package api

import (
	"context"
	"errors"
	"log/slog"
	"net/http"
	"strings"

	"git.k6n.net/mats/fullstack-template/internal/browse"
)

// browseHandler adapts HTTP requests to the browse service: read the url
// query parameter, call Inspect, map errors to the wire. No fetching or
// conversion logic lives here.
type browseHandler struct {
	svc    *browse.Service
	logger *slog.Logger
}

func (h *browseHandler) get(w http.ResponseWriter, r *http.Request) {
	raw := strings.TrimSpace(r.URL.Query().Get("url"))
	snap, err := h.svc.Inspect(r.Context(), raw)
	if err != nil {
		h.fail(w, err)
		return
	}
	writeJSON(w, http.StatusOK, snap)
}

// fail is the translation point from browse errors to the wire:
// *ValidationError → 400, *FetchError → 502 (the site is the problem),
// context deadline → 504, anything else → 500 (logged).
func (h *browseHandler) fail(w http.ResponseWriter, err error) {
	var vErr *browse.ValidationError
	var fErr *browse.FetchError
	switch {
	case errors.As(err, &vErr):
		writeError(w, http.StatusBadRequest, "validation_failed", vErr.Error())
	case errors.As(err, &fErr):
		h.logger.Info("browse fetch failed", "url", fErr.URL, "err", fErr.Err)
		writeError(w, http.StatusBadGateway, "unavailable", "could not fetch "+fErr.URL)
	case errors.Is(err, context.DeadlineExceeded):
		writeError(w, http.StatusGatewayTimeout, "timeout", "the site took too long to answer")
	default:
		h.logger.Error("browse failed", "err", err)
		writeError(w, http.StatusInternalServerError, "internal_error", "an internal error occurred")
	}
}