// Top-level overlay chrome shared across panels: which panels are visible, the
// global "show debug details" switch, rolling frame-timing stats, and the main
// menu bar that drives them. Keeping this in one place lets the individual panels
// stay focused on their own pipeline while presenting a consistent shell.
#pragma once

#include <algorithm>

namespace coop
{

// Visibility + verbosity shared by all panels. Panels read `debug_details` to
// gate verbose diagnostics; the main loop reads the per-panel flags to decide
// what to draw.
struct UiState
{
	bool show_controllers = true;
	bool show_injection = true;
	bool show_video = true;
	bool show_audio = true;
	bool show_log = true;
	bool debug_details = false; // off = general status; on = full diagnostics
};

// The overlay panels, for the shared default layout below.
enum class Panel
{
	Injection,   // left column, full height (room for hook diagnostics)
	Controllers, // center column, top
	Video,       // center column, below Controllers
	Audio,       // center column, below Video
	Log,         // right column, full height (max room for the log stream)
};

// Position + size the next ImGui window per the default 3-column layout, so panels
// open without overlapping or needing a manual resize. First-use only, unless a
// layout reset was just requested (then it re-applies once). Call right before the
// panel's ImGui::Begin.
void apply_panel_layout(Panel panel);

// "View -> Reset layout" sets this; it forces apply_panel_layout to re-place every
// panel on the next frame. apply_layout_end_frame() clears it after the panels draw.
void request_layout_reset();
void apply_layout_end_frame();

// Rolling frame-timing over a ~1 s window, recomputed each window so the status
// bar can show a stable FPS plus the min/max frame time (jitter) underneath it.
class FrameStats
{
public:
	// Number of frame samples kept for the graphs (~2 s at 120 FPS).
	static constexpr int kHistory = 240;

	void tick(float dt_ms)
	{
		if (dt_ms < cur_min_)
		{
			cur_min_ = dt_ms;
		}
		if (dt_ms > cur_max_)
		{
			cur_max_ = dt_ms;
		}
		accum_ms_ += dt_ms;
		++frames_;
		if (accum_ms_ >= 1000.0f && frames_ > 0)
		{
			avg_ms_ = accum_ms_ / static_cast<float>(frames_);
			min_ms_ = cur_min_;
			max_ms_ = cur_max_;
			cur_min_ = 1.0e9f;
			cur_max_ = 0.0f;
			accum_ms_ = 0.0f;
			frames_ = 0;
		}

		history_[hist_pos_] = dt_ms;
		hist_pos_ = (hist_pos_ + 1) % kHistory;
		if (hist_count_ < kHistory)
		{
			++hist_count_;
		}
	}

	// --- 1 s windowed aggregates (stable readout for the menu bar) ---------
	[[nodiscard]] float avg_ms() const
	{
		return avg_ms_;
	}
	[[nodiscard]] float min_ms() const
	{
		return min_ms_;
	}
	[[nodiscard]] float max_ms() const
	{
		return max_ms_;
	}
	[[nodiscard]] float fps() const
	{
		return avg_ms_ > 0.0f ? 1000.0f / avg_ms_ : 0.0f;
	}

	// --- Sample history (for graphs) ---------------------------------------
	[[nodiscard]] int history_size() const
	{
		return hist_count_;
	}

	// Copy the frame-time samples (ms) into `out` oldest-to-newest; `out` must
	// hold at least kHistory floats. Returns the number written.
	int copy_frame_ms(float* out) const
	{
		const int start = (hist_pos_ - hist_count_ + kHistory * 2) % kHistory;
		for (int i = 0; i < hist_count_; ++i)
		{
			out[i] = history_[(start + i) % kHistory];
		}
		return hist_count_;
	}

	// min / max / mean over the whole retained history (order-independent).
	void history_stats(float& min_ms, float& max_ms, float& avg_ms) const
	{
		if (hist_count_ == 0)
		{
			min_ms = max_ms = avg_ms = 0.0f;
			return;
		}
		float mn = 1.0e9f, mx = 0.0f, sum = 0.0f;
		for (int i = 0; i < hist_count_; ++i)
		{
			const float v = history_[i];
			mn = std::min(mn, v);
			mx = std::max(mx, v);
			sum += v;
		}
		min_ms = mn;
		max_ms = mx;
		avg_ms = sum / static_cast<float>(hist_count_);
	}

private:
	float accum_ms_ = 0.0f;
	int frames_ = 0;
	float cur_min_ = 1.0e9f;
	float cur_max_ = 0.0f;
	float avg_ms_ = 0.0f;
	float min_ms_ = 0.0f;
	float max_ms_ = 0.0f;

	float history_[kHistory] = {};
	int hist_pos_ = 0;
	int hist_count_ = 0;
};

// Draw the main menu bar (app name, View menu of panel toggles + debug switch,
// and a right-aligned FPS readout). Returns the menu bar height so the caller can
// keep panels clear of it on first layout.
float draw_main_menu_bar(UiState& ui, const FrameStats& stats);

} // namespace coop