/**
 * @node sdcpp-upscaler-load
 * @name SD.cpp Load Upscaler
 * @category sdcpp
 * @version 1.0.0
 * @description Make sure an upscaler is loaded, without reloading one that already is
 * @icon maximize
 */

const configSchema = {
    type: 'object',
    properties: {
        serverUrl: {
            type: 'string', title: 'Server URL',
            description: 'Base address of the sdcpp-restapi server',
            default: 'http://localhost:8077'
        },
        credentialId: {
            type: 'string', title: 'Credential',
            description: 'A basic credential holding the sdcpp-restapi username and password',
            dynamicOptions: { source: 'credentials', filter: { type: ['basic'] } }
        },
        modelName: {
            type: 'string', title: 'Upscaler',
            description: 'File name of the ESRGAN-family upscaler. Usually supplied by an SD.cpp Model node set to type esrgan'
        },
        force: {
            type: 'boolean', title: 'Force Reload',
            default: false,
            description: 'Load again even when this upscaler is already loaded'
        },
        timeout: { type: 'number', title: 'Timeout (ms)', default: 120000 }
    },
    required: []
};

const inputSchema = { type: 'object', properties: { data: { type: 'any' } } };

const outputSchema = {
    type: 'object',
    properties: {
        upscalerName: { type: 'string' },
        loaded: { type: 'boolean', description: 'True when this node performed a load' },
        alreadyLoaded: { type: 'boolean' },
        previousUpscaler: { type: 'string' },
        elapsedMs: { type: 'number' }
    }
};

function normalizeServer(url) {
    const value = String(url || '').trim();
    if (!value) {
        throw new Error('SD.cpp: a server URL is required, such as http://localhost:8077');
    }
    return value.replace(/\/+$/, '');
}

function readCredential(credentialId) {
    const auth = smartbotic.credentials.get(credentialId);
    if (!auth || auth.success !== true) {
        throw new Error('SD.cpp: could not read the credential: ' +
            ((auth && auth.error) || 'unknown error'));
    }

    const value = auth.headerValue || '';
    if (value.indexOf('Basic ') !== 0) {
        throw new Error('SD.cpp: the credential must be a basic one, holding the sdcpp-restapi ' +
            'username and password');
    }

    const decoded = smartbotic.utils.base64Decode(value.substring(6));
    const separator = decoded.indexOf(':');
    if (separator < 1) {
        throw new Error('SD.cpp: the credential is malformed, expected a username and a password');
    }

    return {
        username: decoded.substring(0, separator),
        password: decoded.substring(separator + 1)
    };
}

function call(options) {
    const response = smartbotic.http.request(options);

    let body = response.data;
    if (typeof body === 'string' && body.length > 0) {
        try {
            body = JSON.parse(body);
        } catch (e) {
            const snippet = body.substring(0, 200).replace(/\s+/g, ' ');
            throw new Error('SD.cpp: ' + options.what + ' returned HTTP ' + response.status +
                ' with a body that is not JSON: ' + snippet);
        }
    }

    if (response.status < 200 || response.status >= 300) {
        const detail = (body && (body.message || body.error)) || ('HTTP ' + response.status);
        throw new Error('SD.cpp: ' + options.what + ' failed: ' + detail);
    }

    return body || {};
}

function login(server, credential, timeout) {
    const session = call({
        method: 'POST',
        url: server + '/auth/login',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({
            username: credential.username,
            password: credential.password
        }),
        timeout: timeout,
        what: 'signing in'
    });

    if (!session.token) {
        throw new Error('SD.cpp: the server accepted the login but returned no token');
    }
    return session.token;
}

// /health is unauthenticated, and it is the only way to find out what is
// already loaded without asking for a token first.
function readHealth(server, timeout) {
    return call({
        method: 'GET',
        url: server + '/health',
        timeout: timeout,
        what: 'reading server health'
    });
}

function putIfSet(target, key, value) {
    if (value === undefined || value === null || value === '') {
        return;
    }
    target[key] = value;
}

async function execute(config, input, context) {
    const server = normalizeServer(config.serverUrl);
    const timeout = config.timeout > 0 ? config.timeout : 120000;
    const modelName = String(config.modelName || '').trim();

    if (!modelName) {
        throw new Error('SD.cpp: an upscaler name is required. Connect an SD.cpp Model node ' +
            'set to type esrgan, or type the file name');
    }

    const startedAt = Date.now();
    const health = readHealth(server, Math.min(timeout, 15000));
    const current = health.upscaler_name || '';

    // The upscaler lives in its own slot, independent of the main model, so
    // loading one does not disturb whatever is generating.
    if (current === modelName && config.force !== true) {
        smartbotic.log.info('SD.cpp: upscaler ' + modelName + ' is already loaded');
        return {
            upscalerName: current,
            loaded: false,
            alreadyLoaded: true,
            previousUpscaler: '',
            elapsedMs: Date.now() - startedAt
        };
    }

    const credential = readCredential(config.credentialId);
    const token = login(server, credential, Math.min(timeout, 30000));

    call({
        method: 'POST',
        url: server + '/upscaler/load',
        headers: { 'Content-Type': 'application/json', 'Authorization': 'Bearer ' + token },
        body: JSON.stringify({ model_name: modelName }),
        timeout: timeout,
        what: 'loading upscaler ' + modelName
    });

    smartbotic.log.info('SD.cpp: loaded upscaler ' + modelName);

    return {
        upscalerName: modelName,
        loaded: true,
        alreadyLoaded: false,
        previousUpscaler: current === modelName ? '' : current,
        elapsedMs: Date.now() - startedAt
    };
}

module.exports = { configSchema, inputSchema, outputSchema, execute };