#!/bin/bash

# A script to set up a complete Android and Flutter development environment on a Debian-based Linux system.
# It installs dependencies, Java, Node.js, the Android SDK (with dynamic package discovery), and Flutter.

set -e
set -o pipefail

# --- Configuration ---
SDK_ROOT="$HOME/Android/Sdk"
FLUTTER_DIR="$HOME/flutter"
REPO_URL="https://dl.google.com/android/repository/repository2-1.xml"
PROFILE_FILE="$HOME/.bashrc"
if [ -f "$HOME/.zshrc" ]; then
    PROFILE_FILE="$HOME/.zshrc"
fi


# --- OS Detection ---
OS_NAME=""
case "$(uname -s)" in
    Linux*)     OS_NAME="linux";;
    Darwin*)    OS_NAME="macosx";;
    *)          echo "Unsupported OS: $(uname -s). This script currently supports Debian/Ubuntu Linux and macOS."; exit 1;;
esac

# --- Helper Functions ---

# Function to print colored text
print_info() {
    echo -e "\n\e[34m[INFO]\e[0m $1"
}

print_success() {
    echo -e "\e[32m[SUCCESS]\e[0m $1"
}

print_error() {
    echo -e "\e[31m[ERROR]\e[0m $1" >&2
}

# Add a line to the user's shell profile file if it's not already there.
add_to_profile() {
    local line="$1"
    if ! grep -qF -- "$line" "$PROFILE_FILE"; then
        print_info "Adding to profile: $line"
        echo -e "\n# Added by dev setup script\n$line" >> "$PROFILE_FILE"
    else
        echo "[SKIPPED] '$line' already exists in $PROFILE_FILE."
    fi
}

# Find the latest version string (e.g., "34.0.0") for a package prefix.
get_latest_version_id() {
    local package_path_prefix="$1"
    local xml_file="$2"
    
    # The XPath finds all non-obsolete packages for the current OS that match the prefix.
    # It then extracts the version part from the path, sorts it version-wise, and gets the latest.
    latest_version=$(xmllint --xpath "//remotePackage[starts-with(@path, '${package_path_prefix};') and not(@obsolete) and .//archive[host-os='${OS_NAME}']]" "$xml_file" | \
        grep -o 'path="[^"]*"' | \
        sed -e "s/path=\"${package_path_prefix};//" -e 's/"//' | \
        sort -V | tail -n 1)

    if [ -z "$latest_version" ]; then
        print_error "Could not find any version for package prefix '$package_path_prefix' for OS '$OS_NAME'."
        return 1
    fi
    
    echo "${package_path_prefix};${latest_version}"
}

# Get the download URL for a package that has a fixed path in the repository XML.
get_fixed_path_url() {
    local package_path="$1"
    local xml_file="$2"

    url=$(xmllint --xpath "string(//remotePackage[@path='${package_path}' and not(@obsolete) and .//archive[host-os='${OS_NAME}']]//archive[host-os='${OS_NAME}']/complete/url)" "$xml_file")
    
    if [ -z "$url" ]; then
        print_error "Could not find download URL for package '$package_path'."
        return 1
    fi

    echo "$url"
}


# --- Main Execution Flow ---

main() {
    # STEP 1: SYSTEM DEPENDENCIES
    if [[ "$OS_NAME" == "linux" ]]; then
        print_info "Updating package lists and installing foundational dependencies for Linux..."
        sudo apt-get update -y
        sudo apt-get install -y curl git unzip xz-utils zip libglu1-mesa clang cmake ninja-build pkg-config \
                                libgtk-3-dev liblzma-dev libstdc++-12-dev libxml2-utils openjdk-17-jdk
    else
        print_info "Please ensure Xcode Command Line Tools, curl, git, and unzip are installed."
    fi

    # STEP 2: JAVA DEVELOPMENT KIT (JDK)
    print_info "Configuring JAVA_HOME..."
    if [[ "$OS_NAME" == "linux" ]]; then
        JAVA_HOME_PATH=$(update-java-alternatives -l | grep '1.17' | head -n 1 | awk '{print $3}')
        if [ -z "$JAVA_HOME_PATH" ]; then
            print_error "Could not determine JAVA_HOME path for OpenJDK 17."
            exit 1
        fi
        add_to_profile "export JAVA_HOME=$JAVA_HOME_PATH"
        export JAVA_HOME="$JAVA_HOME_PATH"
        print_success "JAVA_HOME set to $JAVA_HOME"
    else
        print_info "On macOS, JAVA_HOME is typically managed by the system. Skipping manual configuration."
    fi
    
    # STEP 3: NODE.JS with NVM (Optional but common for modern dev)
    print_info "Installing Node Version Manager (NVM) and latest LTS Node.js..."
    curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/refs/heads/master/install.sh | bash
    export NVM_DIR="$HOME/.nvm"
    [ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh" # Source NVM for the current session
    nvm install --lts
    nvm alias default 'lts/*'
    nvm use default
    add_to_profile 'export NVM_DIR="$HOME/.nvm"'
    add_to_profile '[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"  # This loads nvm'
    
    # STEP 4: ANDROID SDK
    print_info "Setting up Android SDK in $SDK_ROOT..."
    mkdir -p "$SDK_ROOT"

    # Download repository index to find the command-line tools URL
    XML_FILE=$(mktemp)
    trap 'rm -f "$XML_FILE"' EXIT # Ensure temp file is cleaned up
    print_info "Downloading Android SDK repository index..."
    if ! curl -s -L -o "$XML_FILE" "$REPO_URL"; then
        print_error "Failed to download repository index. Exiting."
        exit 1
    fi
    print_success "Repository index downloaded."

