#!/bin/bash

# Git Credential Manager Installer
# Supports Debian, Ubuntu, RHEL, CentOS, Fedora, and other Linux distributions
# Downloads and installs the latest version from GitHub releases

set -e

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
NC='\033[0m' # No Color

# Configuration
GITHUB_REPO="git-ecosystem/git-credential-manager"
INSTALL_DIR="/usr/local/bin"
TEMP_DIR="/tmp/gcm-install"

# Function to print colored output
print_status() {
    echo -e "${BLUE}[INFO]${NC} $1"
}

print_success() {
    echo -e "${GREEN}[SUCCESS]${NC} $1"
}

print_warning() {
    echo -e "${YELLOW}[WARNING]${NC} $1"
}

print_error() {
    echo -e "${RED}[ERROR]${NC} $1"
}

# Function to check if command exists
command_exists() {
    command -v "$1" >/dev/null 2>&1
}

# Function to detect OS and package manager
detect_os() {
    if [[ -f /etc/os-release ]]; then
        . /etc/os-release
        OS="$ID"
        OS_VERSION="$VERSION_ID"
    else
        print_error "Cannot detect operating system"
        exit 1
    fi
    
    # Detect package manager
    if command_exists apt; then
        PKG_MANAGER="apt"
    elif command_exists yum; then
        PKG_MANAGER="yum"
    elif command_exists dnf; then
        PKG_MANAGER="dnf"
    elif command_exists pacman; then
        PKG_MANAGER="pacman"
    elif command_exists zypper; then
        PKG_MANAGER="zypper"
    else
        PKG_MANAGER="unknown"
    fi
    
    print_status "Detected OS: $OS $OS_VERSION"
    print_status "Package manager: $PKG_MANAGER"
}

# Function to get system architecture
get_arch() {
    ARCH=$(uname -m)
    case $ARCH in
        x86_64)
            echo "amd64"
            ;;
        aarch64|arm64)
            echo "arm64"
            ;;
        armv7l)
            echo "arm"
            ;;
        *)
            print_error "Unsupported architecture: $ARCH"
            exit 1
            ;;
    esac
}

# Function to get current installed version
get_current_version() {
    if command_exists git-credential-manager; then
        # Extract version from output like "2.6.1+786ab03440ddc82e807a97c0e540f5247e44cec6"
        local version_output=$(git-credential-manager --version 2>/dev/null)
        CURRENT_VERSION=$(echo "$version_output" | grep -o '[0-9]\+\.[0-9]\+\.[0-9]\+' | head -n 1)
        if [[ -n "$CURRENT_VERSION" ]]; then
            CURRENT_VERSION="v$CURRENT_VERSION"
        else
            CURRENT_VERSION="unknown"
        fi
    else
        CURRENT_VERSION="not_installed"
    fi
    echo "$CURRENT_VERSION"
}

# Function to compare versions (returns 0 if first >= second, 1 if first < second)
compare_versions() {
    local version1="$1"
    local version2="$2"
    
    # Remove 'v' prefix if present
    version1=${version1#v}
    version2=${version2#v}
    
    # Split versions into arrays
    IFS='.' read -ra V1 <<< "$version1"
    IFS='.' read -ra V2 <<< "$version2"
    
    # Compare major, minor, patch
    for i in {0..2}; do
        local v1=${V1[$i]:-0}
        local v2=${V2[$i]:-0}
        
        if (( v1 > v2 )); then
            return 0  # version1 > version2
        elif (( v1 < v2 )); then
            return 1  # version1 < version2
        fi
    done
    
    return 0  # versions are equal
}

# Function to get latest release info
get_latest_release() {
    print_status "Fetching latest release information..."
    
    if command_exists curl; then
        RELEASE_INFO=$(curl -s "https://api.github.com/repos/$GITHUB_REPO/releases/latest")
    elif command_exists wget; then
        RELEASE_INFO=$(wget -qO- "https://api.github.com/repos/$GITHUB_REPO/releases/latest")
    else
        print_error "curl or wget is required"
        exit 1
    fi
    
    if [[ -z "$RELEASE_INFO" ]]; then
        print_error "Failed to fetch release information"
        exit 1
    fi
    
