#!/bin/bash

# Graceful Degradation Test Suite
# Tests system behavior under various failure conditions

set -e

echo "╔════════════════════════════════════════════════════════════════╗"
echo "║         GRACEFUL DEGRADATION TEST SUITE                        ║"
echo "║         Testing System Resilience Under Failures               ║"
echo "╚════════════════════════════════════════════════════════════════╝"
echo ""

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Test results tracking
TESTS_PASSED=0
TESTS_FAILED=0
TESTS_TOTAL=0

# Helper functions
log_test() {
    echo -e "${BLUE}[TEST]${NC} $1"
    TESTS_TOTAL=$((TESTS_TOTAL + 1))
}

log_pass() {
    echo -e "${GREEN}[PASS]${NC} $1"
    TESTS_PASSED=$((TESTS_PASSED + 1))
}

log_fail() {
    echo -e "${RED}[FAIL]${NC} $1"
    TESTS_FAILED=$((TESTS_FAILED + 1))
}

log_info() {
    echo -e "${YELLOW}[INFO]${NC} $1"
}

# Function to check Docker container health
check_container_health() {
    local container=$1
    local status=$(docker inspect --format='{{.State.Health.Status}}' $container 2>/dev/null)
    if [ "$status" = "healthy" ]; then
        return 0
    else
        return 1
    fi
}

# Function to check service responds (not auth failure)
check_service_responsive() {
    local port=$1
    if nc -zv localhost $port 2>&1 | grep -q "succeeded"; then
        return 0
    else
        return 1
    fi
}

# Capture baseline metrics
echo "═══════════════════════════════════════════════════════════════"
echo "BASELINE: Capturing Normal Operation Metrics"
echo "═══════════════════════════════════════════════════════════════"

log_test "Baseline: All Docker containers healthy"
BASELINE_HEALTHY=true

containers=("foxhunt-api-gateway" "foxhunt-trading-service" "foxhunt-backtesting-service" "foxhunt-ml-training-service" "foxhunt-postgres" "foxhunt-redis")
for container in "${containers[@]}"; do
    if check_container_health "$container"; then
        log_pass "$container is healthy"
    else
        log_fail "$container is unhealthy"
        BASELINE_HEALTHY=false
    fi
done

if [ "$BASELINE_HEALTHY" = false ]; then
    echo ""
    echo -e "${RED}ERROR: Baseline health check failed. Cannot proceed with degradation tests.${NC}"
    exit 1
fi

log_test "Baseline: Services respond to connections"
# Check TCP connectivity (proves services are listening)
services=("api_gateway:50051" "trading_service:50052" "backtesting_service:50053" "ml_training_service:50054")
for svc in "${services[@]}"; do
    name="${svc%%:*}"
    port="${svc##*:}"
    if check_service_responsive "$port"; then
        log_pass "$name responds on port $port"
    else
        log_fail "$name not responding on port $port"
        BASELINE_HEALTHY=false
    fi
done

log_test "Baseline: Prometheus monitoring operational"
if curl -sf http://localhost:9090/-/healthy > /dev/null 2>&1; then
    log_pass "Prometheus is healthy"
else
    log_fail "Prometheus is unhealthy"
fi

echo ""

# TEST 1: Redis Failure
echo "═══════════════════════════════════════════════════════════════"
echo "TEST 1: Redis Failure Degradation"
echo "═══════════════════════════════════════════════════════════════"
echo "Expected: Services continue with degraded caching, no catastrophic failure"
echo ""

log_test "Stopping Redis container"
docker stop foxhunt-redis > /dev/null 2>&1
sleep 3

log_test "Checking services continue to operate without Redis"

# API Gateway should continue (rate limiting degraded)
if check_container_health "foxhunt-api-gateway"; then
    log_pass "API Gateway operational without Redis (degraded rate limiting)"
else
    if docker ps | grep -q foxhunt-api-gateway; then
        log_pass "API Gateway running without Redis (may show unhealthy but not crashed)"
    else
        log_fail "API Gateway crashed when Redis failed"
    fi
fi

# Trading Service should continue (caching degraded)
if check_service_responsive "50052"; then
    log_pass "Trading Service responds without Redis (degraded caching)"
else
    log_fail "Trading Service not responding without Redis"
fi

# Check service logs for graceful degradation messages
log_info "Checking for degradation warnings in logs..."
if docker logs foxhunt-api-gateway --tail 20 2>&1 | grep -qi "redis"; then
    log_pass "API Gateway logs Redis connection issues (expected)"
fi

log_test "Restoring Redis"
docker start foxhunt-redis > /dev/null 2>&1
sleep 5

# Wait for Redis to be healthy
log_info "Waiting for Redis recovery..."
for i in {1..10}; do
    if docker exec foxhunt-redis redis-cli ping 2>/dev/null | grep -q PONG; then
        log_pass "Redis recovered successfully"
        break
    fi
    sleep 1
done

# Check services recover
sleep 3
if check_container_health "foxhunt-api-gateway"; then
    log_pass "API Gateway recovered after Redis restore"
else
    log_fail "API Gateway did not fully recover"
fi

echo ""

# TEST 2: ML Service Down
echo "═══════════════════════════════════════════════════════════════"
echo "TEST 2: ML Service Down Degradation"
echo "═══════════════════════════════════════════════════════════════"
echo "Expected: Trading continues without ML predictions"
echo ""

log_test "Stopping ML Training Service"
docker stop foxhunt-ml-training-service > /dev/null 2>&1
sleep 2

log_test "Verifying trading continues without ML service"

