package transport

import (
	"strings"

	"github.com/gin-gonic/gin"

	"github.com/geo-platform/tenant-api/internal/bootstrap"
	"github.com/geo-platform/tenant-api/internal/shared/response"
	tenantapp "github.com/geo-platform/tenant-api/internal/tenant/app"
)

func registerInternalMetricsRoutes(app *bootstrap.App) {
	token := strings.TrimSpace(app.Config.Scheduler.InternalMetricsToken)
	if token == "" {
		app.Logger.Warn("tenant-api internal metrics routes not registered: scheduler.internal_metrics_token is required")
		return
	}

	metrics := app.Engine.Group("/api/internal/metrics")
	metrics.Use(internalMetricsAuthMiddleware(token))
	metrics.GET("/monitoring/heartbeat-primary-lease", func(c *gin.Context) {
		response.Success(c, tenantapp.MonitoringHeartbeatPrimaryLeaseMetricsSnapshotValue())
	})
	primaryLeasePrometheusHandler := tenantapp.MonitoringHeartbeatPrimaryLeaseMetricsPrometheusHandler()
	metrics.GET("/monitoring/heartbeat-primary-lease/prometheus", func(c *gin.Context) {
		primaryLeasePrometheusHandler.ServeHTTP(c.Writer, c.Request)
	})
	metrics.GET("/monitoring/heartbeat-snapshots", func(c *gin.Context) {
		response.Success(c, tenantapp.MonitoringHeartbeatSnapshotMetricsSnapshotValue())
	})
	snapshotPrometheusHandler := tenantapp.MonitoringHeartbeatSnapshotMetricsPrometheusHandler()
	metrics.GET("/monitoring/heartbeat-snapshots/prometheus", func(c *gin.Context) {
		snapshotPrometheusHandler.ServeHTTP(c.Writer, c.Request)
	})
}

func internalMetricsAuthMiddleware(token string) gin.HandlerFunc {
	expected := strings.TrimSpace(token)
	return func(c *gin.Context) {
		if expected == "" || !internalMetricsTokenMatches(c, expected) {
			response.Error(c, response.ErrUnauthorized(40181, "internal_metrics_unauthorized", "valid internal metrics token is required"))
			c.Abort()
			return
		}
		c.Next()
	}
}

func internalMetricsTokenMatches(c *gin.Context, expected string) bool {
	if c == nil {
		return false
	}
	header := strings.TrimSpace(c.GetHeader("Authorization"))
	if strings.HasPrefix(strings.ToLower(header), "bearer ") {
		if strings.TrimSpace(header[len("bearer "):]) == expected {
			return true
		}
	}
	return strings.TrimSpace(c.GetHeader("X-Internal-Metrics-Token")) == expected
}