portapack-mayhem/firmware/application/apps/ui_scanner.cpp

/*
 * Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
 * Copyright (C) 2018 Furrtek
 *
 * This file is part of PortaPack.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#include "ui_scanner.hpp"
#include "ui_fileman.hpp"

using namespace portapack;

namespace ui {

ScannerThread::ScannerThread(std::vector<rf::Frequency> frequency_list) : frequency_list_ {  std::move(frequency_list) }
{
	_manual_search = false;
	create_thread();
}

ScannerThread::ScannerThread(const jammer::jammer_range_t& frequency_range, size_t def_step_hz) : frequency_range_(frequency_range), def_step_hz_(def_step_hz)
{
	_manual_search = true;
	create_thread();
}

ScannerThread::~ScannerThread() {
	stop();
}

void ScannerThread::create_thread()
{
	thread = chThdCreateFromHeap(NULL, 1024, NORMALPRIO + 10, ScannerThread::static_fn, this);
}

void ScannerThread::stop() {
	if( thread ) {
		chThdTerminate(thread);
		chThdWait(thread);
		thread = nullptr;
	}
}

//Set by "userpause"
void ScannerThread::set_scanning(const bool v) {
	_scanning = v;
}

bool ScannerThread::is_scanning() {
	return _scanning;
}

void ScannerThread::set_freq_lock(const uint32_t v) {
	_freq_lock = v;
}

uint32_t ScannerThread::is_freq_lock() {
	return _freq_lock;
}

//Delete an entry from frequency list
//Caller must pause scan_thread AND can't delete a second one until this field is cleared
void ScannerThread::set_freq_del(const rf::Frequency v) {
	_freq_del = v;
}

//Force a one-time forward or reverse frequency index change; OK to do this without pausing scan thread
//(used when rotary encoder is turned)
void ScannerThread::set_index_stepper(const int32_t v) {
	_index_stepper = v;
}

//Set scanning direction; OK to do this without pausing scan_thread
void ScannerThread::set_scanning_direction(bool fwd) {
	int32_t new_stepper = fwd? 1 : -1;

	if (_stepper != new_stepper) {
		_stepper = new_stepper;
		chThdSleepMilliseconds(300);	//Give some pause after reversing scanning direction
	}
}

msg_t ScannerThread::static_fn(void* arg) {
	auto obj = static_cast<ScannerThread*>(arg);
	obj->run();
	return 0;
}

void ScannerThread::run() {
	RetuneMessage message { };

	if (!_manual_search && frequency_list_.size()) {			//IF NOT MANUAL MODE AND THERE IS A FREQUENCY LIST ...
		int32_t size = frequency_list_.size();
		int32_t frequency_index = (_stepper > 0)? size : 0;		//Forcing wraparound to starting frequency on 1st pass

		while( !chThdShouldTerminate() ) {
			bool force_one_step = (_index_stepper != 0);
			int32_t step = force_one_step? _index_stepper : _stepper;		//_index_stepper direction takes priority

			if (_scanning || force_one_step) {						//Scanning, or paused and using rotary encoder
				if ((_freq_lock == 0) || force_one_step) {			//normal scanning (not performing freq_lock)
					frequency_index += step;
					if (frequency_index >= size)					//Wrap
						frequency_index = 0;	
					else if (frequency_index < 0)
						frequency_index = size-1;

					if (force_one_step)
						_index_stepper = 0;

					receiver_model.set_tuning_frequency(frequency_list_[frequency_index]);	// Retune
				} 
				message.freq = frequency_list_[frequency_index];
				message.range = frequency_index;	//Inform freq (for coloring purposes also!)
				EventDispatcher::send_message(message);		
			}
			else if (_freq_del != 0) {				//There is a frequency to delete
				for (int32_t i = 0; i < size; i++) {	//Search for the freq to delete
					if (frequency_list_[i] == _freq_del) 
					{							//found: Erase it
						frequency_list_.erase(frequency_list_.begin() + i);
						size = frequency_list_.size();
						break;
					}
				}
				_freq_del = 0;					//deleted.
			}

			chThdSleepMilliseconds(SCANNER_SLEEP_MS);	//Needed to (eventually) stabilize the receiver into new freq
		}
	}else if(_manual_search && (def_step_hz_ > 0)) 	// manual search range mode
	{
		int64_t size = (frequency_range_.max - frequency_range_.min) / def_step_hz_;
		int64_t frequency_index = (_stepper > 0)? size : 0;				//Forcing wraparound to starting frequency on 1st pass

