package idgen

import (
	"bytes"
	"io"
	"strings"
	"testing"

	"galaxy/lobby/internal/domain/common"

	"github.com/stretchr/testify/require"
)

func TestNewGameIDShape(t *testing.T) {
	t.Parallel()

	gen := NewGenerator()

	gameID, err := gen.NewGameID()
	require.NoError(t, err)
	require.NoError(t, gameID.Validate())
	require.True(t, strings.HasPrefix(gameID.String(), "game-"))
	require.Equal(t, strings.ToLower(gameID.String()), gameID.String())
}

func TestNewGameIDDeterministicWithFixedReader(t *testing.T) {
	t.Parallel()

	source := bytes.NewReader(bytes.Repeat([]byte{0x00}, gameIDTokenBytes*2))

	gen := NewGenerator(WithRandomSource(source))

	first, err := gen.NewGameID()
	require.NoError(t, err)
	require.Equal(t, common.GameID("game-aaaaaaaaaaaaaaaa"), first)

	second, err := gen.NewGameID()
	require.NoError(t, err)
	require.Equal(t, common.GameID("game-aaaaaaaaaaaaaaaa"), second)
}

func TestNewGameIDUniquenessOverManyDraws(t *testing.T) {
	t.Parallel()

	gen := NewGenerator()

	seen := make(map[common.GameID]struct{}, 1024)
	for i := range 1024 {
		gameID, err := gen.NewGameID()
		require.NoError(t, err)
		_, dup := seen[gameID]
		require.False(t, dup, "duplicate game id %q on draw %d", gameID, i)
		seen[gameID] = struct{}{}
	}
}

func TestNewGameIDSourceError(t *testing.T) {
	t.Parallel()

	gen := NewGenerator(WithRandomSource(failingReader{}))

	_, err := gen.NewGameID()
	require.Error(t, err)
	require.Contains(t, err.Error(), "generate game id")
}

func TestNewApplicationIDShape(t *testing.T) {
	t.Parallel()

	gen := NewGenerator()

	applicationID, err := gen.NewApplicationID()
	require.NoError(t, err)
	require.NoError(t, applicationID.Validate())
	require.True(t, strings.HasPrefix(applicationID.String(), "application-"))
	require.Equal(t, strings.ToLower(applicationID.String()), applicationID.String())
}

func TestNewApplicationIDDeterministicWithFixedReader(t *testing.T) {
	t.Parallel()

	source := bytes.NewReader(bytes.Repeat([]byte{0x00}, applicationIDTokenBytes*2))

	gen := NewGenerator(WithRandomSource(source))

	first, err := gen.NewApplicationID()
	require.NoError(t, err)
	require.Equal(t, common.ApplicationID("application-aaaaaaaaaaaaaaaa"), first)

	second, err := gen.NewApplicationID()
	require.NoError(t, err)
	require.Equal(t, common.ApplicationID("application-aaaaaaaaaaaaaaaa"), second)
}

func TestNewApplicationIDUniquenessOverManyDraws(t *testing.T) {
	t.Parallel()

	gen := NewGenerator()

	seen := make(map[common.ApplicationID]struct{}, 1024)
	for i := range 1024 {
		applicationID, err := gen.NewApplicationID()
		require.NoError(t, err)
		_, dup := seen[applicationID]
		require.False(t, dup, "duplicate application id %q on draw %d", applicationID, i)
		seen[applicationID] = struct{}{}
	}
}

func TestNewApplicationIDSourceError(t *testing.T) {
	t.Parallel()

	gen := NewGenerator(WithRandomSource(failingReader{}))

	_, err := gen.NewApplicationID()
	require.Error(t, err)
	require.Contains(t, err.Error(), "generate application id")
}

func TestNewInviteIDShape(t *testing.T) {
	t.Parallel()

	gen := NewGenerator()

	inviteID, err := gen.NewInviteID()
	require.NoError(t, err)
	require.NoError(t, inviteID.Validate())
	require.True(t, strings.HasPrefix(inviteID.String(), "invite-"))
	require.Equal(t, strings.ToLower(inviteID.String()), inviteID.String())
}

func TestNewInviteIDDeterministicWithFixedReader(t *testing.T) {
	t.Parallel()

	source := bytes.NewReader(bytes.Repeat([]byte{0x00}, inviteIDTokenBytes*2))

	gen := NewGenerator(WithRandomSource(source))

	first, err := gen.NewInviteID()
	require.NoError(t, err)
	require.Equal(t, common.InviteID("invite-aaaaaaaaaaaaaaaa"), first)

	second, err := gen.NewInviteID()
	require.NoError(t, err)
	require.Equal(t, common.InviteID("invite-aaaaaaaaaaaaaaaa"), second)
}

func TestNewInviteIDUniquenessOverManyDraws(t *testing.T) {
	t.Parallel()

	gen := NewGenerator()

	seen := make(map[common.InviteID]struct{}, 1024)
	for i := range 1024 {
		inviteID, err := gen.NewInviteID()
		require.NoError(t, err)
		_, dup := seen[inviteID]
		require.False(t, dup, "duplicate invite id %q on draw %d", inviteID, i)
		seen[inviteID] = struct{}{}
	}
}

func TestNewInviteIDSourceError(t *testing.T) {
	t.Parallel()

	gen := NewGenerator(WithRandomSource(failingReader{}))

	_, err := gen.NewInviteID()
	require.Error(t, err)
	require.Contains(t, err.Error(), "generate invite id")
}

func TestNewMembershipIDShape(t *testing.T) {
	t.Parallel()

	gen := NewGenerator()

	membershipID, err := gen.NewMembershipID()
	require.NoError(t, err)
	require.NoError(t, membershipID.Validate())
	require.True(t, strings.HasPrefix(membershipID.String(), "membership-"))
	require.Equal(t, strings.ToLower(membershipID.String()), membershipID.String())
}

func TestNewMembershipIDDeterministicWithFixedReader(t *testing.T) {
	t.Parallel()

	source := bytes.NewReader(bytes.Repeat([]byte{0x00}, membershipIDTokenBytes*2))

	gen := NewGenerator(WithRandomSource(source))

	first, err := gen.NewMembershipID()
	require.NoError(t, err)
	require.Equal(t, common.MembershipID("membership-aaaaaaaaaaaaaaaa"), first)

	second, err := gen.NewMembershipID()
	require.NoError(t, err)
	require.Equal(t, common.MembershipID("membership-aaaaaaaaaaaaaaaa"), second)
}

func TestNewMembershipIDUniquenessOverManyDraws(t *testing.T) {
	t.Parallel()

	gen := NewGenerator()

	seen := make(map[common.MembershipID]struct{}, 1024)
	for i := range 1024 {
		membershipID, err := gen.NewMembershipID()
		require.NoError(t, err)
		_, dup := seen[membershipID]
		require.False(t, dup, "duplicate membership id %q on draw %d", membershipID, i)
		seen[membershipID] = struct{}{}
	}
}

func TestNewMembershipIDSourceError(t *testing.T) {
	t.Parallel()

	gen := NewGenerator(WithRandomSource(failingReader{}))

	_, err := gen.NewMembershipID()
	require.Error(t, err)
	require.Contains(t, err.Error(), "generate membership id")
}

type failingReader struct{}

func (failingReader) Read(_ []byte) (int, error) {
	return 0, io.ErrUnexpectedEOF
}