    # Extract version and download URLs
    LATEST_VERSION=$(echo "$RELEASE_INFO" | grep -o '"tag_name": *"[^"]*"' | sed -E 's/.*"([^"]+)".*/\1/')
    
    if [[ -z "$LATEST_VERSION" ]]; then
        print_error "Failed to parse release information"
        exit 1
    fi
    
    print_success "Latest version: $LATEST_VERSION"
}

# Function to check if update is needed
check_update_needed() {
    local current_version=$(get_current_version)
    local latest_version="$1"
    
    print_status "Current version: $current_version"
    print_status "Latest version: $latest_version"
    
    if [[ "$current_version" == "not_installed" ]]; then
        print_status "git-credential-manager is not installed"
        return 0  # Need to install
    fi
    
    if [[ "$current_version" == "unknown" ]]; then
        print_warning "Cannot determine current version, proceeding with update"
        return 0  # Assume update needed
    fi
    
    if compare_versions "$latest_version" "$current_version"; then
        if [[ "$latest_version" == "$current_version" ]]; then
            print_success "You already have the latest version ($current_version)"
            if [[ "$force_reinstall" == "true" ]]; then
                print_status "Force reinstall requested, proceeding..."
                return 0
            else
                return 1  # No update needed
            fi
        else
            print_status "Newer version available: $latest_version > $current_version"
            return 0  # Update needed
        fi
    else
        print_success "Your version ($current_version) is newer than latest release ($latest_version)"
        return 1  # No update needed
    fi
}

# Function to download file
download_file() {
    local url="$1"
    local filename="$2"
    
    print_status "Downloading $filename..."
    
    if command_exists curl; then
        curl -L -o "$TEMP_DIR/$filename" "$url"
    elif command_exists wget; then
        wget -O "$TEMP_DIR/$filename" "$url"
    else
        print_error "curl or wget is required"
        exit 1
    fi
    
    if [[ ! -f "$TEMP_DIR/$filename" ]]; then
        print_error "Failed to download $filename"
        exit 1
    fi
    
    print_success "Downloaded $filename"
}

# Function to install from package manager
install_from_package_manager() {
    print_status "Attempting to install from package manager..."
    
    case $PKG_MANAGER in
        apt)
            # Check if git-credential-manager is available in repos
            if apt-cache show git-credential-manager >/dev/null 2>&1; then
                print_status "Installing git-credential-manager from apt repository..."
                sudo apt update
                sudo apt install -y git-credential-manager
                return 0
            else
                print_warning "git-credential-manager not available in apt repositories"
                return 1
            fi
            ;;
        yum|dnf)
            # Check EPEL repositories for RHEL/CentOS/Fedora
            if command_exists git-credential-manager; then
                print_success "git-credential-manager is already installed"
                return 0
            else
                print_warning "git-credential-manager not available in $PKG_MANAGER repositories"
                return 1
            fi
            ;;
        pacman)
            # Arch Linux has git-credential-manager in community repo
            if pacman -Si git-credential-manager >/dev/null 2>&1; then
                print_status "Installing git-credential-manager from pacman repository..."
                sudo pacman -S --noconfirm git-credential-manager
                return 0
            else
                print_warning "git-credential-manager not available in pacman repositories"
                return 1
            fi
            ;;
        *)
            print_warning "Package manager $PKG_MANAGER not supported for automatic installation"
            return 1
            ;;
    esac
}

# Function to install from DEB package
install_from_deb() {
    local arch="$1"
    local version="$2"
    
    local deb_name="gcm-linux_${arch}.${version#v}.deb"
    local download_url="https://github.com/$GITHUB_REPO/releases/download/$version/$deb_name"
    
    download_file "$download_url" "$deb_name"
    
    print_status "Installing DEB package..."
    sudo dpkg -i "$TEMP_DIR/$deb_name" || {
        print_warning "dpkg failed, attempting to fix dependencies..."
        sudo apt-get install -f -y
    }
    
    print_success "DEB package installed successfully"
}

# Function to install from tar.gz
install_from_tarball() {
    local arch="$1"
    local version="$2"
    
    local tar_name="gcm-linux_${arch}.${version#v}.tar.gz"
    local download_url="https://github.com/$GITHUB_REPO/releases/download/$version/$tar_name"
    
    download_file "$download_url" "$tar_name"
    
    print_status "Extracting tarball..."
    cd "$TEMP_DIR"
    tar -xzf "$tar_name"
    
