package controller

import (
	"errors"
	"testing"

	"github.com/stretchr/testify/require"

	"github.com/nezhahq/nezha/model"
)

// 旧 agent 不识别 TaskTypeExec/TaskTypeFs* 等新 task type，会走 default
// 分支不回 TaskResult；dashboard 必须在调 CallAgent 之前依据 Host.Version
// 快速失败，否则用户要等到 30s/24h timeout 才知道 agent 不支持。
// MinServerTransferAgentVersion 已为同类问题在 transfer 路径上确立了
// release-time 必填的版本下限——这里把 MCP 也纳入同一不变量。
func TestMCPMinAgentVersionIsPinnedToRelease(t *testing.T) {
	require.NotEmpty(t, MCPMinAgentVersion,
		"MCPMinAgentVersion must be set to the lowest agent build that ships MCP handlers; an empty string disables the gate and lets old agents hang dashboard requests until timeout")
}

func TestRequireAgentSupportsMCPRejectsBelowMinVersion(t *testing.T) {
	old := &model.Server{Host: &model.Host{Version: "v0.0.1"}}
	err := requireAgentSupportsMCP(old)
	require.Error(t, err, "agents older than MCPMinAgentVersion must be rejected before CallAgent")
	require.True(t, errors.Is(err, errMCPUnsupported) || err.Error() == errMCPUnsupported.Error(),
		"expected the errMCPUnsupported sentinel, got %v", err)
}

func TestRequireAgentSupportsMCPAcceptsCurrentVersion(t *testing.T) {
	current := &model.Server{Host: &model.Host{Version: MCPMinAgentVersion}}
	require.NoError(t, requireAgentSupportsMCP(current),
		"server reporting exactly MCPMinAgentVersion must be accepted")
}

// 钉住「最近一个不带 MCP handler 的已发布 agent tag (v2.0.4) 必须被拒绝」。
// v2.0.4 的 model/task.go 还没有 TaskTypeExec/TaskTypeFs* 常量，cmd/agent/
// mcp_handlers.go 也不存在；如果版本门槛把它放行，dashboard 调 MCP tool
// 后 agent 会走 default 分支不回 TaskResult，CallAgent 必须等 30s 超时。
func TestRequireAgentSupportsMCPRejectsLastReleaseWithoutMCP(t *testing.T) {
	noMCP := &model.Server{Host: &model.Host{Version: "v2.0.4"}}
	err := requireAgentSupportsMCP(noMCP)
	require.Error(t, err,
		"v2.0.4 is the latest released agent tag that ships *without* MCP handlers; bumping MCPMinAgentVersion below the first MCP release re-introduces the silent-timeout bug")
	require.True(t, errors.Is(err, errMCPUnsupported) || err.Error() == errMCPUnsupported.Error(),
		"expected the errMCPUnsupported sentinel, got %v", err)
}

func TestRequireAgentSupportsMCPDefersWhenAgentNeverReported(t *testing.T) {
	require.NoError(t, requireAgentSupportsMCP(&model.Server{Host: nil}),
		"Host==nil means agent never reported its build; defer the version decision to the CallAgent timeout layer")
}