#pragma once
// GPS trail viewer. Tools › Trail.
// Summary view: counters, distance, time, speed.
// Map view: pixel-by-pixel auto-fit of the polyline with start (+) and current (×) markers.
// Phase 3 adds a per-point list view.
// Included by UITask.cpp after Trail store + ToolsScreen.

#include "../Trail.h"
#include <math.h>

class TrailScreen : public UIScreen {
  UITask*     _task;
  TrailStore* _store;

  enum View { V_SUMMARY = 0, V_MAP = 1, V_LIST = 2, V_COUNT };
  uint8_t _view = V_SUMMARY;
  int     _summary_scroll = 0;  // top visible item index in Summary view
  int     _list_scroll    = 0;  // top visible row in List view (newest = row 0)
  bool    _opts_open      = false;  // tool-local options popup (min-delta)

  static const int SUMMARY_ITEM_COUNT = 5;

public:
  TrailScreen(UITask* task, TrailStore* store) : _task(task), _store(store) {}

  void enter() { /* nothing to reset; live trail stays */ }

  int render(DisplayDriver& display) override {
    display.setTextSize(1);
    display.setColor(DisplayDriver::LIGHT);
    const char* title = (_view == V_MAP)  ? "TRAIL MAP"
                       : (_view == V_LIST) ? "TRAIL LIST"
                       :                      "TRAIL";
    display.drawTextCentered(display.width() / 2, 0, title);
    display.fillRect(0, display.headerH() - 1, display.width(), display.sepH());

    if      (_view == V_MAP)  renderMap(display);
    else if (_view == V_LIST) renderList(display);
    else                       renderSummary(display);

    // Bottom hint — current view indicator + control reminders.
    display.setColor(DisplayDriver::LIGHT);
    int hint_y = display.height() - display.lineStep();
    char hint[28];
    snprintf(hint, sizeof(hint), "<>%d/%d  [Ent] %s",
             (int)_view + 1, (int)V_COUNT,
             _store->isActive() ? "stop" : "start");
    display.setCursor(2, hint_y);
    display.print(hint);

    // Options popup overlay (Hold Enter to open) — tool-local Min-delta setting.
    if (_opts_open) renderOptions(display);

    return _store->isActive() ? 1000 : 5000;
  }

  bool handleInput(char c) override {
    // Options popup consumes all input while open.
    if (_opts_open) {
      if (c == KEY_CANCEL || c == KEY_CONTEXT_MENU) { _opts_open = false; return true; }
      if (c == KEY_ENTER) {
        NodePrefs* p = _task->getNodePrefs();
        if (p) {
          uint8_t idx = p->trail_min_delta_idx;
          if (idx >= TrailStore::MIN_DELTA_COUNT) idx = 0;
          idx = (idx + 1) % TrailStore::MIN_DELTA_COUNT;
          p->trail_min_delta_idx = idx;
          the_mesh.savePrefs();
        }
      }
      return true;
    }

    if (c == KEY_CANCEL)        { _task->gotoToolsScreen(); return true; }
    if (c == KEY_CONTEXT_MENU)  { _opts_open = true;        return true; }
    if (c == KEY_LEFT  || c == KEY_PREV) { _view = (_view + V_COUNT - 1) % V_COUNT; return true; }
    if (c == KEY_RIGHT || c == KEY_NEXT) { _view = (_view + 1)           % V_COUNT; return true; }
    if (_view == V_SUMMARY && c == KEY_UP   && _summary_scroll > 0) { _summary_scroll--; return true; }
    if (_view == V_SUMMARY && c == KEY_DOWN)                        { _summary_scroll++; return true; }  // clamped on render
    if (_view == V_LIST    && c == KEY_UP   && _list_scroll > 0)    { _list_scroll--;    return true; }
    if (_view == V_LIST    && c == KEY_DOWN)                        { _list_scroll++;    return true; }  // clamped on render
    if (c == KEY_ENTER) {
      bool now_active = !_store->isActive();
      _store->setActive(now_active);
      if (now_active) {
        _task->showAlert(gpsHasFix() ? "Tracking started" : "Waiting for GPS fix", 1000);
      } else {
        _task->showAlert("Tracking stopped", 800);
      }
      return true;
    }
    return false;
  }

