# setup R error handling to go to stderr
library("getopt")
options(show.error.messages = F, error = function() {
  cat(geterrmessage(), file = stderr()); q("no", 1, F)
})
options(stringAsFactors = FALSE, useFancyQuotes = FALSE)

setup_cmdline_options <- function() {
  args <- commandArgs(trailingOnly = TRUE)
  spec <- matrix(c(
    "help", "h", 0, "logical",
    "alpha", "a", 1, "double",
    "min_mean_count", "min_c", 1, "double",
    "min_k", "min_k", 1, "double",
    "max_k", "max_k", 1, "double",
    "sample_json", "s", 1, "character",
    "plots", "p", 1, "character",
    "header", "H", 0, "logical",
    "txtype", "y", 1, "character",
    "tx2gene", "x", 1, "character"), # a space-sep tx-to-gene map or GTF file (auto detect .gtf/.GTF)
    byrow = TRUE, ncol = 4)

  opt <- getopt(spec)
  # if help was asked for print a friendly message
  # and exit with a non-zero error code
  if (!is.null(opt$help)) {
    cat(getopt(spec, usage = TRUE))
    q(status = 1)
  } else {
    load_libraries()
  }
  return(opt)
}

load_libraries <- function() {
  # Allows displaying help without waiting for libraries to load
  library("tools")
  library("jsonlite")
  library("reshape2")
  library("RUVSeq")
  library("RColorBrewer")
  library("tximport")
  library("DESeq2")
  library("ggrepel")
}

source_local <- function(fname) {
    argv <- commandArgs(trailingOnly = FALSE)
    base_dir <- dirname(substring(argv[grep("--file=", argv)], 8))
    source(paste(base_dir, fname, sep = "/"))
}

# Source get_deseq_dataset.R for getting deseq dataset from htseq/featurecounts/tximport
source_local("get_deseq_dataset.R")

# RUVseq function definitions

plot_pca_rle <- function(set, title) {
  x <- pData(set)[, 1]
  colors <- brewer.pal(3, "Set2")
  label <- paste0(" for ", title)
  plotRLE(set, outline = FALSE, ylim = c(-4, 4), col = colors[x])
  title(main = paste0("RLE", label))
  plotPCA(set, col = colors[x], cex = 1.2)
  title(main = paste0("PCA", label))
}

plot_factors_of_unwanted_var <- function(set, method, k) {
  pd <- pData(set)
  pd["sample"] <- row.names(pd)
  colnames(pd)[1] <- "condition"
  d <- melt(pd, id.vars = c("sample", "condition"))
  d["x"] <- 1  # There is no information on the X, so we just fake it to be able to do a scatterplot
  print(ggplot(d, aes(x = x, y = value, color = condition, label = sample)) +
  geom_point() +
  ggtitle(paste0("Factors of unwanted variation for method: ", method, ", k=", k)) +
  facet_wrap(~ variable, scales = "free_x") +
  geom_text_repel() +
  theme(axis.title.x = element_blank(),
        axis.text.x = element_blank(),
        axis.ticks.x = element_blank(),
        plot.title = element_text(hjust = 0.5))
  )
}

create_seq_expression_set <- function(dds, min_mean_count) {
  count_values <- counts(dds)
  print(paste0("feature count before filtering :", nrow(count_values), "\n"))
  print(paste0("Filtering features which mean expression is less or eq. than ", min_mean_count, " counts\n"))
  filter <- apply(count_values, 1, function(x) mean(x) > min_mean_count)
  filtered <- count_values[filter, ]
  print(paste0("feature count after filtering :", nrow(filtered), "\n"))
  set <- newSeqExpressionSet(as.matrix(filtered),
                            phenoData = data.frame(colData(dds)$condition, row.names = colnames(filtered)))
  plot_pca_rle(set = set, title = "raw data")
  set <- betweenLaneNormalization(set, which = "upper")
  plot_pca_rle(set = set, title = "upper quartile normalized")
  return(set)
}

