#!/bin/bash
# Azure DevOps Self-Hosted Agent Setup Script
# Installs and configures Azure DevOps agent on a Proxmox VM

set -e

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m'

# Azure DevOps configuration
AZP_URL="${AZP_URL:-}"
AZP_TOKEN="${AZP_TOKEN:-}"
AZP_AGENT_NAME="${AZP_AGENT_NAME:-$(hostname)}"
AZP_POOL="${AZP_POOL:-Default}"
AZP_WORK="${AZP_WORK:-_work}"

log_info() {
    echo -e "${GREEN}[INFO]${NC} $1"
}

log_warn() {
    echo -e "${YELLOW}[WARN]${NC} $1"
}

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

check_root() {
    if [ "$EUID" -ne 0 ]; then 
        log_error "Please run as root"
        exit 1
    fi
}

validate_config() {
    if [ -z "$AZP_URL" ] || [ -z "$AZP_TOKEN" ]; then
        log_error "Required Azure DevOps configuration missing"
        log_info "Required environment variables:"
        log_info "  AZP_URL - Azure DevOps organization URL (e.g., https://dev.azure.com/yourorg)"
        log_info "  AZP_TOKEN - Personal Access Token with Agent Pools (Read & Manage) permission"
        log_info ""
        log_info "Optional:"
        log_info "  AZP_AGENT_NAME - Agent name (default: hostname)"
        log_info "  AZP_POOL - Agent pool name (default: Default)"
        exit 1
    fi
}

detect_os() {
    if [ -f /etc/os-release ]; then
        . /etc/os-release
        OS=$ID
        VERSION=$VERSION_ID
        log_info "Detected OS: $OS $VERSION"
    else
        log_error "Cannot detect operating system"
        exit 1
    fi
}

install_dependencies() {
    log_info "Installing dependencies..."
    
    case "$OS" in
        ubuntu|debian)
            apt-get update
            apt-get install -y curl jq git
            ;;
        rhel|centos|fedora)
            yum install -y curl jq git
            ;;
        *)
            log_warn "Unknown OS. Please install: curl, jq, git"
            ;;
    esac
}

download_agent() {
    log_info "Downloading Azure DevOps agent..."
    
    AGENT_DIR="/opt/azp-agent"
    mkdir -p "$AGENT_DIR"
    cd "$AGENT_DIR"
    
    # Download agent package
    case "$(uname -m)" in
        x86_64)
            AGENT_URL="https://vstsagentpackage.azureedge.net/agent/2.220.0/vsts-agent-linux-x64-2.220.0.tar.gz"
            ;;
        arm64|aarch64)
            AGENT_URL="https://vstsagentpackage.azureedge.net/agent/2.220.0/vsts-agent-linux-arm64-2.220.0.tar.gz"
            ;;
        *)
            log_error "Unsupported architecture: $(uname -m)"
            exit 1
            ;;
    esac
    
    curl -LsS "$AGENT_URL" | tar -xz
    log_info "Agent downloaded to $AGENT_DIR"
}

configure_agent() {
    log_info "Configuring Azure DevOps agent..."
    
    cd "$AGENT_DIR"
    
    ./config.sh \
        --unattended \
        --url "$AZP_URL" \
        --auth pat \
        --token "$AZP_TOKEN" \
        --pool "$AZP_POOL" \
        --agent "$AZP_AGENT_NAME" \
        --work "$AZP_WORK" \
        --replace \
        --acceptTeeEula
    
    if [ $? -eq 0 ]; then
        log_info "Agent configured successfully"
    else
        log_error "Agent configuration failed"
        exit 1
    fi
}

install_service() {
    log_info "Installing Azure DevOps agent as a systemd service..."
    
    cd "$AGENT_DIR"
    ./svc.sh install
    
    if [ $? -eq 0 ]; then
        log_info "Service installed successfully"
    else
        log_error "Service installation failed"
        exit 1
    fi
}

start_service() {
    log_info "Starting Azure DevOps agent service..."
    
    ./svc.sh start
    
    sleep 5
    
    if systemctl is-active --quiet azp-agent; then
        log_info "Agent service is running"
        systemctl status azp-agent --no-pager
    else
        log_error "Agent service failed to start"
        systemctl status azp-agent --no-pager
        exit 1
    fi
}

show_info() {
    log_info "Azure DevOps agent setup completed!"
    log_info ""
    log_info "Agent details:"
    log_info "  Name: $AZP_AGENT_NAME"
    log_info "  Pool: $AZP_POOL"
    log_info "  Work directory: $AGENT_DIR/$AZP_WORK"
    log_info ""
    log_info "Useful commands:"
    log_info "  Status:   systemctl status azp-agent"
    log_info "  Stop:     systemctl stop azp-agent"
    log_info "  Start:    systemctl start azp-agent"
    log_info "  Restart:  systemctl restart azp-agent"
    log_info "  Logs:     journalctl -u azp-agent -f"
    log_info ""
    log_info "View agent in Azure DevOps:"
    log_info "  $AZP_URL/_settings/agentpools"
}

main() {
    log_info "Starting Azure DevOps agent setup..."
    check_root
    validate_config
    detect_os
    install_dependencies
    download_agent
    configure_agent
    install_service
    start_service
    show_info
}

main "$@"