import 'package:flutter_test/flutter_test.dart';
import 'package:rippr/src/hud/hud_metric.dart';
import 'package:rippr/src/hud/hud_widget_layout.dart';

/// FB-03: the JSON round-trip, grid-clamp math, overlap check, and free-slot search
/// are all exercised directly with fixed inputs -- no real gestures needed to test
/// any of these, per the ticket's own Tests section.
void main() {
  group('JSON round trip', () {
    test('encodes and decodes exactly', () {
      const original = HudWidgetLayout(
        metric: HudMetric.speed,
        col: 1,
        row: 2,
        colSpan: 3,
        rowSpan: 2,
        visible: true,
      );

      final decoded = HudWidgetLayout.fromJson(HudMetric.speed, original.toJson());

      expect(decoded.col, original.col);
      expect(decoded.row, original.row);
      expect(decoded.colSpan, original.colSpan);
      expect(decoded.rowSpan, original.rowSpan);
      expect(decoded.visible, original.visible);
    });

    test('a malformed entry falls back to the default rather than crashing', () {
      final decoded = HudWidgetLayout.fromJson(HudMetric.distance, {'col': 'not a number'});
      final default_ = HudWidgetLayout.defaultFor(HudMetric.distance);

      expect(decoded.col, default_.col);
      expect(decoded.colSpan, default_.colSpan);
    });

    test('a missing field falls back to the default rather than crashing', () {
      final decoded = HudWidgetLayout.fromJson(HudMetric.maxSpeed, {'col': 1, 'row': 1});
      final default_ = HudWidgetLayout.defaultFor(HudMetric.maxSpeed);

      expect(decoded.col, default_.col);
    });

    test('an old-shaped (pre-grid) saved layout falls back to the default rather '
        'than crashing', () {
      final decoded = HudWidgetLayout.fromJson(
        HudMetric.speed,
        {'x': 0.1, 'y': 0.2, 'width': 0.3, 'height': 0.15, 'visible': true},
      );
      final default_ = HudWidgetLayout.defaultFor(HudMetric.speed);

      expect(decoded.col, default_.col);
      expect(decoded.row, default_.row);
      expect(decoded.colSpan, default_.colSpan);
      expect(decoded.rowSpan, default_.rowSpan);
    });
  });

  group('defaultFor', () {
    test('every metric gets a distinct, non-overlapping default rect', () {
      final layouts = HudMetric.values.map(HudWidgetLayout.defaultFor).toList();
      for (var i = 0; i < layouts.length; i++) {
        for (var j = i + 1; j < layouts.length; j++) {
          expect(hudRectsOverlap(layouts[i], layouts[j]), isFalse,
              reason: 'no two metrics should default to overlapping rects');
        }
      }
    });

    test('the first four metrics (the Map HUD mockup\'s fixed row: Speed/Avg Speed/'
        'Dist/Time) start visible', () {
      expect(HudWidgetLayout.defaultFor(HudMetric.speed).visible, isTrue);
      expect(HudWidgetLayout.defaultFor(HudMetric.avgSpeed).visible, isTrue);
      expect(HudWidgetLayout.defaultFor(HudMetric.distance).visible, isTrue);
      expect(HudWidgetLayout.defaultFor(HudMetric.elapsedTime).visible, isTrue);
    });

    test('metrics beyond the fixed row start hidden', () {
      expect(HudWidgetLayout.defaultFor(HudMetric.maxSpeed).visible, isFalse);
      expect(HudWidgetLayout.defaultFor(HudMetric.elevationGain).visible, isFalse);
    });

    test('every default is already within the valid grid bounds', () {
      for (final metric in HudMetric.values) {
        final layout = HudWidgetLayout.defaultFor(metric);
        expect(layout.clampedToGrid().col, layout.col);
        expect(layout.clampedToGrid().row, layout.row);
        expect(layout.clampedToGrid().colSpan, layout.colSpan);
        expect(layout.clampedToGrid().rowSpan, layout.rowSpan);
      }
    });

    test('every metric\'s colSpan is at least its own title-driven minimum', () {
      for (final metric in HudMetric.values) {
        final layout = HudWidgetLayout.defaultFor(metric);
        expect(
          layout.colSpan,
          greaterThanOrEqualTo(minColSpanForLabel(metric.label)),
        );
      }
    });

    test('no row\'s members ever sum past hudGridColumns (the packing '
        'algorithm\'s own invariant)', () {
      final layouts = HudMetric.values.map(HudWidgetLayout.defaultFor).toList();
      final byRow = <int, int>{};
      for (final layout in layouts) {
        byRow[layout.row] = (byRow[layout.row] ?? 0) + layout.colSpan;
      }
      for (final sum in byRow.values) {
        expect(sum, lessThanOrEqualTo(hudGridColumns));
      }
    });
  });

  group('minColSpanForLabel', () {
    test('a label under 10 characters fits one column', () {
      expect(minColSpanForLabel(HudMetric.speed.label), 1);
    });

