/*  OpenTally: Open-source election vote counting
 *  Copyright © 2021–2022 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/>.
 */

use opentally::election::{CandidateState, CountState, Election};
use opentally::numbers::{Fixed, GuardedFixed, Number};
use opentally::parser::blt;
use opentally::stv;

use xmltree::Element;

use std::fs::File;
use std::ops;

#[test]
fn scotland_linn07_fixed5() {
	let stv_opts = stv::STVOptionsBuilder::default()
		.round_surplus_fractions(Some(5))
		//.round_values(Some(5))
		//.round_votes(Some(5))
		.round_quota(Some(0))
		.round_subtransfers(stv::RoundSubtransfersMode::PerBallot)
		.quota_criterion(stv::QuotaCriterion::GreaterOrEqual)
		.early_bulk_elect(false)
		.pp_decimals(5)
		.build().unwrap();
	
	Fixed::set_dps(5);
	
	assert_eq!(stv_opts.describe::<Fixed>(), "--numbers fixed --decimals 5 --round-surplus-fractions 5 --round-quota 0 --round-subtransfers per_ballot --quota-criterion geq --no-early-bulk-elect --pp-decimals 5");
	
	scotland_linn07::<Fixed>(stv_opts);
}

#[test]
fn scotland_linn07_gfixed5() {
	let stv_opts = stv::STVOptionsBuilder::default()
		.round_surplus_fractions(Some(5))
		.round_values(Some(5)) // Must specify rounding as guarded decimals represented to 10 dps internally
		.round_votes(Some(5))
		.round_quota(Some(0))
		.round_subtransfers(stv::RoundSubtransfersMode::PerBallot)
		.quota_criterion(stv::QuotaCriterion::GreaterOrEqual)
		.early_bulk_elect(false)
		.pp_decimals(5)
		.build().unwrap();
	
	GuardedFixed::set_dps(5);
	
	assert_eq!(stv_opts.describe::<GuardedFixed>(), "--numbers gfixed --decimals 5 --round-surplus-fractions 5 --round-values 5 --round-votes 5 --round-quota 0 --round-subtransfers per_ballot --quota-criterion geq --no-early-bulk-elect --pp-decimals 5");
	
	scotland_linn07::<GuardedFixed>(stv_opts);
}

fn scotland_linn07<N: Number>(stv_opts: stv::STVOptions)
where
	for<'r> &'r N: ops::Add<&'r N, Output=N>,
	for<'r> &'r N: ops::Sub<&'r N, Output=N>,
	for<'r> &'r N: ops::Mul<&'r N, Output=N>,
	for<'r> &'r N: ops::Div<&'r N, Output=N>,
	for<'r> &'r N: ops::Neg<Output=N>,
{
	// Read XML file
	let file = File::open("tests/data/linn07.xml").expect("IO Error");
	let root = Element::parse(file).expect("Parse Error");
	
	let mut candidates: Vec<&Element> = root.children.iter()
		.filter_map(|n| match n {
			xmltree::XMLNode::Element(e) => if e.name == "candidate" { Some(e) } else { None },
			_ => None,
		})
		.collect();
	let cand_nt = candidates.pop().unwrap();
	
	// TODO: Validate candidate names
	
	let num_stages = root.get_child("headerrow").expect("Syntax Error").children.len();
	
	// Read BLT
	let mut election: Election<N> = blt::parse_path("tests/data/linn07.blt").expect("Syntax Error");
	
	// !!! FOR SCOTTISH STV !!!
	election.normalise_ballots();
	
	// Initialise count state
	let mut state = CountState::new(&election);
	
	// Distribute first preferences
	stv::count_init(&mut state, &stv_opts).unwrap();
	let mut stage_num = 1;
	
	for i in 0..num_stages {
		println!("Stage {}", stage_num);
		
		// Validate NT
		let nt_votes = get_cand_stage(cand_nt, i)
			.get_child("value").unwrap()
			.get_text().unwrap()
			.to_string();
		
		assert!((&state.exhausted.votes + &state.loss_fraction.votes) == parse_str(&nt_votes), "Failed to validate NTs. Expected {}, got {}", nt_votes, &state.exhausted.votes + &state.loss_fraction.votes);
		
		for (candidate, cand_xml) in state.election.candidates.iter().zip(candidates.iter()) {
			let count_card = state.candidates.get(candidate).unwrap();
			
			// Validate candidate votes
			let cand_votes = get_cand_stage(cand_xml, i)
				.get_child("value").unwrap()
				.get_text().unwrap()
				.to_string();
			let cand_votes = parse_str(&cand_votes);
			assert!(count_card.votes == cand_votes, "Failed to validate votes for candidate {}. Expected {}, got {}", candidate.name, cand_votes, count_card.votes);
			
			// Validate candidate states
			let cand_state = get_cand_stage(cand_xml, i)
				.get_child("status").unwrap()
				.get_text().unwrap()
				.to_string();
			if cand_state == "Continuing" {
				assert!(count_card.state == CandidateState::Hopeful);
			} else if cand_state == "Elected" {
				assert!(count_card.state == CandidateState::Elected);
			} else if cand_state == "Excluded" {
				assert!(count_card.state == CandidateState::Excluded);
			} else {
				panic!("Unknown state descriptor {}", cand_state);
			}
		}
		
		assert_eq!(stv::count_one_stage(&mut state, &stv_opts).unwrap(), false);
		stage_num += 1;
	}
	
	assert_eq!(stv::count_one_stage(&mut state, &stv_opts).unwrap(), true);
}

fn get_cand_stage(candidate: &Element, idx: usize) -> &Element {
	return candidate.children.iter()
		.filter_map(|n| match n {
			xmltree::XMLNode::Element(e) => if e.name == "stage" { Some(e) } else { None },
			_ => None,
		})
		.nth(idx).unwrap();
}

fn parse_str<N: Number>(s: &str) -> N {
	if s == "-" { return N::zero(); }
	return N::parse(s);
}