fix: 修复若干问题，添加java lsp

backend/internal/monitor/lsp_status_monitor.go

@@ -0,0 +1,180 @@
+package monitor
+
+import (
+	"context"
+	"strings"
+	"sync"
+	"time"
+
+	"monica-go-completion-backend/internal/completion"
+)
+
+// Config 控制探测间隔与下线阈值。
+type Config struct {
+	ProbeInterval    time.Duration
+	ProbeTimeout     time.Duration
+	FailureThreshold int
+}
+
+// LanguageStatus 表示单语言探测状态。
+type LanguageStatus struct {
+	Language            string    `json:"language"`
+	Online              bool      `json:"online"`
+	LastCheckedAt       time.Time `json:"lastCheckedAt"`
+	LastSuccessAt       time.Time `json:"lastSuccessAt,omitempty"`
+	ConsecutiveFailures int       `json:"consecutiveFailures"`
+	LastError           string    `json:"lastError,omitempty"`
+}
+
+// LSPStatusMonitor 周期性探测各语言 LSP 是否可用。
+type LSPStatusMonitor struct {
+	specs        []completion.LanguageServerSpec
+	workspaceDir string
+	factory      completion.ClientFactory
+	cfg          Config
+
+	mu       sync.RWMutex
+	statuses map[string]LanguageStatus
+
+	stopCh   chan struct{}
+	stopOnce sync.Once
+}
+
+// NewLSPStatusMonitor 创建并启动探测协程。
+func NewLSPStatusMonitor(
+	specs []completion.LanguageServerSpec,
+	workspaceDir string,
+	factory completion.ClientFactory,
+	cfg Config,
+) *LSPStatusMonitor {
+	if cfg.ProbeInterval <= 0 {
+		cfg.ProbeInterval = 8 * time.Second
+	}
+	if cfg.ProbeTimeout <= 0 {
+		cfg.ProbeTimeout = 5 * time.Second
+	}
+	if cfg.FailureThreshold <= 0 {
+		cfg.FailureThreshold = 2
+	}
+
+	normalized := make([]completion.LanguageServerSpec, 0, len(specs))
+	statuses := make(map[string]LanguageStatus)
+	for _, spec := range specs {
+		lang := normalizeLanguage(spec.Language)
+		if lang == "" {
+			continue
+		}
+		spec.Language = lang
+		normalized = append(normalized, spec)
+		statuses[lang] = LanguageStatus{
+			Language: lang,
+			Online:   false,
+		}
+	}
+
+	m := &LSPStatusMonitor{
+		specs:        normalized,
+		workspaceDir: workspaceDir,
+		factory:      factory,
+		cfg:          cfg,
+		statuses:     statuses,
+		stopCh:       make(chan struct{}),
+	}
+	go m.loop()
+	return m
+}
+
+// LspServiceStatus 返回按语言聚合的状态快照。
+func (m *LSPStatusMonitor) LspServiceStatus() map[string]any {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	out := make(map[string]any, len(m.statuses))
+	for language, status := range m.statuses {
+		out[language] = status
+	}
+	return out
+}
+
+// Close 停止后台探测循环。
+func (m *LSPStatusMonitor) Close() {
+	m.stopOnce.Do(func() {
+		close(m.stopCh)
+	})
+}
+
+func (m *LSPStatusMonitor) loop() {
+	// 启动后先做一轮探测，避免首次读取全是未知状态。
+	m.probeAll()
+
+	ticker := time.NewTicker(m.cfg.ProbeInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ticker.C:
+			m.probeAll()
+		case <-m.stopCh:
+			return
+		}
+	}
+}
+
+func (m *LSPStatusMonitor) probeAll() {
+	for _, spec := range m.specs {
+		m.probeOne(spec)
+	}
+}
+
+func (m *LSPStatusMonitor) probeOne(spec completion.LanguageServerSpec) {
+	language := normalizeLanguage(spec.Language)
+	if language == "" {
+		return
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), m.cfg.ProbeTimeout)
+	defer cancel()
+
+	client, err := m.factory(ctx, spec, m.workspaceDir)
+	if err != nil {
+		m.markFailure(language, err)
+		return
+	}
+	_ = client.Close()
+	m.markSuccess(language)
+}
+
+func (m *LSPStatusMonitor) markSuccess(language string) {
+	now := time.Now()
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	st := m.statuses[language]
+	st.LastCheckedAt = now
+	st.LastSuccessAt = now
+	st.ConsecutiveFailures = 0
+	st.LastError = ""
+	st.Online = true
+	m.statuses[language] = st
+}
+
+func (m *LSPStatusMonitor) markFailure(language string, err error) {
+	now := time.Now()
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	st := m.statuses[language]
+	st.LastCheckedAt = now
+	st.ConsecutiveFailures++
+	if err != nil {
+		st.LastError = err.Error()
+	}
+	if st.ConsecutiveFailures >= m.cfg.FailureThreshold {
+		st.Online = false
+	}
+	m.statuses[language] = st
+}
+
+func normalizeLanguage(language string) string {
+	return strings.ToLower(strings.TrimSpace(language))
+}