    # Check if binary was extracted directly
    if [[ -f "git-credential-manager" ]]; then
        print_status "Installing binary to $INSTALL_DIR..."
        sudo install -m 755 git-credential-manager "$INSTALL_DIR/git-credential-manager"
        sudo ln -sf "$INSTALL_DIR/git-credential-manager" "$INSTALL_DIR/git-credential-manager-core"
        
        # Install shared libraries if present
        for lib in lib*.so; do
            if [[ -f "$lib" ]]; then
                sudo install -m 644 "$lib" "$INSTALL_DIR/"
                print_status "Installed library: $lib"
            fi
        done
    else
        # Try to find extracted directory (fallback)
        local extracted_dir=$(find . -maxdepth 1 -type d -name "git-credential-manager*" | head -n 1)
        if [[ -z "$extracted_dir" ]]; then
            print_error "Could not find git-credential-manager binary after extraction"
            exit 1
        fi
        
        cd "$extracted_dir"
        print_status "Installing binary to $INSTALL_DIR..."
        sudo install -m 755 git-credential-manager "$INSTALL_DIR/git-credential-manager"
        sudo ln -sf "$INSTALL_DIR/git-credential-manager" "$INSTALL_DIR/git-credential-manager-core"
    fi
    
    print_success "Binary installed successfully"
}

# Function to check and configure Git presets
configure_git_presets() {
    print_status "Checking and configuring Git presets..."

    local presets_configured=0
    local presets_needed=()

    # Check global credential helper
    local current_helper=""
    current_helper=$(git config --global --get credential.helper 2>/dev/null) || current_helper=""
    if [[ "$current_helper" == "manager" ]] || [[ "$current_helper" == "git-credential-manager" ]]; then
        print_success "✓ Global credential helper: $current_helper"
        presets_configured=$((presets_configured + 1))
    else
        print_warning "✗ Global credential helper not set to manager"
        presets_needed+=("git config --global credential.helper manager")
    fi

    # Check GitHub-specific configuration
    local github_helper=""
    github_helper=$(git config --global --get credential.https://github.com.helper 2>/dev/null) || github_helper=""
    if [[ -n "$github_helper" ]]; then
        print_success "✓ GitHub credential helper configured ($github_helper)"
        presets_configured=$((presets_configured + 1))
    else
        print_warning "✗ GitHub credential helper not configured"
        presets_needed+=("git config --global credential.https://github.com.helper manager")
    fi

    # Check GitLab-specific configuration
    local gitlab_helper=""
    gitlab_helper=$(git config --global --get credential.https://gitlab.com.helper 2>/dev/null) || gitlab_helper=""
    if [[ -n "$gitlab_helper" ]]; then
        print_success "✓ GitLab credential helper configured"
        presets_configured=$((presets_configured + 1))
    else
        print_warning "✗ GitLab credential helper not configured"
        presets_needed+=("git config --global credential.https://gitlab.com.helper manager")
    fi

    # Check Azure DevOps configuration
    local azure_useHttpPath=""
    azure_useHttpPath=$(git config --global --get credential.https://dev.azure.com.useHttpPath 2>/dev/null) || azure_useHttpPath=""
    if [[ "$azure_useHttpPath" == "true" ]]; then
        print_success "✓ Azure DevOps useHttpPath configured"
        presets_configured=$((presets_configured + 1))
    else
        print_warning "✗ Azure DevOps useHttpPath not configured"
        presets_needed+=("git config --global credential.https://dev.azure.com.useHttpPath true")
    fi