    # Dynamically find the command-line tools URL
    CMDLINE_TOOLS_FILENAME=$(get_fixed_path_url 'cmdline-tools;latest' "$XML_FILE")
    if [ -z "$CMDLINE_TOOLS_FILENAME" ]; then
        print_error "Could not determine command-line tools URL. Exiting."
        exit 1
    fi
    CMDLINE_TOOLS_URL="https://dl.google.com/android/repository/${CMDLINE_TOOLS_FILENAME}"
    
    # Download and set up command-line tools
    CMDLINE_TOOLS_ZIP="$HOME/cmdline-tools.zip"
    print_info "Downloading Android command-line tools..."
    curl -# -L "$CMDLINE_TOOLS_URL" -o "$CMDLINE_TOOLS_ZIP"
    
    print_info "Installing command-line tools..."
    # FIX: Ensure the final destination directory exists before trying to move files.
    mkdir -p "$SDK_ROOT/cmdline-tools/latest"

    # Unzip into a temporary folder, then move the contents into the final destination.
    unzip -q -o "$CMDLINE_TOOLS_ZIP" -d "$SDK_ROOT/cmdline-tools_temp"
    
    # The zip contains a 'cmdline-tools' directory, move its contents to 'latest'
    mv "$SDK_ROOT/cmdline-tools_temp/cmdline-tools"/* "$SDK_ROOT/cmdline-tools/latest/"
    
    # Cleanup temporary files
    rm -rf "$SDK_ROOT/cmdline-tools_temp"
    rm "$CMDLINE_TOOLS_ZIP"

    # Add SDK paths to the current session's PATH to use sdkmanager immediately
    export ANDROID_HOME="$SDK_ROOT"
    export PATH="$PATH:$ANDROID_HOME/cmdline-tools/latest/bin:$ANDROID_HOME/platform-tools:$ANDROID_HOME/emulator"

    # Add to profile for future sessions
    add_to_profile "export ANDROID_HOME=$SDK_ROOT"
    add_to_profile 'export PATH="$PATH:$ANDROID_HOME/cmdline-tools/latest/bin"'
    add_to_profile 'export PATH="$PATH:$ANDROID_HOME/platform-tools"'
    add_to_profile 'export PATH="$PATH:$ANDROID_HOME/emulator"'
    
    # Find latest package versions using the downloaded XML
    print_info "Finding latest SDK package versions..."
    LATEST_BUILD_TOOLS=$(get_latest_version_id 'build-tools' "$XML_FILE")
    LATEST_CMAKE=$(get_latest_version_id 'cmake' "$XML_FILE")
    LATEST_NDK=$(get_latest_version_id 'ndk' "$XML_FILE")
    print_success "Latest build-tools: $LATEST_BUILD_TOOLS"
    print_success "Latest CMake: $LATEST_CMAKE"
    print_success "Latest NDK: $LATEST_NDK"

    print_info "Installing core Android SDK packages using sdkmanager..."
    yes | sdkmanager --licenses > /dev/null # Accept all licenses
    sdkmanager --update
    sdkmanager --install \
        "platform-tools" \
        "$LATEST_BUILD_TOOLS" \
        "$LATEST_CMAKE" \
        "$LATEST_NDK" \
        "platforms;android-34" \
        "system-images;android-34;google_apis;x86_64" \
        "emulator"

    # Add CMAKE and create NDK bundle link
    LATEST_CMAKE_VER=$(echo "$LATEST_CMAKE" | cut -d';' -f2)
    add_to_profile 'export PATH="$PATH:$ANDROID_HOME/cmake/'"$LATEST_CMAKE_VER"'/bin"'
    
    # For compatibility, create an 'ndk-bundle' symlink pointing to the installed NDK version
    LATEST_NDK_VER=$(echo "$LATEST_NDK" | cut -d';' -f2)
    if [ -d "$SDK_ROOT/ndk/$LATEST_NDK_VER" ]; then
        ln -sfn "$SDK_ROOT/ndk/$LATEST_NDK_VER" "$SDK_ROOT/ndk-bundle"
        add_to_profile 'export PATH="$PATH:$ANDROID_HOME/ndk-bundle"'
    fi

    # STEP 5: FLUTTER SDK
    print_info "Installing Flutter SDK to $FLUTTER_DIR..."
    if [ -d "$FLUTTER_DIR" ]; then
        print_info "Flutter directory exists. Updating..."
        (cd "$FLUTTER_DIR" && git pull)
    else
        git clone https://github.com/flutter/flutter.git -b stable "$FLUTTER_DIR"
    fi
    add_to_profile "export PATH=\"\$PATH:$FLUTTER_DIR/bin\""
    export PATH="$PATH:$FLUTTER_DIR/bin"

    # STEP 6: FINALIZATION
    print_info "Finalizing Flutter Configuration..."
    flutter config --android-sdk "$SDK_ROOT"
    flutter precache
    flutter doctor --android-licenses

    print_info "Disabling Flutter analytics..."
    flutter --disable-analytics

    echo ""
    echo "========================================================"
    echo "  Development Environment Setup Complete!"
    echo "  To apply all changes, run: source $PROFILE_FILE"
    echo "  OR open a new terminal."
    echo "  Then, run 'flutter doctor' to verify the setup."
    echo "========================================================"
    echo ""
}

main


echo ""
echo "========================================================"
echo "  Development Environment Setup Complete!"
echo "  To activate fully, run: source ~/.bashrc"
echo "  OR open a new terminal."
echo "  Then, run 'flutter doctor' to verify."
echo "========================================================"
echo ""