		while( !chThdShouldTerminate() ) {
			bool force_one_step = (_index_stepper != 0);
			int32_t step = force_one_step? _index_stepper : _stepper;		//_index_stepper direction takes priority

			if (_scanning || force_one_step) {					//Scanning, or paused and using rotary encoder
				if ((_freq_lock == 0) || force_one_step) {		//normal scanning (not performing freq_lock)
					frequency_index += step;
					if (frequency_index >= size)				//Wrap
						frequency_index = 0;	
					else if (frequency_index < 0)
						frequency_index = size-1;

					if (force_one_step)
						_index_stepper = 0;

					receiver_model.set_tuning_frequency(frequency_range_.min + frequency_index * def_step_hz_);	// Retune
				} 
				message.freq = frequency_range_.min + frequency_index * def_step_hz_;
				message.range = 0;						//Inform freq (for coloring purposes also!)
				EventDispatcher::send_message(message);
			} 

			chThdSleepMilliseconds(SCANNER_SLEEP_MS);	//Needed to (eventually) stabilize the receiver into new freq
		}
	}
}

void ScannerView::bigdisplay_update(int32_t v) {
	if (v != bigdisplay_current_color) {				
		if (v!=-1)
			bigdisplay_current_color = v;				// -1 means refresh display but keep current color

		switch (bigdisplay_current_color) {
			case BDC_GREY:	big_display.set_style(&style_grey);   break;
			case BDC_YELLOW:big_display.set_style(&style_yellow); break;
			case BDC_GREEN:	big_display.set_style(&style_green);  break;
			case BDC_RED:	big_display.set_style(&style_red);    break;
			default:	break;
		}

		// update frequency display
		bigdisplay_current_frequency = current_frequency;
		big_display.set(bigdisplay_current_frequency);
	} else {

		// no style change, but update frequency display if it's changed
		if (current_frequency != bigdisplay_current_frequency) {
			bigdisplay_current_frequency = current_frequency;
			big_display.set(bigdisplay_current_frequency);
		}
	}
}

void ScannerView::handle_retune(int64_t freq, uint32_t freq_idx) {
	current_index = freq_idx;	//since it is an ongoing scan, this is a new index
	current_frequency = freq;

	if (scan_thread) {
		switch (scan_thread->is_freq_lock())
		{
		case 0:										//NO FREQ LOCK, ONGOING STANDARD SCANNING
			bigdisplay_update(BDC_GREY);
			break;
		case 1:										//STARTING LOCK FREQ
			bigdisplay_update(BDC_YELLOW);
			break;
		case MAX_FREQ_LOCK:							//FREQ IS STRONG: GREEN and scanner will pause when on_statistics_update()
			bigdisplay_update(BDC_GREEN);
			break;
		default:	//freq lock is checking the signal, do not update display
			return;
		}
	}

	if (!manual_search) {
		if (frequency_list.size() > 0) {
			text_current_index.set( to_string_dec_uint(freq_idx + 1, 3) );
		}

		if (freq_idx < description_list.size() && description_list[freq_idx].size() > 1)
			desc_current_index.set( description_list[freq_idx] );	//Show description from file
		else
			desc_current_index.set(desc_freq_list_scan);			//Show Scan file name (no description in file)
	}
}

void ScannerView::focus() {
	field_mode.focus();
}

ScannerView::~ScannerView() {
	// make sure to stop the thread before shutting down the receiver
	scan_thread.reset();
	audio::output::stop();
	receiver_model.disable();
	baseband::shutdown();
}

void ScannerView::show_max_index() {		//show total number of freqs to scan
	text_current_index.set("---");

	if (frequency_list.size() == FREQMAN_MAX_PER_FILE ) {
		text_max_index.set_style(&style_red);
		text_max_index.set( "/ " + to_string_dec_uint(FREQMAN_MAX_PER_FILE ) + " (DB MAX!)");
	}
	else {
		text_max_index.set_style(&style_grey);
		text_max_index.set( "/ " + to_string_dec_uint(frequency_list.size()));
	}
}