    test('a label under 15 characters needs two', () {
      expect(minColSpanForLabel(HudMetric.elapsedTime.label), 2);
    });

    test('a label of 15 or more characters needs three', () {
      expect(minColSpanForLabel(HudMetric.pointsCaptured.label), 3);
    });
  });

  group('clampedToGrid', () {
    const base = HudWidgetLayout(
      metric: HudMetric.speed,
      col: 1,
      row: 1,
      colSpan: 2,
      rowSpan: 2,
      visible: true,
    );

    test('a position dragged past the right/bottom edge is pulled back onto the '
        'grid', () {
      final result = base.copyWith(col: 20, row: 20).clampedToGrid();
      expect(result.col, hudGridColumns - base.colSpan);
      expect(result.row, hudGridRows - base.rowSpan);
    });

    test('a position dragged past the left/top edge is pulled back onto the grid', () {
      final result = base.copyWith(col: -5, row: -5).clampedToGrid();
      expect(result.col, 0);
      expect(result.row, 0);
    });

    test('a resize below the legibility floor is corrected up to the minimum', () {
      final result = base.copyWith(colSpan: 0, rowSpan: 0).clampedToGrid();
      expect(result.colSpan, hudMinSpan);
      expect(result.rowSpan, hudMinSpan);
    });

    test('a resize above the sane ceiling is corrected down to the maximum', () {
      final result = base.copyWith(colSpan: 99, rowSpan: 99).clampedToGrid();
      expect(result.colSpan, hudMaxColSpan);
      expect(result.rowSpan, hudMaxRowSpan);
    });

    test('shrinking to fit happens before repositioning, so a widget resized past '
        'the edge shrinks rather than silently relocates', () {
      final result = base.copyWith(col: 3, colSpan: 4).clampedToGrid();
      expect(result.colSpan, hudMaxColSpan);
      // col itself is still clamped against the (now-bounded) span so the widget
      // never sits even partially off the grid either.
      expect(result.col + result.colSpan, lessThanOrEqualTo(hudGridColumns));
    });

    test('an already-valid layout is unchanged', () {
      expect(base.clampedToGrid().col, base.col);
      expect(base.clampedToGrid().row, base.row);
      expect(base.clampedToGrid().colSpan, base.colSpan);
      expect(base.clampedToGrid().rowSpan, base.rowSpan);
    });
  });

  group('hudRectsOverlap', () {
    const a = HudWidgetLayout(
      metric: HudMetric.speed,
      col: 1,
      row: 1,
      colSpan: 2,
      rowSpan: 2,
      visible: true,
    );

    test('two identical rects overlap', () {
      expect(hudRectsOverlap(a, a), isTrue);
    });

    test('two rects sharing only an edge (touching, not overlapping) do not overlap', () {
      final rightNeighbor = a.copyWith(col: a.col + a.colSpan);
      expect(hudRectsOverlap(a, rightNeighbor), isFalse);

      final belowNeighbor = a.copyWith(row: a.row + a.rowSpan);
      expect(hudRectsOverlap(a, belowNeighbor), isFalse);
    });

    test('two disjoint rects do not overlap', () {
      final far = a.copyWith(col: a.col + a.colSpan + 3, row: a.row + a.rowSpan + 3);
      expect(hudRectsOverlap(a, far), isFalse);
    });

    test('a rect fully containing another overlaps', () {
      const big = HudWidgetLayout(
        metric: HudMetric.distance,
        col: 0,
        row: 0,
        colSpan: 4,
        rowSpan: 4,
        visible: true,
      );
      expect(hudRectsOverlap(big, a), isTrue);
    });

    test('two partially-overlapping rects overlap', () {
      final overlapping = a.copyWith(col: a.col + 1, row: a.row + 1);
      expect(hudRectsOverlap(a, overlapping), isTrue);
    });
  });

  group('nextFreeSlot', () {
    test('returns a rect that does not collide with any occupied visible layout, '
        'when the metric\'s own default position is taken', () {
      final occupier = HudWidgetLayout.defaultFor(HudMetric.speed);
      final occupied = {HudMetric.speed: occupier};

      final result = HudWidgetLayout.nextFreeSlot(
        HudMetric.avgSpeed,
        occupied: occupied,
        colSpan: occupier.colSpan,
        rowSpan: occupier.rowSpan,
      );

      expect(hudRectsOverlap(result, occupier), isFalse);
    });

    test('returns the same rect defaultFor would have (or another valid one) when '
        'occupied is empty', () {
      final result = HudWidgetLayout.nextFreeSlot(HudMetric.speed, occupied: {});
      expect(result.col, 0);
      expect(result.row, 0);
    });

    test('returns the same rect defaultFor would have (or another valid one) when '
        'occupied is all-hidden', () {
      final hidden = HudWidgetLayout.defaultFor(HudMetric.speed).copyWith(visible: false);
      final result = HudWidgetLayout.nextFreeSlot(
        HudMetric.avgSpeed,
        occupied: {HudMetric.speed: hidden},
      );
      expect(result.col, 0);
      expect(result.row, 0);
    });
  });
}