// Copyright (c) 2018, Compiler Explorer Authors
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//     * Redistributions of source code must retain the above copyright notice,
//       this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

import http from 'http';
import https from 'https';
import path from 'path';
import { promisify } from 'util';

import fs from 'fs-extra';
import _ from 'underscore';
import urljoin from 'url-join';

import { InstanceFetcher } from './aws';
import { logger } from './logger';

const sleep = promisify(setTimeout);

/***
 * Finds and initializes the compilers stored on the properties files
 */
export class CompilerFinder {
    /***
     * @param {CompileHandler} compileHandler
     * @param {CompilerProps} compilerProps
     * @param {propsFor} awsProps
     * @param {Object} args
     * @param {Object} optionsHandler
     */
    constructor(compileHandler, compilerProps, awsProps, args, optionsHandler) {
        this.compilerProps = compilerProps.get.bind(compilerProps);
        this.ceProps = compilerProps.ceProps;
        this.awsProps = awsProps;
        this.args = args;
        this.compileHandler = compileHandler;
        this.languages = compilerProps.languages;
        this.awsPoller = null;
        this.optionsHandler = optionsHandler;
    }

    awsInstances() {
        if (!this.awsPoller) this.awsPoller = new InstanceFetcher(this.awsProps);
        return this.awsPoller.getInstances();
    }

    async fetchRemote(host, port, uriBase, props, langId) {
        const requestLib = port === 443 ? https : http;
        const uriSchema = port === 443 ? 'https' : 'http';
        const uri = urljoin(`${uriSchema}://${host}:${port}`, uriBase);
        const apiPath = urljoin('/', uriBase || '', 'api/compilers', langId || '', '?fields=all');
        logger.info(`Fetching compilers from remote source ${uri}`);
        return this.retryPromise(
            () => {
                return new Promise((resolve, reject) => {
                    const request = requestLib.get({
                        hostname: host,
                        port: port,
                        path: apiPath,
                        headers: {
                            Accept: 'application/json',
                        },
                    }, res => {
                        let error;
                        const {statusCode, headers: {'content-type': contentType}} = res;

                        if (statusCode !== 200) {
                            error = new Error('Failed fetching remote compilers from ' +
                                `${uriSchema}://${host}:${port}${apiPath}\n` +
                                `Status Code: ${statusCode}`);
                        } else if (!/^application\/json/.test(contentType)) {
                            error = new Error('Invalid content-type.\n' +
                                `Expected application/json but received ${contentType}`);
                        }
                        if (error) {
                            logger.error(error.message);
                            // consume response data to free up memory
                            res.resume();
                            reject(error);
                            return;
                        }
                        let str = '';
                        res.on('data', chunk => {
                            str += chunk;
                        });
                        res.on('end', () => {
                            try {
                                const compilers = JSON.parse(str).map(compiler => {
                                    // Fix up old upstream implementations of Compiler Explorer
                                    // e.g. https://www.godbolt.ms
                                    // (see https://github.com/compiler-explorer/compiler-explorer/issues/1768)
                                    if (!compiler.alias) compiler.alias = [];
                                    if (typeof compiler.alias == 'string') compiler.alias = [compiler.alias];
                                    // End fixup
                                    compiler.exe = null;
                                    compiler.remote = {
                                        target: `${uriSchema}://${host}:${port}`,
                                        path: urljoin('/', uriBase, 'api/compiler', compiler.id, 'compile'),
                                    };
                                    return compiler;
                                });
                                resolve(compilers);
                            } catch (e) {
                                logger.error(`Error parsing response from ${uri} '${str}': ${e.message}`);
                                reject(e);
                            }
                        });
                    })
                        .on('error', reject)
                        .on('timeout', () => reject('timeout'));
                    request.setTimeout(this.awsProps('proxyTimeout', 1000));
                });
            },
            `${host}:${port}`,
            props('proxyRetries', 5),
            props('proxyRetryMs', 500),
        ).catch(() => {
            logger.warn(`Unable to contact ${host}:${port}; skipping`);
            return [];
        });
    }

    async fetchAws() {
        logger.info('Fetching instances from AWS');
        const instances = await this.awsInstances();
        return Promise.all(instances.map(instance => {
            logger.info('Checking instance ' + instance.InstanceId);
            const address = this.awsProps('externalTestMode', false) ? instance.PublicDnsName : instance.PrivateDnsName;
            return this.fetchRemote(address, this.args.port, '', this.awsProps, null);
        }));
    }

    async compilerConfigFor(langId, compilerName, parentProps) {
        const base = `compiler.${compilerName}.`;