ScannerView::ScannerView(
	NavigationView& nav
	) : nav_ { nav } , loaded_file_name { "SCANNER" }
{
	add_children({
		&labels,
		&field_lna,
		&field_vga,
		&field_rf_amp,
		&field_volume,
		&field_bw,
		&field_squelch,
		&field_browse_wait,
		&field_lock_wait,
		&button_load,
		&button_clear,
		&rssi,
		&text_current_index,
		&text_max_index,
		&desc_current_index,
		&big_display,
		&button_manual_start,
		&button_manual_end,
		&field_mode,
		&field_step,
		&button_manual_search,
		&button_pause,
		&button_dir,
		&button_audio_app,
		&button_mic_app,
		&button_add,
		&button_remove

	});

	//Populate option text for these fields
	freqman_set_modulation_option( field_mode );
	freqman_set_step_option( field_step );

	// Default starting modulation (these may be overridden in SCANNER.TXT)
	change_mode(AM_MODULATION);					//Default modulation
	field_mode.set_by_value(AM_MODULATION);		//Reflect the mode into the manual selector
	field_step.set_by_value(9000);				//Default step interval (Hz)

	//FUTURE: perhaps additional settings should be stored in persistent memory vs using defaults
	//HELPER: Pre-setting a manual range, based on stored frequency
	rf::Frequency stored_freq = persistent_memory::tuned_frequency();
	frequency_range.min = stored_freq - 1000000;
	button_manual_start.set_text(to_string_short_freq(frequency_range.min));
	frequency_range.max = stored_freq + 1000000;
	button_manual_end.set_text(to_string_short_freq(frequency_range.max));

	// Button to load txt files from the FREQMAN folder
	button_load.on_select = [this, &nav](Button&) {
		auto open_view = nav.push<FileLoadView>(".TXT");
		open_view->on_changed = [this](std::filesystem::path new_file_path) {

			std::string dir_filter = "FREQMAN/";
			std::string str_file_path = new_file_path.string();

			if (str_file_path.find(dir_filter) != string::npos) { // assert file from the FREQMAN folder
				scan_pause();
				// get the filename without txt extension so we can use load_freqman_file fcn
				std::string str_file_name = new_file_path.stem().string();
				frequency_file_load(str_file_name, true);
			} else {
				nav_.display_modal("LOAD ERROR", "A valid file from\nFREQMAN directory is\nrequired.");
			}
		};
	};

	// Button to clear in-memory frequency list
	button_clear.on_select = [this, &nav](Button&) {
		if (scan_thread && frequency_list.size()) {
			scan_thread->stop();					//STOP SCANNER THREAD
			frequency_list.clear();
			description_list.clear();

			show_max_index();						//UPDATE new list size on screen
			text_current_index.set("");
			desc_current_index.set(desc_freq_list_scan);
			scan_thread->set_freq_lock(0); 			//Reset the scanner lock

			//FUTURE: Consider switching to manual search mode automatically after clear (but would need to validate freq range)
		}
	};

	// Button to configure starting frequency for a manual range search
	button_manual_start.on_select = [this, &nav](Button& button) {
		auto new_view = nav_.push<FrequencyKeypadView>(frequency_range.min);
		new_view->on_changed = [this, &button](rf::Frequency f) {
			frequency_range.min = f;
			button_manual_start.set_text(to_string_short_freq(f));
		};
	};
	
	// Button to configure ending frequency for a manual range search
	button_manual_end.on_select = [this, &nav](Button& button) {
		auto new_view = nav.push<FrequencyKeypadView>(frequency_range.max);
		new_view->on_changed = [this, &button](rf::Frequency f) {
			frequency_range.max = f;
			button_manual_end.set_text(to_string_short_freq(f));
		};
	};

	// Button to pause/resume scan (note that some other buttons will trigger resume also)
	button_pause.on_select = [this](ButtonWithEncoder&) {
		if ( userpause )
			user_resume();
		else {
			scan_pause();
			button_pause.set_text("<RESUME>");	//PAUSED, show resume
			userpause=true;
		}
	};

	// Encoder dial causes frequency change when focus is on pause button
	button_pause.on_change = [this]() {
		int32_t encoder_delta { (button_pause.get_encoder_delta()>0)? 1 : -1 };

		if (scan_thread)
			scan_thread->set_index_stepper(encoder_delta);

		//Restart browse timer when frequency changes
		if (browse_timer != 0)
			browse_timer = 1;

		button_pause.set_encoder_delta( 0 );
	};

	// Button to switch to Audio app
	button_audio_app.on_select = [this](Button&) {
		if (scan_thread)
			scan_thread->stop();
		nav_.pop();
		nav_.push<AnalogAudioView>();
	};