# API Gateway should continue (ML methods will fail but gateway operational)
if check_service_responsive "50051"; then
    log_pass "API Gateway operational without ML service"
else
    log_fail "API Gateway affected by ML service failure"
fi

# Trading Service should continue (no ML dependency)
if check_service_responsive "50052"; then
    log_pass "Trading Service operational without ML predictions"
else
    log_fail "Trading Service depends on ML service (CRITICAL)"
fi

# Backtesting should continue
if check_service_responsive "50053"; then
    log_pass "Backtesting Service operational without ML"
else
    log_fail "Backtesting Service affected by ML failure"
fi

log_test "Restoring ML Training Service"
docker start foxhunt-ml-training-service > /dev/null 2>&1
sleep 10

log_info "Waiting for ML service recovery..."
for i in {1..15}; do
    if check_container_health "foxhunt-ml-training-service"; then
        log_pass "ML Training Service recovered successfully"
        break
    fi
    sleep 1
done

echo ""

# TEST 3: Backtesting Service Failure
echo "═══════════════════════════════════════════════════════════════"
echo "TEST 3: Backtesting Service Failure"
echo "═══════════════════════════════════════════════════════════════"
echo "Expected: Core trading and API Gateway unaffected"
echo ""

log_test "Stopping Backtesting Service"
docker stop foxhunt-backtesting-service > /dev/null 2>&1
sleep 2

log_test "Verifying core services continue"

if check_service_responsive "50051"; then
    log_pass "API Gateway operational without Backtesting"
else
    log_fail "API Gateway requires Backtesting service"
fi

if check_service_responsive "50052"; then
    log_pass "Trading Service operational without Backtesting"
else
    log_fail "Trading Service requires Backtesting service"
fi

log_test "Restoring Backtesting Service"
docker start foxhunt-backtesting-service > /dev/null 2>&1
sleep 10

for i in {1..10}; do
    if check_container_health "foxhunt-backtesting-service"; then
        log_pass "Backtesting Service recovered"
        break
    fi
    sleep 1
done

echo ""

# TEST 4: Service Recovery
echo "═══════════════════════════════════════════════════════════════"
echo "TEST 4: Automatic Service Recovery"
echo "═══════════════════════════════════════════════════════════════"
echo "Expected: All services recover automatically"
echo ""

log_test "Testing automatic recovery"
log_info "All services should be healthy again"

# Give services time to stabilize
sleep 5

# Check all services healthy again
RECOVERY_SUCCESS=true
for container in "${containers[@]}"; do
    if check_container_health "$container"; then
        log_pass "$container recovered successfully"
    else
        log_fail "$container failed to recover"
        RECOVERY_SUCCESS=false
    fi
done

if [ "$RECOVERY_SUCCESS" = true ]; then
    log_pass "All services recovered automatically"
else
    log_fail "Some services failed to recover"
fi

echo ""

# TEST 5: Critical Function Availability
echo "═══════════════════════════════════════════════════════════════"
echo "TEST 5: Critical Function Availability During Degradation"
echo "═══════════════════════════════════════════════════════════════"
echo "Expected: Core functions survive all failure scenarios"
echo ""

log_test "Verifying critical functions always available"

# Authentication (JWT validation is stateless, no dependencies)
if check_service_responsive "50051"; then
    log_pass "Authentication available (JWT validation stateless)"
else
    log_fail "Authentication unavailable"
fi

# Trading operations (core function)
if check_service_responsive "50052"; then
    log_pass "Trading operations available"
else
    log_fail "Trading operations unavailable"
fi

# Monitoring (Prometheus should continue)
if curl -sf http://localhost:9090/-/healthy > /dev/null 2>&1; then
    log_pass "Monitoring operational (Prometheus)"
else
    log_fail "Monitoring unavailable"
fi

# Metrics endpoints (services should export metrics even when degraded)
if curl -sf http://localhost:9092/metrics > /dev/null 2>&1; then
    log_pass "Metrics collection operational"
else
    log_fail "Metrics collection unavailable"
fi

echo ""

# Final Summary
echo "═══════════════════════════════════════════════════════════════"
echo "TEST SUMMARY"
echo "═══════════════════════════════════════════════════════════════"
echo "Total Tests:  $TESTS_TOTAL"
echo "Passed:       $TESTS_PASSED"
echo "Failed:       $TESTS_FAILED"
echo ""

if [ $TESTS_FAILED -eq 0 ]; then
    echo -e "${GREEN}✓ ALL TESTS PASSED${NC}"
    echo "System demonstrates excellent graceful degradation"
    exit 0
else
    PASS_RATE=$((TESTS_PASSED * 100 / TESTS_TOTAL))
    if [ $PASS_RATE -ge 80 ]; then
        echo -e "${GREEN}✓ ACCEPTABLE PASS RATE${NC}"
        echo "Pass Rate: ${PASS_RATE}%"
        echo "System demonstrates good graceful degradation"
        exit 0
    else
        echo -e "${YELLOW}⚠ SOME TESTS FAILED${NC}"
        echo "Pass Rate: ${PASS_RATE}%"
        echo "System shows degradation gaps"
        exit 1
    fi
fi