package tracing

import (
	"github.com/juju/errors"

	"go.opentelemetry.io/otel/sdk/resource"

	sdktrace "go.opentelemetry.io/otel/sdk/trace"
	semconv "go.opentelemetry.io/otel/semconv/v1.12.0"
)

// Init will try to initialize tracing by trying to retrieve config from multiple source.
func Init() (*sdktrace.TracerProvider, error) {

	// loading configuration
	c, err := loadConfig()
	if err != nil {
		return nil, errors.Trace(err)
	}

	return initFromSource(c)
}

// InitFromCustomVaultSecret will initialize tracing with a vault secret.
func InitFromCustomVaultSecret(secret string) (*sdktrace.TracerProvider, error) {

	c, err := loadConfigFromVault(secret)
	if err != nil {
		return nil, errors.Trace(err)
	}

	return initFromSource(c)
}

// InitFromCustomFile will initialize tracing with a config file.
func InitFromCustomFile(path string) (*sdktrace.TracerProvider, error) {

	c, err := loadConfigFromFile(path)
	if err != nil {
		return nil, errors.Trace(err)
	}

	return initFromSource(c)
}

func initFromSource(c *ConfigStruct) (*sdktrace.TracerProvider, error) {
	err := c.applyEnv()
	if err != nil {
		return nil, errors.Trace(err)
	}

	return InitFromCustomConfig(c)
}

// InitFromCustomConfig will initialize tracing from a gaven config.
func InitFromCustomConfig(c *ConfigStruct) (*sdktrace.TracerProvider, error) {

	err := c.IsValid()
	if err != nil {
		return nil, errors.Trace(err)
	}

	// Ensure default SDK resources and the required service name are set.
	r, err := resource.Merge(
		resource.Default(),
		resource.NewWithAttributes(
			semconv.SchemaURL,
			semconv.ServiceNameKey.String("myService"),
			semconv.ServiceVersionKey.String("1.0.0"),
			semconv.ServiceInstanceIDKey.String("abcdef12345"),
		),
	)

	if err != nil {
		panic(err)
	}

	return sdktrace.NewTracerProvider(
		sdktrace.WithResource(r),
	), nil
}