	// Button to switch to Mic app
	button_mic_app.on_select = [this](Button&) {
		if (scan_thread)
			scan_thread->stop();
		nav_.pop();
		nav_.push<MicTXView>();
	};

	// Button to delete current frequency from scan Freq List
	button_remove.on_select = [this](Button&) {
		if (scan_thread && (frequency_list.size() > current_index)) {
			scan_thread->set_scanning(false);		//PAUSE Scanning if necessary

			// Remove frequency from the Freq List in memory (it is not removed from the file)
			scan_thread->set_freq_del(frequency_list[current_index]);
			description_list.erase(description_list.begin() + current_index);
			frequency_list.erase(frequency_list.begin() + current_index);

			show_max_index();						//UPDATE new list size on screen
			desc_current_index.set("");				//Clean up description (cosmetic detail)
			scan_thread->set_freq_lock(0); 			//Reset the scanner lock
		}
	};

	// Button to toggle between Manual Search and Freq List Scan modes
	button_manual_search.on_select = [this](Button&) {
		if (!manual_search) {
			if (!frequency_range.min || !frequency_range.max) {
				nav_.display_modal("Error", "Both START and END freqs\nneed a value");
			} else if (frequency_range.min > frequency_range.max) {
				nav_.display_modal("Error", "END freq\nis lower than START");
			} else {
				manual_search = true;					//Switch to Manual Search mode
			}
		} else {
			manual_search = false;						// Switch to List Scan mode
		}

		audio::output::stop();

		if (scan_thread)
			scan_thread->stop();					//STOP SCANNER THREAD

		if ( userpause ) 							//If user-paused, resume
			user_resume();

		start_scan_thread(); 						//RESTART SCANNER THREAD in selected mode
	};

	// Mode field was changed (AM/NFM/WFM)
	field_mode.on_change = [this](size_t, OptionsField::value_t v) {
		receiver_model.disable();
		baseband::shutdown();
		change_mode((freqman_index_t)v);
		if ( scan_thread && !scan_thread->is_scanning() ) 	//for some motive, audio output gets stopped.
			audio::output::start();						//So if scan was stopped we resume audio
		receiver_model.enable(); 
	};

	// Step field was changed (Hz) -- only affects manual Search mode
	field_step.on_change = [this](size_t, OptionsField::value_t v) {
		(void)v;		// prevent compiler Unused warning

		if ( manual_search && scan_thread ) {
			//Restart scan thread with new step value
			scan_thread->stop();						//STOP SCANNER THREAD

			//Resuming pause automatically
			//FUTURE: Consider whether we should stay in Pause mode...
			if ( userpause ) 							//If user-paused, resume
				user_resume();

			start_scan_thread();				 		//RESTART SCANNER THREAD in Manual Search mode
		}
	};

	// Button to toggle Forward/Reverse
	button_dir.on_select = [this](Button&) {
		fwd = !fwd;
		if (scan_thread)
			scan_thread->set_scanning_direction(fwd);
		if ( userpause ) 						//If user-paused, resume
			user_resume();
		button_dir.set_text(fwd? "REVERSE":"FORWARD");
		bigdisplay_update(BDC_GREY);			//Back to grey color
	};

	// Button to add current frequency (found during Search) to the Scan Frequency List
	button_add.on_select = [this](Button&) { 
		File scanner_file;
		const std::string freq_file_path = "FREQMAN/" + loaded_file_name + ".TXT";
		auto result = scanner_file.open(freq_file_path);	//First search if freq is already in txt
		
		if (!result.is_valid()) {
			const std::string frequency_to_add = "f=" 
				+ to_string_dec_uint(current_frequency / 1000) 
				+ to_string_dec_uint(current_frequency % 1000UL, 3, '0');

			bool found=false;
			constexpr size_t buffer_size = 1024;
			char buffer[buffer_size];

			for (size_t pointer = 0, freq_str_idx = 0; pointer < scanner_file.size(); pointer += buffer_size) {
				size_t adjusted_buffer_size;
				if (pointer + buffer_size >= scanner_file.size()) {
					memset(buffer, 0, sizeof(buffer));
					adjusted_buffer_size = scanner_file.size() - pointer;
				}
				else {
					adjusted_buffer_size = buffer_size;
				}

