/*
*******************************************************************************
* Copyright (c) 2021 by M5Stack
*                  Equipped with M5Core2 sample source code
*                          配套  M5Core2 示例源代码
* Visit for more information: https://docs.m5stack.com/en/core/core2
* 获取更多资料请访问: https://docs.m5stack.com/zh_CN/core/core2
*
* Describe: WiFi connect.  wifi连接
* Date: 2021/7/27
*******************************************************************************
*/
#include <M5Core2.h>
#include <WiFi.h>
#include <ESPmDNS.h>
#include <WiFiClient.h>
#include "WebServer.h"
#include <Preferences.h>

boolean restoreConfig();
boolean checkConnection();
void startWebServer();
void setupMode();
String makePage(String title, String contents);
String urlDecode(String input);

const IPAddress apIP(
    192, 168, 4, 1);  // Define the address of the wireless AP. 定义无线AP的地址
const char* apSSID = "M5STACK_SETUP";  // Define the name of the created
                                       // hotspot.  定义创建热点的名称
boolean settingMode;
String ssidList;
String wifi_ssid;  // Store the name of the wireless network. 存储无线网络的名称
String wifi_password;  // Store the password of the wireless network.
                       // 存储无线网络的密码

// DNSServer dnsServer;.  webServer的类
WebServer webServer(80);

// wifi config store.  wifi配置存储的类
Preferences preferences;

void setup() {
    M5.begin();  // Init M5Core2.  初始化M5Core2
    M5.Lcd.setTextColor(
        YELLOW);  // Set the font color to yellow.  设置字体颜色为黄色
    preferences.begin("wifi-config");
    delay(10);
    if (restoreConfig()) {  // Check if wifi configuration information has been
                            // stored.  检测是否已存储wifi配置信息
        if (checkConnection()) {  // Check wifi connection.  检测wifi连接情况
            settingMode = false;  // Turn off setting mode.  关闭设置模式
            startWebServer();  // Turn on network service.  开启网络服务
            return;            // Exit setup().  退出setup()
        }
    }
    settingMode =
        true;  // If there is no stored wifi configuration information, turn on
               // the setting mode.  若没有已存储的wifi配置信息,则开启设置模式
    setupMode();
}

void loop() {
    if (settingMode) {
    }
    webServer
        .handleClient();  // Check that there is no facility to send requests to
                          // the M5StickC Web server over the network.
                          // 检查有没有设备通过网络向M5Core2网络服务器发送请求
}

boolean
restoreConfig() { /* Check whether there is wifi configuration information
                     storage, if there is 1 return, if no return 0.
                          检测是否有wifi配置信息存储,若有返回1,无返回0 */
    wifi_ssid     = preferences.getString("WIFI_SSID");
    wifi_password = preferences.getString("WIFI_PASSWD");
    M5.Lcd.printf(
        "WIFI-SSID: %s\n",
        wifi_ssid);  // Screen print format string.  屏幕打印格式化字符串
    M5.Lcd.printf("WIFI-PASSWD: %s\n", wifi_password);
    WiFi.begin(wifi_ssid.c_str(), wifi_password.c_str());

    if (wifi_ssid.length() > 0) {
        return true;
    } else {
        return false;
    }
}

boolean checkConnection() {  // Check wifi connection.  检测wifi连接情况
    int count = 0;           // count.  计数
    M5.Lcd.print("Waiting for Wi-Fi connection");
    while (
        count <
        30) { /* If you fail to connect to wifi within 30*350ms
                 (10.5s), return false; otherwise return true.
                            若在30*500ms(15s)内未能连上wifi,返回false;否则返回true
               */
        if (WiFi.status() == WL_CONNECTED) {
            M5.Lcd.printf("\nConnected!\n");
            return (true);
        }
        delay(350);
        M5.Lcd.print(".");
        count++;
    }
    M5.Lcd.println("Timed out.");
    return false;
}

void startWebServer() {  // Open the web service.  打开Web服务
    if (settingMode) {  // If the setting mode is on.  如果设置模式处于开启状态
        M5.Lcd.print("Starting Web Server at: ");
        M5.Lcd.print(
            WiFi.softAPIP());  // Output AP address (you can change the address
                               // you want through apIP at the beginning).
                               // 输出AP地址(可通过开头的apIP更改自己想要的地址)
        webServer.on(
            "/settings", []() {  // AP web interface settings.  AP网页界面设置
                String s =
                    "<h1>Wi-Fi Settings</h1><p>Please enter your password by "
                    "selecting the SSID.</p>";
                s += "<form method=\"get\" action=\"setap\"><label>SSID: "
                     "</label><select name=\"ssid\">";
                s += ssidList;
                s += "</select><br>Password: <input name=\"pass\" length=64 "
                     "type=\"password\"><input type=\"submit\"></form>";
                webServer.send(200, "text/html", makePage("Wi-Fi Settings", s));
            });
        webServer.on("/setap", []() {
            String ssid = urlDecode(webServer.arg("ssid"));
            M5.Lcd.printf("SSID: %s\n", ssid);
            String pass = urlDecode(webServer.arg("pass"));
            M5.Lcd.printf("Password: %s\n\nWriting SSID to EEPROM...\n", pass);

