"""
Systemd service generator — a single, generic Generator that produces a fully-configured
systemd unit for arbitrary user-provided commands. Plus presets for common cases.
"""
from . import register, Generator, Field
from . import bash_header, quote, bool_str, yes


class SystemdGeneric(Generator):
    id = "systemd-generic"
    title = "通用 systemd 服务"
    category = "systemd"
    icon = "🛠️"
    tags = ["systemd", "service", "unit"]
    description = "为任意可执行命令生成 systemd unit 文件,支持开机自启、自动重启、日志轮转。"
    fields = [
        Field("service_name", "服务名", "text", default="myapp",
              help="将创建 /etc/systemd/system/<name>.service"),
        Field("description", "Description", "text", default="My custom app"),
        Field("exec_start", "ExecStart 命令", "textarea", required=True,
              default="/opt/myapp/bin/server --config /etc/myapp/server.conf",
              help="要执行的命令,可以有多行(用 ; 串接)或用绝对路径。"),
        Field("exec_stop", "ExecStop 命令", "text", default="",
              help="留空则发 SIGTERM;填入完整命令。"),
        Field("exec_reload", "ExecReload 命令", "text", default="",
              help="通常是 'kill -HUP $MAINPID' 或 nginx -s reload。"),
        Field("type", "Type", "select", default="simple",
              options=["simple", "forking", "oneshot", "notify", "exec"]),
        Field("user", "运行用户", "text", default="root"),
        Field("group", "运行组", "text", default="root"),
        Field("working_dir", "WorkingDirectory", "text", default="/"),
        Field("env_vars", "环境变量", "textarea", default="NODE_ENV=production\nLOG_LEVEL=info",
              help="每行 KEY=VALUE。"),
        Field("restart", "Restart 策略", "select", default="on-failure",
              options=["no", "always", "on-success", "on-failure", "on-abnormal",
                       "on-abort", "on-watchdog"]),
        Field("restart_sec", "RestartSec (秒)", "number", default="5"),
        Field("limit_nofile", "LimitNOFILE", "number", default="65536"),
        Field("limit_nproc", "LimitNPROC", "number", default="65536"),
        Field("kill_mode", "KillMode", "select", default="mixed",
              options=["control-group", "process", "mixed", "none"]),
        Field("enable_after_network", "After=network.target", "checkbox", default="yes"),
        Field("enable_log_dir", "创建日志目录 /var/log/<name>", "checkbox", default="yes"),
        Field("auto_start", "脚本执行完自动 enable+start", "checkbox", default="yes"),
    ]

    def render(self, p):
        name = p.get("service_name", "myapp").replace(" ", "-")
        desc = p.get("description", "My custom app")
        exec_start = p.get("exec_start", "").strip()
        if not exec_start:
            raise ValueError("exec_start 不能为空")
        exec_stop = p.get("exec_stop", "").strip()
        exec_reload = p.get("exec_reload", "").strip()
        type_ = p.get("type", "simple")
        user = p.get("user", "root")
        group = p.get("group", "root")
        wd = p.get("working_dir", "/")
        envs = [e.strip() for e in (p.get("env_vars", "") or "").splitlines() if e.strip() and "=" in e]
        restart = p.get("restart", "on-failure")
        restart_sec = str(p.get("restart_sec", "5"))
        nofile = str(p.get("limit_nofile", "65536"))
        nproc = str(p.get("limit_nproc", "65536"))
        kill = p.get("kill_mode", "mixed")
        after_nw = bool_str(p.get("enable_after_network", True))
        log_dir = bool_str(p.get("enable_log_dir", True))
        auto = bool_str(p.get("auto_start", True))

        out = [bash_header(self.title)]
        out.append('log "Writing unit file /etc/systemd/system/' + name + '.service"')
        out.append('mkdir -p /etc/systemd/system')
        if log_dir:
            out.append('mkdir -p /var/log/' + name)
        unit = ['[Unit]']
        unit.append('Description=' + desc)
        if after_nw:
            unit.append('After=network.target network-online.target')
            unit.append('Wants=network-online.target')
        unit.append('')
        unit.append('[Service]')
        unit.append('Type=' + type_)
        unit.append('User=' + user)
        unit.append('Group=' + group)
        unit.append('WorkingDirectory=' + wd)
        for env in envs:
            unit.append('Environment="' + env.replace('"', '\\"') + '"')
        unit.append('ExecStart=' + exec_start.replace('\n', ' && '))
        if exec_stop:
            unit.append('ExecStop=' + exec_stop)
        if exec_reload:
            unit.append('ExecReload=' + exec_reload)
        unit.append('Restart=' + restart)
        unit.append('RestartSec=' + restart_sec)
        unit.append('LimitNOFILE=' + nofile)
        unit.append('LimitNPROC=' + nproc)
        unit.append('KillMode=' + kill)
        unit.append('StandardOutput=journal')
        unit.append('StandardError=journal')
        if log_dir:
            unit.append('StandardOutput=append:/var/log/' + name + '/stdout.log')
            unit.append('StandardError=append:/var/log/' + name + '/stderr.log')
        unit.append('')
        unit.append('[Install]')
        unit.append('WantedBy=multi-user.target')
        out.append('cat > /etc/systemd/system/' + name + '.service <<UNIT_EOF\n' + '\n'.join(unit) + '\nUNIT_EOF')
        out.append('systemctl daemon-reload')
        if auto:
            out.append('systemctl enable --now ' + name)
            out.append('sleep 1')
            out.append('systemctl --no-pager status ' + name + ' || true')
        else:
            out.append('log "Unit installed but not started. Run: systemctl enable --now ' + name + '"')
        out.append('log "Useful commands:')
        out.append('  systemctl status ' + name)
        out.append('  journalctl -u ' + name + ' -f')
        out.append('  systemctl restart ' + name + '"')
        return "\n".join(out) + "\n"


