/**
 * Methods for manipulating symbol names in JSDoc.
 *
 * @alias @jsdoc/core.name
 */
const _ = require('lodash');
const escape = require('escape-string-regexp');

const hasOwnProp = Object.prototype.hasOwnProperty;

/**
 * Longnames that have a special meaning in JSDoc.
 *
 * @enum {string}
 * @static
 * @memberof module:jsdoc/name
 */
exports.LONGNAMES = {
    /** Longname used for doclets that do not have a longname, such as anonymous functions. */
    ANONYMOUS: '<anonymous>',
    /** Longname that represents global scope. */
    GLOBAL: '<global>'
};

// Module namespace prefix.
exports.MODULE_NAMESPACE = 'module:';

/**
 * Names and punctuation marks that identify doclet scopes.
 *
 * @enum {string}
 * @static
 * @memberof module:jsdoc/name
 */
const SCOPE = exports.SCOPE = {
    NAMES: {
        GLOBAL: 'global',
        INNER: 'inner',
        INSTANCE: 'instance',
        STATIC: 'static'
    },
    PUNC: {
        INNER: '~',
        INSTANCE: '#',
        STATIC: '.'
    }
};

// Keys must be lowercase.
const SCOPE_TO_PUNC = exports.SCOPE_TO_PUNC = {
    inner: SCOPE.PUNC.INNER,
    instance: SCOPE.PUNC.INSTANCE,
    static: SCOPE.PUNC.STATIC
};

exports.PUNC_TO_SCOPE = _.invert(SCOPE_TO_PUNC);

const SCOPE_PUNC = _.values(SCOPE.PUNC);
const SCOPE_PUNC_STRING = `[${SCOPE_PUNC.join()}]`;
const REGEXP_LEADING_SCOPE = new RegExp(`^(${SCOPE_PUNC_STRING})`);
const REGEXP_TRAILING_SCOPE = new RegExp(`(${SCOPE_PUNC_STRING})$`);

const DESCRIPTION = '(?:(?:[ \\t]*\\-\\s*|\\s+)(\\S[\\s\\S]*))?$';
const REGEXP_DESCRIPTION = new RegExp(DESCRIPTION);
const REGEXP_NAME_DESCRIPTION = new RegExp(`^(\\[[^\\]]+\\]|\\S+)${DESCRIPTION}`);

/**
 * Check whether a name appears to represent a complete longname that is a member of the specified
 * parent.
 *
 * @example
 * exports.nameIsLongname('foo.bar', 'foo');  // true
 * exports.nameIsLongname('foo.bar', 'baz');  // false
 * exports.nameIsLongname('bar', 'foo');      // false
 * @param {string} name - The name to check.
 * @param {string} memberof - The parent of the name.
 * @returns {boolean} `true` if the name represents a complete longname that is a member of the
 * parent; otherwise, `false`.
 */
exports.nameIsLongname = (name, memberof) => {
    const regexp = new RegExp(`^${escape(memberof)}${SCOPE_PUNC_STRING}`);

    return regexp.test(name);
};

/**
 * For names that identify a property of a prototype, replace the `prototype` portion of the name
 * with `#`, which indicates instance-level scope. For example, `Foo.prototype.bar` becomes
 * `Foo#bar`.
 *
 * @param {string} name - The name in which to change `prototype` to `#`.
 * @returns {string} The updated name.
 */
const prototypeToPunc = exports.prototypeToPunc = name => {
    // Don't mangle symbols named `prototype`.
    if (name === 'prototype') {
        return name;
    }

    return name.replace(/(?:^|\.)prototype\.?/g, SCOPE.PUNC.INSTANCE);
};

/**
 * Check whether a name begins with a character that identifies a scope.
 *
 * @param {string} name - The name to check.
 * @returns {boolean} `true` if the name begins with a scope character; otherwise, `false`.
 */
exports.hasLeadingScope = name => REGEXP_LEADING_SCOPE.test(name);