            // Store wifi config.  存储wifi配置信息
            M5.Lcd.println("Writing Password to nvr...");
            preferences.putString("WIFI_SSID", ssid);
            preferences.putString("WIFI_PASSWD", pass);

            M5.Lcd.println("Write nvr done!");
            String s =
                "<h1>Setup complete.</h1><p>device will be connected to \"";
            s += ssid;
            s += "\" after the restart.";
            webServer.send(200, "text/html", makePage("Wi-Fi Settings", s));
            delay(2000);
            ESP.restart();  // Restart MPU.  重启MPU
        });
        webServer.onNotFound([]() {
            String s =
                "<h1>AP mode</h1><p><a href=\"/settings\">Wi-Fi "
                "Settings</a></p>";
            webServer.send(200, "text/html", makePage("AP mode", s));
        });
    } else {  // If the setting mode is off.  如果设置模式处于关闭状态
        M5.Lcd.print("Starting Web Server at ");
        M5.Lcd.println(WiFi.localIP());
        webServer.on("/", []() {  // AP web interface settings.  AP网页界面设置
            String s =
                "<h1>STA mode</h1><p><a href=\"/reset\">Reset Wi-Fi "
                "Settings</a></p>";
            webServer.send(200, "text/html", makePage("STA mode", s));
        });
        webServer.on("/reset", []() {
            // reset the wifi config
            preferences.remove("WIFI_SSID");
            preferences.remove("WIFI_PASSWD");
            String s =
                "<h1>Wi-Fi settings was reset.</h1><p>Please reset device.</p>";
            webServer.send(200, "text/html",
                           makePage("Reset Wi-Fi Settings", s));
            delay(2000);
            ESP.restart();
        });
    }
    webServer.begin();  // Start web service.  开启web服务
}

void setupMode() {
    WiFi.mode(WIFI_MODE_STA);  // Set Wi-Fi mode to WIFI_MODE_STA.
                               // 设置Wi-Fi模式为WIFI_MODE_STA
    WiFi.disconnect();         // Disconnect wifi connection.  断开wifi连接
    delay(100);
    int n = WiFi.scanNetworks();  // Store the number of wifi scanned into n.
                                  // 将扫描到的wifi个数存储到n中
    delay(100);
    M5.Lcd.println("");
    for (int i = 0; i < n; ++i) {  // Save each wifi name scanned to ssidList.
                                   // 将扫描到的每个wifi名称保存到ssidList中
        ssidList += "<option value=\"";
        ssidList += WiFi.SSID(i);
        ssidList += "\">";
        ssidList += WiFi.SSID(i);
        ssidList += "</option>";
    }
    delay(100);
    WiFi.softAPConfig(apIP, apIP, IPAddress(255, 255, 255, 0));
    WiFi.softAP(apSSID);  // Turn on Ap mode.  开启Ap模式
    WiFi.mode(WIFI_MODE_AP);  // Set WiFi to soft-AP mode. 设置WiFi为soft-AP模式
    startWebServer();         // Open the web service.  打开Web服务
    M5.Lcd.printf("\nStarting Access Point at \"%s\"\n\n", apSSID);
}

String makePage(String title, String contents) {
    String s = "<!DOCTYPE html><html><head>";
    s += "<meta name=\"viewport\" "
         "content=\"width=device-width,user-scalable=0\">";
    s += "<title>";
    s += title;
    s += "</title></head><body>";
    s += contents;
    s += "</body></html>";
    return s;
}

String urlDecode(String input) {
    String s = input;
    s.replace("%20", " ");
    s.replace("+", " ");
    s.replace("%21", "!");
    s.replace("%22", "\"");
    s.replace("%23", "#");
    s.replace("%24", "$");
    s.replace("%25", "%");
    s.replace("%26", "&");
    s.replace("%27", "\'");
    s.replace("%28", "(");
    s.replace("%29", ")");
    s.replace("%30", "*");
    s.replace("%31", "+");
    s.replace("%2C", ",");
    s.replace("%2E", ".");
    s.replace("%2F", "/");
    s.replace("%2C", ",");
    s.replace("%3A", ":");
    s.replace("%3A", ";");
    s.replace("%3C", "<");
    s.replace("%3D", "=");
    s.replace("%3E", ">");
    s.replace("%3F", "?");
    s.replace("%40", "@");
    s.replace("%5B", "[");
    s.replace("%5C", "\\");
    s.replace("%5D", "]");
    s.replace("%5E", "^");
    s.replace("%5F", "-");
    s.replace("%60", "`");
    return s;
}