/*
 * VFX Review — ESP32 dot-matrix dashboard
 *
 * Hardware : ESP32 dev board + 4× MAX7219 8×8 modules chained (8×32 display)
 * Libraries (install via Arduino Library Manager):
 *   - MD_Parola  by majicDesigns  (≥3.7)
 *   - MD_MAX72XX by majicDesigns  (≥3.5)
 *   - ArduinoJson by Benoit Blanchon (≥7)
 *
 * Behaviour:
 *   Normal  → scrolls "APR:142  CHG:12  TODO:38" on a loop
 *   Event   → interrupts with e.g. "OK SH0010" / "REVISE SH0010" / "NOTE SH0010"
 *             held for NOTIFY_HOLD_MS then resumes stats scroll
 */

#include <Arduino.h>
#include <WiFi.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>
#include <Preferences.h>
#include <MD_Parola.h>
#include <MD_MAX72xx.h>
#include <SPI.h>
#include "config.h"

// ── Display setup ─────────────────────────────────────────────────────────────
#define HARDWARE_TYPE MD_MAX72XX::FC16_HW
MD_Parola display(HARDWARE_TYPE, CS_PIN, NUM_DEVICES);

// ── State ─────────────────────────────────────────────────────────────────────
Preferences prefs;

int  approvedCount  = 0;
int  changesCount   = 0;
int  todoCount      = 0;
int  lastEventId    = 0;

bool      notifyActive  = false;
uint32_t  notifyUntil   = 0;

char statsMsg[64];      // "APR:142  CHG:12  TODO:38"
char notifyMsg[64];     // interrupt message

uint32_t lastStatsFetch  = 0;
uint32_t lastEventsFetch = 0;

// ── Helpers ───────────────────────────────────────────────────────────────────

void buildStatsMsg() {
  snprintf(statsMsg, sizeof(statsMsg),
    "APR:%d  CHG:%d  TODO:%d",
    approvedCount, changesCount, todoCount);
}

// Truncate a string to maxLen chars, safe for display
void truncate(const char* src, char* dst, int maxLen) {
  strncpy(dst, src, maxLen);
  dst[maxLen] = '\0';
}

void connectWiFi() {
  Serial.printf("[WiFi] Connecting to %s", WIFI_SSID);
  WiFi.mode(WIFI_STA);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print('.');
  }
  Serial.printf("\n[WiFi] Connected — IP: %s\n", WiFi.localIP().toString().c_str());
}

// Make an authenticated GET request; fills `out` with the response body.
// Returns HTTP status code, or -1 on connection failure.
int apiGet(const char* path, String& out) {
  if (WiFi.status() != WL_CONNECTED) connectWiFi();

  char url[256];
  snprintf(url, sizeof(url), "http://%s:%d%s", SERVER_HOST, SERVER_PORT, path);

  HTTPClient http;
  http.begin(url);
  http.addHeader("x-display-key", DISPLAY_API_KEY);
  http.setTimeout(8000);

  int code = http.GET();
  if (code > 0) out = http.getString();
  http.end();
  return code;
}

// ── Stats fetch ───────────────────────────────────────────────────────────────

void fetchStats() {
  String body;
  int code = apiGet("/api/dashboard/stats", body);
  if (code != 200) {
    Serial.printf("[Stats] HTTP %d\n", code);
    return;
  }

  JsonDocument doc;
  if (deserializeJson(doc, body)) { Serial.println("[Stats] JSON parse error"); return; }

  approvedCount = doc["approved"] | approvedCount;
  changesCount  = doc["changes"]  | changesCount;
  todoCount     = doc["todo"]     | todoCount;

  buildStatsMsg();
  Serial.printf("[Stats] APR:%d CHG:%d TODO:%d\n", approvedCount, changesCount, todoCount);
}

// ── Events fetch ──────────────────────────────────────────────────────────────

void fetchEvents() {
  char path[64];
  snprintf(path, sizeof(path), "/api/display/events?after=%d", lastEventId);

  String body;
  int code = apiGet(path, body);
  if (code != 200) {
    Serial.printf("[Events] HTTP %d\n", code);
    return;
  }

  JsonDocument doc;
  if (deserializeJson(doc, body)) { Serial.println("[Events] JSON parse error"); return; }

  JsonArray arr = doc.as<JsonArray>();
  if (arr.isNull() || arr.size() == 0) return;

  // Pick the most recent event to display, update lastEventId across all
  const char* bestType     = nullptr;
  const char* bestShotCode = nullptr;
  const char* bestBy       = nullptr;
  int         newestId     = lastEventId;

  for (JsonObject ev : arr) {
    int  id       = ev["id"]       | 0;
    const char* t = ev["type"]     | "";
    const char* s = ev["shotCode"] | "";
    const char* b = ev["by"]       | "";

    if (id > newestId) {
      newestId     = id;
      bestType     = t;
      bestShotCode = s;
      bestBy       = b;
    }
  }

  if (newestId > lastEventId) {
    lastEventId = newestId;
    prefs.putInt("lastEvtId", lastEventId);
  }

  if (!bestType || !bestShotCode) return;

