Fix high prio recommendations, add error / health screen

health.go

@@ -0,0 +1,157 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+)
+
+type requestCoordinator struct {
+	mu     sync.Mutex
+	id     uint64
+	cancel context.CancelFunc
+}
+
+func (r *requestCoordinator) start(timeout time.Duration) (context.Context, context.CancelFunc, uint64) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	if r.cancel != nil {
+		r.cancel()
+	}
+	r.id++
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	r.cancel = cancel
+	return ctx, cancel, r.id
+}
+
+func (r *requestCoordinator) current(id uint64) bool {
+	if id == 0 {
+		return true
+	}
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	return r.id == id
+}
+
+type HealthLevel string
+
+const (
+	healthOK      HealthLevel = "ok"
+	healthInfo    HealthLevel = "info"
+	healthWarning HealthLevel = "warning"
+	healthError   HealthLevel = "error"
+	healthUnknown HealthLevel = "unknown"
+)
+
+type HealthComponent struct {
+	Name      string
+	Level     HealthLevel
+	Summary   string
+	Detail    string
+	UpdatedAt time.Time
+}
+
+type HealthEvent struct {
+	Component string
+	Level     HealthLevel
+	Message   string
+	At        time.Time
+}
+
+type RateLimitSnapshot struct {
+	Limit      int
+	Remaining  int
+	Used       int
+	ResetAt    time.Time
+	RetryAfter time.Time
+	UpdatedAt  time.Time
+}
+
+type healthProvider interface {
+	HealthReport() []HealthComponent
+	RateLimit() RateLimitSnapshot
+}
+
+type healthTracker struct {
+	mu         sync.Mutex
+	components map[string]HealthComponent
+	rate       RateLimitSnapshot
+}
+
+func (h *healthTracker) set(component HealthComponent) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	if h.components == nil {
+		h.components = make(map[string]HealthComponent)
+	}
+	if component.UpdatedAt.IsZero() {
+		component.UpdatedAt = time.Now()
+	}
+	h.components[component.Name] = component
+}
+
+func (h *healthTracker) setRate(rate RateLimitSnapshot) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	h.rate = rate
+}
+
+func (h *healthTracker) report() []HealthComponent {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	components := make([]HealthComponent, 0, len(h.components))
+	for _, component := range h.components {
+		components = append(components, component)
+	}
+	sort.Slice(components, func(i, j int) bool {
+		return strings.ToLower(components[i].Name) < strings.ToLower(components[j].Name)
+	})
+	return components
+}
+
+func (h *healthTracker) rateLimit() RateLimitSnapshot {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	return h.rate
+}
+
+func (m *App) recordHealth(component string, level HealthLevel, message string) {
+	if strings.TrimSpace(message) == "" {
+		return
+	}
+	event := HealthEvent{Component: component, Level: level, Message: message, At: time.Now()}
+	const maximumHealthEvents = 100
+	m.healthEvents = append(m.healthEvents, event)
+	if len(m.healthEvents) > maximumHealthEvents {
+		m.healthEvents = append([]HealthEvent(nil), m.healthEvents[len(m.healthEvents)-maximumHealthEvents:]...)
+	}
+}
+
+func healthLevelLabel(level HealthLevel) string {
+	switch level {
+	case healthOK:
+		return "OK"
+	case healthInfo:
+		return "INFO"
+	case healthWarning:
+		return "WARN"
+	case healthError:
+		return "ERROR"
+	default:
+		return "UNKNOWN"
+	}
+}
+
+func healthComponentText(component HealthComponent) string {
+	text := component.Summary
+	if component.Detail != "" {
+		text += " — " + component.Detail
+	}
+	if !component.UpdatedAt.IsZero() {
+		text += "  (" + component.UpdatedAt.Local().Format("15:04:05") + ")"
+	}
+	return fmt.Sprintf("%-7s  %-20s  %s", healthLevelLabel(component.Level), component.Name, text)
+}