAFANA_URL}/api/health" | grep -q '"database":"ok"'; do
    sleep 5
done
echo "Grafana is ready!"

# Check if Prometheus datasource already exists
echo "Checking for existing Prometheus datasource..."
DATASOURCES=$(curl -s -u "${GRAFANA_USER}:${GRAFANA_PASSWORD}" "${GRAFANA_URL}/api/datasources")

if echo "$DATASOURCES" | grep -q '"name":"Prometheus"'; then
    echo "Prometheus datasource already exists. Updating configuration..."
    
    # Get the datasource ID
    DATASOURCE_ID=$(echo "$DATASOURCES" | grep -o '"id":[0-9]*' | head -1 | cut -d: -f2)
    
    # Update the datasource
    curl -s -X PUT "${GRAFANA_URL}/api/datasources/${DATASOURCE_ID}" \
        -u "${GRAFANA_USER}:${GRAFANA_PASSWORD}" \
        -H "Content-Type: application/json" \
        -d "{
            \"name\": \"Prometheus\",
            \"type\": \"prometheus\",
            \"url\": \"${PROMETHEUS_URL}\",
            \"access\": \"proxy\",
            \"basicAuth\": true,
            \"basicAuthUser\": \"${PROMETHEUS_USER}\",
            \"basicAuthPassword\": \"${PROMETHEUS_PASSWORD}\",
            \"isDefault\": true
        }"
    
    echo "Prometheus datasource updated successfully!"
else
    echo "Creating Prometheus datasource..."
    
    # Create the datasource
    curl -s -X POST "${GRAFANA_URL}/api/datasources" \
        -u "${GRAFANA_USER}:${GRAFANA_PASSWORD}" \
        -H "Content-Type: application/json" \
        -d "{
            \"name\": \"Prometheus\",
            \"type\": \"prometheus\",
            \"url\": \"${PROMETHEUS_URL}\",
            \"access\": \"proxy\",
            \"basicAuth\": true,
            \"basicAuthUser\": \"${PROMETHEUS_USER}\",
            \"basicAuthPassword\": \"${PROMETHEUS_PASSWORD}\",
            \"isDefault\": true
        }"
    
    echo "Prometheus datasource created successfully!"
fi

# Test the datasource connection
echo "Testing Prometheus datasource connection..."
TEST_RESULT=$(curl -s -u "${GRAFANA_USER}:${GRAFANA_PASSWORD}" "${GRAFANA_URL}/api/datasources/1/health")

if echo "$TEST_RESULT" | grep -q '"status":"OK"'; then
    echo "✅ Prometheus datasource connection test passed!"
else
    echo "❌ Prometheus datasource connection test failed:"
    echo "$TEST_RESULT"
fi

echo "Grafana configuration completed!"