Reorganize shell completion code

completion/bash/yadm

@@ -0,0 +1,105 @@
+# test if git completion is missing, but loader exists, attempt to load
+if ! declare -F _git > /dev/null && declare -F _completion_loader > /dev/null; then
+  _completion_loader git
+fi
+
+# only operate if git completion is present
+if declare -F _git > /dev/null; then
+
+  _yadm() {
+
+    local current=${COMP_WORDS[COMP_CWORD]}
+    local penultimate
+    if [ "$((COMP_CWORD-1))" -ge "0" ]; then
+      penultimate=${COMP_WORDS[COMP_CWORD-1]}
+    fi
+    local antepenultimate
+    if [ "$((COMP_CWORD-2))" -ge "0" ]; then
+      antepenultimate=${COMP_WORDS[COMP_CWORD-2]}
+    fi
+
+    local -x GIT_DIR
+    # shellcheck disable=SC2034
+    GIT_DIR="$(yadm introspect repo 2>/dev/null)"
+
+    case "$penultimate" in
+      bootstrap)
+        COMPREPLY=()
+        return 0
+      ;;
+      config)
+        COMPREPLY=( $(compgen -W "$(yadm introspect configs 2>/dev/null)") )
+        return 0
+		  ;;
+      decrypt)
+        COMPREPLY=( $(compgen -W "-l" -- "$current") )
+        return 0
+		  ;;
+      init)
+        COMPREPLY=( $(compgen -W "-f -w" -- "$current") )
+        return 0
+		  ;;
+      introspect)
+        COMPREPLY=( $(compgen -W "commands configs repo switches" -- "$current") )
+        return 0
+		  ;;
+      help)
+        COMPREPLY=() # no specific help yet
+        return 0
+      ;;
+      list)
+        COMPREPLY=( $(compgen -W "-a" -- "$current") )
+        return 0
+		  ;;
+    esac
+
+    case "$antepenultimate" in
+      clone)
+        COMPREPLY=( $(compgen -W "-f -w -b --bootstrap --no-bootstrap" -- "$current") )
+        return 0
+		  ;;
+    esac
+
+    local yadm_switches=( $(yadm introspect switches 2>/dev/null) )
+
+    # this condition is so files are completed properly for --yadm-xxx options
+    if [[ " ${yadm_switches[*]} " != *" $penultimate "* ]]; then
+      # TODO: somehow solve the problem with [--yadm-xxx option] being
+      #       incompatible with what git expects, namely [--arg=option]
+      _git
+    fi
+    if [[ "$current" =~ ^- ]]; then
+      local matching
+      matching=$(compgen -W "${yadm_switches[*]}" -- "$current")
+      __gitcompappend "$matching"
+    fi
+
+    # Find the index of where the sub-command argument should go.
+    local command_idx
+    for (( command_idx=1 ; command_idx < ${#COMP_WORDS[@]} ; command_idx++ )); do
+      local command_idx_arg="${COMP_WORDS[$command_idx]}"
+      if [[ " ${yadm_switches[*]} " = *" $command_idx_arg "* ]]; then
+        let command_idx++
+      elif [[ "$command_idx_arg" = -* ]]; then
+        :
+      else
+        break
+      fi
+    done
+    if [[ "$COMP_CWORD" = "$command_idx" ]]; then
+      local matching
+      matching=$(compgen -W "$(yadm introspect commands 2>/dev/null)" -- "$current")
+      __gitcompappend "$matching"
+    fi
+
+    # remove duplicates found in COMPREPLY (a native bash way could be better)
+    if [ -n "${COMPREPLY[*]}" ]; then
+      COMPREPLY=($(echo "${COMPREPLY[@]}" | sort -u))
+    fi
+
+  }
+
+	complete -o bashdefault -o default -F _yadm yadm 2>/dev/null \
+		|| complete -o default -F _yadm yadm
+
+fi