  // Small modal overlay with the only tool-local option: minimum distance
  // between consecutive samples. Pressing Enter cycles through the 4 options
  // (5/10/25/100 m) so the user can keep tapping; Esc closes the popup.
  void renderOptions(DisplayDriver& display) {
    NodePrefs* p = _task->getNodePrefs();
    int step = display.lineStep();
    int bw = display.width() - 16;
    int bh = step * 3 + 4;
    int bx = (display.width()  - bw) / 2;
    int by = (display.height() - bh) / 2;

    display.setColor(DisplayDriver::DARK);
    display.fillRect(bx, by, bw, bh);
    display.setColor(DisplayDriver::LIGHT);
    display.drawRect(bx, by, bw, bh);

    display.setCursor(bx + 4, by + 2);
    display.print("Trail options");
    display.fillRect(bx, by + step + 1, bw, 1);

    char buf[24];
    snprintf(buf, sizeof(buf), "Min dist: %s",
              TrailStore::minDeltaLabel(p ? p->trail_min_delta_idx : 0));
    display.setCursor(bx + 4, by + step + 3);
    display.print(buf);

    display.setCursor(bx + 4, by + step * 2 + 3);
    display.print("[Ent] cycle [Esc]");
  }

  // True when the global SensorManager has a usable GPS fix.
  static bool gpsHasFix() {
#if ENV_INCLUDE_GPS == 1
    LocationProvider* loc = sensors.getLocationProvider();
    return loc && loc->isValid();
#else
    return false;
#endif
  }

private:
  // Format the i-th summary line into buf. Indices match SUMMARY_ITEM_COUNT.
  void summaryItem(int i, char* buf, size_t n) const {
    switch (i) {
      case 0: {
        const char* st;
        if (!_store->isActive())     st = "stopped";
        else if (_store->empty())    st = "waiting fix";
        else                          st = "tracking";
        snprintf(buf, n, "Status: %s", st);
        break;
      }
      case 1:
        snprintf(buf, n, "Points: %d / %d", _store->count(), TrailStore::CAPACITY);
        break;
      case 2: {
        uint32_t d = _store->totalDistanceMeters();
        if (d < 1000) snprintf(buf, n, "Dist: %lu m", (unsigned long)d);
        else          snprintf(buf, n, "Dist: %lu.%02lu km",
                                (unsigned long)(d / 1000), (unsigned long)((d % 1000) / 10));
        break;
      }
      case 3: {
        uint32_t es = _store->elapsedSeconds();
        // Below 1 h show m:ss so the seconds counter updates visibly each refresh.
        if (es < 3600) snprintf(buf, n, "Time: %lu:%02lu",
                                  (unsigned long)(es / 60), (unsigned long)(es % 60));
        else           snprintf(buf, n, "Time: %lu:%02lu",
                                  (unsigned long)(es / 3600), (unsigned long)((es % 3600) / 60));
        break;
      }
      case 4:
        snprintf(buf, n, "Avg speed: %u km/h", (unsigned)_store->avgSpeedKmh());
        break;
      default:
        buf[0] = '\0';
    }
  }

  void renderSummary(DisplayDriver& display) {
    const int y0     = display.listStart();
    const int step   = display.lineStep();
    const int hint_h = step;
    const int avail  = display.height() - y0 - hint_h - 2;
    int visible      = avail / step;
    if (visible < 1) visible = 1;
    if (visible > SUMMARY_ITEM_COUNT) visible = SUMMARY_ITEM_COUNT;

    // Clamp scroll once we know visible count.
    int max_scroll = SUMMARY_ITEM_COUNT - visible;
    if (_summary_scroll > max_scroll) _summary_scroll = max_scroll;
    if (_summary_scroll < 0)          _summary_scroll = 0;

    for (int i = 0; i < visible; i++) {
      int idx = _summary_scroll + i;
      if (idx >= SUMMARY_ITEM_COUNT) break;
      char buf[28];
      summaryItem(idx, buf, sizeof(buf));
      display.setCursor(2, y0 + i * step);
      display.print(buf);
    }

