package site

import (
	"net/http"
	"strings"

	"gsg/internal/core"
)

// CompareRequest parses {range} into the base and head refs. The refs are
// still resolved by core through gitx.Repo.Resolve; this only splits text.
func CompareRequest(r *http.Request) (core.Request, error) {
	rng := r.PathValue("range")
	// Check three dots first: "a...b" also contains "..".
	if base, head, ok := strings.Cut(rng, "..."); ok {
		return core.Request{
			Ref:   head,
			Range: &core.Range{Base: base, ThreeDot: true},
		}, nil
	}
	if base, head, ok := strings.Cut(rng, ".."); ok {
		return core.Request{
			Ref:   head,
			Range: &core.Range{Base: base},
		}, nil
	}
	return core.Request{}, core.Errorf(http.StatusBadRequest, "compare needs base..head")
}