package apptoken

import (
	"context"
	"encoding/json"

	"github.com/hashicorp/vault/sdk/framework"
	"github.com/hashicorp/vault/sdk/logical"
)

const (
	jwksPath         = ".well-known/jwks.json"
	openidConfigPath = ".well-known/openid-configuration"
)

func pathJWKS(b *appTokenBackend) *framework.Path {
	return &framework.Path{
		Pattern: jwksPath + "$",
		DisplayAttrs: &framework.DisplayAttributes{
			OperationPrefix: "apptoken",
			OperationSuffix: "jwks",
		},
		Operations: map[logical.Operation]framework.OperationHandler{
			logical.ReadOperation: &framework.PathOperation{Callback: b.pathJWKSRead},
		},
		HelpSynopsis:    "Public JSON Web Key Set for offline token validation.",
		HelpDescription: "Unauthenticated. Returns the public signing keys (current plus retained) so services can verify app tokens without contacting Vault per request.",
	}
}

func pathOpenIDConfig(b *appTokenBackend) *framework.Path {
	return &framework.Path{
		Pattern: openidConfigPath + "$",
		DisplayAttrs: &framework.DisplayAttributes{
			OperationPrefix: "apptoken",
			OperationSuffix: "openid-configuration",
		},
		Operations: map[logical.Operation]framework.OperationHandler{
			logical.ReadOperation: &framework.PathOperation{Callback: b.pathOpenIDConfigRead},
		},
		HelpSynopsis:    "OIDC issuer metadata.",
		HelpDescription: "Unauthenticated. Advertises the issuer and jwks_uri so standard OIDC/JWT clients can discover the validation keys.",
	}
}

// rawJSONResponse renders a body as an unauthenticated raw JSON HTTP response,
// the form OIDC/JWKS clients expect (rather than Vault's data-wrapped JSON).
func rawJSONResponse(body interface{}) (*logical.Response, error) {
	data, err := json.Marshal(body)
	if err != nil {
		return nil, err
	}
	return &logical.Response{
		Data: map[string]interface{}{
			logical.HTTPContentType: "application/json",
			logical.HTTPRawBody:     data,
			logical.HTTPStatusCode:  200,
		},
	}, nil
}

func (b *appTokenBackend) pathJWKSRead(ctx context.Context, req *logical.Request, _ *framework.FieldData) (*logical.Response, error) {
	ks, err := b.getKeyset(ctx, req.Storage)
	if err != nil {
		return nil, err
	}
	jwks, err := ks.jwks()
	if err != nil {
		return nil, err
	}
	return rawJSONResponse(jwks)
}

func (b *appTokenBackend) pathOpenIDConfigRead(ctx context.Context, req *logical.Request, _ *framework.FieldData) (*logical.Response, error) {
	cfg, err := b.getConfig(ctx, req.Storage)
	if err != nil {
		return nil, err
	}
	issuer := ""
	if cfg != nil {
		issuer = cfg.Issuer
	}

	meta := map[string]interface{}{
		"issuer":                                issuer,
		"jwks_uri":                              issuer + "/" + jwksPath,
		"response_types_supported":              []string{"token"},
		"subject_types_supported":               []string{"public"},
		"id_token_signing_alg_values_supported": []string{algEdDSA, algRS256},
	}
	return rawJSONResponse(meta)
}