'use strict';

var types = require('@smithy/types');

class EndpointCache {
    capacity;
    data = new Map();
    parameters = [];
    constructor({ size, params }) {
        this.capacity = size ?? 50;
        if (params) {
            this.parameters = params;
        }
    }
    get(endpointParams, resolver) {
        const key = this.hash(endpointParams);
        if (key === false) {
            return resolver();
        }
        if (!this.data.has(key)) {
            if (this.data.size > this.capacity + 10) {
                const keys = this.data.keys();
                let i = 0;
                while (true) {
                    const { value, done } = keys.next();
                    this.data.delete(value);
                    if (done || ++i > 10) {
                        break;
                    }
                }
            }
            this.data.set(key, resolver());
        }
        return this.data.get(key);
    }
    size() {
        return this.data.size;
    }
    hash(endpointParams) {
        let buffer = "";
        const { parameters } = this;
        if (parameters.length === 0) {
            return false;
        }
        for (const param of parameters) {
            const val = String(endpointParams[param] ?? "");
            if (val.includes("|;")) {
                return false;
            }
            buffer += val + "|;";
        }
        return buffer;
    }
}

const IP_V4_REGEX = new RegExp(`^(?:25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]\\d|\\d)(?:\\.(?:25[0-5]|2[0-4]\\d|1\\d\\d|[1-9]\\d|\\d)){3}$`);
const isIpAddress = (value) => IP_V4_REGEX.test(value) || (value.startsWith("[") && value.endsWith("]"));

const VALID_HOST_LABEL_REGEX = new RegExp(`^(?!.*-$)(?!-)[a-zA-Z0-9-]{1,63}$`);
const isValidHostLabel = (value, allowSubDomains = false) => {
    if (!allowSubDomains) {
        return VALID_HOST_LABEL_REGEX.test(value);
    }
    const labels = value.split(".");
    for (const label of labels) {
        if (!isValidHostLabel(label)) {
            return false;
        }
    }
    return true;
};

const customEndpointFunctions = {};

const debugId = "endpoints";

function toDebugString(input) {
    if (typeof input !== "object" || input == null) {
        return input;
    }
    if ("ref" in input) {
        return `$${toDebugString(input.ref)}`;
    }
    if ("fn" in input) {
        return `${input.fn}(${(input.argv || []).map(toDebugString).join(", ")})`;
    }
    return JSON.stringify(input, null, 2);
}

class EndpointError extends Error {
    constructor(message) {
        super(message);
        this.name = "EndpointError";
    }
}

const booleanEquals = (value1, value2) => value1 === value2;

const getAttrPathList = (path) => {
    const parts = path.split(".");
    const pathList = [];
    for (const part of parts) {
        const squareBracketIndex = part.indexOf("[");
        if (squareBracketIndex !== -1) {
            if (part.indexOf("]") !== part.length - 1) {
                throw new EndpointError(`Path: '${path}' does not end with ']'`);
            }
            const arrayIndex = part.slice(squareBracketIndex + 1, -1);
            if (Number.isNaN(parseInt(arrayIndex))) {
                throw new EndpointError(`Invalid array index: '${arrayIndex}' in path: '${path}'`);
            }
            if (squareBracketIndex !== 0) {
                pathList.push(part.slice(0, squareBracketIndex));
            }
            pathList.push(arrayIndex);
        }
        else {
            pathList.push(part);
        }
    }
    return pathList;
};

const getAttr = (value, path) => getAttrPathList(path).reduce((acc, index) => {
    if (typeof acc !== "object") {
        throw new EndpointError(`Index '${index}' in '${path}' not found in '${JSON.stringify(value)}'`);
    }
    else if (Array.isArray(acc)) {
        return acc[parseInt(index)];
    }
    return acc[index];
}, value);

const isSet = (value) => value != null;

const not = (value) => !value;

const DEFAULT_PORTS = {
    [types.EndpointURLScheme.HTTP]: 80,
    [types.EndpointURLScheme.HTTPS]: 443,
};
const parseURL = (value) => {
    const whatwgURL = (() => {
        try {
            if (value instanceof URL) {
                return value;
            }
            if (typeof value === "object" && "hostname" in value) {
                const { hostname, port, protocol = "", path = "", query = {} } = value;
                const url = new URL(`${protocol}//${hostname}${port ? `:${port}` : ""}${path}`);
                url.search = Object.entries(query)
                    .map(([k, v]) => `${k}=${v}`)
                    .join("&");
                return url;
            }
            return new URL(value);
        }
        catch (error) {
            return null;
        }
    })();
    if (!whatwgURL) {
        console.error(`Unable to parse ${JSON.stringify(value)} as a whatwg URL.`);
        return null;
    }
    const urlString = whatwgURL.href;
    const { host, hostname, pathname, protocol, search } = whatwgURL;
    if (search) {
        return null;
    }
    const scheme = protocol.slice(0, -1);
    if (!Object.values(types.EndpointURLScheme).includes(scheme)) {
        return null;
    }
    const isIp = isIpAddress(hostname);
    const inputContainsDefaultPort = urlString.includes(`${host}:${DEFAULT_PORTS[scheme]}`) ||
        (typeof value === "string" && value.includes(`${host}:${DEFAULT_PORTS[scheme]}`));
    const authority = `${host}${inputContainsDefaultPort ? `:${DEFAULT_PORTS[scheme]}` : ``}`;
    return {
        scheme,
        authority,
        path: pathname,
        normalizedPath: pathname.endsWith("/") ? pathname : `${pathname}/`,
        isIp,
    };
};