				scanner_file.seek(pointer);
				scanner_file.read(buffer, adjusted_buffer_size);

				for (size_t i = 0; i < adjusted_buffer_size; ++i) {
					if (buffer[i] == frequency_to_add.data()[freq_str_idx]) {
						++freq_str_idx;
						if (freq_str_idx >= frequency_to_add.size()) {
							found = true;
							break;
						}
					}
					else {
						freq_str_idx = 0;
					}
				}

				if (found) {
					break;
				}
			}	

			if (found) {
				nav_.display_modal("Error", "Frequency already exists");
				bigdisplay_update(-1);				//After showing an error
			}
			else {
				scanner_file.append(freq_file_path); //Second: append if it is not there
				scanner_file.write_line(frequency_to_add);

				// Add to frequency_list in memory too, since we can now switch back from manual mode
				// Note that we are allowing freqs to be added to file (code above) that exceed the max count we can load into memory
				if (frequency_list.size() < FREQMAN_MAX_PER_FILE) {
					frequency_list.push_back(current_frequency);
					description_list.push_back("");

					show_max_index();				//Display updated frequency list size
				}
			}
		} else
		{
			nav_.display_modal("Error", "Cannot open " + loaded_file_name + ".TXT\nfor appending freq.");
			bigdisplay_update(-1);					//After showing an error
		}
	};

	//PRE-CONFIGURATION:
	field_browse_wait.on_change = [this](int32_t v) { browse_wait = v; };
	field_browse_wait.set_value(5);

	field_lock_wait.on_change = [this](int32_t v) { lock_wait = v; };
	field_lock_wait.set_value(2);

	field_squelch.on_change = [this](int32_t v) { squelch = v; };
	field_squelch.set_value(-10);

	field_volume.set_value((receiver_model.headphone_volume() - audio::headphone::volume_range().max).decibel() + 99);
	field_volume.on_change = [this](int32_t v) { this->on_headphone_volume_changed(v);	};

	// LEARN FREQUENCIES
	std::string scanner_txt = "SCANNER";
	frequency_file_load(scanner_txt);
}

void ScannerView::frequency_file_load(std::string file_name, bool stop_all_before) {

	bool found_range { false };
	bool found_single { false };
	freqman_index_t def_mod_index { -1 };
	freqman_index_t def_bw_index { -1 };
	freqman_index_t def_step_index { -1 };

	// stop everything running now if required
	if (stop_all_before) {
		scan_thread->stop();
		frequency_list.clear(); // clear the existing frequency list (expected behavior)
		description_list.clear();
	}

	if ( load_freqman_file(file_name, database)  ) {
		loaded_file_name = file_name; // keep loaded filename in memory
		for(auto& entry : database) {									// READ LINE PER LINE
			if (frequency_list.size() < FREQMAN_MAX_PER_FILE) {			//We got space!
				//
				// Get modulation & bw & step from file if specified
				// Note these values could be different for each line in the file, but we only look at the first one
				//
				// Note that freqman requires a very specific string for these parameters,
				// so check syntax in frequency file if specified value isn't being loaded
				//
				if (def_mod_index == -1)
					def_mod_index = entry.modulation;

				if (def_bw_index == -1)
					def_bw_index = entry.bandwidth;

				if (def_step_index == -1)
					def_step_index = entry.step;

				// Get frequency
				if (entry.type == RANGE)  {
					if (!found_range) {
						// Set Start & End Search Range instead of populating the small in-memory frequency table
						// NOTE:  There may be multiple single frequencies in file, but only one search range is supported.
						found_range = true;
						frequency_range.min = entry.frequency_a;
						button_manual_start.set_text(to_string_short_freq(frequency_range.min));
						frequency_range.max = entry.frequency_b;
						button_manual_end.set_text(to_string_short_freq(frequency_range.max));
					}
				}
				else if ( entry.type == SINGLE )  {
					found_single = true;
					frequency_list.push_back(entry.frequency_a);
					description_list.push_back(entry.description);
				}
				else if ( entry.type == HAMRADIO ) {
					// For HAM repeaters, add both receive & transmit frequencies to scan list and modify description
					// (FUTURE fw versions might handle these differently)
					found_single = true;
					frequency_list.push_back(entry.frequency_a);
					description_list.push_back("R:" + entry.description);

