#!/bin/bash
# verify_alertmanager.sh
# Verify the communication between Prometheus and Alertmanager after deployment

set -euo pipefail

echo "[INFO] Verifying Prometheus ↔ Alertmanager communication..."

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
TEST_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
TMP_DIR="$TEST_ROOT/tmp"
mkdir -p "$TMP_DIR"

PRIVATE_CORE="$TEST_ROOT/private"

#=============================
# Load environment variables
#=============================
if [[ -f "$TEST_ROOT/.env" ]]; then
  set -a; source "$TEST_ROOT/.env"; set +a
fi

#=============================
# Basic configuration
#=============================
PROM_URL="http://localhost:${PROMETHEUS_PORT:-9090}"
ALERT_URL="http://localhost:${ALERTMANAGER_PORT:-9093}"
RULE_DIR="$PRIVATE_CORE/argus/metric/prometheus/rules"
TMP_RULE="$TMP_DIR/test_rule.yml"

#=============================
# Helper functions
#=============================
GREEN="\033[32m"; RED="\033[31m"; YELLOW="\033[33m"; RESET="\033[0m"

log_info()    { echo -e "${YELLOW}[INFO]${RESET} $1"; }
log_success() { echo -e "${GREEN}[OK]${RESET} $1"; }
log_warn()    { echo -e "${YELLOW}[WARN]${RESET} $1"; }
log_error()   { echo -e "${RED}[ERROR]${RESET} $1"; }

fail_exit() { log_error "$1"; exit 1; }

#=============================
# Step 1: Check Alertmanager accessibility
#=============================
log_info "Checking Alertmanager status..."
if curl -sSf "${ALERT_URL}/api/v2/status" >/dev/null 2>&1; then
  log_success "Alertmanager is reachable at ${ALERT_URL}"
else
  fail_exit "Alertmanager is not reachable. Please check container or port mapping."
fi

#=============================
# Step 2: Create and load a temporary test alert rule
#=============================
log_info "Creating temporary alert rule at ${TMP_RULE}..."
cat <<EOF > "${TMP_RULE}"
groups:
- name: deploy-verify-group
  rules:
  - alert: DeployVerifyAlert
    expr: vector(1)
    labels:
      severity: warning
    annotations:
      summary: "Deployment verification alert"
EOF

mkdir -p "${RULE_DIR}"
cp "${TMP_RULE}" "${RULE_DIR}/test_rule.yml"

log_info "Reloading Prometheus to apply the test rule..."
if curl -s -X POST "${PROM_URL}/-/reload" >/dev/null; then
  log_success "Prometheus successfully reloaded rules"
else
  fail_exit "Failed to reload Prometheus. Check API accessibility."
fi

#=============================
# Step 3: Verify alert received by Alertmanager
#=============================
log_info "Waiting for alert propagation (~30 seconds)..."
sleep 30

if curl -s "${ALERT_URL}/api/v2/alerts" | grep -q "DeployVerifyAlert"; then
  log_success "Prometheus → Alertmanager alert path verified successfully"
else
  fail_exit "DeployVerifyAlert not found in Alertmanager. Check configuration or network."
fi

#=============================
# Step 4: Cleanup test rule
#=============================
log_info "Cleaning up temporary alert rule..."
rm -f "${RULE_DIR}/test_rule.yml" "${TMP_RULE}"

if curl -s -X POST "${PROM_URL}/-/reload" >/dev/null; then
  log_success "Prometheus successfully reloaded after cleanup"
else
  log_warn "Prometheus reload after cleanup failed. Please check manually."
fi

log_success "Alertmanager verification completed successfully. Communication with Prometheus is healthy."