#
# Summary statistics
#

# Sum
goalsScored <- function(matches, team) {
  home_goals <- matches %>%
    filter(home_team == team) %>%
    select(home_score) %>% sum()
    
  away_goals <- matches %>%
    filter(away_team == team) %>%
    select(away_score) %>% sum()
  
  goals_scored <- tribble(
    ~home_goals, ~away_goals, ~overall,
    home_goals, away_goals, home_goals + away_goals
  )
  
  return(goals_scored)
}

goalsLost <- function(matches, team) {
  home_goals <- matches %>%
    filter(home_team != team) %>%
    select(home_score) %>% sum()
  
  away_goals <- matches %>%
    filter(away_team != team) %>%
    select(away_score) %>% sum()
  
  goals_lost <- tribble(
    ~home_goals, ~away_goals, ~overall,
    home_goals, away_goals, home_goals + away_goals
  )
  
  return(goals_scored)
}

matchesNumber <- function(matches, team) {
  home_matches <- matches %>%
    filter(home_team == team) %>% nrow()
  
  away_matches <- matches %>%
    filter(away_team == team) %>% nrow()
  
  matches_number <- tribble(
    ~home_matches, ~away_matches, ~overall,
    home_matches, away_matches, home_matches + away_matches
  )

  return(matches_number)
}

# Mean
avgGoalsScored <- function(matches, team) {
  goals_scored <- goalsScored(matches, team)
  matches_number <- matchesNumber(matches, team)
  avg_goals_scored <- tribble(
    ~home_goals_avg, ~away_goals_avg, ~overall_avg,
    goals_scored$home_goals / matches_number$home_matches,
    goals_scored$away_goals / matches_number$away_matches,
    goals_scored$overall / matches_number$overall
  )
  
  return(avg_goals_scored)
}

avgGoalsLost <- function(matches, team) {
  goals_lost <- goalsLost(matches, team)
  matches_number <- matchesNumber(matches, team)
  avg_goals_lost <- tribble(
    ~home_goals_avg, ~away_goals_avg, ~overall_avg,
    goals_lost$home_goals / matches_number$home_matches,
    goals_lost$away_goals / matches_number$away_matches,
    goals_lost$overall / matches_number$overall
  )
  
  return(avg_goals_lost)
}