    # Check Bitbucket configuration
    local bitbucket_helper=""
    bitbucket_helper=$(git config --global --get credential.https://bitbucket.org.helper 2>/dev/null) || bitbucket_helper=""
    if [[ -n "$bitbucket_helper" ]]; then
        print_success "✓ Bitbucket credential helper configured"
        presets_configured=$((presets_configured + 1))
    else
        print_warning "✗ Bitbucket credential helper not configured"
        presets_needed+=("git config --global credential.https://bitbucket.org.helper manager")
    fi

    # Check specific Gitea configurations
    local gitea_configured=0
    local gitea_needed=()

    # Check go-gitea.mywire.org
    local gitea1_helper=""
    gitea1_helper=$(git config --global --get credential.https://go-gitea.mywire.org.helper 2>/dev/null) || gitea1_helper=""
    if [[ "$gitea1_helper" == "manager" ]]; then
        print_success "✓ Gitea (go-gitea.mywire.org) credential helper configured"
        gitea_configured=$((gitea_configured + 1))
    else
        print_warning "✗ Gitea (go-gitea.mywire.org) credential helper not configured"
        gitea_needed+=("git config --global credential.https://go-gitea.mywire.org.helper manager")
    fi

    # Check 192.168.88.97:3000
    local gitea2_helper=""
    gitea2_helper=$(git config --global --get credential.https://192.168.88.97:3000.helper 2>/dev/null) || gitea2_helper=""
    if [[ "$gitea2_helper" == "manager" ]]; then
        print_success "✓ Gitea (192.168.88.97:3000) credential helper configured"
        gitea_configured=$((gitea_configured + 1))
    else
        print_warning "✗ Gitea (192.168.88.97:3000) credential helper not configured"
        gitea_needed+=("git config --global credential.https://192.168.88.97:3000.helper manager")
    fi

    # Check for other Gitea configurations
    local other_gitea_urls=0
    other_gitea_urls=$(git config --global --get-regexp "credential.*gitea.*helper" 2>/dev/null | grep -v "go-gitea.mywire.org\|192.168.88.97:3000" | wc -l) || other_gitea_urls=0
    if [[ $other_gitea_urls -gt 0 ]]; then
        print_success "✓ Additional Gitea credential helpers configured ($other_gitea_urls found)"
    fi

    if [[ $gitea_configured -eq 2 ]]; then
        presets_configured=$((presets_configured + 1))
    fi

    # Add needed Gitea configs to presets_needed
    if [[ ${#gitea_needed[@]} -gt 0 ]]; then
        presets_needed+=("# Configure Gitea credential helpers:")
        presets_needed+=("${gitea_needed[@]}")
    fi

    # Summary
    echo
    print_status "Git Credential Manager Configuration Summary:"
    print_status "Presets configured: $presets_configured/7"

    if [[ ${#presets_needed[@]} -eq 0 ]]; then
        print_success "All recommended presets are configured!"
        echo
        print_status "Your Git Credential Manager is fully configured and ready to use."
        echo "When you run Git commands that require authentication, GCM will:"
        echo "1. Prompt for credentials on first use"
        echo "2. Securely store them in your system's credential store"
        echo "3. Automatically provide them for subsequent operations"
    else
        print_warning "Some presets need to be configured manually."
        echo
        print_status "Run these commands to complete the configuration:"
        for cmd in "${presets_needed[@]}"; do
            echo "  $cmd"
        done
        echo
        print_status "After configuring, test with:"
        echo "  git config --global --list | grep credential"
    fi

    return 0
}

# Function to verify installation
verify_installation() {
    print_status "Verifying installation..."

    if command_exists git-credential-manager; then
        local version=$(git-credential-manager --version 2>/dev/null || echo "unknown")
        print_success "git-credential-manager installed: $version"

        # Configure basic Git settings
        print_status "Configuring basic Git settings..."
        git config --global credential.helper manager
        print_success "Basic Git configuration completed"

        # Check all presets
        configure_git_presets

        return 0
    else
        print_error "git-credential-manager installation verification failed"
        return 1
    fi
}

# Function to cleanup
cleanup() {
    if [[ -d "$TEMP_DIR" ]]; then
        rm -rf "$TEMP_DIR"
        print_status "Cleaned up temporary files"
    fi
}