const stringEquals = (value1, value2) => value1 === value2;

const substring = (input, start, stop, reverse) => {
    if (start >= stop || input.length < stop) {
        return null;
    }
    if (!reverse) {
        return input.substring(start, stop);
    }
    return input.substring(input.length - stop, input.length - start);
};

const uriEncode = (value) => encodeURIComponent(value).replace(/[!*'()]/g, (c) => `%${c.charCodeAt(0).toString(16).toUpperCase()}`);

const endpointFunctions = {
    booleanEquals,
    getAttr,
    isSet,
    isValidHostLabel,
    not,
    parseURL,
    stringEquals,
    substring,
    uriEncode,
};

const evaluateTemplate = (template, options) => {
    const evaluatedTemplateArr = [];
    const templateContext = {
        ...options.endpointParams,
        ...options.referenceRecord,
    };
    let currentIndex = 0;
    while (currentIndex < template.length) {
        const openingBraceIndex = template.indexOf("{", currentIndex);
        if (openingBraceIndex === -1) {
            evaluatedTemplateArr.push(template.slice(currentIndex));
            break;
        }
        evaluatedTemplateArr.push(template.slice(currentIndex, openingBraceIndex));
        const closingBraceIndex = template.indexOf("}", openingBraceIndex);
        if (closingBraceIndex === -1) {
            evaluatedTemplateArr.push(template.slice(openingBraceIndex));
            break;
        }
        if (template[openingBraceIndex + 1] === "{" && template[closingBraceIndex + 1] === "}") {
            evaluatedTemplateArr.push(template.slice(openingBraceIndex + 1, closingBraceIndex));
            currentIndex = closingBraceIndex + 2;
        }
        const parameterName = template.substring(openingBraceIndex + 1, closingBraceIndex);
        if (parameterName.includes("#")) {
            const [refName, attrName] = parameterName.split("#");
            evaluatedTemplateArr.push(getAttr(templateContext[refName], attrName));
        }
        else {
            evaluatedTemplateArr.push(templateContext[parameterName]);
        }
        currentIndex = closingBraceIndex + 1;
    }
    return evaluatedTemplateArr.join("");
};

const getReferenceValue = ({ ref }, options) => {
    const referenceRecord = {
        ...options.endpointParams,
        ...options.referenceRecord,
    };
    return referenceRecord[ref];
};

const evaluateExpression = (obj, keyName, options) => {
    if (typeof obj === "string") {
        return evaluateTemplate(obj, options);
    }
    else if (obj["fn"]) {
        return callFunction(obj, options);
    }
    else if (obj["ref"]) {
        return getReferenceValue(obj, options);
    }
    throw new EndpointError(`'${keyName}': ${String(obj)} is not a string, function or reference.`);
};

const callFunction = ({ fn, argv }, options) => {
    const evaluatedArgs = argv.map((arg) => ["boolean", "number"].includes(typeof arg) ? arg : evaluateExpression(arg, "arg", options));
    const fnSegments = fn.split(".");
    if (fnSegments[0] in customEndpointFunctions && fnSegments[1] != null) {
        return customEndpointFunctions[fnSegments[0]][fnSegments[1]](...evaluatedArgs);
    }
    return endpointFunctions[fn](...evaluatedArgs);
};

const evaluateCondition = ({ assign, ...fnArgs }, options) => {
    if (assign && assign in options.referenceRecord) {
        throw new EndpointError(`'${assign}' is already defined in Reference Record.`);
    }
    const value = callFunction(fnArgs, options);
    options.logger?.debug?.(`${debugId} evaluateCondition: ${toDebugString(fnArgs)} = ${toDebugString(value)}`);
    return {
        result: value === "" ? true : !!value,
        ...(assign != null && { toAssign: { name: assign, value } }),
    };
};

const evaluateConditions = (conditions = [], options) => {
    const conditionsReferenceRecord = {};
    for (const condition of conditions) {
        const { result, toAssign } = evaluateCondition(condition, {
            ...options,
            referenceRecord: {
                ...options.referenceRecord,
                ...conditionsReferenceRecord,
            },
        });
        if (!result) {
            return { result };
        }
        if (toAssign) {
            conditionsReferenceRecord[toAssign.name] = toAssign.value;
            options.logger?.debug?.(`${debugId} assign: ${toAssign.name} := ${toDebugString(toAssign.value)}`);
        }
    }
    return { result: true, referenceRecord: conditionsReferenceRecord };
};

const getEndpointHeaders = (headers, options) => Object.entries(headers).reduce((acc, [headerKey, headerVal]) => ({
    ...acc,
    [headerKey]: headerVal.map((headerValEntry) => {
        const processedExpr = evaluateExpression(headerValEntry, "Header value entry", options);
        if (typeof processedExpr !== "string") {
            throw new EndpointError(`Header '${headerKey}' value '${processedExpr}' is not a string`);
        }
        return processedExpr;
    }),
}), {});

