/*  OpenTally: Open-source election vote counting
 *  Copyright © 2021 Lee Yingtong Li (RunasSudo)
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, 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 Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

/// Smart logger used in election counts
pub struct Logger<'a> {
	/// [Vec] of log entries for the current stage
	pub entries: Vec<LogEntry<'a>>,
}

impl<'a> Logger<'a> {
	/// Append a new entry to the log
	///
	/// If consecutive smart log entries have the same templates, they will be merged
	pub fn log(&mut self, entry: LogEntry<'a>) {
		if let LogEntry::Smart(mut smart) = entry {
			if self.entries.len() > 0 {
				if let LogEntry::Smart(last_smart) = self.entries.last_mut().unwrap() {
					if last_smart.template1 == smart.template1 && last_smart.template2 == smart.template2 {
						&last_smart.data.append(&mut smart.data);
					} else {
						self.entries.push(LogEntry::Smart(smart));
					}
				} else {
					self.entries.push(LogEntry::Smart(smart));
				}
			} else {
				self.entries.push(LogEntry::Smart(smart));
			}
		} else {
			self.entries.push(entry);
		}
	}
	
	/// Append a new literal log entry
	pub fn log_literal(&mut self, literal: String) {
		self.log(LogEntry::Literal(literal));
	}
	
	/// Append a new smart log entry
	///
	/// If consecutive smart log entries have the same templates, they will be merged
	pub fn log_smart(&mut self, template1: &'a str, template2: &'a str, data: Vec<&'a str>) {
		self.log(LogEntry::Smart(SmartLogEntry {
			template1: template1,
			template2: template2,
			data: data,
		}));
	}
	
	/// Render the log to a [String]
	pub fn render(&self) -> Vec<String> {
		return self.entries.iter().map(|e| match e {
			LogEntry::Smart(smart) => smart.render(),
			LogEntry::Literal(literal) => literal.to_string(),
		}).collect();
	}
}

/// Represents either a literal or smart log entry
pub enum LogEntry<'a> {
	/// Smart log entry - see [SmartLogEntry]
	Smart(SmartLogEntry<'a>),
	/// Literal log entry
	Literal(String)
}

/// Smart log entry
pub struct SmartLogEntry<'a> {
	template1: &'a str,
	template2: &'a str,
	data: Vec<&'a str>,
}

impl<'a> SmartLogEntry<'a> {
	/// Render the [SmartLogEntry] to a [String]
	pub fn render(&self) -> String {
		if self.data.len() == 0 {
			panic!("Attempted to format smart log entry with no data");
		} else if self.data.len() == 1 {
			return String::from(self.template1).replace("{}", self.data.first().unwrap());
		} else {
			return String::from(self.template2).replace("{}", &smart_join(&self.data));
		}
	}
}

/// Join the given strings, with commas and terminal "and"
pub fn smart_join(data: &Vec<&str>) -> String {
	return format!("{} and {}", data[0..data.len()-1].join(", "), data.last().unwrap());
}