#include "harness.hpp"

#include <plot/input/controller.hpp>
#include <plot/plot/plot.hpp>
#include <plot/data/array_series.hpp>

#include <cmath>
#include <utility>
#include <vector>

namespace {

using plot::f32;
using plot::f64;
using plot::u32;

constexpr u32 kShift = static_cast<u32>(plot::input::Mod::Shift);
constexpr u32 kCtrl = static_cast<u32>(plot::input::Mod::Ctrl);
constexpr u32 kNoAxis = ~u32{0};

/// A 800x400 plot with one x axis spanning [0, 100] and the controller attached.
struct Fixture {
  plot::Plot plot;
  u32 ax = kNoAxis;
  u32 ay = kNoAxis;
  plot::input::Controller controller{plot};

  Fixture() {
    plot.set_viewport({0.0f, 0.0f, 800.0f, 400.0f});
    ax = plot.add_x_axis({"t", {0.0, 100.0}, false, plot::AxisPlace::Bottom, false});
    controller.set_viewport({0.0f, 0.0f, 800.0f, 400.0f});
  }
};

f32 screen_x_of(const plot::Plot& p, u32 axis, f64 data) {
  return static_cast<f32>(p.x_transform(axis).to_screen_x(data));
}

}  // namespace

PLOT_TEST(wheel_zoom_keeps_data_under_cursor_fixed) {
  plot::Plot p;
  p.set_viewport({0, 0, 800, 400});
  const u32 ax = p.add_x_axis({"t", {0.0, 100.0}, true, plot::AxisPlace::Bottom, false});
  plot::input::Controller c(p);
  c.set_viewport({0, 0, 800, 400});
  const f32 cursor_x = 200.0f;
  const f64 before = p.x_transform(ax).to_data_x(cursor_x);
  plot::input::WheelEvent w{cursor_x, 100.0f, 0.0f, 1.0f, 0};
  c.on_wheel(w);
  const f64 after = p.x_transform(ax).to_data_x(cursor_x);
  PLOT_CHECK_NEAR(before, after, 1e-6);
  PLOT_CHECK(plot::Range{p.x_range(ax)}.span() < 100.0);  // zoomed in
}

PLOT_TEST(left_drag_pans_without_changing_span) {
  plot::Plot p;
  p.set_viewport({0, 0, 800, 400});
  const u32 ax = p.add_x_axis({"t", {0.0, 100.0}, true, plot::AxisPlace::Bottom, false});
  const u32 ay = p.add_y_axis({"v", {-1.0, 1.0}, true, plot::AxisPlace::Left, false});
  plot::input::Controller c(p);
  c.set_viewport({0, 0, 800, 400});
  const double span_before = p.x_range(ax).span();
  c.on_pointer({100, 100, 0, 0, plot::input::Button::Left, 0, true, true, false});
  PLOT_CHECK(c.drag_mode() == plot::input::DragMode::Pan);
  c.on_pointer({180, 130, 80, 30, plot::input::Button::Left, 0, true, false, false});
  c.on_pointer({180, 130, 0, 0, plot::input::Button::Left, 0, false, false, true});
  PLOT_CHECK(c.drag_mode() == plot::input::DragMode::None);
  PLOT_CHECK_NEAR(p.x_range(ax).span(), span_before, 1e-9);  // span unchanged
  // 80 px right-drag on an 800 px plot showing [0, 100] reveals 10 units of
  // earlier data: the data follows the cursor. (The brief printed +10.0 here.)
  PLOT_CHECK_NEAR(p.x_range(ax).min, -10.0, 1e-6);
  PLOT_CHECK(p.y_range(ay).max > 1.0);  // moving down raises y range
}

PLOT_TEST(shift_drag_box_zooms_to_selection) {
  plot::Plot p;
  p.set_viewport({0, 0, 800, 400});
  const u32 ax = p.add_x_axis({"t", {0.0, 800.0}, true, plot::AxisPlace::Bottom, false});
  plot::input::Controller c(p);
  c.set_viewport({0, 0, 800, 400});
  const u32 e_shift = 1u << 0;  // Mod::Shift
  c.on_pointer({100, 50, 0, 0, plot::input::Button::Left, e_shift, true, true, false});
  PLOT_CHECK(c.drag_mode() == plot::input::DragMode::BoxZoom);
  c.on_pointer({300, 150, 200, 100, plot::input::Button::Left, e_shift, true, false, false});
  PLOT_CHECK_NEAR(c.selection_rect().x, 100.0, 1e-6);
  PLOT_CHECK_NEAR(c.selection_rect().w, 200.0, 1e-6);
  c.on_pointer({300, 150, 0, 0, plot::input::Button::Left, e_shift, false, false, true});
  PLOT_CHECK_NEAR(p.x_range(ax).min, 100.0, 1e-6);
  PLOT_CHECK_NEAR(p.x_range(ax).max, 300.0, 1e-6);
}