  // Build notification message
  char shotBuf[16];
  truncate(bestShotCode, shotBuf, 12);

  if (strcmp(bestType, "APPROVED") == 0) {
    snprintf(notifyMsg, sizeof(notifyMsg), "OK: %s", shotBuf);
  } else if (strcmp(bestType, "CHANGES") == 0) {
    snprintf(notifyMsg, sizeof(notifyMsg), "REVISE: %s", shotBuf);
  } else if (strcmp(bestType, "REJECTED") == 0) {
    snprintf(notifyMsg, sizeof(notifyMsg), "REJECT: %s", shotBuf);
  } else if (strcmp(bestType, "COMMENT") == 0) {
    char byBuf[10];
    truncate(bestBy, byBuf, 8);
    snprintf(notifyMsg, sizeof(notifyMsg), "NOTE: %s", shotBuf);
  } else {
    snprintf(notifyMsg, sizeof(notifyMsg), "%s", shotBuf);
  }

  Serial.printf("[Events] id=%d type=%s shot=%s\n", newestId, bestType, bestShotCode);

  notifyActive = true;
  notifyUntil  = millis() + NOTIFY_HOLD_MS;

  display.displayClear();
  display.displayText(notifyMsg, PA_CENTER, SCROLL_SPEED, 500, PA_SCROLL_LEFT, PA_SCROLL_LEFT);
}

// ── Arduino setup ─────────────────────────────────────────────────────────────

void setup() {
  Serial.begin(115200);
  delay(500);

  // Restore last seen event ID from NVS so we don't replay old events on reboot
  prefs.begin("vfxdisp", false);
  lastEventId = prefs.getInt("lastEvtId", 0);
  Serial.printf("[Init] lastEventId restored = %d\n", lastEventId);

  // Display init
  display.begin();
  display.setIntensity(BRIGHTNESS);
  display.displayClear();
  display.setTextAlignment(PA_LEFT);
  display.setScrollSpacing(4);

  // Show connecting message
  display.displayText("Connecting...", PA_LEFT, SCROLL_SPEED, 0, PA_SCROLL_LEFT, PA_SCROLL_LEFT);
  while (!display.displayAnimate()) {}

  connectWiFi();

  // Initial data fetch
  fetchStats();

  // Prime the events endpoint — catch up to current without showing stale events
  // We do a silent fetch just to advance lastEventId to now
  {
    char path[64];
    snprintf(path, sizeof(path), "/api/display/events?after=%d", lastEventId);
    String body;
    int code = apiGet(path, body);
    if (code == 200) {
      JsonDocument doc;
      if (!deserializeJson(doc, body)) {
        JsonArray arr = doc.as<JsonArray>();
        for (JsonObject ev : arr) {
          int id = ev["id"] | 0;
          if (id > lastEventId) lastEventId = id;
        }
        prefs.putInt("lastEvtId", lastEventId);
      }
    }
  }

  // Kick off the scrolling stats message
  buildStatsMsg();
  display.displayClear();
  display.displayText(statsMsg, PA_LEFT, SCROLL_SPEED, 0, PA_SCROLL_LEFT, PA_SCROLL_LEFT);

  lastStatsFetch  = millis();
  lastEventsFetch = millis();
}

// ── Arduino loop ──────────────────────────────────────────────────────────────

void loop() {
  uint32_t now = millis();

  // ── Timed fetches ──
  if (now - lastStatsFetch >= STATS_INTERVAL_MS) {
    lastStatsFetch = now;
    fetchStats();
    // If no notification is active, refresh the scrolling text immediately
    if (!notifyActive) {
      display.displayClear();
      display.displayText(statsMsg, PA_LEFT, SCROLL_SPEED, 0, PA_SCROLL_LEFT, PA_SCROLL_LEFT);
    }
  }

  if (now - lastEventsFetch >= EVENTS_INTERVAL_MS) {
    lastEventsFetch = now;
    if (!notifyActive) fetchEvents();  // don't overlap notifications
  }

  // ── Notification expiry ──
  if (notifyActive && now >= notifyUntil) {
    notifyActive = false;
    display.displayClear();
    display.displayText(statsMsg, PA_LEFT, SCROLL_SPEED, 0, PA_SCROLL_LEFT, PA_SCROLL_LEFT);
  }

  // ── Animate display ──
  // When a scroll finishes, restart it (loops the message)
  if (display.displayAnimate()) {
    display.displayReset();
  }
}