use chrono::Duration;
use clap::{
	crate_authors, crate_description, crate_version, App, Arg, ArgMatches,
};
use colored::*;

use budget::*;

fn main() {
	let matches = get_cli_matches();

	let no_color = matches.occurrences_of("plain") > 0;
	let force_color = matches.occurrences_of("force-color") > 0;
	let input = matches.value_of("INPUT").unwrap();

	let account = match budget::parse_account(input) {
		Ok(data) => data,
		Err(error) => {
			match error {
				ParseError::IOError(kind) => {
					println!("IO error while parsing: {:?}", kind);
				}
				ParseError::DeserializerError(_) => {
					println!("Can't parse the file, invalid syntax");
				}
			}

			::std::process::exit(1);
		}
	};
	let maybe_calculated = budget::calculate(&account);

	if no_color && !force_color {
		colored::control::set_override(false);
	} else if force_color {
		colored::control::set_override(true);
	}

	output(account, maybe_calculated);
}

fn get_cli_matches() -> ArgMatches<'static> {
	App::new("finbudg")
		.version(crate_version!())
		.author(crate_authors!())
		.about(crate_description!())
		.arg(
			Arg::with_name("plain")
				.short("p")
				.long("plain")
				.help(
					"Don't colorize the output. Can also be set \
            with the NO_COLOR environment variable.",
				)
				.takes_value(false),
		)
		.arg(
			Arg::with_name("force-color")
				.long("force-color")
				.help(
					"Forces colorized output even when piping. Takes \
            precedence over --plain flag and NO_COLOR environment \
            variable",
				)
				.takes_value(false),
		)
		.arg(
			Arg::with_name("INPUT")
				.help("Expenses file to calculate from. For more information \
				on the format of this file see 'man 5 finbudg'")
				.required(true)
				.index(1),
		)
		.get_matches()
}

fn output(account: Account, maybe_calculated: Option<Calculated>) {
	println!(
		"{}",
		format!(
			"Your expenses for the period of {} - {}",
			account.start_date.format("%Y-%m-%d"),
			account.end_date.format("%Y-%m-%d"),
		)
		.cyan(),
	);

	let calculated = match maybe_calculated {
		Some(data) => data,
		None => {
			println!();
			println!("{}", "You have no expenses...".italic());

			::std::process::exit(0);
		}
	};

	let days_until_end = account.end_date - calculated.last_day;

	println!(
		"{}",
		format!(
			"Last day on entry: {}",
			calculated.last_day.format("%Y-%m-%d"),
		)
		.cyan(),
	);

	println!(
		"{}",
		format!("Days until period end: {}", days_until_end.num_days(),).cyan(),
	);

	if days_until_end < Duration::zero() {
		println!();
		println!(
			"{}",
			"Your last day on entry is set after the last date of the period!"
				.yellow(),
		);
		println!();
	}

	println!("{}", format!("Budget: {:.2}", account.budget,).cyan(),);

	println!();

	for (category, expenses) in calculated.categories_day_average.iter() {
		println!("Average per day in {}: {:.2}", category, expenses,);
	}

	println!(
		"Average per day in essential expenses: {:.2}",
		calculated.essential_day_average,
	);

	println!("Average per day: {:.2}", calculated.all_day_average,);

	println!();

	for (category, expenses) in calculated.categories_subtotal.iter() {
		println!("Total in {}: {:.2}", category, expenses,);
	}

	println!(
		"Total in essential expenses: {:.2}",
		calculated.essential_subtotal,
	);

	println!("Total: {:.2}", calculated.total,);

	println!();

	let balance_output = format!("{:.2}", calculated.balance);
	let balance_output = if calculated.balance > 0.0 {
		if account.budget / calculated.balance < 10.0 {
			balance_output.green()
		} else {
			balance_output.yellow()
		}
	} else {
		balance_output.red()
	};

	println!("Left on balance: {}", balance_output);

	println!();

	for (n, owed) in calculated.total_owed.iter() {
		println!(
			"{} person(s) owe you in shared expenses: {:.2}",
			n - 1,
			owed,
		);

		if *n > 2 {
			println!("Each owes you: {}", *owed / (*n as f64 - 1.0));
		}

		println!();
	}

	println!("Days until balance runs out:");

	let days_left_output = format!("{:.2}", calculated.days_left,);
	let days_left_essential_output =
		format!("{:.2}", calculated.days_left_essential,);

	// TODO: also show much money would be left by the end of the period

	let mut all_are_healthy = true;
	let mut essential_are_healthy = true;

	let days_left_output =
		if days_until_end.num_days() as f64 <= calculated.days_left {
			days_left_output.green()
		} else {
			all_are_healthy = false;

			days_left_output.red()
		};
	let days_left_essential_output =
		if days_until_end.num_days() as f64 <= calculated.days_left_essential {
			days_left_essential_output.green()
		} else {
			essential_are_healthy = false;

			days_left_essential_output.red()
		};

	println!("...taking into account all expenses: {}", days_left_output,);
	println!(
		"...taking into account only essential expenses: {}",
		days_left_essential_output,
	);
	println!();

	if all_are_healthy {
		println!(
			"{}",
			"Your expenses are healthy, they should last you from your last \
            day on entry through your last day of the period."
				.green(),
		);
	} else {
		println!(
			"{}",
			"You are spending more than you can afford with your current \
            budget. Try minimizing your expenses"
				.red(),
		);
		if essential_are_healthy {
			println!(
				"{}",
				"On the other hand, if you only spend money on essentials, \
                you should be able keep within your budget."
					.yellow(),
			);
		}
	}
}