package metrics

import (
	"context"
	"fmt"
	"time"
)

// Collector collects and exposes metrics
type Collector struct {
	metrics map[string]Metric
}

// NewCollector creates a new metrics collector
func NewCollector() *Collector {
	return &Collector{
		metrics: make(map[string]Metric),
	}
}

// Metric represents a metric
type Metric struct {
	Name      string
	Value     float64
	Type      string // "counter", "gauge", "histogram"
	Labels    map[string]string
	Timestamp time.Time
}

// IncrementCounter increments a counter metric
func (c *Collector) IncrementCounter(ctx context.Context, name string, labels map[string]string) {
	key := c.metricKey(name, labels)
	if metric, ok := c.metrics[key]; ok {
		metric.Value++
		metric.Timestamp = time.Now()
		c.metrics[key] = metric
	} else {
		c.metrics[key] = Metric{
			Name:      name,
			Value:     1,
			Type:      "counter",
			Labels:    labels,
			Timestamp: time.Now(),
		}
	}
}

// SetGauge sets a gauge metric
func (c *Collector) SetGauge(ctx context.Context, name string, value float64, labels map[string]string) {
	key := c.metricKey(name, labels)
	c.metrics[key] = Metric{
		Name:      name,
		Value:     value,
		Type:      "gauge",
		Labels:    labels,
		Timestamp: time.Now(),
	}
}

// GetMetrics gets all metrics
func (c *Collector) GetMetrics() map[string]Metric {
	return c.metrics
}

// metricKey creates a key for a metric
func (c *Collector) metricKey(name string, labels map[string]string) string {
	key := name
	for k, v := range labels {
		key += fmt.Sprintf(":%s=%s", k, v)
	}
	return key
}