    // Scroll arrows on the right edge when there's more above/below.
    int cw = display.getCharWidth();
    if (_summary_scroll > 0) {
      display.setCursor(display.width() - cw, y0);
      display.print("^");
    }
    if (_summary_scroll + visible < SUMMARY_ITEM_COUNT) {
      display.setCursor(display.width() - cw, y0 + (visible - 1) * step);
      display.print("v");
    }
  }

  // Per-point list, newest first. Each row: HH:MM (local) + delta from the
  // previous point in the same segment, or "start" for segment-start rows.
  void renderList(DisplayDriver& display) {
    const int top    = display.listStart();
    const int step   = display.lineStep();
    const int hint_h = step;
    const int avail  = display.height() - top - hint_h - 2;

    if (_store->empty()) {
      display.drawTextCentered(display.width() / 2, top + avail / 2, "No trail yet");
      return;
    }

    int visible = avail / step;
    if (visible < 1) visible = 1;
    const int total = _store->count();
    if (visible > total) visible = total;

    int max_scroll = total - visible;
    if (_list_scroll > max_scroll) _list_scroll = max_scroll;
    if (_list_scroll < 0)          _list_scroll = 0;

    NodePrefs* p = _task->getNodePrefs();
    int32_t tz_off = (int32_t)(p ? p->tz_offset_hours : 0) * 3600;

    for (int i = 0; i < visible; i++) {
      int idx = total - 1 - (_list_scroll + i);  // newest first
      if (idx < 0) break;
      const TrailPoint& pt = _store->at(idx);

      time_t lt = (time_t)((int32_t)pt.ts + tz_off);
      struct tm* ti = gmtime(&lt);

      char dist[12];
      if (idx == 0 || (pt.flags & TRAIL_FLAG_SEG_START)) {
        snprintf(dist, sizeof(dist), "start");
      } else {
        const TrailPoint& prev = _store->at(idx - 1);
        float d = TrailStore::haversineMeters(prev.lat_1e6, prev.lon_1e6,
                                                pt.lat_1e6,    pt.lon_1e6);
        if (d < 1000.0f) snprintf(dist, sizeof(dist), "+%d m", (int)d);
        else             snprintf(dist, sizeof(dist), "+%.1f km", d / 1000.0f);
      }

      char row[28];
      snprintf(row, sizeof(row), "%02d:%02d  %s",
                ti->tm_hour, ti->tm_min, dist);
      display.setCursor(2, top + i * step);
      display.print(row);
    }

    int cw = display.getCharWidth();
    if (_list_scroll > 0) {
      display.setCursor(display.width() - cw, top);
      display.print("^");
    }
    if (_list_scroll + visible < total) {
      display.setCursor(display.width() - cw, top + (visible - 1) * step);
      display.print("v");
    }
  }

  // Pixel-by-pixel polyline. Bounds are auto-fitted to the available area and
  // longitude is scaled by cos(avg_lat) so high-latitude trails don't stretch.
  void renderMap(DisplayDriver& display) {
    const int top    = display.listStart();
    const int bottom = display.height() - display.lineStep() - 1;

    if (_store->empty()) {
      display.drawTextCentered(display.width() / 2, (top + bottom) / 2, "No trail yet");
      return;
    }

    const int area_x = 2;
    const int area_y = top + 1;
    const int area_w = display.width() - 4;
    const int area_h = bottom - top - 2;
    if (area_w < 6 || area_h < 6) return;  // no room to draw anything sensible

    int32_t min_lat, min_lon, max_lat, max_lon;
    _store->boundingBox(min_lat, min_lon, max_lat, max_lon);

    if (_store->count() == 1 || (min_lat == max_lat && min_lon == max_lon)) {
      // Degenerate — single point or all samples colocated. Mark centre.
      drawCurrentMarker(display, area_x + area_w / 2, area_y + area_h / 2);
      return;
    }

    // cos(lat) correction prevents east/west stretching at higher latitudes.
    float avg_lat_rad = ((min_lat + max_lat) / 2.0e6f) * (float)M_PI / 180.0f;
    float lon_scale_geo = cosf(avg_lat_rad);
    if (lon_scale_geo < 0.05f) lon_scale_geo = 0.05f;  // guard near poles

    float lat_span = (float)(max_lat - min_lat);
    float lon_span = (float)(max_lon - min_lon) * lon_scale_geo;

