package collector

import (
	"context"
	"fmt"
	"sync"
)

// Registry 采集器注册中心
type Registry struct {
	collectors map[string]Collector
	mu         sync.RWMutex
}

// NewRegistry 创建采集器注册中心
func NewRegistry() *Registry {
	return &Registry{
		collectors: make(map[string]Collector),
	}
}

// Register 注册一个采集器
func (r *Registry) Register(c Collector) error {
	r.mu.Lock()
	defer r.mu.Unlock()

	name := c.Name()
	if _, exists := r.collectors[name]; exists {
		return fmt.Errorf("collector already registered: %s", name)
	}

	r.collectors[name] = c
	return nil
}

// Get 获取指定名称的采集器
func (r *Registry) Get(name string) (Collector, bool) {
	r.mu.RLock()
	defer r.mu.RUnlock()

	c, ok := r.collectors[name]
	return c, ok
}

// List 列出所有已注册的采集器
func (r *Registry) List() []Collector {
	r.mu.RLock()
	defer r.mu.RUnlock()

	result := make([]Collector, 0, len(r.collectors))
	for _, c := range r.collectors {
		result = append(result, c)
	}
	return result
}

// ListByCategory 按分类列出采集器
func (r *Registry) ListByCategory(cat Category) []Collector {
	r.mu.RLock()
	defer r.mu.RUnlock()

	var result []Collector
	for _, c := range r.collectors {
		if c.Category() == cat {
			result = append(result, c)
		}
	}
	return result
}

// Available 返回当前系统上可用的采集器
func (r *Registry) Available(ctx context.Context) []Collector {
	r.mu.RLock()
	defer r.mu.RUnlock()

	var result []Collector
	for _, c := range r.collectors {
		if c.IsAvailable(ctx) {
			result = append(result, c)
		}
	}
	return result
}

// ScanAll 使用所有可用的采集器扫描
func (r *Registry) ScanAll(ctx context.Context, opts ScanOptions) ([]*ScanResult, error) {
	available := r.Available(ctx)

	var (
		results []*ScanResult
		mu      sync.Mutex
		wg      sync.WaitGroup
		errs    []error
	)

	for _, c := range available {
		wg.Add(1)
		go func(collector Collector) {
			defer wg.Done()

			result, err := collector.Scan(ctx, opts)

			mu.Lock()
			defer mu.Unlock()

			if err != nil {
				errs = append(errs, fmt.Errorf("%s: %w", collector.Name(), err))
				return
			}
			results = append(results, result)
		}(c)
	}

	wg.Wait()

	if len(errs) > 0 && len(results) == 0 {
		return nil, fmt.Errorf("all collectors failed: %v", errs)
	}

	return results, nil
}