        function props(propName, def) {
            const propsForCompiler = parentProps(langId, base + propName);
            if (propsForCompiler !== undefined) return propsForCompiler;
            return parentProps(langId, propName, def);
        }

        const ceToolsPath = props('ceToolsPath', './');

        const supportsBinary = !!props('supportsBinary', true);
        const interpreted = !!props('interpreted', false);
        const supportsExecute = (interpreted || supportsBinary) && !!props('supportsExecute', true);
        const executionWrapper = props('executionWrapper', '');
        const supportsLibraryCodeFilter = !!props('supportsLibraryCodeFilter', true);

        const group = props('group', '');

        const demanglerProp = props('demangler', '');
        const demangler = demanglerProp ? path.normalize(demanglerProp.replace('${ceToolsPath}', ceToolsPath)) : '';

        const isSemVer = props('isSemVer', false);
        const baseName = props('baseName', null);
        const semverVer = props('semver', '');

        const name = props('name', compilerName);

        const baseOptions = props('baseOptions', '');
        const options = props('options', '');
        const actualOptions = _.compact([baseOptions, options]).join(' ');

        const envVars = (() => {
            const envVarsString = props('envVars', '');
            if (envVarsString === '') {
                return [];
            }
            const arr = [];
            for (const el of envVarsString.split(':')) {
                const [env, setting] = el.split('=');
                arr.push([env, setting]);
            }
            return arr;
        })();
        const exe = props('exe', compilerName);
        const exePath = path.dirname(exe);
        const compilerInfo = {
            id: compilerName,
            exe: exe,
            name: isSemVer && baseName ? `${baseName} ${semverVer}` : name,
            alias: _.filter(props('alias', '').split(':'), (a) => a !== ''),
            options: actualOptions,
            versionFlag: props('versionFlag'),
            versionRe: props('versionRe'),
            explicitVersion: props('explicitVersion'),
            compilerType: props('compilerType', ''),
            demangler: demangler,
            demanglerType: props('demanglerType', ''),
            objdumper: props('objdumper', ''),
            objdumperType: props('objdumperType', ''),
            intelAsm: props('intelAsm', ''),
            instructionSet: props('instructionSet', ''),
            needsMulti: !!props('needsMulti', true),
            supportsDemangle: !!demangler,
            supportsBinary,
            interpreted,
            supportsExecute,
            executionWrapper,
            supportsLibraryCodeFilter: supportsLibraryCodeFilter,
            postProcess: props('postProcess', '').split('|'),
            lang: langId,
            group: group,
            groupName: props('groupName', ''),
            includeFlag: props('includeFlag', '-isystem'),
            includePath: props('includePath', ''),
            linkFlag: props('linkFlag', '-l'),
            rpathFlag: props('rpathFlag', '-Wl,-rpath,'),
            libpathFlag: props('libpathFlag', '-L'),
            libPath: props('libPath', ''),
            ldPath: props('ldPath', '')
                .split('|')
                .map(x => path.normalize(x.replace('${exePath}', exePath))),
            envVars: envVars,
            notification: props('notification', ''),
            isSemVer: isSemVer,
            semver: semverVer,
            libsArr: this.getSupportedLibrariesArr(props, langId),
            tools: _.omit(
                this.optionsHandler.get().tools[langId],
                tool => tool.isCompilerExcluded(compilerName, props)),
            unwiseOptions: props('unwiseOptions', '').split('|'),
            hidden: props('hidden', false),
            buildenvsetup: {
                id: props('buildenvsetup', ''),
                props: (name, def) => {
                    return props(`buildenvsetup.${name}`, def);
                },
            },
        };

        if (props('demanglerClassFile') !== undefined) {
            logger.error(`Error in compiler.${compilerName}: ` +
                'demanglerClassFile is no longer supported, please use demanglerType');
            return [];
        }

        if (process.platform === 'win32') {
            compilerInfo.libPath = compilerInfo.libPath.split(';').filter((p) => p !== '');
        } else {
            compilerInfo.libPath = compilerInfo.libPath.split(':').filter((p) => p !== '');
        }

        logger.debug('Found compiler', compilerInfo);
        return compilerInfo;
    }

    getSupportedLibrariesArr(props) {
        return _.filter(props('supportsLibraries', '').split(':'), (a) => a !== '');
    }

