#!/bin/bash
# Script: validate_input.sh
# Description: Validates prerequisites and input parameters for building and pushing a Docker image.
# This script ensures that Docker, Docker Buildx, and input variables (architectures, tags, image name, registry URL)
# meet the required criteria. If any check fails, the script provides informative error messages and exits.

# Exit immediately if a command exits with a non-zero status.
set -e

echo "============================================"
echo "Starting Validation Script"
echo "============================================"

# ---------------------------- Docker Installation --------------------------- #
echo "🔍 Checking Docker installation..."
if docker --version >/dev/null 2>&1; then
    DOCKER_VERSION=$(docker --version)
    echo "✅ Docker is installed: $DOCKER_VERSION"
else
    echo "❌ Docker is not installed."
    echo "ℹ️ Please install Docker from: https://docs.docker.com/get-docker/"
    exit 1
fi

# ---------------------------- Buildx Installation --------------------------- #
echo "🔍 Checking Docker Buildx installation..."
if docker buildx version >/dev/null 2>&1; then
    BUILDX_VERSION=$(docker buildx version)
    echo "✅ Docker Buildx is installed: $BUILDX_VERSION"
else
    echo "❌ Docker Buildx is not installed."
    echo "ℹ️ Please install Docker Buildx. See: https://docs.docker.com/buildx/working-with-buildx/"
    exit 1
fi

# ---------------------------- Validate Architectures --------------------------- #
# Architectures are CSV (amd64,arm64)
# Usage: ./ensure_lowercase.sh "Architecture" amd64,arm64
echo "🔍 Validating architectures..."
for arch in $(echo $ARCHITECTURES | tr "," "\n"); do
    # Ensure architecture is lowercase.
    if [[ "$arch" != "${arch,,}" ]]; then
        echo "❌ Invalid Architecture: $arch"
        echo "ℹ️ Architecture must be lowercase"
        exit 1
    else
        echo "✅ Architecture is valid: $arch"
    fi

    # Ensure architecture is supported by Docker Buildx.
    if docker buildx inspect --bootstrap | grep -q $arch; then
        echo "✅ Architecture is supported by Docker Buildx: $arch"
    else
        echo "❌ Architecture is not supported by Docker Buildx: $arch"
        echo "ℹ️ Please check the supported platforms: https://docs.docker.com/buildx/working-with-buildx/"
        exit 1
    fi
done
echo "✅ All specified architectures are valid."