import fs from 'fs-extra';
import path from 'path';
import yaml from 'js-yaml';
import { sum } from 'lodash';
import readYamlCases, { convertIniConfig } from '@hydrooj/utils/lib/cases';
import { changeErrorType } from '@hydrooj/utils/lib/utils';
import { FormatError, SystemError } from './error';
import { parseTimeMS, parseMemoryMB, ensureFile } from './utils';
import { getConfig } from './config';

interface Re0 {
    reg: RegExp,
    output: (a: RegExpExecArray) => string,
    id: (a: RegExpExecArray) => number,
}

interface Re1 extends Re0 {
    subtask: (a: RegExpExecArray) => number,
}

const RE0: Re0[] = [
    {
        reg: /^([a-z+_\-A-Z]*)([0-9]+).in$/,
        output: (a) => `${a[1] + a[2]}.out`,
        id: (a) => parseInt(a[2], 10),
    },
    {
        reg: /^([a-z+_\-A-Z]*)([0-9]+).in$/,
        output: (a) => `${a[1] + a[2]}.ans`,
        id: (a) => parseInt(a[2], 10),
    },
    {
        reg: /^([a-z+_\-A-Z0-9]*)\.in([0-9]+)$/,
        output: (a) => `${a[1]}.ou${a[2]}`,
        id: (a) => parseInt(a[2], 10),
    },
    {
        reg: /^(input)([0-9]+).txt$/,
        output: (a) => `output${a[2]}.txt`,
        id: (a) => parseInt(a[2], 10),
    },
    {
        reg: /^input\/([a-z+_\-A-Z]*)([0-9]+).in$/,
        output: (a) => `output/${a[1] + a[2]}.out`,
        id: (a) => parseInt(a[2], 10),
    },
    {
        reg: /^input\/([a-z+_\-A-Z]*)([0-9]+).in$/,
        output: (a) => `output/${a[1] + a[2]}.ans`,
        id: (a) => parseInt(a[2], 10),
    },
    {
        reg: /^input\/([a-z+_\-A-Z0-9]*)\.in([0-9]+)$/,
        output: (a) => `output/${a[1]}.ou${a[2]}`,
        id: (a) => parseInt(a[2], 10),
    },
    {
        reg: /^input\/(input)([0-9]+).txt$/,
        output: (a) => `output/output${a[2]}.txt`,
        id: (a) => parseInt(a[2], 10),
    },
];
const RE1: Re1[] = [
    {
        reg: /^([a-z+_\-A-Z]*)([0-9]+)-([0-9]+).in$/,
        output: (a) => `${a[1] + a[2]}-${a[3]}.out`,
        subtask: (a) => parseInt(a[2], 10),
        id: (a) => parseInt(a[3], 10),
    },
];

async function read0(folder: string, files: string[], checkFile, cfg) {
    const cases = [];
    for (const file of files) {
        for (const REG of RE0) {
            if (REG.reg.test(file)) {
                const data = REG.reg.exec(file);
                const c = { input: file, output: REG.output(data), id: REG.id(data) };
                if (fs.existsSync(path.resolve(folder, c.output))) {
                    cases.push(c);
                    break;
                }
            }
        }
    }
    cases.sort((a, b) => (a.id - b.id));
    const extra = cases.length - (100 % cases.length);
    const config = {
        count: 0,
        subtasks: [{
            time: parseTimeMS(cfg.time || '1s'),
            memory: parseMemoryMB(cfg.memory || '256m'),
            type: 'sum',
            cases: [],
            score: Math.floor(100 / cases.length),
        }],
    };
    for (let i = 0; i < extra; i++) {
        config.count++;
        config.subtasks[0].cases.push({
            id: config.count,
            input: checkFile(cases[i].input),
            output: checkFile(cases[i].output),
        });
    }
    if (extra < cases.length) {
        config.subtasks.push({
            time: parseTimeMS(cfg.time || '1s'),
            memory: parseMemoryMB(cfg.memory || '256m'),
            type: 'sum',
            cases: [],
            score: Math.floor(100 / cases.length) + 1,
        });
        for (let i = extra; i < cases.length; i++) {
            config.count++;
            config.subtasks[1].cases.push({
                id: config.count,
                input: checkFile(cases[i].input),
                output: checkFile(cases[i].output),
            });
        }
    }
    return config;
}

