#!/usr/bin/env bash
# events.sh - Filesystem-first event system for homelab

EVENTS_BASE_DIR="${RUNTIME_PATH:-/opt/homelab}/events"

# Emit a normalized JSON event
# Usage: emit_event <type> <severity> <source> <service> <correlation_id> <payload_json>
emit_event() {
    local type=$1
    local severity=$2
    local source=$3
    local service=$4
    local correlation_id=$5
    local payload=${6:-"{}"}
    
    local node=$(hostname)
    local timestamp=$(date -u +"%Y-%m-%dT%H:%M:%SZ")
    local date_dir=$(date +"%Y-%m-%d")
    
    local event_dir="${EVENTS_BASE_DIR}/${date_dir}/${node}"
    mkdir -p "$event_dir"
    
    # Generate a unique filename for the event to ensure append-only/no-overwrite
    local event_id=$(cat /proc/sys/kernel/random/uuid 2>/dev/null || date +%s%N)
    local event_file="${event_dir}/${timestamp}_${type}_${event_id}.json"
    
    # Construct JSON
    cat <<EOF > "$event_file"
{
  "timestamp": "$timestamp",
  "node": "$node",
  "type": "$type",
  "severity": "$severity",
  "source": "$source",
  "service": "$service",
  "correlation_id": "$correlation_id",
  "payload": $payload
}
EOF

    # Also log to standard logging if available
    if command -v log >/dev/null 2>&1; then
        log "EVENT" "[$type] service=$service severity=$severity cid=$correlation_id"
    fi
}

# Query recent events (last N events or by date)
# Usage: list_events [date] [node]
list_events() {
    local target_date=${1:-$(date +"%Y-%m-%d")}
    local target_node=$2
    
    local search_path="${EVENTS_BASE_DIR}/${target_date}"
    if [[ -n "$target_node" ]]; then
        search_path="${search_path}/${target_node}"
    fi
    
    if [[ -d "$search_path" ]]; then
        find "$search_path" -name "*.json" | sort
    fi
}

# Simple filter helper
# Usage: filter_events <field> <value>
filter_events() {
    local field=$1
    local value=$2
    local files=$3
    
    for f in $files; do
        if grep -q "\"$field\": \"$value\"" "$f"; then
            echo "$f"
        fi
    done
}

# export -f emit_event
# export -f list_events
# export -f filter_events