#!/bin/bash

# ==============================================
# Go 语言安装脚本 for CentOS
# 版本：1.3
# 作者：您的名字
# ==============================================

# 启用严格模式
set -euo pipefail

# --------------------------
# 配置区（可根据需要修改）
# --------------------------
GO_VERSION="1.22.0"          # 默认安装版本
INSTALL_DIR="/usr/local"     # 安装目录
GOPATH="$HOME/go"            # GOPATH 设置
PROFILE_FILE="/etc/profile.d/go.sh"  # 环境变量文件

# --------------------------
# 颜色定义
# --------------------------
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[0;33m'
NC='\033[0m' # No Color

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

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

log_error() {
    echo -e "${RED}[ERROR]${NC} $1" >&2
}

# --------------------------
# 检查root权限
# --------------------------
check_root() {
    if [ "$(id -u)" -ne 0 ]; then
        log_error "请使用root用户或通过sudo运行此脚本"
        exit 1
    fi
}

# --------------------------
# 安装依赖
# --------------------------
install_deps() {
    log_info "正在安装必要依赖..."
    yum install -y curl tar gzip wget git make gcc
}

# --------------------------
# 获取最新Go版本
# --------------------------
get_latest_version() {
    log_info "正在获取最新Go版本..."
    local latest
    latest=$(curl -s https://go.dev/VERSION?m=text | head -1)
    if [[ "$latest" =~ ^go[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
        GO_VERSION="${latest#go}"
        log_info "检测到最新版本: ${GO_VERSION}"
    else
        log_warn "无法获取最新版本，使用默认版本: ${GO_VERSION}"
    fi
}

# --------------------------
# 下载Go安装包
# --------------------------
download_go() {
    local url="https://dl.google.com/go/go${GO_VERSION}.linux-amd64.tar.gz"
    local tmp_file="/tmp/go${GO_VERSION}.tar.gz"

    if [ -f "$tmp_file" ]; then
        log_info "发现本地缓存安装包，跳过下载"
        return
    fi

    log_info "正在下载Go ${GO_VERSION}..."
    if ! curl -fSL --progress-bar -o "$tmp_file" "$url"; then
        log_error "下载失败，请检查网络连接或版本是否存在"
        exit 1
    fi
}

# --------------------------
# 安装Go
# --------------------------
install_go() {
    local tmp_file="/tmp/go${GO_VERSION}.tar.gz"

    log_info "正在安装Go到 ${INSTALL_DIR}..."
    tar -C "$INSTALL_DIR" -xzf "$tmp_file"
    rm -f "$tmp_file"
}

# --------------------------
# 配置环境变量
# --------------------------
setup_env() {
    log_info "正在配置环境变量..."

    # 创建环境变量文件
    cat > "$PROFILE_FILE" <<EOF
export GOROOT=${INSTALL_DIR}/go
export GOPATH=${GOPATH}
export PATH=\$GOROOT/bin:\$GOPATH/bin:\$PATH
EOF

    # 立即生效
    source "$PROFILE_FILE"

    # 创建GOPATH目录
    mkdir -p "${GOPATH}/"{src,bin,pkg}
}

# --------------------------
# 验证安装
# --------------------------
verify_install() {
    log_info "验证安装..."
    if ! command -v go &> /dev/null; then
        log_error "Go安装失败，请检查错误"
        exit 1
    fi

    echo -e "\n${GREEN}Go安装成功！${NC}"
    echo "============================="
    go version
    echo "GOROOT: $(go env GOROOT)"
    echo "GOPATH: $(go env GOPATH)"
    echo "============================="
}

# --------------------------
# 卸载Go
# --------------------------
uninstall_go() {
    log_info "正在卸载Go..."
    rm -rf "${INSTALL_DIR}/go"
    rm -f "$PROFILE_FILE"
    log_info "Go已卸载"
}

# --------------------------
# 清理缓存
# --------------------------
clean_cache() {
    log_info "正在清理缓存..."
    rm -f "/tmp/go${GO_VERSION}.tar.gz"
    log_info "缓存已清理"
}

# --------------------------
# 主函数
# --------------------------
main() {
    case "$1" in
        install)
            check_root
            install_deps

            # 如果想安装最新版本，取消下面注释
            # get_latest_version

            download_go
            install_go
            setup_env
            verify_install

            log_info "安装完成！请重新登录或运行 'source ${PROFILE_FILE}' 使环境变量生效"
            ;;
        uninstall)
            check_root
            uninstall_go
            ;;
        clean)
            clean_cache
            ;;
        *)
            echo "用法: $0 {install|uninstall|clean}"
            echo "  install   安装Go"
            echo "  uninstall 卸载Go"
            echo "  clean     清理缓存"
            exit 1
            ;;
    esac
}

# --------------------------
# 执行主函数
# --------------------------
main "$@"
exit 0