/**
 * Check whether a name ends with a character that identifies a scope.
 *
 * @param {string} name - The name to check.
 * @returns {boolean} `true` if the name ends with a scope character; otherwise, `false`.
 */
exports.hasTrailingScope = name => REGEXP_TRAILING_SCOPE.test(name);

/**
 * Get a symbol's basename, which is the first part of its full name before any punctuation (other
 * than an underscore). For example, all of the following names have the basename `Foo`:
 *
 * + `Foo`
 * + `Foo.bar`
 * + `Foo.prototype.bar`
 * + `Foo#bar`
 *
 * @param {?string} [name] - The symbol's full name.
 * @returns {?string} The symbol's basename.
 */
exports.getBasename = name => {
    if (!name) {
        return null;
    }

    return name.replace(/^([$a-z_][$a-z_0-9]*).*?$/i, '$1');
};

// TODO: docs
exports.stripNamespace = longname => longname.replace(/^[a-zA-Z]+:/, '');

// TODO: docs
function slice(longname, sliceChars, forcedMemberof) {
    let i;
    let memberof = '';
    let name = '';
    let parts;
    let partsRegExp;
    let scopePunc = '';
    let token;
    const tokens = [];
    let variation;

    sliceChars = sliceChars || SCOPE_PUNC;

    // Quoted strings in a longname are atomic, so we convert them to tokens:
    // foo["bar"] => foo.@{1}@
    // Foo.prototype["bar"] => Foo#@{1}
    longname = longname.replace(/(prototype|#)?(\[?["'].+?["']\]?)/g, ($, p1, p2) => {
        let punc = '';

        // Is there a leading bracket?
        if ( /^\[/.test(p2) ) {
            // Is it a static or instance member?
            punc = p1 ? SCOPE.PUNC.INSTANCE : SCOPE.PUNC.STATIC;
            p2 = p2.replace(/^\[/g, '')
                .replace(/\]$/g, '');
        }

        token = `@{${tokens.length}}@`;
        tokens.push(p2);

        return punc + token;
    });

    longname = prototypeToPunc(longname);

    if (typeof forcedMemberof !== 'undefined') {
        partsRegExp = new RegExp(`^(.*?)([${sliceChars.join()}]?)$`);
        name = longname.substr(forcedMemberof.length);
        parts = forcedMemberof.match(partsRegExp);

        if (parts[1]) {
            memberof = parts[1] || forcedMemberof;
        }
        if (parts[2]) {
            scopePunc = parts[2];
        }
    }
    else if (longname) {
        parts = longname.match(new RegExp(`^(:?(.+)([${sliceChars.join()}]))?(.+?)$`)) || [];
        name = parts.pop() || '';
        scopePunc = parts.pop() || '';
        memberof = parts.pop() || '';
    }

    // Like `@name foo.bar(2)`.
    if (/(.+)\(([^)]+)\)$/.test(name)) {
        name = RegExp.$1;
        variation = RegExp.$2;
    }

    // Restore quoted strings.
    i = tokens.length;
    while (i--) {
        longname = longname.replace(`@{${i}}@`, tokens[i]);
        memberof = memberof.replace(`@{${i}}@`, tokens[i]);
        scopePunc = scopePunc.replace(`@{${i}}@`, tokens[i]);
        name = name.replace(`@{${i}}@`, tokens[i]);
    }

    return {
        longname: longname,
        memberof: memberof,
        scope: scopePunc,
        name: name,
        variation: variation
    };
}

/**
 * Given a longname like `a.b#c(2)`, split it into the following parts:
 *
 * + `longname`
 * + `memberof`
 * + `scope`
 * + `name`
 * + `variation`
 *
 * @param {string} longname - The longname to divide into parts.
 * @param {string} forcedMemberof
 * @returns {object} Representing the properties of the given name.
 */
exports.toParts = (longname, forcedMemberof) => slice(
    longname, null, forcedMemberof
);