# A few presets that wrap the same engine with sensible defaults
def _make_preset(id_, title, icon, description, defaults, tags=()):
    class G(SystemdGeneric):
        pass
    G.id = id_
    G.title = title
    G.icon = icon
    G.description = description
    G.tags = list(tags)
    G.fields = []  # CRITICAL: avoid mutating the parent's shared list
    for f in SystemdGeneric.fields:
        f2 = Field(f.name, f.label, f.type, f.default, f.placeholder, f.help,
                   f.options, f.required, f.min, f.max, f.step, f.pattern, f.group)
        if f.name in defaults:
            f2.default = defaults[f.name]
        G.fields.append(f2)
    return G


# preset: Python uvicorn/gunicorn web app
GunicornSvc = _make_preset(
    id_="svc-gunicorn",
    title="Gunicorn (Python) systemd 服务",
    icon="🐍",
    description="为 gunicorn 应用生成 systemd unit,自动设置 GUNICORN_CMD_ARGS、日志目录。",
    defaults={
        "service_name": "myapp",
        "description": "My Python web app (gunicorn)",
        "exec_start": "/opt/myapp/venv/bin/gunicorn --workers 3 --bind 0.0.0.0:8000 app:app",
        "type": "simple",
        "user": "app",
        "working_dir": "/opt/myapp",
        "env_vars": "PYTHONUNBUFFERED=1\nLOG_LEVEL=info",
    },
    tags=("python", "gunicorn", "flask", "django", "fastapi"),
)
register(GunicornSvc())


# preset: Node.js pm2-style systemd
NodeSvc = _make_preset(
    id_="svc-nodejs",
    title="Node.js (npm start) systemd 服务",
    icon="🟢",
    description="为 Node.js 应用生成 systemd unit,支持 npm start / node 直接启动。",
    defaults={
        "service_name": "nodeapp",
        "description": "Node.js application",
        "exec_start": "/usr/bin/node /opt/nodeapp/server.js",
        "user": "app",
        "working_dir": "/opt/nodeapp",
        "env_vars": "NODE_ENV=production\nPORT=3000",
    },
    tags=("nodejs", "node", "express", "next"),
)
register(NodeSvc())


# preset: Java -jar
JavaSvc = _make_preset(
    id_="svc-java",
    title="Java -jar systemd 服务",
    icon="☕",
    description="为 SpringBoot/任意 Java -jar 应用生成 systemd unit,自动设置 JAVA_HOME。",
    defaults={
        "service_name": "javaapp",
        "description": "Java application",
        "exec_start": "/usr/bin/java -Xms512m -Xmx1024m -jar /opt/javaapp/app.jar --server.port=8080",
        "user": "app",
        "working_dir": "/opt/javaapp",
        "env_vars": "JAVA_HOME=/usr/lib/jvm/java-17-openjdk",
    },
    tags=("java", "springboot", "jar"),
)
register(JavaSvc())


# preset: Go binary
GoSvc = _make_preset(
    id_="svc-go",
    title="Go binary systemd 服务",
    icon="🐹",
    description="为编译后的 Go 二进制生成 systemd unit。",
    defaults={
        "service_name": "goapp",
        "description": "Go application",
        "exec_start": "/opt/goapp/bin/server -config /etc/goapp/server.yaml",
        "user": "app",
        "working_dir": "/opt/goapp",
    },
    tags=("go", "golang"),
)
register(GoSvc())


# preset: shell script
ShellSvc = _make_preset(
    id_="svc-shell",
    title="Shell 脚本 systemd 服务",
    icon="📜",
    description="为任意 shell 脚本生成 systemd unit,适合定时/常驻脚本。",
    defaults={
        "service_name": "myscript",
        "description": "Custom shell script service",
        "exec_start": "/opt/myscript/run.sh",
        "user": "root",
        "working_dir": "/opt/myscript",
    },
    tags=("bash", "script"),
)
register(ShellSvc())


# Register the generic one as well
register(SystemdGeneric())