Smart Water-Saving Faucet

#include <Arduino.h>
#include <WiFi.h>
#include <WebServer.h>
#include <HTTPClient.h>
#include <WiFiClientSecure.h>
#include <Preferences.h>
#include <LittleFS.h>
#include <time.h>
// Configure these before deployment. Leave endpoint empty for local-only use.
const char *SSID="", *PASS="", *ENDPOINT="", *TOKEN="", *ROOT_CA="";
const char *TZ_RULE="UTC0"; // Set household timezone including daylight-saving rules.
WebServer web(80); Preferences prefs;
volatile uint32_t pulses=0, edgeUs=0;
portMUX_TYPE mux=portMUX_INITIALIZER_UNLOCKED;
void IRAM_ATTR pulse(){uint32_t now=micros(); if(now-edgeUs<1000)return; edgeUs=now; portENTER_CRITICAL_ISR(&mux); pulses++; portEXIT_CRITICAL_ISR(&mux);}
float ppl=450, liters=0, seconds=0, baseL=0, baseS=0, todayL=0;
uint32_t samples=0, lastTick=0, lastFlow=0, startMs=0, closeMs=0, seq=0;
int bursts=0, rewards=0, streak=0, dayKey=0, todayUses=0;
bool active=false, flowing=false, closed=false, bypass=false, invalid=false, fsOK=false;
time_t startTime=0; String apPass, userId; float history[7]={};
String day(){time_t t=time(nullptr); if(t<1700000000)return "unsynced"; tm z; localtime_r(&t,&z); char b[16]; strftime(b,sizeof(b),"%Y-%m-%d",&z); return b;}
void valve(bool close){closed=close; digitalWrite(26,LOW);digitalWrite(25,close?HIGH:LOW);if(close)closeMs=millis();}
void saveDay(){prefs.putInt("uses",todayUses);prefs.putFloat("today",todayL);prefs.putInt("rewards",rewards);prefs.putInt("streak",streak);prefs.putInt("day",dayKey);prefs.putBytes("history",history,sizeof(history));}
void calendar(){time_t t=time(nullptr);if(t<1700000000)return;tm z;localtime_r(&t,&z);int key=(z.tm_year+1900)*1000+z.tm_yday;
if(dayKey && key!=dayKey){bool consecutive=(key==dayKey+1)||(z.tm_yday==0 && dayKey%1000>=364 && key/1000==dayKey/1000+1);streak=(consecutive && todayL>0 && samples>=30 && todayUses>0 && todayL/todayUses<=baseL)?streak+1:0;for(int i=6;i>0;i--)history[i]=history[i-1];history[0]=todayL;todayL=0;todayUses=0;rewards=0;}if(key!=dayKey){dayKey=key;saveDay();}}
void record(){
 bool credible=!invalid && liters>=0.05 && seconds>=1;
 bool learned=samples>=30; bool efficient=credible&&learned&&liters<=baseL*.7f&&seconds<=baseS*.7f;
 bool interrupted=credible&&bursts>=2&&bursts<=4&&seconds<=30&&(millis()-startMs)<=90000;
 bool credit=credible&&learned&&(efficient||interrupted)&&rewards<3&&startTime>=1700000000;
 if(credit)rewards++;
 seq++;prefs.putUInt("seq",seq);
 String json="{\"id\":\""+userId+"-"+String(seq)+"\",\"start_epoch\":"+String((unsigned long)startTime)+",\"date\":\""+day()+"\",\"liters\":"+String(liters,4)+",\"flow_seconds\":"+String(seconds,2)+",\"credible\":"+(credible?"true":"false")+",\"efficient\":"+(efficient?"true":"false")+",\"interrupted_flow_candidate\":"+(interrupted?"true":"false")+",\"reward_candidate\":"+(credit?"true":"false")+"}";
 if(fsOK){File f=LittleFS.open("/events.ndjson","a");if(f && f.size()<500000){f.println(json);f.flush();}else Serial.println("Storage full: event NOT saved; no unlimited offline guarantee");f.close();}
 Serial.println(json);
 if(credible){todayL+=liters;todayUses++;if(samples<30){baseL=(baseL*samples+liters)/(samples+1);baseS=(baseS*samples+seconds)/(samples+1);samples++;prefs.putFloat("bl",baseL);prefs.putFloat("bs",baseS);prefs.putUInt("n",samples);}saveDay();}
 active=false;flowing=false;liters=seconds=0;bursts=0;invalid=false;
}
String status(){String s="{\"date\":\""+day()+"\",\"today_liters\":"+String(todayL,3)+",\"live_liters\":"+String(liters,3)+",\"live_seconds\":"+String(seconds,1)+",\"baseline_liters_per_use\":"+String(baseL,3)+",\"baseline_seconds_per_use\":"+String(baseS,1)+",\"learning_uses\":"+String(samples)+",\"daily_reward_candidates\":"+String(rewards)+",\"streak_estimate\":"+String(streak)+",\"valve_closed\":"+(closed?"true":"false")+",\"override\":"+(bypass?"true":"false")+",\"reminder\":"+((active&&seconds>30)?"true":"false")+",\"weekly_liters\":[";for(int i=0;i<7;i++){if(i)s+=",";s+=String(history[i],3);}return s+"]}";}
bool auth(){if(web.authenticate("taply",apPass.c_str()))return true;web.requestAuthentication();return false;}
