/*
 Copyright 2012-2015, Yahoo Inc.
 Copyrights licensed under the New BSD License. See the accompanying LICENSE file for terms.
 */
const { transformSync } = require('@babel/core');
const { defaults } = require('@istanbuljs/schema');
const programVisitor = require('./visitor');
const readInitialCoverage = require('./read-coverage');

/**
 * Instrumenter is the public API for the instrument library.
 * It is typically used for ES5 code. For ES6 code that you
 * are already running under `babel` use the coverage plugin
 * instead.
 * @param {Object} opts optional.
 * @param {string} [opts.coverageVariable=__coverage__] name of global coverage variable.
 * @param {boolean} [opts.reportLogic=false] report boolean value of logical expressions.
 * @param {boolean} [opts.preserveComments=false] preserve comments in output.
 * @param {boolean} [opts.compact=true] generate compact code.
 * @param {boolean} [opts.esModules=false] set to true to instrument ES6 modules.
 * @param {boolean} [opts.autoWrap=false] set to true to allow `return` statements outside of functions.
 * @param {boolean} [opts.produceSourceMap=false] set to true to produce a source map for the instrumented code.
 * @param {Array} [opts.ignoreClassMethods=[]] set to array of class method names to ignore for coverage.
 * @param {Function} [opts.sourceMapUrlCallback=null] a callback function that is called when a source map URL
 *     is found in the original code. This function is called with the source file name and the source map URL.
 * @param {boolean} [opts.debug=false] - turn debugging on.
 * @param {array} [opts.parserPlugins] - set babel parser plugins, see @istanbuljs/schema for defaults.
 * @param {string} [opts.coverageGlobalScope=this] the global coverage variable scope.
 * @param {boolean} [opts.coverageGlobalScopeFunc=true] use an evaluated function to find coverageGlobalScope.
 * @param {Object} [opts.generatorOpts] - set babel generator options
 */
class Instrumenter {
    constructor(opts = {}) {
        this.opts = {
            ...defaults.instrumenter,
            ...opts
        };
        this.fileCoverage = null;
        this.sourceMap = null;
    }
    /**
     * instrument the supplied code and track coverage against the supplied
     * filename. It throws if invalid code is passed to it. ES5 and ES6 syntax
     * is supported. To instrument ES6 modules, make sure that you set the
     * `esModules` property to `true` when creating the instrumenter.
     *
     * @param {string} code - the code to instrument
     * @param {string} filename - the filename against which to track coverage.
     * @param {object} [inputSourceMap] - the source map that maps the not instrumented code back to it's original form.
     * Is assigned to the coverage object and therefore, is available in the json output and can be used to remap the
     * coverage to the untranspiled source.
     * @returns {string} the instrumented code.
     */
    instrumentSync(code, filename, inputSourceMap) {
        if (typeof code !== 'string') {
            throw new Error('Code must be a string');
        }
        filename = filename || String(new Date().getTime()) + '.js';
        const { opts } = this;
        let output = {};
        const babelOpts = {
            configFile: false,
            babelrc: false,
            ast: true,
            filename: filename || String(new Date().getTime()) + '.js',
            inputSourceMap,
            sourceMaps: opts.produceSourceMap,
            compact: opts.compact,
            comments: opts.preserveComments,
            parserOpts: {
                allowReturnOutsideFunction: opts.autoWrap,
                sourceType: opts.esModules ? 'module' : 'script',
                plugins: opts.parserPlugins
            },
            generatorOpts: opts.generatorOpts,
            plugins: [
                [
                    ({ types }) => {
                        const ee = programVisitor(types, filename, {
                            coverageVariable: opts.coverageVariable,
                            reportLogic: opts.reportLogic,
                            coverageGlobalScope: opts.coverageGlobalScope,
                            coverageGlobalScopeFunc:
                                opts.coverageGlobalScopeFunc,
                            ignoreClassMethods: opts.ignoreClassMethods,
                            inputSourceMap
                        });

                        return {
                            visitor: {
                                Program: {
                                    enter: ee.enter,
                                    exit(path) {
                                        output = ee.exit(path);
                                    }
                                }
                            }
                        };
                    }
                ]
            ]
        };

        const codeMap = transformSync(code, babelOpts);

        if (!output || !output.fileCoverage) {
            const initialCoverage =
                readInitialCoverage(codeMap.ast) ||
                /* istanbul ignore next: paranoid check */ {};
            this.fileCoverage = initialCoverage.coverageData;
            this.sourceMap = inputSourceMap;
            return code;
        }

        this.fileCoverage = output.fileCoverage;
        this.sourceMap = codeMap.map;
        const cb = this.opts.sourceMapUrlCallback;
        if (cb && output.sourceMappingURL) {
            cb(filename, output.sourceMappingURL);
        }

        return codeMap.code;
    }
    /**
     * callback-style instrument method that calls back with an error
     * as opposed to throwing one. Note that in the current implementation,
     * the callback will be called in the same process tick and is not asynchronous.
     *
     * @param {string} code - the code to instrument
     * @param {string} filename - the filename against which to track coverage.
     * @param {Function} callback - the callback
     * @param {Object} inputSourceMap - the source map that maps the not instrumented code back to it's original form.
     * Is assigned to the coverage object and therefore, is available in the json output and can be used to remap the
     * coverage to the untranspiled source.
     */
    instrument(code, filename, callback, inputSourceMap) {
        if (!callback && typeof filename === 'function') {
            callback = filename;
            filename = null;
        }
        try {
            const out = this.instrumentSync(code, filename, inputSourceMap);
            callback(null, out);
        } catch (ex) {
            callback(ex);
        }
    }
    /**
     * returns the file coverage object for the last file instrumented.
     * @returns {Object} the file coverage object.
     */
    lastFileCoverage() {
        return this.fileCoverage;
    }
    /**
     * returns the source map produced for the last file instrumented.
     * @returns {null|Object} the source map object.
     */
    lastSourceMap() {
        return this.sourceMap;
    }
}

module.exports = Instrumenter;
