#include <Adafruit_GFX.h>
#include <Adafruit_ST7735.h>
#include <SPI.h>
#include "config.h"
#include "display_ui.h"

// Non-static so displayRender() can reference it via extern.
Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);

void displayBegin() {
  pinMode(TFT_BLK, OUTPUT);
  digitalWrite(TFT_BLK, HIGH);           // backlight on
  tft.initR(INITR_MINI160x80);           // 0.96" ST7735S
  tft.invertDisplay(false);              // this panel: no inversion
  tft.setRotation(3);                    // landscape, 160 wide x 80 tall
  tft.fillScreen(ST77XX_BLACK);
}

void displaySplash(const char* line1, const char* line2) {
  tft.fillScreen(ST77XX_BLACK);
  tft.setTextColor(ST77XX_WHITE);
  tft.setTextSize(2);
  tft.setCursor(4, 20);
  tft.print(line1);
  tft.setTextSize(1);
  tft.setCursor(4, 50);
  tft.print(line2);
}

// Simple 34x34 weather icon at (x, y).
static void drawIcon(WxCategory c, int x, int y) {
  uint16_t sun   = ST77XX_YELLOW;
  uint16_t cloud = ST77XX_WHITE;
  uint16_t rain  = ST77XX_CYAN;
  switch (c) {
    case WX_FINE:
      tft.fillCircle(x + 17, y + 17, 11, sun);
      break;
    case WX_FAIR:
      tft.fillCircle(x + 12, y + 12, 8, sun);
      tft.fillRoundRect(x + 8, y + 18, 24, 12, 6, cloud);
      break;
    case WX_CHANGEABLE:
      tft.fillRoundRect(x + 4, y + 12, 26, 14, 7, cloud);
      break;
    case WX_RAIN:
      tft.fillRoundRect(x + 4, y + 8, 26, 14, 7, cloud);
      for (int i = 0; i < 3; i++)
        tft.drawFastVLine(x + 9 + i * 8, y + 24, 8, rain);
      break;
    case WX_STORM:
      tft.fillRoundRect(x + 4, y + 8, 26, 14, 7, cloud);
      tft.fillTriangle(x + 16, y + 22, x + 12, y + 32, x + 20, y + 30, ST77XX_YELLOW);
      break;
    default:
      tft.drawRect(x + 4, y + 10, 26, 18, cloud);  // unknown / collecting
      break;
  }
}

// Layout for landscape 160 x 80.
void displayRender(const AppState& s) {
  tft.fillScreen(ST77XX_BLACK);
  tft.setTextColor(ST77XX_WHITE);
  char buf[24];

  // Time (large), top-left
  snprintf(buf, sizeof(buf), "%02u:%02u", s.now.hour, s.now.minute);
  tft.setTextSize(2);
  tft.setCursor(4, 4);
  tft.print(buf);

  // Icon, top-right
  drawIcon(s.haveTrend ? s.forecast.category : WX_UNKNOWN, 120, 4);

  // Date
  snprintf(buf, sizeof(buf), "%04u-%02u-%02u", s.now.year, s.now.month, s.now.day);
  tft.setTextSize(1);
  tft.setCursor(4, 26);
  tft.print(buf);

  // Pressure + trend arrow
  snprintf(buf, sizeof(buf), "%.0f hPa", s.mslHpa);
  tft.setCursor(4, 40);
  tft.print(buf);
  const char* arrow = (s.trend == TREND_RISING) ? "^" : (s.trend == TREND_FALLING ? "v" : "=");
  tft.setCursor(96, 40);
  tft.setTextColor(ST77XX_CYAN);
  tft.print(arrow);
  tft.setTextColor(ST77XX_WHITE);

  // Temperature
  snprintf(buf, sizeof(buf), "%.1f C", s.tempC);
  tft.setCursor(4, 52);
  tft.print(buf);

  // Forecast short label (full width, bottom row)
  tft.setTextColor(ST77XX_YELLOW);
  tft.setCursor(4, 66);
  tft.print(s.haveTrend ? categoryShort(s.forecast.category) : "Collecting...");
  tft.setTextColor(ST77XX_WHITE);
}