1 files changed, 109 insertions, 0 deletions
diff --git a/src/playlist-utils.js b/src/playlist-utils.js
new file mode 100644
index 0000000..d853456
--- /dev/null
+++ b/src/playlist-utils.js
@@ -0,0 +1,109 @@
+'use strict'
+
+function flattenPlaylist(playlist) {
+  const groups = playlist.filter(x => Array.isArray(x[1]))
+  const nonGroups = playlist.filter(x => x[1] && !(Array.isArray(x[1])))
+  return groups.map(g => flattenPlaylist(g[1]))
+    .reduce((a, b) => a.concat(b), nonGroups)
+}
+
+function filterPlaylistByPathString(playlist, pathString) {
+  return filterPlaylistByPath(playlist, parsePathString(pathString))
+}
+
+function filterPlaylistByPath(playlist, pathParts) {
+  // Note this can be used as a utility function, rather than just as
+  // a function for use by the argv-handler!
+
+  let cur = pathParts[0]
+
+  const match = playlist.find(g => g[0] === cur || g[0] === cur + '/')
+
+  if (match) {
+    const groupContents = match[1]
+    if (pathParts.length > 1) {
+      const rest = pathParts.slice(1)
+      return filterPlaylistByPath(groupContents, rest)
+    } else {
+      return match
+    }
+  } else {
+    console.warn(`Not found: "${cur}"`)
+    return playlist
+  }
+}
+
+function ignoreGroupByPathString(playlist, pathString) {
+  const pathParts = parsePathString(pathString)
+  return ignoreGroupByPath(playlist, pathParts)
+}
+
+function ignoreGroupByPath(playlist, pathParts) {
+  // TODO: Ideally this wouldn't mutate the given playlist.
+
+  const groupToRemove = filterPlaylistByPath(playlist, pathParts)
+
+  const parentPath = pathParts.slice(0, pathParts.length - 1)
+  let parent
+
+  if (parentPath.length === 0) {
+    parent = playlist
+  } else {
+    parent = filterPlaylistByPath(playlist, pathParts.slice(0, -1))
+  }
+
+  const index = parent.indexOf(groupToRemove)
+
+  if (index >= 0) {
+    parent.splice(index, 1)
+  } else {
+    console.error(
+      'Group ' + pathParts.join('/') + ' doesn\'t exist, so we can\'t ' +
+      'explicitly ignore it.'
+    )
+  }
+}
+
+function getPlaylistTreeString(playlist, showTracks = false) {
+  function recursive(group) {
+    const groups = group.filter(x => Array.isArray(x[1]))
+    const nonGroups = group.filter(x => x[1] && !(Array.isArray(x[1])))
+
+    const childrenString = groups.map(g => {
+      const groupString = recursive(g[1])
+
+      if (groupString) {
+        const indented = groupString.split('\n').map(l => '| ' + l).join('\n')
+        return '\n' + g[0] + '\n' + indented
+      } else {
+        return g[0]
+      }
+    }).join('\n')
+
+    const tracksString = (showTracks ? nonGroups.map(g => g[0]).join('\n') : '')
+
+    if (tracksString && childrenString) {
+      return tracksString + '\n' + childrenString
+    } else if (childrenString) {
+      return childrenString
+    } else if (tracksString) {
+      return tracksString
+    } else {
+      return ''
+    }
+  }
+
+  return recursive(playlist)
+}
+
+function parsePathString(pathString) {
+  const pathParts = pathString.split('/')
+  return pathParts
+}
+
+module.exports = {
+  flattenPlaylist,
+  filterPlaylistByPathString, filterPlaylistByPath,
+  ignoreGroupByPathString, ignoreGroupByPath,
+  parsePathString
+}