package unitel

import (
	"fmt"
	"time"

	"github.com/getsentry/sentry-go"
	"github.com/gofiber/fiber/v2"
	"github.com/gofiber/fiber/v2/utils"
	"github.com/rs/zerolog"
	"go.opentelemetry.io/otel/trace"
)

const requestBufferSize = 1000

func RequestLogger(l zerolog.Logger, requestHeaders, responseHeaders bool) fiber.Handler {
	type request struct {
		Method          string
		Path            string
		Status          int
		Duration        time.Duration
		RequestHeaders  map[string][]string
		ResponseHeaders map[string][]string
		OtelSpanID      *trace.SpanID
		SentrySpanID    *sentry.SpanID
	}

	reqs := make(chan request, requestBufferSize)

	go func() {
		for {
			r := <-reqs

			l2 := l.Trace().
				Str("method", r.Method).
				Str("path", r.Path).
				Int("status", r.Status).
				Dur("duration", r.Duration)

			if r.OtelSpanID != nil {
				l2 = l2.Str("otel_span_id", r.OtelSpanID.String())
			}

			if r.SentrySpanID != nil {
				l2 = l2.Str("sentry_span_id", r.SentrySpanID.String())
			}

			if requestHeaders {
				for k, v := range r.RequestHeaders {
					for i, vv := range v {
						attr := fmt.Sprintf("request.headers.%s", k)

						if len(v) != 1 {
							attr = fmt.Sprintf("%s.%d", attr, i)
						}

						l2 = l2.Str(attr, vv)
					}
				}
			}

			if responseHeaders {
				for k, v := range r.ResponseHeaders {
					for i, vv := range v {
						attr := fmt.Sprintf("response.headers.%s", k)

						if len(v) != 1 {
							attr = fmt.Sprintf("%s.%d", attr, i)
						}

						l2 = l2.Str(attr, vv)
					}
				}
			}

			l2.Msg("request")
		}
	}()

	return func(c *fiber.Ctx) error {
		var otelSpanId *trace.SpanID = nil
		if spanId := trace.SpanContextFromContext(c.UserContext()).SpanID(); spanId.IsValid() {
			otelSpanId = &spanId
		}

		var sentrySpanId *sentry.SpanID = nil
		if span := sentry.SpanFromContext(c.UserContext()); span != nil {
			sentrySpanId = &span.SpanID
		}

		start := time.Now()
		err := c.Next()
		duration := time.Since(start)

		status := c.Response().StatusCode()

		if err != nil {
			if e, ok := err.(*fiber.Error); ok {
				status = e.Code
			} else {
				status = fiber.StatusInternalServerError
			}
		}

		// pushing the request to the logger, so we don't block the requests
		req := request{
			Method:       c.Method(),
			Path:         c.Path(),
			Status:       status,
			Duration:     duration,
			OtelSpanID:   otelSpanId,
			SentrySpanID: sentrySpanId,
		}

		if requestHeaders {
			req.RequestHeaders = make(map[string][]string)
			for k, v := range c.GetReqHeaders() {
				for _, vv := range v {
					req.RequestHeaders[k] = append(req.RequestHeaders[k], utils.CopyString(vv))
				}
			}
		}

		if responseHeaders {
			req.ResponseHeaders = make(map[string][]string)
			for k, v := range c.GetRespHeaders() {
				for _, vv := range v {
					req.ResponseHeaders[k] = append(req.ResponseHeaders[k], utils.CopyString(vv))
				}
			}
		}

		reqs <- req

		return err
	}
}