/// Implemantation of the playing Table.

use std::collections::VecDeque;

use crate::card::Card;
use crate::row::Row;
use crate::player::PlayerCard;

#[derive(Debug)]
/// A playing Table, containing 5 [`Row`]s and some [`PlayerCard`]s.
/// A Table can do some useful function with its cards, like picking
/// closest row or moving cards.
pub(crate) struct Table {
    rows: Vec<Row>,
    player_cards: VecDeque<PlayerCard>, // owned by a player
}

impl Table {
    /// Creates a new `Table`, filling Rows from `row_cards`.
    pub(crate) fn new(row_cards: VecDeque<Card>) -> Self {
        // We have exactly 5 Rows.
        let mut rows = Vec::with_capacity(5);
        for card in row_cards {
            // create a new row then put a card into it
            let mut row = Row::new();
            if let Some(_) = row.push_or_collect(card) {
                // Row should have one card, so... mustn't happen.
                panic!("Freshly created row overflowed");
            }
            // Put the new row onto the Table.
            rows.push( row );
        }

        // And return the newly created Table.
        Table {
            rows,
            player_cards: VecDeque::new(),
        }
    }

    /// Gets a [`Card`] from a [`Player`] and put it into the `player_cards` area,
    /// remembering whose (`player_id`) card it was.
    pub(crate) fn lay_player_card( &mut self, card: Card, player_id: i32 ) {
        self.player_cards.push_back( PlayerCard { player_id, card } );
    }

    /// Sort the [`Card`]s thrown by the [`Player`]s, since we'd need
    /// to get them ordered by value later.
    pub(crate) fn sort_cards( &mut self ) {
        // Sorting a normal VecDeque is not possible since it may contain
        // holes, so we need to de-hole it first, then it's sortable (through
        // a returned pointer slice).
        self.player_cards.make_contiguous().sort_by( |a,b| b.card.cmp(&a.card) );
    }

    /// Returns true if we have unprocessed Player cards on the table.
    pub(crate) fn has_player_cards( &self ) -> bool {
        self.player_cards.len() > 0
    }

    /// Return the smallest player card on the table.
    /// FIXME: shall check whether it's ordered.
    pub(crate) fn get_smallest_player_card( &mut self ) -> PlayerCard {
        // FIXME: check orderedness!
        // FIXME: check asking when empty!
        self.player_cards.pop_back().expect("out of player cards on table")
    }

    /// Return the row which is closest to the `pcard` arg, or None if
    /// all Row tails are larger.
    pub(crate) fn get_closest_row( &self, pcard: &PlayerCard ) -> Option<usize> {
        // get the row id with last card closest smaller to players'
        let row_tails = self.get_row_tails();
        let mut closest_val = None;
        let mut diff = 127; // larger than any
        // Check all the row tail cards
        for i in 0..row_tails.len() {
            if row_tails[i] < pcard.card.value && pcard.card.value - row_tails[i] < diff {
                // it is smaller than pcard and closer than the old closest one: match!
                // Store the row index
                closest_val = Some(i); 
                diff = pcard.card.value - row_tails[i];
                // debug!("DEBUG: pcard {}, row {}, head {}, diff {}, closest {:?}", pcard.card.value, i, row_heads[i], diff, closest_val);
            }
        }

        closest_val
    }

    /// Put a [`Card`] into the `row_id` Row (tail).
    /// Returns `None` if ok or `Some(cards)` when the Row is full.
    pub(crate) fn put_card_into_row( &mut self, pcard: PlayerCard, row_id: usize ) -> Option<VecDeque<Card>> {
        // We actually ask the Row to do it properly.
        self.rows[row_id].push_or_collect(pcard.card)
    }

    pub(crate) fn get_row_tails( &self ) -> Vec<i8> {
        let mut heads: Vec<i8> = Vec::new();
        for i in 0..self.rows.len() {
            heads.push( self.rows[i].last_card_value() );
        }
        heads
    }

    // take a whole row and hand it over
    pub(crate) fn take_row( &mut self, row_id: usize ) -> VecDeque<Card> {
        self.rows[row_id].take_row()
    }

    // collect remaining cards in the rows at the end of round
    pub(crate) fn collect_rows( &mut self ) -> VecDeque<Card> {
        let mut cards = VecDeque::new();
        for row in 0..self.rows.len() {
            self.rows[row]
                .take_row()
                .into_iter()
                .for_each(|card| cards.push_back(card));
        }
        cards
    }

    /// Return a non-mutable borrow of the rows to look at
    pub fn peek_rows(&self) -> &Vec<Row> {
        &self.rows
    }
}