    async recurseGetCompilers(langId, compilerName, parentProps) {
        // Don't treat @ in paths as remote addresses if requested
        if (this.args.fetchCompilersFromRemote && compilerName.includes('@')) {
            const bits = compilerName.split('@');
            const host = bits[0];
            const pathParts = bits[1].split('/');
            const port = parseInt(pathParts.shift());
            const path = pathParts.join('/');
            return this.fetchRemote(host, port, path, this.ceProps, langId);
        }
        if (compilerName.indexOf('&') === 0) {
            const groupName = compilerName.substr(1);

            const props = (langId, name, def) => {
                if (name === 'group') {
                    return groupName;
                }
                return this.compilerProps(langId, `group.${groupName}.${name}`, parentProps(langId, name, def));
            };
            const exes = _.compact(this.compilerProps(langId, `group.${groupName}.compilers`, '').split(':'));
            logger.debug(`Processing compilers from group ${groupName}`);
            return Promise.all(exes.map(compiler => this.recurseGetCompilers(langId, compiler, props)));
        }
        if (compilerName === 'AWS') return this.fetchAws();
        return this.compilerConfigFor(langId, compilerName, parentProps);
    }

    async getCompilers() {
        const compilers = [];
        _.each(this.getExes(), (exs, langId) => {
            _.each(exs, exe => compilers.push(this.recurseGetCompilers(langId, exe, this.compilerProps)));
        });
        return Promise.all(compilers);
    }

    ensureDistinct(compilers) {
        const ids = {};
        let foundClash = false;
        _.each(compilers, compiler => {
            if (!ids[compiler.id]) ids[compiler.id] = [];
            ids[compiler.id].push(compiler);
        });
        _.each(ids, (list, id) => {
            if (list.length !== 1) {
                foundClash = true;
                logger.error(`Compiler ID clash for '${id}' - used by ${
                    _.map(list, o => `lang:${o.lang} name:${o.name}`).join(', ')}`);
            }
        });
        return {compilers, foundClash};
    }

    async retryPromise(promiseFunc, name, maxFails, retryMs) {
        for (let fails = 0; fails < maxFails; ++fails) {
            try {
                return await promiseFunc();
            } catch (e) {
                if (fails < (maxFails - 1)) {
                    logger.warn(`Failed ${name} : ${e}, retrying`);
                    await sleep(retryMs);
                } else {
                    logger.error(`Too many retries for ${name} : ${e}`);
                    throw e;
                }
            }
        }
    }

    getExes() {
        const langToCompilers = this.compilerProps(this.languages, 'compilers', '', exs => _.compact(exs.split(':')));
        this.addNdkExes(langToCompilers);
        logger.info('Exes found:', langToCompilers);
        return langToCompilers;
    }

    addNdkExes(langToCompilers) {
        const ndkPaths = this.compilerProps(this.languages, 'androidNdk');
        _.each(ndkPaths, (ndkPath, langId) => {
            if (ndkPath) {
                const toolchains = fs.readdirSync(`${ndkPath}/toolchains`);
                for (const [version, index] of toolchains) {
                    const path = `${ndkPath}/toolchains/${version}/prebuilt/linux-x86_64/bin/`;
                    if (fs.existsSync(path)) {
                        const cc = fs.readdirSync(path).find(filename => filename.includes('g++'));
                        toolchains[index] = path + cc;
                    } else {
                        toolchains[index] = null;
                    }
                }
                langToCompilers[langId].push(toolchains.filter(x => x !== null));
            }
        });
    }

    async find() {
        const compilerList = await this.getCompilers();
        const compilers = await this.compileHandler.setCompilers(
            compilerList.flat(Infinity), this.optionsHandler.get());
        const result = this.ensureDistinct(_.compact(compilers));
        return {foundClash: result.foundClash, compilers: _.sortBy(result.compilers, 'name')};
    }

    async loadPrediscovered(compilers) {
        for (const compiler of compilers) {
            const langId = compiler.lang;

            if (compiler.buildenvsetup) {
                compiler.buildenvsetup.props = (propName, def) => {
                    return this.compilerProps(langId, 'buildenvsetup.' + propName, def);
                };
            }

            const fullOptions = this.optionsHandler.get();

            compiler.tools = _.omit(
                fullOptions.tools[langId],
                tool => tool.isCompilerExcluded(compiler.id, (propName, def) => {
                    let val = this.compilerProps(langId, `compiler.${compiler.id}.${propName}`);
                    if (!val) {
                        if (compiler.group) {
                            val = this.compilerProps(langId, `group.${compiler.group}.${propName}`);
                            if (!val) return def;
                        }
                    }
                    return val;
                }));
        }
        return this.compileHandler.setCompilers(compilers, this.optionsHandler.get());
    }
}