From 25323f2bff8327c9185385e1b43fb055e33244a8 Mon Sep 17 00:00:00 2001
From: tcgriffith <ztc.ustcer@gmail.com>
Date: Thu, 31 Oct 2019 11:34:47 +1000
Subject: [PATCH 1/2] shadow_clone done

---
 NAMESPACE           |  1 +
 R/ninjutsu.R        | 72 +++++++++++++++++++++++++++++++++++++++++++++
 man/shadow_clone.Rd | 26 ++++++++++++++++
 3 files changed, 99 insertions(+)
 create mode 100644 R/ninjutsu.R
 create mode 100644 man/shadow_clone.Rd

diff --git a/NAMESPACE b/NAMESPACE
index bed722e3..3ecb4897 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -4,6 +4,7 @@ export(decktape)
 export(inf_mr)
 export(infinite_moon_reader)
 export(moon_reader)
+export(shadow_clone)
 export(summon_remark)
 export(tsukuyomi)
 import(stats)
diff --git a/R/ninjutsu.R b/R/ninjutsu.R
new file mode 100644
index 00000000..fb3935eb
--- /dev/null
+++ b/R/ninjutsu.R
@@ -0,0 +1,72 @@
+#' Use a new xaringan theme.
+#'
+#' This function clones an xaringan theme for you to use. Include it in a code chunk in the xaringan slide source.
+#'
+#'
+#' @param theme Either a built-in theme shipped with xaringan, or the repository address of the theme in the format of username/repo
+#' @param ref desired git reference. could be a commit SHA, or a branch name. Defauts to master
+#'
+#'
+#' @return The cloned theme
+#' @export
+#'
+#' @examples
+#' # built-in
+#' shadow_clone("kunoichi")
+#' # remote
+#' shadow_clone("tcgriffith/xaringan_theme_example")
+#'
+shadow_clone = function(theme=NULL, ref="master"){
+
+  ## retrieve built-in themes
+  builtin_css = xaringan:::list_css()
+  builtin_theme = names(builtin_css)
+
+  ## similar to remotes::install_github, convert repo into full url on github
+  ## theme=tcgriffith/xaringan_theme_example ->
+  ## css_remote = https://raw.githubusercontent.com/tcgriffith/xaringan_theme_example/master/xaringan_theme_example.css
+
+  if (is.null(theme)) return(NULL)
+
+  bn = basename(theme)
+  css_remote = sprintf("https://raw.githubusercontent.com/%s/%s/%s.css",
+                       theme,
+                       ref,
+                       bn)
+  css_local = basename(css_remote)
+
+  ## built-in theme
+  if (theme %in% builtin_theme) {
+    message("Theme: ", theme)
+    message(sprintf("To use the same theme, try shadow_clone(%s)",theme))
+    css_local = builtin_css[theme]
+  }
+  ## remote theme
+  else {
+    ## extract git hash as ref and print out as message
+    repo = paste0("https://github.com/", theme)
+    cmd = paste0("git ls-remote ",repo," refs/heads/master")
+    rslt = system(command=cmd, intern=TRUE)
+    ref = stringr::str_sub(rslt, 1,8)
+
+    message("Theme repo:", repo)
+    message("ref: ", ref)
+    message(sprintf("To use the same theme, try shadow_clone(%s,%s)",theme, ref))
+
+    ## download remote css when css_local doesn't exist
+    if (!file.exists(css_local)){
+      try_dl = try(xfun::download_file(css_remote))
+      ## if download failed, fallback to default CSS. warning
+      if(try_dl != 0 ) {
+        warning("# Shadow clone failed. Theme not found.")
+        css_local = NULL
+      }
+    }
+  }
+
+  ## include CSS in the final xaringan html.
+
+  if(!is.null(css_local)){
+    htmltools::includeCSS(css_local)
+  }
+}
diff --git a/man/shadow_clone.Rd b/man/shadow_clone.Rd
new file mode 100644
index 00000000..bbece526
--- /dev/null
+++ b/man/shadow_clone.Rd
@@ -0,0 +1,26 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/ninjutsu.R
+\name{shadow_clone}
+\alias{shadow_clone}
+\title{Use a new xaringan theme.}
+\usage{
+shadow_clone(theme = NULL, ref = "master")
+}
+\arguments{
+\item{theme}{Either a built-in theme shipped with xaringan, or the repository address of the theme in the format of username/repo}
+
+\item{ref}{desired git reference. could be a commit SHA, or a branch name. Defauts to master}
+}
+\value{
+The cloned theme
+}
+\description{
+This function clones an xaringan theme for you to use. Include it in a code chunk in the xaringan slide source.
+}
+\examples{
+# built-in
+shadow_clone("kunoichi")
+# remote
+shadow_clone("tcgriffith/xaringan_theme_example")
+
+}

From e20b94a49486f17c7a69411580b9620f6b605408 Mon Sep 17 00:00:00 2001
From: tcgriffith <ztc.ustcer@gmail.com>
Date: Thu, 31 Oct 2019 12:14:57 +1000
Subject: [PATCH 2/2] remove stringr dependency

---
 R/ninjutsu.R    | 4 ++--
 man/decktape.Rd | 3 +--
 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/R/ninjutsu.R b/R/ninjutsu.R
index fb3935eb..1afad699 100644
--- a/R/ninjutsu.R
+++ b/R/ninjutsu.R
@@ -19,7 +19,7 @@
 shadow_clone = function(theme=NULL, ref="master"){
 
   ## retrieve built-in themes
-  builtin_css = xaringan:::list_css()
+  builtin_css = list_css()
   builtin_theme = names(builtin_css)
 
   ## similar to remotes::install_github, convert repo into full url on github
@@ -47,7 +47,7 @@ shadow_clone = function(theme=NULL, ref="master"){
     repo = paste0("https://github.com/", theme)
     cmd = paste0("git ls-remote ",repo," refs/heads/master")
     rslt = system(command=cmd, intern=TRUE)
-    ref = stringr::str_sub(rslt, 1,8)
+    ref = substr(rslt, 1,8)
 
     message("Theme repo:", repo)
     message("ref: ", ref)
diff --git a/man/decktape.Rd b/man/decktape.Rd
index 61fadc7d..ce6a5431 100644
--- a/man/decktape.Rd
+++ b/man/decktape.Rd
@@ -43,8 +43,7 @@ For some operating systems you may need to
 }
 \examples{
 if (interactive()) {
-    xaringan::decktape("https://slides.yihui.name/xaringan", "xaringan.pdf", 
-        docker = FALSE)
+  xaringan::decktape('https://slides.yihui.name/xaringan', 'xaringan.pdf', docker = FALSE)
 }
 }
 \references{