check_java.sh

#!/usr/bin/env bash

source "$(dirname "${BASH_SOURCE[0]}")/utils.sh"

require_bash

check_java_installation() {
    echo "Checking Java installation..." >&2
    if [ -z "$JAVA_HOME" ]; then
        echo "Error: JAVA_HOME environment variable is not set" >&2
        return 1
    fi

    if ! get_real_path "$JAVA_HOME"; then
        echo "Error: Failed to resolve JAVA_HOME path: $JAVA_HOME" >&2
        return 1
    fi
    local resolved_java_home="$GET_REAL_PATH_RESULT"

    if [ ! -d "$resolved_java_home" ]; then
        echo "Error: JAVA_HOME directory does not exist: $resolved_java_home" >&2
        return 1
    fi

    local java_cmd="$resolved_java_home/bin/java"

    if get_real_path "$java_cmd"; then
        local resolved_java_cmd="$GET_REAL_PATH_RESULT"
        if [ ! -x "$resolved_java_cmd" ]; then
            echo "Error: Java executable not found or not executable: $resolved_java_cmd" >&2
            return 1
        fi
        java_cmd="$resolved_java_cmd"
    else
        if [ ! -x "$java_cmd" ]; then
            echo "Error: Java executable not found or not executable: $java_cmd" >&2
            return 1
        fi
    fi

    local javac_cmd="$resolved_java_home/bin/javac"

    if get_real_path "$javac_cmd"; then
        local resolved_javac_cmd="$GET_REAL_PATH_RESULT"
        if [ ! -x "$resolved_javac_cmd" ]; then
            echo "Warning: javac not found - this might be a JRE instead of JDK" >&2
        fi
    else
        if [ ! -x "$javac_cmd" ]; then
            echo "Warning: javac not found - this might be a JRE instead of JDK" >&2
        fi
    fi

    local java_version=$("$java_cmd" -version 2>&1 | awk -F '"' '/version/ {print $2}')

    if [ -z "$java_version" ]; then
        echo "Error: Failed to get Java version" >&2
        return 1
    fi

    echo "Java validation successful: version $java_version, JAVA_HOME=$resolved_java_home" >&2
    return 0
}


find_java_installation() {
    local java_cmd=""
    local java_home=""

    if type -p java > /dev/null 2>&1; then
        echo "Found java executable in PATH" >&2
        java_cmd=$(which java)

        if get_real_path "$java_cmd" && [ -n "$GET_REAL_PATH_RESULT" ]; then
            local java_cmd_real="$GET_REAL_PATH_RESULT"
            local java_bin_dir=$(dirname "$java_cmd_real")
            if [ "$(basename "$java_bin_dir")" = "bin" ]; then
                java_home=$(dirname "$java_bin_dir")
                echo "Derived JAVA_HOME from java executable: $java_home" >&2
            fi
        fi
    elif [[ -n "$JAVA_HOME" ]] && [[ -x "$JAVA_HOME/bin/java" ]]; then
        echo "Found java executable in JAVA_HOME" >&2

        if get_real_path "$JAVA_HOME" && [ -n "$GET_REAL_PATH_RESULT" ]; then
            java_home="$GET_REAL_PATH_RESULT"
            echo "Resolved JAVA_HOME to: $java_home" >&2
        else
            java_home="$JAVA_HOME"
        fi
        java_cmd="$java_home/bin/java"
    else
        echo "The JAVA_HOME environment variable is not defined correctly" >&2
        echo "JAVA_HOME should point to a JDK not a JRE" >&2
        echo "Also, no java executable found in PATH" >&2
        return 1
    fi

    if [[ "$java_cmd" ]]; then
        local java_version=$("$java_cmd" -version 2>&1 | awk -F '"' '/version/ {print $2}')

        local java_cmd_real_display="$java_cmd"
        if get_real_path "$java_cmd" && [ -n "$GET_REAL_PATH_RESULT" ]; then
            java_cmd_real_display="$GET_REAL_PATH_RESULT"
        fi

        echo "Java executable: $java_cmd_real_display" >&2
        echo "Java version: $java_version" >&2
        if [ -n "$java_home" ]; then
            echo "JAVA_HOME: $java_home" >&2
        fi

        JAVA_CMD="$java_cmd"
        JAVA_HOME="$java_home"
        JAVA_VERSION="$java_version"
    else
        return 1
    fi
}

if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
    require_interactive_shell

    if check_java_installation "$JAVA_HOME"; then
        echo "Java is properly configured" >&2
    else
        echo "JAVA_HOME is not properly configured. Trying to find java installation..." >&2
        if find_java_installation; then
            echo "Java successfully found and configured" >&2
            echo "Do you want to save JAVA_HOME to ~/.profile? (y/n)"
            read -r response
            if [[ "$response" =~ ^[Yy]$ ]]; then
                remove_env_variable "JAVA_HOME" ~/.profile
                echo "export JAVA_HOME=${JAVA_HOME}" >> ~/.profile
                echo "JAVA_HOME has been saved to ~/.profile"
                echo "Please run 'source ~/.profile' or restart your terminal to apply changes"
            fi
        else
            exit 1
        fi
    fi
fi