async function read1(folder: string, files: string[], checkFile, cfg) {
    const subtask = {};
    const subtasks = [];
    for (const file of files) {
        for (const REG of RE1) {
            if (REG.reg.test(file)) {
                const data = REG.reg.exec(file);
                const c = { input: file, output: REG.output(data), id: REG.id(data) };
                if (fs.existsSync(path.resolve(folder, c.output))) {
                    if (!subtask[REG.subtask(data)]) {
                        subtask[REG.subtask(data)] = [{
                            time: parseTimeMS(cfg.time || '1s'),
                            memory: parseMemoryMB(cfg.memory || '256m'),
                            type: 'min',
                            cases: [c],
                        }];
                    } else subtask[REG.subtask(data)].cases.push(c);
                    break;
                }
            }
        }
    }
    for (const i in subtask) {
        subtask[i].cases.sort((a, b) => (a.id - b.id));
        subtasks.push(subtask[i]);
    }
    const base = Math.floor(100 / subtasks.length);
    const extra = subtasks.length - (100 % subtasks.length);
    const config = { count: 0, subtasks };
    const keys = Object.keys(subtask);
    for (let i = 0; i < keys.length; i++) {
        if (extra < i) subtask[keys[i]].score = base;
        else subtask[keys[i]].score = base + 1;
        for (const j of subtask[keys[i]].cases) {
            config.count++;
            j.input = checkFile(j.input);
            j.output = checkFile(j.output);
            j.id = config.count;
        }
    }
    return config;
}

async function readAutoCases(folder, { next }, cfg) {
    const config = {
        checker_type: 'default',
        count: 0,
        subtasks: [],
        judge_extra_files: [],
        user_extra_files: [],
    };
    const checkFile = ensureFile(folder);
    try {
        const files = await fs.readdir(folder);
        if (await fs.pathExists(path.resolve(folder, 'input'))) {
            const inputs = await fs.readdir(path.resolve(folder, 'input'));
            files.push(...inputs.map((i) => `input/${i}`));
        }
        if (await fs.pathExists(path.resolve(folder, 'output'))) {
            const outputs = await fs.readdir(path.resolve(folder, 'output'));
            files.push(...outputs.map((i) => `output/${i}`));
        }
        let result = await read0(folder, files, checkFile, cfg);
        if (!result.count) result = await read1(folder, files, checkFile, cfg);
        Object.assign(config, result);
        next({ message: { message: 'Found {0} testcases.', params: [config.count] } });
    } catch (e) {
        throw new SystemError('Cannot parse testdata.', [e]);
    }
    return config;
}

function isValidConfig(config) {
    if (config.count > (getConfig('testcases_max') || 100)) {
        throw new FormatError('Too many testcases. Cancelled.');
    }
    const total_time = sum(config.subtasks.map((subtask) => subtask.time * subtask.cases.length));
    if (total_time > (getConfig('total_time_limit') || 60) * 1000) {
        throw new FormatError('Total time limit longer than {0}s. Cancelled.', [+getConfig('total_time_limit') || 60]);
    }
}

export default async function readCases(folder: string, cfg: Record<string, any> = {}, args) {
    const iniConfig = path.resolve(folder, 'config.ini');
    const yamlConfig = path.resolve(folder, 'config.yaml');
    const ymlConfig = path.resolve(folder, 'config.yml');
    let config;
    if (fs.existsSync(yamlConfig)) {
        config = { ...yaml.load(fs.readFileSync(yamlConfig).toString()) as object, ...cfg };
    } else if (fs.existsSync(ymlConfig)) {
        config = { ...yaml.load(fs.readFileSync(ymlConfig).toString()) as object, ...cfg };
    } else if (fs.existsSync(iniConfig)) {
        try {
            config = { ...convertIniConfig(fs.readFileSync(iniConfig).toString()), ...cfg };
        } catch (e) {
            throw changeErrorType(e, FormatError);
        }
    } else config = cfg;
    let result;
    try {
        result = await readYamlCases(config, ensureFile(folder));
    } catch (e) {
        throw changeErrorType(e, FormatError);
    }
    if (!(result.outputs || result.subtasks.length)) {
        const c = await readAutoCases(folder, args, cfg);
        config.subtasks = c.subtasks;
        config.count = c.count;
    }
    isValidConfig(result);
    return result;
}