package telemetry

import (
	"fmt"
	"net/http"
	"sync/atomic"

	"aigw/internal/billing"
)

type Metrics struct {
	requests            atomic.Uint64
	failed              atomic.Uint64
	inFlight            atomic.Int64
	attempts            atomic.Uint64
	droppedUsage        atomic.Uint64
	settlementBacklog   atomic.Int64
	settlementSpool     atomic.Int64
	stripeRefundBacklog atomic.Int64
	stripeUncollected   atomic.Int64
	stripeMismatches    atomic.Int64
	stripeWebhooks      atomic.Int64
	unmeteredSuccesses  atomic.Int64
	ready               atomic.Int64
}

func (m *Metrics) SetSettlementQueue(backlog int64, spool int) {
	m.settlementBacklog.Store(backlog)
	m.settlementSpool.Store(int64(spool))
}
func (m *Metrics) SetReady(ready bool) {
	if ready {
		m.ready.Store(1)
	} else {
		m.ready.Store(0)
	}
}

func (m *Metrics) SetStripeOperations(status billing.OperationalStatus) {
	m.stripeRefundBacklog.Store(status.RefundBacklog)
	m.stripeUncollected.Store(status.UncollectedMicros)
	m.stripeMismatches.Store(status.ReconciliationMismatches)
	m.stripeWebhooks.Store(status.UnprocessedWebhooks)
	m.unmeteredSuccesses.Store(status.UnmeteredSuccesses)
}

func (m *Metrics) RequestStarted() {
	m.requests.Add(1)
	m.inFlight.Add(1)
}

func (m *Metrics) RequestFinished(success bool) {
	m.inFlight.Add(-1)
	if !success {
		m.failed.Add(1)
	}
}

func (m *Metrics) UpstreamAttempt() {
	m.attempts.Add(1)
}

func (m *Metrics) UsageDropped() {
	m.droppedUsage.Add(1)
}

func (m *Metrics) ServeHTTP(w http.ResponseWriter, _ *http.Request) {
	w.Header().Set("Content-Type", "text/plain; version=0.0.4")
	fmt.Fprintf(w, "# TYPE aigw_requests_total counter\naigw_requests_total %d\n", m.requests.Load())
	fmt.Fprintf(w, "# TYPE aigw_requests_failed_total counter\naigw_requests_failed_total %d\n", m.failed.Load())
	fmt.Fprintf(w, "# TYPE aigw_requests_in_flight gauge\naigw_requests_in_flight %d\n", m.inFlight.Load())
	fmt.Fprintf(w, "# TYPE aigw_upstream_attempts_total counter\naigw_upstream_attempts_total %d\n", m.attempts.Load())
	fmt.Fprintf(w, "# TYPE aigw_usage_events_dropped_total counter\naigw_usage_events_dropped_total %d\n", m.droppedUsage.Load())
	fmt.Fprintf(w, "# TYPE aigw_billing_settlement_backlog gauge\naigw_billing_settlement_backlog %d\n", m.settlementBacklog.Load())
	fmt.Fprintf(w, "# TYPE aigw_billing_settlement_spool_records gauge\naigw_billing_settlement_spool_records %d\n", m.settlementSpool.Load())
	fmt.Fprintf(w, "# TYPE aigw_stripe_refund_backlog gauge\naigw_stripe_refund_backlog %d\n", m.stripeRefundBacklog.Load())
	fmt.Fprintf(w, "# TYPE aigw_billing_uncollected_micros gauge\naigw_billing_uncollected_micros %d\n", m.stripeUncollected.Load())
	fmt.Fprintf(w, "# TYPE aigw_stripe_reconciliation_mismatches gauge\naigw_stripe_reconciliation_mismatches %d\n", m.stripeMismatches.Load())
	fmt.Fprintf(w, "# TYPE aigw_stripe_webhook_backlog gauge\naigw_stripe_webhook_backlog %d\n", m.stripeWebhooks.Load())
	fmt.Fprintf(w, "# TYPE aigw_billing_unmetered_successes gauge\naigw_billing_unmetered_successes %d\n", m.unmeteredSuccesses.Load())
	fmt.Fprintf(w, "# TYPE aigw_ready gauge\naigw_ready %d\n", m.ready.Load())
}