package handlers

import (
	"sneak.berlin/go/webhooker/internal/database"
	"sneak.berlin/go/webhooker/internal/signature"
)

// signatureUnavailable is what an entrypoint's scheme renders as when
// the stored value is not one this build supports. The stored string
// is never echoed as a fallback: it is operator-supplied and the row
// is already in a state the receiver refuses, so the UI says so
// rather than inventing a description for it.
const signatureUnavailable = "(unavailable)"

// signatureNotVerified is the label for an entrypoint that performs
// no inbound verification.
const signatureNotVerified = "not verified"

// signatureMisconfigured is the label for a row holding one half of
// the scheme/secret pair. The receiver answers every request to such
// an entrypoint 500, so calling it "not verified" would describe a
// receiver that is refusing everything as one that is accepting
// everything. The form cannot create the state; a hand-edited
// database or a downgrade past a scheme can.
const signatureMisconfigured = "misconfigured"

// EntrypointView is the display-safe projection of an entrypoint for
// the UI. It deliberately has no secret field, so no template —
// present or future — can render the shared secret, in the same way
// delivery.TargetView keeps a target's stored credential away from
// one.
type EntrypointView struct {
	ID          string
	Path        string
	Description string
	Active      bool

	// Configured reports whether inbound requests to this entrypoint
	// are verified.
	Configured bool

	// Scheme is the stored scheme, carried so the form can preselect
	// it. It names an algorithm, not a secret.
	Scheme database.SignatureScheme

	// SchemeLabel and SchemeHeader describe the configured scheme for
	// display: the sender's name, and the header its signature
	// arrives in.
	SchemeLabel  string
	SchemeHeader string
}

// NewEntrypointViews projects entrypoints for rendering, dropping the
// shared secret on the way.
func NewEntrypointViews(
	entrypoints []database.Entrypoint,
) []EntrypointView {
	views := make([]EntrypointView, 0, len(entrypoints))

	for i := range entrypoints {
		e := &entrypoints[i]

		view := EntrypointView{
			ID:           e.ID,
			Path:         e.Path,
			Description:  e.Description,
			Active:       e.Active,
			Configured:   e.SignatureConfigured(),
			Scheme:       e.SignatureScheme,
			SchemeLabel:  signatureNotVerified,
			SchemeHeader: "",
		}

		switch {
		case view.Configured:
			view.SchemeLabel = signatureUnavailable

			info, ok := signature.Info(e.SignatureScheme)
			if ok {
				view.SchemeLabel = info.Label
				view.SchemeHeader = info.Header
			}
		case e.SignatureHalfConfigured():
			view.SchemeLabel = signatureMisconfigured
		}

		views = append(views, view)
	}

	return views
}