void syncEvents(){if(!fsOK||WiFi.status()!=WL_CONNECTED||!strlen(ENDPOINT)||!strlen(ROOT_CA)||!strlen(TOKEN)||!String(ENDPOINT).startsWith("https://"))return;
 uint32_t offset=prefs.getUInt("offset",0);File f=LittleFS.open("/events.ndjson","r");if(!f||offset>=f.size()){f.close();return;}f.seek(offset);String line=f.readStringUntil('\n');uint32_t next=f.position();f.close();
 WiFiClientSecure tls;tls.setCACert(ROOT_CA);HTTPClient http;http.setTimeout(1500);if(http.begin(tls,ENDPOINT)){http.addHeader("Content-Type","application/json");http.addHeader("Authorization",String("Bearer ")+TOKEN);int result=http.POST(line);if(result>=200&&result<300)prefs.putUInt("offset",next);http.end();}}
void setup(){Serial.begin(115200);pinMode(25,OUTPUT);pinMode(26,OUTPUT);valve(false);pinMode(33,INPUT_PULLUP);pinMode(27,INPUT);attachInterrupt(27,pulse,RISING);
 prefs.begin("taply",false);ppl=prefs.getFloat("ppl",450);seq=prefs.getUInt("seq",0);baseL=prefs.getFloat("bl",0);baseS=prefs.getFloat("bs",0);samples=prefs.getUInt("n",0);todayUses=prefs.getInt("uses",0);todayL=prefs.getFloat("today",0);dayKey=prefs.getInt("day",0);rewards=prefs.getInt("rewards",0);streak=prefs.getInt("streak",0);prefs.getBytes("history",history,sizeof(history));
 userId=prefs.getString("id",String((uint32_t)ESP.getEfuseMac(),HEX));apPass=prefs.getString("key","");if(apPass.length()<12){apPass=String(esp_random(),HEX)+String(esp_random(),HEX);prefs.putString("key",apPass);}
 fsOK=LittleFS.begin(false);if(!fsOK){Serial.println("Initializing new storage");fsOK=LittleFS.format()&&LittleFS.begin(false);}WiFi.mode(WIFI_AP_STA);WiFi.softAP(("Taply-"+userId).c_str(),apPass.c_str());if(strlen(SSID))WiFi.begin(SSID,PASS);configTzTime(TZ_RULE,"pool.ntp.org","time.nist.gov");Serial.println("AP password and web password: "+apPass);Serial.println("Dashboard: http://192.168.4.1 user taply");
 web.on("/",[]{if(!auth())return;web.send(200,"text/html",R"HTML(<h1>Taply prototype</h1><p>Automatic measurement. Baseline learns 30 valid uses. Rewards are candidates, not game currency.</p><pre id="s"></pre><a href="/export">Export event history</a><p>Maintenance: POST /calibrate?ppl=450; POST /override; POST /delete. Physical button releases valve.</p><script>setInterval(async()=>{document.getElementById('s').textContent=JSON.stringify(await(await fetch('/status')).json(),null,2)},1000)</script>)HTML");});
 web.on("/status",[]{if(auth())web.send(200,"application/json",status());});
 web.on("/export",[]{if(!auth())return;File f=LittleFS.open("/events.ndjson","r");web.streamFile(f,"application/x-ndjson");f.close();});
 web.on("/calibrate",HTTP_POST,[]{if(!auth())return;float v=web.arg("ppl").toFloat();if(active||v<10||v>100000){web.send(400,"text/plain","Idle only; pulses/liter must be 10..100000");return;}ppl=v;prefs.putFloat("ppl",ppl);web.send(200,"text/plain","Calibration saved");});
 web.on("/override",HTTP_POST,[]{if(!auth())return;bypass=!bypass;valve(false);web.send(200,"text/plain",bypass?"Automatic closing disabled":"Automatic closing enabled");});
 web.on("/delete",HTTP_POST,[]{if(!auth())return;valve(false);LittleFS.remove("/events.ndjson");prefs.clear();web.send(200,"text/plain","Local data deleted. Delete server data separately. Restarting.");delay(200);ESP.restart();});web.begin();}
void loop(){web.handleClient();uint32_t now=millis();if(digitalRead(33)==LOW){bypass=true;valve(false);}if(closed&&now-closeMs>60000){valve(false);bypass=true;} // never hold coil closed indefinitely
 if(now-lastTick>=1000){uint32_t dt=now-lastTick;lastTick=now;uint32_t n;portENTER_CRITICAL(&mux);n=pulses;pulses=0;portEXIT_CRITICAL(&mux);calendar();float amount=n/ppl;
 if(n){if(!active){active=true;startMs=now;startTime=time(nullptr);if(startTime<1700000000)startTime=0;}if(!flowing)bursts++;flowing=true;lastFlow=now;liters+=amount;seconds+=dt/1000.f;if(amount*60000/dt>30)invalid=true;}else flowing=false;
 if(active&&!bypass&&!closed&&(seconds>=120||(samples>=30&&seconds>max(30.f,baseS*3))))valve(true);
 if(active&&now-lastFlow>15000)record();
 // Network work only between uses to keep shutoff responsive.
 static uint32_t lastSync=0;if(!active&&now-lastSync>15000){lastSync=now;syncEvents();}}
 delay(2);}