PLOT_TEST(auto_scale_disabled_by_user_interaction) {
  // A wheel zoom or pan MUST clear auto_scale on the affected axis so the range
  // the user chose is not snapped back by the next autoscale.
  plot::Plot p;
  p.set_viewport({0, 0, 800, 400});
  const u32 ax = p.add_x_axis({"t", {0.0, 100.0}, true, plot::AxisPlace::Bottom, false});
  plot::input::Controller c(p);
  c.set_viewport({0, 0, 800, 400});
  c.on_wheel({400.0f, 200.0f, 0.0f, 1.0f, 0});
  PLOT_CHECK(!p.x_axis(ax).auto_scale);
}

// --- resolutions of the brief's ambiguity, pinned ------------------------

PLOT_TEST(box_zoom_below_threshold_is_a_click) {
  plot::Plot p;
  p.set_viewport({0, 0, 800, 400});
  const u32 ax = p.add_x_axis({"t", {0.0, 800.0}, false, plot::AxisPlace::Bottom, false});
  plot::input::Controller c(p);
  c.set_viewport({0, 0, 800, 400});
  c.on_pointer({100, 50, 0, 0, plot::input::Button::Left, kShift, true, true, false});
  c.on_pointer({102, 52, 2, 2, plot::input::Button::Left, kShift, true, false, false});
  c.on_pointer({102, 52, 0, 0, plot::input::Button::Left, kShift, false, false, true});
  PLOT_CHECK(c.drag_mode() == plot::input::DragMode::None);
  PLOT_CHECK_NEAR(p.x_range(ax).min, 0.0, 1e-9);
  PLOT_CHECK_NEAR(p.x_range(ax).max, 800.0, 1e-9);
}

PLOT_TEST(shift_wheel_zooms_x_only) {
  Fixture f;
  f.ay = f.plot.add_y_axis({"v", {-1.0, 1.0}, false, plot::AxisPlace::Left, false});
  f.controller.on_wheel({400.0f, 200.0f, 0.0f, 1.0f, kShift});
  PLOT_CHECK(f.plot.x_range(f.ax).span() < 100.0);
  PLOT_CHECK_NEAR(f.plot.y_range(f.ay).span(), 2.0, 1e-9);
}

PLOT_TEST(ctrl_wheel_zooms_y_only) {
  Fixture f;
  f.ay = f.plot.add_y_axis({"v", {-1.0, 1.0}, false, plot::AxisPlace::Left, false});
  f.controller.on_wheel({400.0f, 200.0f, 0.0f, 1.0f, kCtrl});
  PLOT_CHECK_NEAR(f.plot.x_range(f.ax).span(), 100.0, 1e-9);
  PLOT_CHECK(f.plot.y_range(f.ay).span() < 2.0);
}

PLOT_TEST(hovered_cursor_only_inside_plot_area) {
  plot::Plot p;
  p.set_viewport({0, 0, 800, 400});
  const u32 ax = p.add_x_axis({"t", {0.0, 100.0}, false, plot::AxisPlace::Bottom, false});
  const u32 cid = p.add_cursor(50.0, plot::Color::hex(0xFF0000));
  plot::input::Controller c(p);
  c.set_viewport({0, 0, 800, 400});
  const f32 sx = screen_x_of(p, ax, 50.0);
  c.on_pointer({sx, 200, 0, 0, plot::input::Button::Left, 0, false, false, false});
  PLOT_CHECK(c.hovered_cursor() == cid);
  // The left label strip is outside the plot area.
  c.on_pointer({10, 200, 0, 0, plot::input::Button::Left, 0, false, false, false});
  PLOT_CHECK(c.hovered_cursor() == plot::kInvalid);
  c.on_pointer({sx, 200, 0, 0, plot::input::Button::Left, 0, false, false, false});
  PLOT_CHECK(c.hovered_cursor() == cid);
}

PLOT_TEST(ctrl_drag_moves_the_nearest_cursor) {
  plot::Plot p;
  p.set_viewport({0, 0, 800, 400});
  const u32 ax = p.add_x_axis({"t", {0.0, 100.0}, false, plot::AxisPlace::Bottom, false});
  const u32 cid = p.add_cursor(20.0, plot::Color::hex(0xFF0000));
  plot::input::Controller c(p);
  c.set_viewport({0, 0, 800, 400});
  const f32 sx = screen_x_of(p, ax, 20.0);
  c.on_pointer({sx, 200, 0, 0, plot::input::Button::Left, kCtrl, true, true, false});
  PLOT_CHECK(c.drag_mode() == plot::input::DragMode::MoveCursor);
  c.on_pointer({sx + 100, 200, 100, 0, plot::input::Button::Left, kCtrl, true, false, false});
  c.on_pointer({sx + 100, 200, 0, 0, plot::input::Button::Left, kCtrl, false, false, true});
  PLOT_CHECK(c.drag_mode() == plot::input::DragMode::None);
  PLOT_CHECK(p.cursor(cid).x > 20.0);
  PLOT_CHECK_NEAR(p.cursor(cid).x, p.x_transform(ax).to_data_x(sx + 100), 1e-9);
}

