metrics/collector.v

module metrics

struct Counter {
	metric Metric
mut:
	data u64
}

struct Gauge {
	metric Metric
pub mut:
	data f64
}

struct Histogram {
	metric Metric
pub mut:
	buckets []f64
}

struct FloatSeries {
	metric Metric
pub mut:
	data []f64
}

[heap]
struct DefaultCollector {
mut:
	counters   shared map[string]&Counter
	histograms shared map[string]&FloatSeries
	gauges     shared map[string]&Gauge
}

pub fn new_default_collector() &DefaultCollector {
	return &DefaultCollector{
		counters: map[string]&Counter{}
		histograms: map[string]&FloatSeries{}
		gauges: map[string]&Gauge{}
	}
}

pub fn (mut c DefaultCollector) counter_increment(metric Metric) {
	lock c.counters {
		mut entry := c.counters[metric.str()] or {
			counter := &Counter{
				metric: metric
				data: 0
			}
			c.counters[metric.str()] = counter

			counter
		}

		entry.data += 1
	}
}

pub fn (mut c DefaultCollector) counter_set(value u64, metric Metric) {
	lock c.counters {
		mut entry := c.counters[metric.str()] or {
			counter := &Counter{
				metric: metric
				data: 0
			}
			c.counters[metric.str()] = counter

			counter
		}

		entry.data = value
	}
}

pub fn (c &DefaultCollector) counter_get(metric Metric) ?u64 {
	return rlock c.counters {
		entry := c.counters[metric.str()] or { return none }

		entry.data
	}
}

pub fn (c &DefaultCollector) counters() []Metric {
	mut metrics := []Metric{}

	rlock c.counters {
		for _, entry in c.counters {
			metrics << entry.metric
		}
	}

	return metrics
}

pub fn (c &DefaultCollector) histogram_record(value f64, metric Metric) {
	lock c.histograms {
		mut entry := c.histograms[metric.str()] or {
			hist := &FloatSeries{
				metric: metric
				data: []f64{}
			}
			c.histograms[metric.str()] = hist

			hist
		}

		entry.data << value
	}
}

pub fn (c &DefaultCollector) histogram_get(metric Metric) ?[]f64 {
	return rlock c.histograms {
		entry := c.histograms[metric.str()] or { return none }

		// Return a clone of the data to prevent user from altering
		// internal structure
		entry.data.clone()
	}
}

pub fn (mut c DefaultCollector) gauge_add(value f64, metric Metric) {
	lock c.gauges {
		mut entry := c.gauges[metric.str()] or {
			gauge := &Gauge{
				metric: metric
				data: 0.0
			}

			c.gauges[metric.str()] = gauge

			gauge
		}

		entry.data += value
	}
}

pub fn (mut c DefaultCollector) gauge_sub(value f64, metric Metric) {
	lock c.gauges {
		mut entry := c.gauges[metric.str()] or {
			gauge := &Gauge{
				metric: metric
				data: 0.0
			}

			c.gauges[metric.str()] = gauge

			gauge
		}

		entry.data -= value
	}
}

pub fn (mut c DefaultCollector) gauge_set(value f64, metric Metric) {
	lock c.gauges {
		mut entry := c.gauges[metric.str()] or {
			gauge := &Gauge{
				metric: metric
				data: 0.0
			}

			c.gauges[metric.str()] = gauge

			gauge
		}

		entry.data = value
	}
}

pub fn (c &DefaultCollector) gauge_get(metric Metric) ?f64 {
	return rlock c.gauges {
		entry := c.gauges[metric.str()] or { return none }

		entry.data
	}
}

pub fn (c &DefaultCollector) histograms() []Metric {
	mut metrics := []Metric{}

	rlock c.histograms {
		for _, entry in c.histograms {
			metrics << entry.metric
		}
	}

	return metrics
}

pub fn (c &DefaultCollector) gauges() []Metric {
	mut metrics := []Metric{}

	rlock c.gauges {
		for _, entry in c.gauges {
			metrics << entry.metric
		}
	}

	return metrics
}