get_empirical_control_genes <- function(set, cutoff_p) {
  x <- pData(set)[, 1]
  design <- model.matrix(~x, data = pData(set))
  y <- DGEList(counts = counts(set), group = x)
  y <- calcNormFactors(y, method = "upperquartile")
  y <- estimateGLMCommonDisp(y, design)
  y <- estimateGLMTagwiseDisp(y, design)
  fit <- glmFit(y, design)
  lrt <- glmLRT(fit, coef = 2)
  top <- topTags(lrt, n = nrow(set))$table
  top_rows <- rownames(top)[which(top$PValue < cutoff_p)]
  empirical <- rownames(set)[which(!(rownames(set) %in% top_rows))]
  return(empirical)
}

ruv_control_gene_method <- function(set, k, control_genes = "empirical", cutoff_p = 0.2) {
  if (control_genes == "empirical") {
    control_genes <- get_empirical_control_genes(set, cutoff_p = cutoff_p)
  }
  set <- RUVg(set, control_genes, k = k)
  plot_pca_rle(set, paste0("RUVg with empirical control genes, k=", k))
  plot_factors_of_unwanted_var(set, method = "RUVg with empirical control genes", k = k)
  return(set)
}

ruv_residual_method <- function(set, k) {
  genes <- rownames(counts(set))
  x <- pData(set)[, 1]
  # Initial edger residuals
  design <- model.matrix(~x, data = pData(set))
  y <- DGEList(counts = counts(set), group = x)
  y <- calcNormFactors(y, method = "upperquartile")
  y <- estimateGLMCommonDisp(y, design)
  y <- estimateGLMTagwiseDisp(y, design)
  fit <- glmFit(y, design)
  res <- residuals(fit, type = "deviance")
  set <- RUVr(set, genes, k = k, res)
  plot_pca_rle(set = set, title = paste0("RUVr using residuals, k=", k))
  plot_factors_of_unwanted_var(set, method = "RUVr using residuals", k = k)
  return(set)
}

ruv_replicate_method <- function(set, k) {
  genes <- rownames(counts(set))
  x <- pData(set)[, 1]
  differences <- makeGroups(x)
  set <- RUVs(set, genes, k = k, differences)
  plot_pca_rle(set, paste0("RUVs with replicate samples, k=", k))
  plot_factors_of_unwanted_var(set, method = "RUVs using replicates", k = k)
  return(set)
}

opt <- setup_cmdline_options()
alpha <- opt$alpha
min_k <- opt$min_k
max_k <- opt$max_k
min_c <- opt$min_mean_count
sample_json <- fromJSON(opt$sample_json)
sample_paths <- sample_json$path
sample_names <- sample_json$label
condition <- as.factor(sample_json$condition)
sample_table <- data.frame(samplename = sample_names, filename = sample_paths, condition = condition)
rownames(sample_table) <- sample_names

dds <- get_deseq_dataset(sample_table, header = opt$header, design_formula = ~ condition, tximport = opt$txtype, txtype = opt$txtype, tx2gene = opt$tx2gene)
if (!is.null(opt$plots)) {
  pdf(opt$plots)
}

# Run through the ruvseq variants
set <- create_seq_expression_set(dds, min_mean_count = min_c)
result <- list(no_correction = set)
for (k in seq(min_k, max_k)) {
  result[[paste0("residual_method_k", k)]] <- ruv_residual_method(set, k = k)
  result[[paste0("replicate_method_k", k)]] <- ruv_replicate_method(set, k = k)
  result[[paste0("control_method_k", k)]] <- ruv_control_gene_method(set, k = k, cutoff_p = 0.5)
}

for (name in names(result)) {
  if (!startsWith(name, "no_correction")) {
    set <- result[[name]]
    unwanted_variation <- pData(set)
    df <- data.frame(identifier = rownames(unwanted_variation))
    df <- cbind(df, unwanted_variation)
    colnames(df)[2] <- "condition"
    write.table(df, file = paste0("batch_effects_", name, ".tabular"),  sep = "\t", quote = F, row.names = F)
  }
}

# close the plot device
if (!is.null(opt$plots)) {
  cat("closing plot device\n")
  dev.off()
}

cat("Session information:\n\n")
sessionInfo()