export const DEFAULT_PARTICIPANT_NAME = '参与者';
export const DEFAULT_PARTICIPANT_AVATAR = '/images/p2.png';

const DEFAULT_MEDIA_STATE = Object.freeze({
    audio: false,
    video: true,
    isSpeaking: false
});

function createParticipantRecord(current = {}, patch = {}) {
    return {
        id: '',
        name: DEFAULT_PARTICIPANT_NAME,
        avatar: DEFAULT_PARTICIPANT_AVATAR,
        mediaState: { ...DEFAULT_MEDIA_STATE },
        status: 'online',
        ...current,
        ...patch,
        mediaState: {
            ...DEFAULT_MEDIA_STATE,
            ...(current.mediaState || {}),
            ...(patch.mediaState || {})
        }
    };
}

export function upsertParticipant(participants, participantId, patch = {}) {
    if (!participantId) {
        return null;
    }

    participants[participantId] = createParticipantRecord(participants[participantId], patch);
    return participants[participantId];
}

export function removeParticipant(participants, participantId) {
    if (!participantId || !participants[participantId]) {
        return false;
    }

    delete participants[participantId];
    return true;
}

export function omitParticipant(participants, excludedParticipantId) {
    const filtered = {};

    for (const [participantId, participant] of Object.entries(participants || {})) {
        if (participantId !== excludedParticipantId) {
            filtered[participantId] = participant;
        }
    }

    return filtered;
}

export function buildParticipantsSyncData(localUser, participants) {
    const memberList = {
        host: {
            id: localUser.id,
            name: localUser.name,
            avatar: localUser.avatar,
            mediaState: { ...localUser.mediaState },
            status: 'online',
            role: 'host'
        }
    };

    for (const [participantId, participant] of Object.entries(participants || {})) {
        memberList[participantId] = {
            ...createParticipantRecord(participant),
            role: 'participant'
        };
    }

    return memberList;
}