use std::collections::HashMap;
use itertools::Itertools;
use crate::{candidate::{Candidate, CandidateName}, csv, party::Party};


#[derive(Debug)]
pub struct Header {
	pub parties: Vec<Party>,
	pub candidates: Vec<Candidate>,
	pub winners: usize,
}

impl Header {
	pub fn parse(row: csv::reader::RowReader, winners: usize) -> Result<Header, Box<dyn std::error::Error>> {
		let mut parties = Vec::<Party>::new();
		let mut candidates = Vec::<Candidate>::new();
		let mut parties_lookup = HashMap::<&str, usize>::new();

		for col in row.skip(6).collect_vec().iter() {
			let [party, name] = col.split(':').next_array().ok_or("Missing ':'")?;
			
			if party == "UG" { // independents
				candidates.push(Candidate {
					name: name.to_owned(),
					party_id: None,
				});
			}
			else if let Some(party_id) = parties_lookup.get(party).copied() {
				parties[party_id].member_ids.push(candidates.len());
				candidates.push(Candidate {
					name: name.to_owned(),
					party_id: Some(party_id),
				});
			}
			else {
				parties_lookup.insert(party, parties.len());
				parties.push(Party::new(name.to_owned()));
			}
		}
		return Ok(Header { parties, candidates, winners });
	}
	pub fn get_candidate_name(&self, index: usize) -> CandidateName {
		self.candidates[index].get_name(self)
	}
	pub fn iter_candidate_name(&self) -> impl Iterator<Item = CandidateName> {
		self.candidates.iter().map(|v| v.get_name(self))
	}
}