PLOT_TEST(middle_drag_on_x_strip_zooms_x_only) {
  Fixture f;
  f.ay = f.plot.add_y_axis({"v", {-1.0, 1.0}, true, plot::AxisPlace::Left, false});
  const plot::PlotLayout& l = f.plot.layout();
  const f32 strip_x = l.axes.x + 0.5f * l.axes.w;
  const f32 strip_y = l.x_label_area.y + 0.5f * l.x_label_area.h;
  f.controller.on_pointer({strip_x, strip_y, 0, 0, plot::input::Button::Middle, 0, true, true, false});
  PLOT_CHECK(f.controller.drag_mode() == plot::input::DragMode::AxisZoomX);
  // Same sign convention as the wheel: a positive dy zooms in.
  f.controller.on_pointer({strip_x, strip_y + 20, 0, 20, plot::input::Button::Middle, 0, true, false, false});
  f.controller.on_pointer({strip_x, strip_y + 20, 0, 0, plot::input::Button::Middle, 0, false, false, true});
  PLOT_CHECK(f.plot.x_range(f.ax).span() < 100.0);
  PLOT_CHECK_NEAR(f.plot.y_range(f.ay).span(), 2.0, 1e-9);
  PLOT_CHECK(!f.plot.x_axis(f.ax).auto_scale);
  PLOT_CHECK(f.plot.y_axis(f.ay).auto_scale);  // the untouched y axis keeps auto scale
}

PLOT_TEST(middle_drag_on_y_strip_zooms_y_only) {
  Fixture f;
  f.ay = f.plot.add_y_axis({"v", {-1.0, 1.0}, false, plot::AxisPlace::Left, false});
  const plot::PlotLayout& l = f.plot.layout();
  const f32 strip_x = l.y_label_area.x + 0.5f * l.y_label_area.w;
  const f32 strip_y = l.axes.y + 0.5f * l.axes.h;
  f.controller.on_pointer({strip_x, strip_y, 0, 0, plot::input::Button::Middle, 0, true, true, false});
  PLOT_CHECK(f.controller.drag_mode() == plot::input::DragMode::AxisZoomY);
  f.controller.on_pointer({strip_x, strip_y + 20, 0, 20, plot::input::Button::Middle, 0, true, false, false});
  f.controller.on_pointer({strip_x, strip_y + 20, 0, 0, plot::input::Button::Middle, 0, false, false, true});
  PLOT_CHECK_NEAR(f.plot.x_range(f.ax).span(), 100.0, 1e-9);
  PLOT_CHECK(f.plot.y_range(f.ay).span() < 2.0);
}

PLOT_TEST(key_plus_zooms_in_about_the_centre) {
  Fixture f;
  const f64 mid_before = 0.5 * (f.plot.x_range(f.ax).min + f.plot.x_range(f.ax).max);
  f.controller.on_key({plot::input::kKeyZoomIn, 0, true});
  PLOT_CHECK(f.plot.x_range(f.ax).span() < 100.0);
  PLOT_CHECK_NEAR(0.5 * (f.plot.x_range(f.ax).min + f.plot.x_range(f.ax).max), mid_before, 1e-9);
  const f64 span_after = f.plot.x_range(f.ax).span();
  f.controller.on_key({plot::input::kKeyZoomIn, 0, false});  // key-up is ignored
  PLOT_CHECK_NEAR(f.plot.x_range(f.ax).span(), span_after, 1e-12);
}

PLOT_TEST(key_minus_zooms_out) {
  Fixture f;
  f.controller.on_key({plot::input::kKeyZoomOut, 0, true});
  PLOT_CHECK(f.plot.x_range(f.ax).span() > 100.0);
}

PLOT_TEST(key_f_auto_fits_traces) {
  plot::Plot p;
  p.set_viewport({0, 0, 800, 400});
  const u32 ax = p.add_x_axis({"t", {0.0, 100.0}, false, plot::AxisPlace::Bottom, false});
  const u32 ay = p.add_y_axis({"v", {-1.0, 1.0}, false, plot::AxisPlace::Left, false});
  std::vector<f32> ys(51);
  for (u64 i = 0; i < ys.size(); ++i) ys[i] = static_cast<f32>(i) * 0.1f;  // 0.0 .. 5.0
  plot::data::ArraySeries s(std::move(ys), 0.0, 1.0);                       // x = 0 .. 50
  p.add_trace({&s, plot::Color::hex(0x4FA3FF), 1.5f, 0, 0});
  plot::input::Controller c(p);
  c.set_viewport({0, 0, 800, 400});
  c.on_key({plot::input::kKeyFit, 0, true});
  PLOT_CHECK(p.x_range(ax).min < 0.0);
  PLOT_CHECK(p.x_range(ax).max < 100.0);  // fitted to the series' 0..50
  PLOT_CHECK(p.y_range(ay).min < 0.0);
  PLOT_CHECK(p.y_range(ay).max > 1.0);  // fitted to the series' 0..5
  PLOT_CHECK(p.x_axis(ax).auto_scale);  // a fit re-arms auto scale
  PLOT_CHECK(p.y_axis(ay).auto_scale);
}