package main

import (
	"fmt"
	"math/rand"
)

// Seed each player 0 through 15
// Play round 1 and advance winners to round 2
// Repeat until you have a winner in round 4
// Count the number of times each player ended in each top 2 spots.
// How to seed?
// 	  First tournament is seeded in no particular order.
//		Next tournament is seeded based on results of last tournament, ties broken by coin flip.
// Finals are best of 5, the rest best of 3

func main() {
	ratings := getRatings()
	names := getNames()
	initSeed := make([]string, 0)
	for player := range ratings {
		initSeed = append(initSeed, player)
	}
	wins := make(map[string][]int64) // 1st and 2nd place finishes
	for player := range ratings {
		wins[player] = []int64{0, 0}
	}
	seeds := getTournamentResults(ratings, initSeed)

	// Simulation
	for i := 1; true; i++ {
		results := getTournamentResults(ratings, seeds)
		wins[results[0]][0]++
		wins[results[1]][1]++
		if i%100000 == 0 {
			fmt.Println("Iteration ", i)
			for _, name := range names {
				fmt.Printf("%.6f  %.6f  %v\n", float64(wins[name][0])/float64(i), float64(wins[name][1])/float64(i), name)
			}
		}
		seeds = results
	}
}

func getTournamentResults(ratings map[string]float64, seeds []string) []string {
	results := make([]string, len(ratings))
	rankIndex := len(results) - 1
	// Round 1
	round2Contestants := make([]string, 0)
	playAndPlace(0, 15, 3, ratings, seeds, &rankIndex, &round2Contestants, &results)
	playAndPlace(1, 14, 3, ratings, seeds, &rankIndex, &round2Contestants, &results)
	playAndPlace(2, 13, 3, ratings, seeds, &rankIndex, &round2Contestants, &results)
	playAndPlace(3, 12, 3, ratings, seeds, &rankIndex, &round2Contestants, &results)
	playAndPlace(4, 11, 3, ratings, seeds, &rankIndex, &round2Contestants, &results)
	playAndPlace(5, 10, 3, ratings, seeds, &rankIndex, &round2Contestants, &results)
	playAndPlace(6, 9, 3, ratings, seeds, &rankIndex, &round2Contestants, &results)
	playAndPlace(7, 8, 3, ratings, seeds, &rankIndex, &round2Contestants, &results)
	// Round 2
	round3Contestants := make([]string, 0)
	playAndPlace(0, 1, 5, ratings, round2Contestants, &rankIndex, &round3Contestants, &results)
	playAndPlace(2, 3, 5, ratings, round2Contestants, &rankIndex, &round3Contestants, &results)
	playAndPlace(4, 5, 5, ratings, round2Contestants, &rankIndex, &round3Contestants, &results)
	playAndPlace(6, 7, 5, ratings, round2Contestants, &rankIndex, &round3Contestants, &results)
	// Round 3
	round4Contestants := make([]string, 0)
	playAndPlace(0, 1, 5, ratings, round3Contestants, &rankIndex, &round4Contestants, &results)
	playAndPlace(2, 3, 5, ratings, round3Contestants, &rankIndex, &round4Contestants, &results)
	// Round 4
	winner := make([]string, 0)
	playAndPlace(0, 1, 5, ratings, round4Contestants, &rankIndex, &winner, &results)
	results[0] = winner[0]
	return results
}

func playAndPlace(seedA, seedB, numGames int, ratings map[string]float64, seeds []string, rankIndex *int, nextRoundContestants *[]string, results *[]string) {
	if wonMatch(numGames, ratings[seeds[seedA]], ratings[seeds[seedB]]) {
		// fmt.Printf("%v beat %v\n", seeds[seedA], seeds[seedB])
		*nextRoundContestants = append(*nextRoundContestants, seeds[seedA])
		(*results)[*rankIndex] = seeds[seedB]
	} else {
		*nextRoundContestants = append(*nextRoundContestants, seeds[seedB])
		(*results)[*rankIndex] = seeds[seedA]
		// fmt.Printf("%v beat %v\n", seeds[seedB], seeds[seedA])
	}
	*rankIndex--
}

// Returns true if player a beats player b in a match of n games
func wonMatch(n int, a, b float64) bool {
	var wins int
	for i := 0; i < n; i++ {
		if getWin(a, b) {
			wins++
		}
	}
	return wins > n/2
}

// The true if a defeats b, based on their elo difference
func getWin(a, b float64) bool {
	chance := a / (a + b)
	return chance >= rand.Float64()
}

func getRatings() map[string]float64 {
	return map[string]float64{
		"Joseph_S":    583.6006,
		"Jonas_N":     506.0191,
		"Green_T":     413.6078,
		"Harry_H":     396.8535,
		"Koryan":      387.0532,
		"DanQZ":       357.6342,
		"Alex_K":      314.4253,
		"Quaid":       302.3414,
		"Svavar_G":    272.5940,
		"Eli_M":       263.8913,
		"Noztrom":     249.9731,
		"Jeff_M":      232.0740,
		"Matt_B":      229.9798,
		"Bo_S":        192.5092,
		"Beastinshen": 188.4295,
		"Shakil_A":    180.4603,
	}
}

func getNames() []string {
	return []string{
		"Joseph_S",
		"Jonas_N",
		"Green_T",
		"Harry_H",
		"Koryan",
		"DanQZ",
		"Alex_K",
		"Quaid",
		"Svavar_G",
		"Eli_M",
		"Noztrom",
		"Jeff_M",
		"Matt_B",
		"Bo_S",
		"Beastinshen",
		"Shakil_A",
	}
}