#!/usr/bin/env bash
# Container Runtime Detection & Configuration
# Detects and uses available container runtime: podman-in-podman > podman > docker-in-docker > docker

set -euo pipefail

# Color codes
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m'

# Export these for use in calling scripts
export CONTAINER_RUNTIME=""
export COMPOSE_CMD=""
export CONTAINER_SOCKET=""
export INSIDE_CONTAINER=""

# Detect if we're inside a container
detect_container_env() {
    if [[ -f /.dockerenv ]] || [[ -f /run/.containerenv ]]; then
        INSIDE_CONTAINER="true"
    else
        INSIDE_CONTAINER="false"
    fi
}

# Find available container runtime
detect_runtime() {
    local runtime_priority=(
        "podman"
        "docker"
    )

    for runtime in "${runtime_priority[@]}"; do
        if command -v "$runtime" &>/dev/null; then
            CONTAINER_RUNTIME="$runtime"

            # Get compose command
            if command -v "${runtime}-compose" &>/dev/null; then
                COMPOSE_CMD="${runtime}-compose"
            elif [[ "$runtime" == "docker" ]] && command -v docker-compose &>/dev/null; then
                COMPOSE_CMD="docker-compose"
            elif [[ "$runtime" == "podman" ]] && command -v podman-compose &>/dev/null; then
                COMPOSE_CMD="podman-compose"
            elif [[ "$runtime" == "podman" ]]; then
                # Fallback: podman has built-in compose
                COMPOSE_CMD="podman compose"
            else
                COMPOSE_CMD="$runtime compose"
            fi

            return 0
        fi
    done

    return 1
}

# Setup DinD (Docker in Docker) socket
setup_dind_socket() {
    local runtime="$1"

    case "$runtime" in
        podman)
            # Podman socket location
            if [[ -S "$XDG_RUNTIME_DIR/podman/podman.sock" ]]; then
                CONTAINER_SOCKET="$XDG_RUNTIME_DIR/podman/podman.sock"
            elif [[ -S "/run/podman/podman.sock" ]]; then
                CONTAINER_SOCKET="/run/podman/podman.sock"
            elif [[ -S "/run/user/$(id -u)/podman/podman.sock" ]]; then
                CONTAINER_SOCKET="/run/user/$(id -u)/podman/podman.sock"
            fi
            ;;
        docker)
            # Docker socket location
            if [[ -S "/var/run/docker.sock" ]]; then
                CONTAINER_SOCKET="/var/run/docker.sock"
            elif [[ -S "/run/docker.sock" ]]; then
                CONTAINER_SOCKET="/run/docker.sock"
            fi
            ;;
    esac
}

# Get mount flags for DinD
get_dind_mount_flags() {
    local runtime="$1"

    if [[ -z "$CONTAINER_SOCKET" ]]; then
        return
    fi

    case "$runtime" in
        podman)
            echo "-v $CONTAINER_SOCKET:/run/podman/podman.sock"
            ;;
        docker)
            echo "-v $CONTAINER_SOCKET:/var/run/docker.sock"
            ;;
    esac
}

# Initialize runtime
init_runtime() {
    detect_container_env

    if ! detect_runtime; then
        echo -e "${RED}❌ Error: No container runtime found (podman or docker required)${NC}" >&2
        return 1
    fi

    setup_dind_socket "$CONTAINER_RUNTIME"

    # Export for subshells
    export CONTAINER_RUNTIME
    export COMPOSE_CMD
    export CONTAINER_SOCKET
    export INSIDE_CONTAINER

    return 0
}

# Display status
show_status() {
    echo -e "${BLUE}Container Runtime Detection:${NC}"
    echo "  Runtime: ${GREEN}$CONTAINER_RUNTIME${NC}"
    echo "  Compose: ${GREEN}$COMPOSE_CMD${NC}"
    echo "  Inside Container: ${GREEN}$INSIDE_CONTAINER${NC}"
    if [[ -n "$CONTAINER_SOCKET" ]]; then
        echo "  Socket: ${GREEN}$CONTAINER_SOCKET${NC}"
    fi
}

# Main execution
if [[ "${1:-}" == "init" ]]; then
    init_runtime
elif [[ "${1:-}" == "status" ]]; then
    init_runtime
    show_status
elif [[ "${1:-}" == "runtime" ]]; then
    init_runtime
    echo "$CONTAINER_RUNTIME"
elif [[ "${1:-}" == "compose" ]]; then
    init_runtime
    echo "$COMPOSE_CMD"
elif [[ "${1:-}" == "socket" ]]; then
    init_runtime
    echo "$CONTAINER_SOCKET"
else
    init_runtime
fi