#include "playlist_manager.h"
#include <SD.h>
#include "spi_master.h"
#include <ArduinoJson.h>

PlaylistManager::PlaylistManager() {
	scan_files();
}

void PlaylistManager::scan_files() {
	SPIMaster::select_sd();
	std::vector<String> folders;
	File root = SD.open("/");
	File entry;
	while (entry = root.openNextFile()) {
		String foldername = entry.name();
		if (foldername.startsWith("/.")) continue;
		foldername.remove(foldername.length());
		folders.push_back(foldername);
		_check_for_special_chars(foldername);
		entry.close();
	}

	_map.clear();
	if (!SD.exists("/_mapping.txt\n")) {
		ERROR("WARNING: File /_mapping.txt not found.\n");
	} else {
		File f = SD.open("/_mapping.txt");
		DEBUG("Reading /_mapping.txt...\n");
		while (f.available()) {
			char buffer[512];
			size_t pos = f.readBytesUntil('\n', buffer, 511);
			buffer[pos] = '\0';

			String data = buffer;
			uint8_t eq = data.indexOf('=');
			if (eq>0 && eq<data.length()-1) {
				String rfid_id = data.substring(0, eq);
				String folder = data.substring(eq + 1);
				TRACE("  Adding mapping: %s=>%s\n", rfid_id.c_str(), folder.c_str());
				_map[rfid_id] = folder;
				
				if (folder.charAt(0)=='/') {
					bool found=false;
					for (String f: folders) {
						if (f.equals(folder)) {
							found = true;
							break;
						}
					}
					if (!found) {
						INFO("WARNING: Found mapping for RFID id %s which maps to non-existing folder %s!\n", rfid_id.c_str(), folder.c_str());
					}
				}
			}
		}
		f.close();
	}
	root.close();

	_unmapped_folders.clear();
	for (String folder: folders) {
		bool found = false;
		for(std::map<String, String>::iterator it = _map.begin(); it != _map.end(); it++) {
			if (it->second.equals(folder)) {
				found = true;
				break;
			}
		}
		if (!found) {
			// Checking folder for media files
			File dir = SD.open(folder);
			while (entry = dir.openNextFile()) {
				String filename = entry.name();
				filename = filename.substring(folder.length() + 1);
				if (!filename.startsWith(".") && filename.endsWith(".mp3")) {
					found = true;
				}
				entry.close();
				if (found) break;
			}
			if (found) {
				_unmapped_folders.push_back(folder);
			}
		}
	}
	SPIMaster::select_sd(false);
}

void PlaylistManager::_check_for_special_chars(String s) {
	for(int i=0; i<s.length(); i++) {
		char c = s.charAt(i);
		if (c < 0x20 || c >= 0x7F) {
			ERROR("WARNING: Folder / file '%s' contains non-ascii chars!\n", s.c_str());
			return;
		}
	}
}

Playlist* PlaylistManager::get_playlist_for_id(String id) {
	if (!_map.count(id)) return NULL;
	String folder = _map[id];
	return get_playlist_for_folder(folder);
}

Playlist* PlaylistManager::get_playlist_for_folder(String folder) {
	Playlist* p;
	if (!_playlists.count(folder)) {
		p = new Playlist(folder);
		_playlists[folder] = p;
		if (p->persistence == PERSIST_PERMANENTLY) {
			// TODO Load persistence from file
			String search = folder;
			search += "=";
			SPIMaster::select_sd();
			if (SD.exists("/_positions.txt")) {
				File f = SD.open("/_positions.txt", "r");
				while (true) {
					String s = f.readStringUntil('\n');
					if (s.length()==0) break;
					if (s.startsWith(search)) {
						s = s.substring(search.length());
						int idx = s.indexOf(',');
						String title_index = s.substring(0, idx);
						uint32_t position = s.substring(idx+1).toInt();
						p->set_track_by_id(title_index);
						p->set_position(position);
						break;
					}
				}
				f.close();
			}
			SPIMaster::select_sd(false);
		}
	} else {
		p = _playlists[folder];
		if (p->persistence == PERSIST_NONE) {
			p->reset();
		}
	}
	return p;
}

void PlaylistManager::dump_ids() {
	for (std::map<String, String>::iterator it = _map.begin(); it!=_map.end(); it++) {
		INFO("  %s -> %s\n", it->first.c_str(), it->second.c_str());
	}
}

String PlaylistManager::json() {
	DynamicJsonDocument json(10240);
	json["_type"] = "playlist_manager";
	JsonObject folders = json.createNestedObject("folders");
	for (std::map<String, String>::iterator it = _map.begin(); it!=_map.end(); it++) {
		folders[it->second] = it->first;
	}
	JsonArray started = json.createNestedArray("started");
	for (std::map<String, Playlist*>::iterator it = _playlists.begin(); it!=_playlists.end(); it++) {
		if (it->second->is_fresh()) continue;
		started.add(it->first);
	}
	JsonArray unmapped = json.createNestedArray("unmapped");
	for(String folder : _unmapped_folders) {
		unmapped.add(folder);
	}
	return json.as<String>();
}

bool PlaylistManager::add_mapping(String id, String folder) {
	DEBUG("Adding mapping: %s=>%s\n", id.c_str(), folder.c_str());
	_map[id] = folder;
	_save_mapping();
	return true;
}

void PlaylistManager::_save_mapping() {
	SPIMaster::select_sd();
	File f = SD.open("/_mapping.txt", "w");
	String s = create_mapping_txt();
	unsigned char* buf = new unsigned char[s.length()];
	s.getBytes(buf, s.length());
	f.write(buf, s.length()-1);
	f.close();
	SPIMaster::select_sd(false);
	delete buf;
}

String PlaylistManager::create_mapping_txt() {
	String s;
	for(std::map<String, String>::iterator it = _map.begin(); it != _map.end(); it++) {
		s += it->first;
		s += "=";
		s += it->second;
		s += '\n';
	}
	return s;
}

void PlaylistManager::persist(Playlist* p) {
	if (p->persistence != PERSIST_PERMANENTLY) return;
	
	String search = p->path();
	search += '=';
	
	bool old_file_existed = false;
	
	SPIMaster::select_sd();
	if (SD.exists("_positions.txt")) {
		SD.rename("/_positions.txt", "/_positions.temp.txt");
		old_file_existed = true;
	}
	File dst = SD.open("/_positions.txt", "w");
	
	if (old_file_existed) {
		File src = SD.open("/_positions.temp.txt", "r");
	
		while (true) {
			String line = src.readStringUntil('\n');
			line.trim();
			if (line.startsWith(search)) continue;
			dst.println(line);
		}
		
		src.close();
		SD.remove("/_positions.temp.txt");
	}
	
	dst.print(search);
	dst.print(p->get_current_track_id());
	dst.print(',');
	dst.println(p->get_position());
	dst.close();
	SPIMaster::select_sd(false);
}