'use strict';

const http = require('node:http');

const host = '127.0.0.1';
const port = 3000;
const teacherPath = '/do/api/call/lxyxt_jzgjbxx';
const unitPath = '/do/api/call/lxyxt_dwxx';
const defaultPageSize = 20;
const pad = (number, length) => String(number).padStart(length, '0');

const colleges = ['文学院', '数学学院', '计算机学院', '外国语学院', '教育学院'].map((name, index) => ({
    DWDM: 'MOCK-U' + pad(index + 1, 2),
    DWMC: '模拟' + name,
    DWJC: name,
    DWCC: 1,
    LSDWDM: '0',
    DWLBDM: '01'
}));

const departments = colleges.map((college, index) => ({
    DWDM: 'MOCK-U' + pad(index + 6, 2),
    DWMC: college.DWMC + '教学系',
    DWJC: college.DWJC + '教学系',
    DWCC: 2,
    LSDWDM: college.DWDM,
    DWLBDM: '01'
}));

const units = [...colleges, ...departments];
const teachers = Array.from({ length: 100 }, (_, index) => {
    const sequence = pad(index + 1, 3);
    const unit = units[index % units.length];
    const doctorate = index % 3 === 0;
    return {
        ZGH: 'MOCK-T' + sequence,
        XM: '模拟教师' + sequence,
        XBMC: Math.floor(index / units.length) % 2 === 0 ? '女' : '男',
        CSRQ: (1975 + index % 23) + '-' + pad(index % 12 + 1, 2) + '-' + pad(index % 28 + 1, 2),
        LXRQ: (2010 + index % 15) + '-' + pad(index % 12 + 1, 2) + '-01',
        DQZTMC: '在岗',
        YRFSDM: '教职工',
        SZDWDM: unit.DWDM,
        SZDW: unit.DWMC,
        MZDM: '01',
        ZGXLMC: doctorate ? '博士研究生' : '硕士研究生',
        ZGXWMC: doctorate ? '博士' : '硕士',
        ZYJSGWLBDMMC: '专业技术岗',
        ZYJSZWDMMC: ['讲师', '副教授', '教授'][index % 3],
        SFSJT: false
    };
});

function sendJson(response, status, body) {
    response.writeHead(status, { 'Content-Type': 'application/json; charset=utf-8' });
    response.end(JSON.stringify(body));
}

function positiveInteger(value) {
    const number = Number(value);
    return (typeof value === 'number' || typeof value === 'string') && Number.isSafeInteger(number) && number > 0;
}

async function handleRequest(request, response) {
    const path = request.url.split('?')[0];
    if (path !== teacherPath && path !== unitPath) {
        sendJson(response, 404, { returnStatus: 0, errorMsg: '接口不存在' });
        return;
    }
    if (request.method !== 'POST') {
        response.setHeader('Allow', 'POST');
        sendJson(response, 405, { returnStatus: 0, errorMsg: '请使用 POST' });
        return;
    }

    let params;
    try {
        let body = '';
        request.setEncoding('utf8');
        for await (const chunk of request) {
            body += chunk;
        }
        params = body.trim() ? JSON.parse(body) : {};
        if (!params || typeof params !== 'object' || Array.isArray(params)) {
            throw new TypeError('请求体必须是 JSON 对象');
        }
    } catch {
        sendJson(response, 400, { returnStatus: 0, errorMsg: '请求体必须是 JSON 对象' });
        return;
    }

    const pageNum = params.pageNum ?? 1;
    const pageSize = params.pageSize ?? defaultPageSize;
    if (!positiveInteger(pageNum) || !positiveInteger(pageSize)) {
        sendJson(response, 400, { returnStatus: 0, errorMsg: 'pageNum 和 pageSize 必须是正整数' });
        return;
    }

    const jobNumber = String(params.zgh ?? '').trim();
    const records = path === unitPath ? units
        : jobNumber ? teachers.filter(teacher => teacher.ZGH === jobNumber) : teachers;
    const start = (Number(pageNum) - 1) * Number(pageSize);
    sendJson(response, 200, {
        returnStatus: 1,
        pageInfo: {
            pageNum: Number(pageNum),
            pageSize: Number(pageSize),
            pages: Math.ceil(records.length / Number(pageSize)),
            total: records.length
        },
        dataSet: records.slice(start, start + Number(pageSize))
    });
}

if (require.main === module) {
    http.createServer(handleRequest).listen(port, host, () => {
        console.log('模拟数据接口 http://' + host + ':' + port);
    });
}

module.exports = { handleRequest };