// TODO: docs
/**
 * @param {string} longname The full longname of the symbol.
 * @param {string} ns The namespace to be applied.
 * @returns {string} The longname with the namespace applied.
 */
exports.applyNamespace = (longname, ns) => {
    const nameParts = slice(longname);
    const name = nameParts.name;

    longname = nameParts.longname;

    if (!/^[a-zA-Z]+?:.+$/i.test(name)) {
        longname = longname.replace(new RegExp(`${escape(name)}$`), `${ns}:${name}`);
    }

    return longname;
};

/**
 * Check whether a parent longname is an ancestor of a child longname.
 *
 * @param {string} parent - The parent longname.
 * @param {string} child - The child longname.
 * @return {boolean} `true` if the parent is an ancestor of the child; otherwise, `false`.
 */
exports.hasAncestor = (parent, child) => {
    let hasAncestor = false;
    let memberof = child;

    if (!parent || !child) {
        return hasAncestor;
    }

    // Fast path for obvious non-ancestors.
    if (child.indexOf(parent) !== 0) {
        return hasAncestor;
    }

    do {
        memberof = slice(memberof).memberof;

        if (memberof === parent) {
            hasAncestor = true;
        }
    } while (!hasAncestor && memberof);

    return hasAncestor;
};

// TODO: docs
const fromParts = exports.fromParts = ({memberof, scope, name, variation}) => [
    (memberof || ''),
    (scope || ''),
    (name || ''),
    (variation ? `(${variation})` : '')
].join('');

// TODO: docs
exports.stripVariation = name => {
    const parts = slice(name);

    parts.variation = '';

    return fromParts(parts);
};

function splitLongname(longname, options) {
    const chunks = [];
    let currentNameInfo;
    const nameInfo = {};
    let previousName = longname;
    const splitters = SCOPE_PUNC.concat('/');

    options = _.defaults(options || {}, {
        includeVariation: true
    });

    do {
        if (!options.includeVariation) {
            previousName = exports.stripVariation(previousName);
        }
        currentNameInfo = nameInfo[previousName] = slice(previousName, splitters);
        previousName = currentNameInfo.memberof;
        chunks.push(currentNameInfo.scope + currentNameInfo.name);
    } while (previousName);

    return {
        chunks: chunks.reverse(),
        nameInfo: nameInfo
    };
}

/**
 * Convert an array of doclet longnames into a tree structure, optionally attaching doclets to the
 * tree.
 *
 * Each level of the tree is an object with the following properties:
 *
 * + `longname {string}`: The longname.
 * + `memberof {string?}`: The memberof.
 * + `scope {string?}`: The longname's scope, represented as a punctuation mark (for example, `#`
 * for instance and `.` for static).
 * + `name {string}`: The short name.
 * + `doclet {Object?}`: The doclet associated with the longname, or `null` if the doclet was not
 * provided.
 * + `children {Object?}`: The children of the current longname. Not present if there are no
 * children.
 *
 * For example, suppose you have the following array of doclet longnames:
 *
 * ```js
 * [
 *   "module:a",
 *   "module:a/b",
 *   "myNamespace",
 *   "myNamespace.Foo",
 *   "myNamespace.Foo#bar"
 * ]
 * ```
 *
 * This method converts these longnames to the following tree:
 *
 * ```js
 * {
 *   "module:a": {
 *     "longname": "module:a",
 *     "memberof": "",
 *     "scope": "",
 *     "name": "module:a",
 *     "doclet": null,
 *     "children": {
 *       "/b": {
 *         "longname": "module:a/b",
 *         "memberof": "module:a",
 *         "scope": "/",
 *         "name": "b",
 *         "doclet": null
 *       }
 *     }
 *   },
 *   "myNamespace": {
 *     "longname": "myNamespace",
 *     "memberof": "",
 *     "scope": "",
 *     "name": "myNamespace",
 *     "doclet": null,
 *     "children": {
 *       ".Foo": {
 *         "longname": "myNamespace.Foo",
 *         "memberof": "myNamespace",
 *         "scope": ".",
 *         "name": "Foo",
 *         "doclet": null,
 *         "children": {
 *           "#bar": {
 *             "longname": "myNamespace.Foo#bar",
 *             "memberof": "myNamespace.Foo",
 *             "scope": "#",
 *             "name": "bar",
 *             "doclet": null
 *           }
 *         }
 *       }
 *     }
 *   }
 * }
 * ```
 *
 * @param {Array<string>} longnames - The longnames to convert into a tree.
 * @param {Object<string, module:jsdoc/doclet.Doclet>} doclets - The doclets to attach to a tree.
 * Each property should be the longname of a doclet, and each value should be the doclet for that
 * longname.
 * @return {Object} A tree with information about each longname in the format shown above.
 */
exports.longnamesToTree = (longnames, doclets) => {
    const splitOptions = { includeVariation: false };
    const tree = {};

