package zipkintracer

import "sync"

// A SpanRecorder handles all of the `RawSpan` data generated via an
// associated `Tracer` (see `NewStandardTracer`) instance. It also names
// the containing process and provides access to a straightforward tag map.
type SpanRecorder interface {
	// Implementations must determine whether and where to store `span`.
	RecordSpan(span RawSpan)
}

// InMemorySpanRecorder is a simple thread-safe implementation of
// SpanRecorder that stores all reported spans in memory, accessible
// via reporter.GetSpans(). It is primarily intended for testing purposes.
type InMemorySpanRecorder struct {
	sync.RWMutex
	spans []RawSpan
}

// NewInMemoryRecorder creates new InMemorySpanRecorder
func NewInMemoryRecorder() *InMemorySpanRecorder {
	return new(InMemorySpanRecorder)
}

// RecordSpan implements the respective method of SpanRecorder.
func (r *InMemorySpanRecorder) RecordSpan(span RawSpan) {
	r.Lock()
	defer r.Unlock()
	r.spans = append(r.spans, span)
}

// GetSpans returns a copy of the array of spans accumulated so far.
func (r *InMemorySpanRecorder) GetSpans() []RawSpan {
	r.RLock()
	defer r.RUnlock()
	spans := make([]RawSpan, len(r.spans))
	copy(spans, r.spans)
	return spans
}

// GetSampledSpans returns a slice of spans accumulated so far which were sampled.
func (r *InMemorySpanRecorder) GetSampledSpans() []RawSpan {
	r.RLock()
	defer r.RUnlock()
	spans := make([]RawSpan, 0, len(r.spans))
	for _, span := range r.spans {
		if span.Context.Sampled {
			spans = append(spans, span)
		}
	}
	return spans
}

// Reset clears the internal array of spans.
func (r *InMemorySpanRecorder) Reset() {
	r.Lock()
	defer r.Unlock()
	r.spans = nil
}