const getEndpointProperty = (property, options) => {
    if (Array.isArray(property)) {
        return property.map((propertyEntry) => getEndpointProperty(propertyEntry, options));
    }
    switch (typeof property) {
        case "string":
            return evaluateTemplate(property, options);
        case "object":
            if (property === null) {
                throw new EndpointError(`Unexpected endpoint property: ${property}`);
            }
            return getEndpointProperties(property, options);
        case "boolean":
            return property;
        default:
            throw new EndpointError(`Unexpected endpoint property type: ${typeof property}`);
    }
};

const getEndpointProperties = (properties, options) => Object.entries(properties).reduce((acc, [propertyKey, propertyVal]) => ({
    ...acc,
    [propertyKey]: getEndpointProperty(propertyVal, options),
}), {});

const getEndpointUrl = (endpointUrl, options) => {
    const expression = evaluateExpression(endpointUrl, "Endpoint URL", options);
    if (typeof expression === "string") {
        try {
            return new URL(expression);
        }
        catch (error) {
            console.error(`Failed to construct URL with ${expression}`, error);
            throw error;
        }
    }
    throw new EndpointError(`Endpoint URL must be a string, got ${typeof expression}`);
};

const evaluateEndpointRule = (endpointRule, options) => {
    const { conditions, endpoint } = endpointRule;
    const { result, referenceRecord } = evaluateConditions(conditions, options);
    if (!result) {
        return;
    }
    const endpointRuleOptions = {
        ...options,
        referenceRecord: { ...options.referenceRecord, ...referenceRecord },
    };
    const { url, properties, headers } = endpoint;
    options.logger?.debug?.(`${debugId} Resolving endpoint from template: ${toDebugString(endpoint)}`);
    return {
        ...(headers != undefined && {
            headers: getEndpointHeaders(headers, endpointRuleOptions),
        }),
        ...(properties != undefined && {
            properties: getEndpointProperties(properties, endpointRuleOptions),
        }),
        url: getEndpointUrl(url, endpointRuleOptions),
    };
};

const evaluateErrorRule = (errorRule, options) => {
    const { conditions, error } = errorRule;
    const { result, referenceRecord } = evaluateConditions(conditions, options);
    if (!result) {
        return;
    }
    throw new EndpointError(evaluateExpression(error, "Error", {
        ...options,
        referenceRecord: { ...options.referenceRecord, ...referenceRecord },
    }));
};

const evaluateTreeRule = (treeRule, options) => {
    const { conditions, rules } = treeRule;
    const { result, referenceRecord } = evaluateConditions(conditions, options);
    if (!result) {
        return;
    }
    return evaluateRules(rules, {
        ...options,
        referenceRecord: { ...options.referenceRecord, ...referenceRecord },
    });
};

const evaluateRules = (rules, options) => {
    for (const rule of rules) {
        if (rule.type === "endpoint") {
            const endpointOrUndefined = evaluateEndpointRule(rule, options);
            if (endpointOrUndefined) {
                return endpointOrUndefined;
            }
        }
        else if (rule.type === "error") {
            evaluateErrorRule(rule, options);
        }
        else if (rule.type === "tree") {
            const endpointOrUndefined = evaluateTreeRule(rule, options);
            if (endpointOrUndefined) {
                return endpointOrUndefined;
            }
        }
        else {
            throw new EndpointError(`Unknown endpoint rule: ${rule}`);
        }
    }
    throw new EndpointError(`Rules evaluation failed`);
};

const resolveEndpoint = (ruleSetObject, options) => {
    const { endpointParams, logger } = options;
    const { parameters, rules } = ruleSetObject;
    options.logger?.debug?.(`${debugId} Initial EndpointParams: ${toDebugString(endpointParams)}`);
    const paramsWithDefault = Object.entries(parameters)
        .filter(([, v]) => v.default != null)
        .map(([k, v]) => [k, v.default]);
    if (paramsWithDefault.length > 0) {
        for (const [paramKey, paramDefaultValue] of paramsWithDefault) {
            endpointParams[paramKey] = endpointParams[paramKey] ?? paramDefaultValue;
        }
    }
    const requiredParams = Object.entries(parameters)
        .filter(([, v]) => v.required)
        .map(([k]) => k);
    for (const requiredParam of requiredParams) {
        if (endpointParams[requiredParam] == null) {
            throw new EndpointError(`Missing required parameter: '${requiredParam}'`);
        }
    }
    const endpoint = evaluateRules(rules, { endpointParams, logger, referenceRecord: {} });
    options.logger?.debug?.(`${debugId} Resolved endpoint: ${toDebugString(endpoint)}`);
    return endpoint;
};

exports.EndpointCache = EndpointCache;
exports.EndpointError = EndpointError;
exports.customEndpointFunctions = customEndpointFunctions;
exports.isIpAddress = isIpAddress;
exports.isValidHostLabel = isValidHostLabel;
exports.resolveEndpoint = resolveEndpoint;