    longnames.forEach(longname => {
        let currentLongname = '';
        let currentParent = tree;
        let nameInfo;
        let processed;

        // Don't try to add empty longnames to the tree.
        if (!longname) {
            return;
        }

        processed = splitLongname(longname, splitOptions);
        nameInfo = processed.nameInfo;

        processed.chunks.forEach(chunk => {
            currentLongname += chunk;

            if (currentParent !== tree) {
                currentParent.children = currentParent.children || {};
                currentParent = currentParent.children;
            }

            if (!hasOwnProp.call(currentParent, chunk)) {
                currentParent[chunk] = nameInfo[currentLongname];
            }

            if (currentParent[chunk]) {
                currentParent[chunk].doclet = doclets ? doclets[currentLongname] : null;
                currentParent = currentParent[chunk];
            }
        });
    });

    return tree;
};

/**
 * Split a string that starts with a name and ends with a description into its parts. Allows the
 * default value (if present) to contain brackets. Returns `null` if the name contains mismatched
 * brackets.
 *
 * @param {string} nameDesc
 * @returns {?Object} Hash with "name" and "description" properties.
 */
function splitNameMatchingBrackets(nameDesc) {
    const buffer = [];
    let c;
    let stack = 0;
    let stringEnd = null;

    for (var i = 0; i < nameDesc.length; ++i) {
        c = nameDesc[i];
        buffer.push(c);

        if (stringEnd) {
            if (c === '\\' && i + 1 < nameDesc.length) {
                buffer.push(nameDesc[++i]);
            } else if (c === stringEnd) {
                stringEnd = null;
            }
        } else if (c === '"' || c === "'") {
            stringEnd = c;
        } else if (c === '[') {
            ++stack;
        } else if (c === ']') {
            if (--stack === 0) {
                break;
            }
        }
    }

    if (stack || stringEnd) {
        return null;
    }

    nameDesc.substr(i).match(REGEXP_DESCRIPTION);

    return {
        name: buffer.join(''),
        description: RegExp.$1
    };
}


/**
 * Split a string that starts with a name and ends with a description into separate parts.
 * @param {string} str - The string that contains the name and description.
 * @returns {object} An object with `name` and `description` properties.
 */
exports.splitNameAndDescription = str => {
    // Like: `name`, `[name]`, `name text`, `[name] text`, `name - text`, or `[name] - text`.
    // To ensure that we don't get confused by leading dashes in Markdown list items, the hyphen
    // must be on the same line as the name.

    // Optional values get special treatment,
    let result = null;

    if (str[0] === '[') {
        result = splitNameMatchingBrackets(str);
        if (result !== null) {
            return result;
        }
    }

    str.match(REGEXP_NAME_DESCRIPTION);

    return {
        name: RegExp.$1,
        description: RegExp.$2
    };
};