#!/bin/bash
# GoChat Health Check Script
# Reference: Chatwoot health_check endpoint pattern
# Checks: HTTP server, database, Redis, worker queues, WebSocket hub
#
# Usage:
#   ./scripts/health_check.sh [--full] [--json] [--timeout SECONDS]
#
# Exit codes:
#   0 = healthy
#   1 = degraded (some checks failed but core is OK)
#   2 = unhealthy (critical checks failed)

set -euo pipefail

# Configuration
GOCHAT_HOST="${GOCHAT_HOST:-localhost}"
GOCHAT_PORT="${GOCHAT_PORT:-3000}"
GOCHAT_METRICS_PORT="${GOCHAT_METRICS_PORT:-9090}"
TIMEOUT="${TIMEOUT:-5}"
FULL_CHECK=false
JSON_OUTPUT=false

# Parse arguments
while [[ $# -gt 0 ]]; do
    case "$1" in
        --full)    FULL_CHECK=true; shift ;;
        --json)    JSON_OUTPUT=true; shift ;;
        --timeout) TIMEOUT="$2"; shift 2 ;;
        --help)    echo "Usage: $0 [--full] [--json] [--timeout SECONDS]"; exit 0 ;;
        *)         echo "Unknown option: $1"; exit 1 ;;
    esac
done

BASE_URL="http://${GOCHAT_HOST}:${GOCHAT_PORT}"
METRICS_URL="http://${GOCHAT_HOST}:${GOCHAT_METRICS_PORT}"

# Result tracking
RESULTS=()
CRITICAL_FAIL=0
DEGRADED_FAIL=0

check_result() {
    local name="$1" status="$2" detail="$3"
    RESULTS+=("${name}|${status}|${detail}")
    if [[ "$status" == "CRITICAL_FAIL" ]]; then
        CRITICAL_FAIL=$((CRITICAL_FAIL + 1))
    elif [[ "$status" == "DEGRADED" ]]; then
        DEGRADED_FAIL=$((DEGRADED_FAIL + 1))
    fi
}

# ---- Check 1: HTTP liveness endpoint ----
check_liveness() {
    local response
    response=$(curl -sf --max-time "${TIMEOUT}" "${BASE_URL}/live" 2>&1) && {
        check_result "liveness" "OK" "${response}"
    } || {
        check_result "liveness" "CRITICAL_FAIL" "HTTP /live endpoint unreachable"
    }
}

# ---- Check 2: HTTP readiness endpoint ----
check_readiness() {
    local response
    response=$(curl -sf --max-time "${TIMEOUT}" "${BASE_URL}/ready" 2>&1) && {
        check_result "readiness" "OK" "${response}"
    } || {
        check_result "readiness" "CRITICAL_FAIL" "HTTP /ready endpoint unreachable"
    }
}

# ---- Check 3: Database connectivity ----
check_database() {
    if [[ "${FULL_CHECK}" == "true" ]]; then
        local response
        response=$(curl -sf --max-time "${TIMEOUT}" "${BASE_URL}/health?check=database" 2>&1) && {
            check_result "database" "OK" "${response}"
        } || {
            check_result "database" "CRITICAL_FAIL" "Database connectivity failed"
        }
    else
        check_result "database" "SKIPPED" "Not in full mode"
    fi
}

# ---- Check 4: Redis connectivity ----
check_redis() {
    if [[ "${FULL_CHECK}" == "true" ]]; then
        local response
        response=$(curl -sf --max-time "${TIMEOUT}" "${BASE_URL}/health?check=redis" 2>&1) && {
            check_result "redis" "OK" "${response}"
        } || {
            check_result "redis" "DEGRADED" "Redis connectivity failed (non-critical)"
        }
    else
        check_result "redis" "SKIPPED" "Not in full mode"
    fi
}

# ---- Check 5: Metrics endpoint ----
check_metrics() {
    local response
    response=$(curl -sf --max-time "${TIMEOUT}" "${METRICS_URL}/metrics" 2>&1) && {
        check_result "metrics" "OK" "Prometheus metrics endpoint responding"
    } || {
        check_result "metrics" "DEGRADED" "Metrics endpoint unreachable (non-critical)"
    }
}

# ---- Check 6: WebSocket hub (full mode) ----
check_websocket() {
    if [[ "${FULL_CHECK}" == "true" ]]; then
        # WebSocket health check via HTTP status endpoint
        local response
        response=$(curl -sf --max-time "${TIMEOUT}" "${BASE_URL}/health?check=websocket" 2>&1) && {
            check_result "websocket" "OK" "${response}"
        } || {
            check_result "websocket" "DEGRADED" "WebSocket hub unreachable"
        }
    else
        check_result "websocket" "SKIPPED" "Not in full mode"
    fi
}

# ---- Run all checks ----
check_liveness
check_readiness
check_database
check_redis
check_metrics
check_websocket

# ---- Output results ----
if [[ "${JSON_OUTPUT}" == "true" ]]; then
    # JSON output for programmatic consumption
    echo '{'
    echo '  "checks": ['
    for i in "${!RESULTS[@]}"; do
        IFS='|' read -r name status detail <<< "${RESULTS[$i]}"
        comma=""
        [[ $i -gt 0 ]] && comma=","
        echo "    ${comma}{\"name\": \"${name}\", \"status\": \"${status}\", \"detail\": \"${detail}\"}"
    done
    echo '  ],'
    echo '  "summary": {'
    echo '    "critical_failures": ${CRITICAL_FAIL},'
    echo '    "degraded_failures": ${DEGRADED_FAIL}'
    echo '  }'
    echo '}'
else
    # Human-readable output
    echo "=== GoChat Health Check Report ==="
    for result in "${RESULTS[@]}"; do
        IFS='|' read -r name status detail <<< "${result}"
        case "$status" in
            OK)           icon="✅" ;;
            CRITICAL_FAIL) icon="❌" ;;
            DEGRADED)     icon="⚠️" ;;
            SKIPPED)      icon="⏭️" ;;
        esac
        echo "  ${icon} ${name}: ${status} — ${detail}"
    done
    echo ""
    echo "Critical failures: ${CRITICAL_FAIL} | Degraded: ${DEGRADED_FAIL}"
fi

# ---- Determine exit code ----
if [[ ${CRITICAL_FAIL} -gt 0 ]]; then
    exit 2
elif [[ ${DEGRADED_FAIL} -gt 0 ]]; then
    exit 1
else
    exit 0
fi