// Package httpx holds small HTTP helpers shared by middleware and handlers.
package httpx

import (
	"encoding/json"
	"net/http"
)

// Problem is an RFC 9457 problem details body.
type Problem struct {
	Type      string `json:"type,omitempty"`
	Status    int    `json:"status"`
	Title     string `json:"title"`
	Detail    string `json:"detail,omitempty"`
	Instance  string `json:"instance,omitempty"`
	RequestID string `json:"requestId,omitempty"`
}

// WriteProblem writes a problem+json error response.
func WriteProblem(
	w http.ResponseWriter, r *http.Request, status int, detail string,
) {
	problem := Problem{
		Type:   "about:blank",
		Title:  http.StatusText(status),
		Status: status,
		Detail: detail,
	}
	if r != nil {
		problem.RequestID = RequestID(r.Context())
	}

	w.Header().Set("Content-Type", "application/problem+json")
	w.Header().Set("X-Content-Type-Options", "nosniff")
	w.WriteHeader(status)
	json.NewEncoder(w).Encode(problem) //nolint:errcheck,gosec // the client may have gone
}