package ownwire_sdk_test

import (
	"context"
	"crypto/ecdh"
	"crypto/rand"
	"encoding/base64"

	. "github.com/onsi/ginkgo/v2"
	. "github.com/onsi/gomega"

	sdk "ownwire.net/ownwire-sdk"
)

var _ = Describe("Handshaker", func() {
	It("sends /create when no resume session_id is provided and derives shared key", func() {
		ctx := context.Background()
		conn := sdk_test_new_inmem_conn()

		client_kp, err := sdk.GenClientKey()
		Expect(err).To(BeNil())

		h := sdk.Handshaker{
			GenClientKeyF: func() (sdk.Keypair, error) {
				return client_kp, nil
			},
		}

		curve := ecdh.P256()
		server_priv, err := curve.GenerateKey(rand.Reader)
		Expect(err).To(BeNil())
		server_pub_raw := server_priv.PublicKey().Bytes()
		server_pub_b64 := base64.StdEncoding.EncodeToString(server_pub_raw)

		salt_raw := make([]byte, 32)
		_, err = rand.Read(salt_raw)
		Expect(err).To(BeNil())
		salt_b64 := base64.StdEncoding.EncodeToString(salt_raw)

		session_id := "cb653f53-6f7d-4aeb-ba0d-d2b17c290d8a"

		go func() {
			written := <-conn.write_ch
			Expect(written).To(HavePrefix("/create:"))

			conn.read_ch <- "/session:" + session_id + ":" + server_pub_b64 + ":" + salt_b64 + ":12:34"
		}()

		state, pending, err := h.Run(ctx, conn, "")
		Expect(err).To(BeNil())
		Expect(pending).To(BeEmpty())

		Expect(state.SessionId).To(Equal(session_id))
		Expect(state.ClientPubKeyB64).ToNot(BeEmpty())

		want_key, err := sdk.DeriveSharedKey(session_id, client_kp.ClientPriv, server_pub_raw, salt_raw)
		Expect(err).To(BeNil())
		Expect(state.SharedKey).To(Equal(want_key))

		Expect(state.SeqOut).To(Equal(uint64(34)))
		Expect(state.SeqInMax).To(Equal(uint64(12)))
	})

	It("sends /open when resume session_id is provided", func() {
		ctx := context.Background()
		conn := sdk_test_new_inmem_conn()

		client_kp, err := sdk.GenClientKey()
		Expect(err).To(BeNil())

		h := sdk.Handshaker{
			GenClientKeyF: func() (sdk.Keypair, error) {
				return client_kp, nil
			},
		}

		curve := ecdh.P256()
		server_priv, err := curve.GenerateKey(rand.Reader)
		Expect(err).To(BeNil())
		server_pub_raw := server_priv.PublicKey().Bytes()
		server_pub_b64 := base64.StdEncoding.EncodeToString(server_pub_raw)

		salt_raw := make([]byte, 32)
		_, err = rand.Read(salt_raw)
		Expect(err).To(BeNil())
		salt_b64 := base64.StdEncoding.EncodeToString(salt_raw)

		session_id := "cb653f53-6f7d-4aeb-ba0d-d2b17c290d8a"

		go func() {
			written := <-conn.write_ch
			Expect(written).To(HavePrefix("/open:" + session_id + ":"))

			conn.read_ch <- "/session:" + session_id + ":" + server_pub_b64 + ":" + salt_b64 + ":1:2"
		}()

		_, pending, err := h.Run(ctx, conn, session_id)
		Expect(err).To(BeNil())
		Expect(pending).To(BeEmpty())
	})
})