					if ( (entry.frequency_a != entry.frequency_b) && 
						 (frequency_list.size() < FREQMAN_MAX_PER_FILE) ) {
						frequency_list.push_back(entry.frequency_b);
						description_list.push_back("T:" + entry.description);
					 }			 
				}
			}
			else
			{
				break; //No more space: Stop reading the txt file !
			}		
		}
	} 
	else 
	{
		loaded_file_name = "SCANNER"; // back to the default frequency file
		desc_current_index.set(" NO " + file_name + ".TXT FILE ..." );
	}

	desc_freq_list_scan = loaded_file_name+".TXT";
	if (desc_freq_list_scan.length() > 23) {	// Truncate description and add ellipses if long file name
		desc_freq_list_scan.resize(20);
		desc_freq_list_scan = desc_freq_list_scan + "...";
	}
		
	if ((def_mod_index != -1) && (def_mod_index != (freqman_index_t)field_mode.selected_index_value()))
		field_mode.set_by_value( def_mod_index );	//Update mode (also triggers a change callback that disables & reenables RF background)

	if (def_bw_index != -1)						//Update BW if specified in file
		field_bw.set_selected_index( def_bw_index );

	if (def_step_index != -1) 					//Update step if specified in file
		field_step.set_selected_index( def_step_index );

	audio::output::stop();

	if ( userpause ) 							//If user-paused, resume
		user_resume();

	// Scan list if we found one, otherwise do manual range search
	manual_search = !found_single;

	start_scan_thread();
}

void ScannerView::update_squelch_while_paused(int32_t max_db) {
	//Update audio & color based on signal level even if paused
	if (++color_timer > 2) {					//Counter to reduce color toggling when weak signal
		if (max_db > squelch) {
			audio::output::start();				//Re-enable audio when signal goes above squelch
			on_headphone_volume_changed(field_volume.value()); // quick fix to make sure WM8731S chips don't stay silent after pause	
			bigdisplay_update(BDC_GREEN);
		} else {
			audio::output::stop();				//Silence audio when signal drops below squelch
			bigdisplay_update(BDC_GREY);		//Back to grey color
		}

		color_timer = 0;
	}
}

void ScannerView::on_statistics_update(const ChannelStatistics& statistics) {

	if (userpause) {
		update_squelch_while_paused(statistics.max_db);
	}
	else if ( scan_thread ) 							//Scanning not user-paused
	{
		//Resume regardless of signal strength if browse time reached
		if ((browse_wait != 0) && (browse_timer >= (browse_wait * STATISTICS_UPDATES_PER_SEC)) ) {
			browse_timer = 0;
			scan_resume();								//Resume scanning
		} 
		else
		{
			if (statistics.max_db > squelch ) {  		//There is something on the air...(statistics.max_db > -squelch) 
				if (scan_thread->is_freq_lock() >= MAX_FREQ_LOCK) { //Pause scanning when signal checking time reached
					if (!browse_timer) 					//Don't bother pausing if already paused
						scan_pause();
					browse_timer++;						// browse_timer!=0 is also an indication that we've paused the scan
					update_squelch_while_paused(statistics.max_db);
				} else {
					scan_thread->set_freq_lock( scan_thread->is_freq_lock() + 1 ); //in lock period, still analyzing the signal
					if (browse_timer)					//Continue incrementing browse timer while paused
						browse_timer++;
				}
				lock_timer = 0;							//Keep resetting lock timer while signal remains
			} else {									//There is NOTHING on the air
				if (!browse_timer) {
					// Signal lost and scan was never paused
					if (scan_thread->is_freq_lock() > 0) {	//But are we already in freq_lock ?
						bigdisplay_update(BDC_GREY);		//Back to grey color
						scan_thread->set_freq_lock(0); 		//Reset the scanner lock, since there is no sig
					}
				} else {
					//Signal lost and scan is still paused
					lock_timer++;						//Bump paused time
					if (lock_timer >= (lock_wait * STATISTICS_UPDATES_PER_SEC)) {	//Stay on freq until lock_wait time elapses
						browse_timer = 0;
						scan_resume();
					} else {
						browse_timer++;				//Bump browse time too (may hit that limit before lock_timer reached)
						update_squelch_while_paused(statistics.max_db);
					}
				} 
			}
		} 
	}
}