    // Pick the limiting axis so the polyline fills the area without distorting.
    float scale_lat = (float)area_h / (lat_span > 0 ? lat_span : 1.0f);
    float scale_lon = (float)area_w / (lon_span > 0 ? lon_span : 1.0f);
    float scale     = (scale_lat < scale_lon) ? scale_lat : scale_lon;

    // After scaling, the used area is smaller in the non-limiting dim; centre it.
    int used_w = (int)(lon_span * scale);
    int used_h = (int)(lat_span * scale);
    int off_x  = area_x + (area_w - used_w) / 2;
    int off_y  = area_y + (area_h - used_h) / 2;

    auto project = [&](const TrailPoint& p, int& px, int& py) {
      float dx = (float)(p.lon_1e6 - min_lon) * lon_scale_geo * scale;
      float dy = (float)(max_lat - p.lat_1e6) * scale;  // north = up
      px = off_x + (int)dx;
      py = off_y + (int)dy;
    };

    // Draw connected segments. A point flagged SEG_START starts a new segment;
    // its predecessor is not joined to it. At every break we mark the segment
    // end (filled dot) and the resume point (open dot) so the user can see
    // where tracking paused.
    int x0, y0;
    project(_store->at(0), x0, y0);
    display.fillRect(x0, y0, 1, 1);
    for (int i = 1; i < _store->count(); i++) {
      int x1, y1;
      project(_store->at(i), x1, y1);
      if (_store->at(i).flags & TRAIL_FLAG_SEG_START) {
        drawFilledDot(display, x0, y0);  // end of the previous segment
        drawOpenDot(display, x1, y1);    // resume point
      } else {
        drawLine(display, x0, y0, x1, y1);
      }
      x0 = x1;
      y0 = y1;
    }

    int sx, sy, ex, ey;
    project(_store->first(), sx, sy);
    project(_store->last(),  ex, ey);
    drawStartMarker(display, sx, sy);
    drawCurrentMarker(display, ex, ey);
  }

  // Bresenham line via 1×1 fillRect. Acceptable for occasional view renders.
  static void drawLine(DisplayDriver& d, int x0, int y0, int x1, int y1) {
    int dx =  abs(x1 - x0), sx = x0 < x1 ? 1 : -1;
    int dy = -abs(y1 - y0), sy = y0 < y1 ? 1 : -1;
    int err = dx + dy;
    while (true) {
      d.fillRect(x0, y0, 1, 1);
      if (x0 == x1 && y0 == y1) break;
      int e2 = err * 2;
      if (e2 >= dy) { err += dy; x0 += sx; }
      if (e2 <= dx) { err += dx; y0 += sy; }
    }
  }

  // 3×3 filled square — end of a segment before a break.
  static void drawFilledDot(DisplayDriver& d, int cx, int cy) {
    d.fillRect(cx - 1, cy - 1, 3, 3);
  }

  // 3×3 outline square — start of a segment after a break (resume point).
  static void drawOpenDot(DisplayDriver& d, int cx, int cy) {
    d.fillRect(cx - 1, cy - 1, 3, 1);  // top
    d.fillRect(cx - 1, cy + 1, 3, 1);  // bottom
    d.fillRect(cx - 1, cy,     1, 1);  // left
    d.fillRect(cx + 1, cy,     1, 1);  // right
  }

  // 5×5 plus-sign marker for the start point.
  static void drawStartMarker(DisplayDriver& d, int cx, int cy) {
    d.fillRect(cx - 2, cy,     5, 1);
    d.fillRect(cx,     cy - 2, 1, 5);
  }

  // 5×5 cross marker for the current/last point.
  static void drawCurrentMarker(DisplayDriver& d, int cx, int cy) {
    for (int i = -2; i <= 2; i++) {
      d.fillRect(cx + i, cy + i, 1, 1);
      d.fillRect(cx + i, cy - i, 1, 1);
    }
  }
};