package unitel

import (
	"fmt"
	"net/http"

	"github.com/getsentry/sentry-go"
	"go.opentelemetry.io/otel/attribute"
	semconv "go.opentelemetry.io/otel/semconv/v1.26.0"
	"go.opentelemetry.io/otel/trace"
)

const httpClientTransportClientID = libBase + "#HTTPTansport"

type HTTPTransport struct {
	telemetry             *Telemetry
	forwardTrace          bool
	tracedRequestHeaders  []string
	tracedResponseHeaders []string
	Transport             http.RoundTripper

	tracer trace.Tracer
}

func (t *Telemetry) NewTracedTransport(transport http.RoundTripper, forwardTrace bool, tracedRequestHeaders []string, tracedResponseHeaders []string) *HTTPTransport {
	return &HTTPTransport{
		telemetry:             t,
		forwardTrace:          forwardTrace,
		tracedRequestHeaders:  tracedRequestHeaders,
		tracedResponseHeaders: tracedResponseHeaders,
		Transport:             transport,

		tracer: t.tracerProvider.Tracer(httpClientTransportClientID, trace.WithInstrumentationVersion(libVersion)),
	}
}

func (t *HTTPTransport) RoundTrip(req *http.Request) (*http.Response, error) {
	span := t.telemetry.
		StartSpan(req.Context(), "http.client", fmt.Sprintf("%s %s", req.Method, req.URL), WithOtelOptions(trace.WithSpanKind(trace.SpanKindClient))).
		AddAttributes(
			semconv.HTTPRequestMethodKey.String(req.Method),
			semconv.URLFull(req.URL.String()),
		)
	defer span.End()
	ctx := span.Context()
	req = req.WithContext(ctx)

	if t.forwardTrace {
		t.telemetry.InjectIntoHeaders(ctx, req.Header)
	}

	for _, header := range t.tracedRequestHeaders {
		if v := req.Header.Get(header); v != "" {
			span.AddAttributes(attribute.String(fmt.Sprintf("http.request.header.%s", header), v))
		}
	}

	resp, err := t.Transport.RoundTrip(req)
	if err != nil {
		if hub := sentry.GetHubFromContext(ctx); hub != nil {
			hub.CaptureException(err)
		}

		return resp, err
	}

	span.
		AddAttributes(semconv.HTTPResponseStatusCode(resp.StatusCode)).
		SetStatus(httpStatusToSpanStatus(resp.StatusCode, false), "")

	for _, header := range t.tracedResponseHeaders {
		if v := resp.Header.Get(header); v != "" {
			span.AddAttributes(attribute.String(fmt.Sprintf("http.response.header.%s", header), v))
		}
	}

	return resp, err
}