void ScannerView::scan_pause() {
	if (scan_thread && scan_thread->is_scanning()) {
		scan_thread->set_freq_lock(0); 		//Reset the scanner lock (because user paused, or MAX_FREQ_LOCK reached) for next freq scan	
		scan_thread->set_scanning(false); 	// WE STOP SCANNING
	}
	audio::output::start();
	on_headphone_volume_changed(field_volume.value()); // quick fix to make sure WM8731S chips don't stay silent after pause	
}

void ScannerView::scan_resume() {
	audio::output::stop();
	bigdisplay_update(BDC_GREY);			//Back to grey color

	if (scan_thread) {
		scan_thread->set_index_stepper(fwd? 1 : -1);
		scan_thread->set_scanning(true);	// RESUME!
	}
}

void ScannerView::user_resume() {
	browse_timer = browse_wait * STATISTICS_UPDATES_PER_SEC;	//Will trigger a scan_resume() on_statistics_update, also advancing to next freq.
	button_pause.set_text("<PAUSE>");	//Show button for pause, arrows indicate rotary encoder enabled for freq change
	userpause=false;					//Resume scanning
}

void ScannerView::on_headphone_volume_changed(int32_t v) {
	const auto new_volume = volume_t::decibel(v - 99) + audio::headphone::volume_range().max;
	receiver_model.set_headphone_volume(new_volume);
}

void ScannerView::change_mode(freqman_index_t new_mod) { //Before this, do a scan_thread->stop();  After this do a start_scan_thread()
	using option_t = std::pair<std::string, int32_t>;
	using options_t = std::vector<option_t>;
	options_t bw;
	field_bw.on_change = [this](size_t n, OptionsField::value_t) { 
		(void)n;  //avoid unused warning 
	};

	switch (new_mod) {
	case AM_MODULATION:
		freqman_set_bandwidth_option( new_mod , field_bw );
		baseband::run_image(portapack::spi_flash::image_tag_am_audio);
		receiver_model.set_modulation(ReceiverModel::Mode::AMAudio);
		field_bw.set_selected_index(0);
		receiver_model.set_am_configuration(field_bw.selected_index());
		field_bw.on_change = [this](size_t n, OptionsField::value_t) { receiver_model.set_am_configuration(n);	};		
		receiver_model.set_sampling_rate(3072000);	receiver_model.set_baseband_bandwidth(1750000); 
		break;	
	case NFM_MODULATION:	//bw 16k (2) default
		freqman_set_bandwidth_option( new_mod , field_bw );
		baseband::run_image(portapack::spi_flash::image_tag_nfm_audio);
		receiver_model.set_modulation(ReceiverModel::Mode::NarrowbandFMAudio);
		field_bw.set_selected_index(2);
		receiver_model.set_nbfm_configuration(field_bw.selected_index());
		field_bw.on_change = [this](size_t n, OptionsField::value_t) { 	receiver_model.set_nbfm_configuration(n); };
		receiver_model.set_sampling_rate(3072000);	receiver_model.set_baseband_bandwidth(1750000);
		break;
	case WFM_MODULATION:
		freqman_set_bandwidth_option( new_mod , field_bw );
		baseband::run_image(portapack::spi_flash::image_tag_wfm_audio);
		receiver_model.set_modulation(ReceiverModel::Mode::WidebandFMAudio);
		field_bw.set_selected_index(0);
		receiver_model.set_wfm_configuration(field_bw.selected_index());
		field_bw.on_change = [this](size_t n, OptionsField::value_t) {	receiver_model.set_wfm_configuration(n); };
		receiver_model.set_sampling_rate(3072000);	receiver_model.set_baseband_bandwidth(2000000);	
		break;
	default:
		break;
	}
}

void ScannerView::start_scan_thread() {
	receiver_model.enable(); 
	receiver_model.set_squelch_level(0);
	show_max_index();

	//Start Scanner Thread
	//FUTURE: Consider passing additional control flags (fwd,userpause,etc) to scanner thread at start (perhaps in a data structure)
	if (manual_search) {
		button_manual_search.set_text("SCAN");	//Update meaning of Manual Scan button
		desc_current_index.set(desc_freq_range_search);
		scan_thread = std::make_unique<ScannerThread>(frequency_range, field_step.selected_index_value() );
	} else {
		button_manual_search.set_text("SRCH");	//Update meaning of Manual Scan button
		desc_current_index.set(desc_freq_list_scan);
		scan_thread = std::make_unique<ScannerThread>(frequency_list);
	}

	scan_thread->set_scanning_direction(fwd);
}

} /* namespace ui */