# Function to show usage
show_usage() {
    echo "Git Credential Manager Installer"
    echo
    echo "Usage: $0 [OPTIONS]"
    echo
    echo "Options:"
    echo "  -h, --help     Show this help message"
    echo "  -v, --version  Install specific version (default: latest)"
    echo "  -f, --force    Force reinstall even if already installed"
    echo "  -p, --package  Force installation from package manager"
    echo "  -d, --deb      Force installation from DEB package"
    echo "  -t, --tarball  Force installation from tarball"
    echo "  -c, --checks   Check Git credential configuration without installing"
    echo
    echo "Examples:"
    echo "  $0                    # Install latest version using best method"
    echo "  $0 -v v2.6.0         # Install specific version"
    echo "  $0 --package          # Force installation from package manager"
    echo "  $0 --deb             # Force installation from DEB package"
    echo "  $0 --checks           # Check configuration without installing"
}

# Function to run configuration checks only
run_checks_only() {
    echo "========================================"
    echo "Git Credential Manager Configuration Check"
    echo "========================================"
    echo

    # Check if GCM is installed
    if ! command_exists git-credential-manager; then
        print_error "Git Credential Manager is not installed"
        echo
        print_status "To install Git Credential Manager, run:"
        echo "  $0"
        echo
        print_status "Or to check configuration after installation:"
        echo "  $0 --checks"
        exit 1
    fi

    # Run configuration checks
    configure_git_presets

    echo
    print_success "Configuration check completed!"
}

# Main installation function
main() {
    local target_version=""
    local force_reinstall=false
    local install_method="auto"
    local checks_only=false

    # Parse command line arguments
    while [[ $# -gt 0 ]]; do
        case $1 in
            -h|--help)
                show_usage
                exit 0
                ;;
            -v|--version)
                target_version="$2"
                shift 2
                ;;
            -f|--force)
                force_reinstall=true
                shift
                ;;
            -p|--package)
                install_method="package"
                shift
                ;;
            -d|--deb)
                install_method="deb"
                shift
                ;;
            -t|--tarball)
                install_method="tarball"
                shift
                ;;
            -c|--checks)
                checks_only=true
                shift
                ;;
            *)
                print_error "Unknown option: $1"
                show_usage
                exit 1
                ;;
        esac
    done

    # If checks only, run checks and exit
    if [[ "$checks_only" == "true" ]]; then
        run_checks_only
        exit 0
    fi
    
    echo "========================================"
    echo "Git Credential Manager Installer"
    echo "========================================"
    echo
    
    # Get latest version if not specified
    if [[ -z "$target_version" ]]; then
        get_latest_release
        target_version="$LATEST_VERSION"
    else
        print_status "Using specified version: $target_version"
    fi
    
    # Check if update is needed
    if ! check_update_needed "$target_version"; then
        print_success "No installation needed. Exiting."
        exit 0
    fi
    
    # Detect system
    detect_os
    ARCH=$(get_arch)
    
    # Create temporary directory
    mkdir -p "$TEMP_DIR"
    
    # Trap cleanup on exit
    trap cleanup EXIT
    
    # Installation logic based on method
    case $install_method in
        auto)
            # Try package manager first
            if install_from_package_manager; then
                verify_installation
                exit 0
            fi
            
            # Fall back to distribution-specific methods
            case $OS in
                ubuntu|debian|linuxmint)
                    install_from_deb "$ARCH" "$target_version"
                    ;;
                *)
                    install_from_tarball "$ARCH" "$target_version"
                    ;;
            esac
            ;;
        package)
            if ! install_from_package_manager; then
                print_error "Package manager installation failed"
                exit 1
            fi
            ;;
        deb)
            install_from_deb "$ARCH" "$target_version"
            ;;
        tarball)
            install_from_tarball "$ARCH" "$target_version"
            ;;
    esac
    
    # Verify installation
    if verify_installation; then
        echo
        print_success "Installation completed successfully!"
        echo
        print_status "Test the installation:"
        echo "  git-credential-manager --version"
        echo "  git config --global --list | grep credential"
    else
        print_error "Installation failed"
        exit 1
    fi
}

# Run main function
main "$@"