#!/bin/bash
set -e

NODE_EXPORTER_VERSION="${NODE_EXPORTER_VERSION:-1.7.0}"
SKILLS_DIR="${SKILLS_DIR:-/skills}"

# Idempotent node_exporter installation
install_node_exporter() {
    if command -v node_exporter &>/dev/null; then
        echo "node_exporter already installed"
        return 0
    fi

    echo "Installing node_exporter v${NODE_EXPORTER_VERSION}..."

    local arch
    case "$(uname -m)" in
        x86_64)  arch="amd64" ;;
        aarch64) arch="arm64" ;;
        armv7l)  arch="armv7" ;;
        *)
            echo "Unsupported architecture: $(uname -m)"
            exit 1
            ;;
    esac

    local url="https://github.com/prometheus/node_exporter/releases/download/v${NODE_EXPORTER_VERSION}/node_exporter-${NODE_EXPORTER_VERSION}.linux-${arch}.tar.gz"

    curl -sSL "$url" -o /tmp/node_exporter.tar.gz
    tar -xzf /tmp/node_exporter.tar.gz -C /tmp
    mv /tmp/node_exporter-*/node_exporter /usr/local/bin/
    rm -rf /tmp/node_exporter*

    echo "node_exporter installed"
}

# Discover skills with metrics ports
discover_metrics_targets() {
    local targets_file="/tmp/metrics_targets.txt"
    echo "# Auto-discovered metrics targets" > "$targets_file"

    for skill_dir in "$SKILLS_DIR"/*/; do
        local skill_name=$(basename "$skill_dir")
        local skill_md="$skill_dir/SKILL.md"

        # Skip self
        [ "$skill_name" = "metrics" ] && continue

        # Check for metrics-port in SKILL.md
        if [ -f "$skill_md" ]; then
            local port=$(yq -r '.metadata.vibestack."metrics-port" // empty' < <(sed -n '/^---$/,/^---$/p' "$skill_md" | sed '1d;$d') 2>/dev/null)
            if [ -n "$port" ] && [ "$port" != "null" ]; then
                echo "$skill_name localhost:$port" >> "$targets_file"
                echo "  $skill_name: metrics on port $port"
            fi
        fi

        # Check for METRICS_PORT_skillname env var
        local env_var="METRICS_PORT_${skill_name//-/_}"
        local env_port="${!env_var}"
        if [ -n "$env_port" ]; then
            echo "$skill_name localhost:$env_port" >> "$targets_file"
            echo "  $skill_name: metrics on port $env_port (from env)"
        fi
    done

    echo "Targets written to $targets_file"
}

# Configure Caddy if present
configure_caddy() {
    local caddy_dir="$SKILLS_DIR/caddy"
    local metrics_port="${METRICS_PORT:-9090}"
    local metrics_domain="${METRICS_DOMAIN:-}"

    if [ ! -d "$caddy_dir" ]; then
        echo "Caddy not found - metrics on port $metrics_port"
        return 0
    fi

    echo "Caddy detected - configuring reverse proxy..."
    mkdir -p "$caddy_dir/snippets.d"

    local snippet="$caddy_dir/snippets.d/metrics.caddy"

    if [ -n "$metrics_domain" ]; then
        cat > "$snippet" << EOF
# Auto-generated by metrics skill
$metrics_domain {
    reverse_proxy localhost:$metrics_port
}
EOF
        echo "Caddy config: $metrics_domain -> localhost:$metrics_port"
    else
        cat > "$snippet" << EOF
# Auto-generated by metrics skill
# Add to your site block:
# handle /metrics {
#     reverse_proxy localhost:$metrics_port
# }
EOF
        echo "Caddy snippet created (manual config needed)"
    fi
}

# Install socat for HTTP server
install_socat() {
    if command -v socat &>/dev/null; then
        echo "socat already installed"
        return 0
    fi

    echo "Installing socat..."
    apt-get update
    apt-get install -y socat
    echo "socat installed"
}

install_node_exporter
install_socat
discover_metrics_targets
configure_caddy

echo "Metrics setup complete"