package main

import (
	"fmt"
)

func (r *Round) PlayDefaultStrategy() {

	currentPlayer := r.currentPlayer

	// Score our hand as if we pick up the discard and discard it immediately
	_, score := FindBestGrouping(r.hands[r.currentPlayer], r.round)
	baseScore := score
	bestDiscardBasedIdx := -1
	bestDiscardBasedScore := score

	if score != 0 {

		// Score our hand as if we pick up the discard card and discard each other card

		for cidx := 0; cidx < r.round; cidx++ {
			// Pick up the last discard card, and discard card@cidx
			theoretically := forkHand(r.hands[r.currentPlayer])
			theoretically[cidx] = r.discard[len(r.discard)-1]
			_, score := FindBestGrouping(theoretically, r.round)

			if score < bestDiscardBasedScore {
				// TODO if the points are equal or near-equal, prefer not to discard a wild for the next player
				bestDiscardBasedIdx = cidx
				bestDiscardBasedScore = score
			}
		}

	}

	// If taking the discard would let us win, or reduce our score by >5, take it
	if bestDiscardBasedScore == 0 || (baseScore-bestDiscardBasedScore) > 5 {

		fmt.Printf("P%d taking %v from the discard pile\n", r.currentPlayer, r.discard[len(r.discard)-1])

		// We're going to win
		if bestDiscardBasedIdx == -1 {
			// Take the discard card + put it back again i.e. no change
			fmt.Printf("P%d discards %v immediately\n", r.currentPlayer, r.discard[len(r.discard)-1])

		} else {
			// Take the discard card and discard cidx
			newCard := r.discard[len(r.discard)-1]
			r.discard = r.discard[0 : len(r.discard)-1]

			unwantedCard := r.hands[r.currentPlayer][bestDiscardBasedIdx]
			r.hands[r.currentPlayer][bestDiscardBasedIdx] = newCard

			r.discard = append(r.discard, unwantedCard) // On top = available for next player

			fmt.Printf("P%d discards %v (position %d)\n", currentPlayer, unwantedCard, bestDiscardBasedIdx)

		}

	} else {
		// The discard card is not going to make us win or significantly lower our
		// score
		// Take from the deck

		newCard := r.d[0]
		r.d = r.d[1:]
		r.hands[r.currentPlayer] = append(r.hands[r.currentPlayer], newCard)

		fmt.Printf("P%d taking %v from the deck\n", r.currentPlayer, newCard)

		bestRandomBasedIdx := -1
		bestRandomBasedScore := (r.round * 50) + 51 // Worse than the worst possible score

		// Look at what we can now drop (hand size + 1 new card). We have to drop something
		for cidx := 0; cidx < r.round+1; cidx++ {
			// Assume we discard that card,
			theoretically := forkHand(r.hands[currentPlayer])
			theoretically[cidx] = Card(-1) // Never matches + worth 0 points
			_, score := FindBestGrouping(theoretically, r.round)

			if score < bestRandomBasedScore {
				// TODO if the points are equal or near-equal, prefer not to discard a wild for the next player
				bestRandomBasedIdx = cidx
				bestRandomBasedScore = score
			}

		}

		// Discard our chosen card
		// Slice tricks: Copy end card into this slot and reslice bounds

		unwantedCard := r.hands[r.currentPlayer][bestRandomBasedIdx]

		fmt.Printf("P%d discards %v (position %d)\n", currentPlayer, unwantedCard, bestRandomBasedIdx)

		r.hands[r.currentPlayer][bestRandomBasedIdx] = r.hands[r.currentPlayer][len(r.hands[r.currentPlayer])-1]
		r.hands[r.currentPlayer] = r.hands[r.currentPlayer][0 : len(r.hands[r.currentPlayer])-1]

		r.discard = append(r.discard, unwantedCard) // On top = available for next player

	}

}