1 files changed, 96 insertions, 0 deletions
diff --git a/packages/meshbay-cli/src/meshbay_cli/commands/completion.py b/packages/meshbay-cli/src/meshbay_cli/commands/completion.py
new file mode 100644
index 0000000..831c012
--- /dev/null
+++ b/packages/meshbay-cli/src/meshbay_cli/commands/completion.py
@@ -0,0 +1,96 @@
+"""
+`completion`: the script that makes Tab complete meshbay-cli in a shell.
+
+bash:        eval "$(meshbay-cli completion bash)"         (in ~/.bashrc)
+PowerShell:  meshbay-cli completion powershell | Out-String | Invoke-Expression
+             (in $PROFILE)
+
+The packages install the bash one where bash-completion finds it. Both scripts
+ask `meshbay-cli __complete` for the candidates (see `complete.py`): actions,
+verbs, options, and the remote paths of the groups this machine is signed in to.
+"""
+
+from ..errors import USAGE, CliError
+from ..output import sentence
+from .context import Context
+
+HELP = "print the script that makes Tab complete meshbay-cli in bash or PowerShell"
+
+BASH = r'''# meshbay-cli completion for bash: eval "$(meshbay-cli completion bash)"
+_meshbay_cli() {
+    local cur=${COMP_WORDS[COMP_CWORD]} line files=0
+    local -a found=()
+    while IFS= read -r line; do
+        if [[ $line == __files__ ]]; then files=1; else found+=("$line"); fi
+    done < <(command meshbay-cli __complete bash "$COMP_CWORD" "${COMP_WORDS[@]}" 2>/dev/null)
+    COMPREPLY=("${found[@]}")
+    if (( files )); then
+        local f
+        while IFS= read -r f; do COMPREPLY+=("$f"); done < <(compgen -f -- "$cur")
+    fi
+    # Quote spaces and the like as for file names; no space after a folder.
+    compopt -o filenames 2>/dev/null
+    local c
+    for c in "${COMPREPLY[@]}"; do
+        if [[ $c == */ ]]; then compopt -o nospace 2>/dev/null; break; fi
+    done
+}
+complete -F _meshbay_cli meshbay-cli
+'''
+
+POWERSHELL = r'''# meshbay-cli completion for PowerShell:
+#   meshbay-cli completion powershell | Out-String | Invoke-Expression
+Register-ArgumentCompleter -Native -CommandName 'meshbay-cli', 'meshbay-cli.exe' -ScriptBlock {
+    param($wordToComplete, $commandAst, $cursorPosition)
+    $elements = @($commandAst.CommandElements)
+    $words = @($elements | ForEach-Object { $_.Extent.Text })
+    $index = $words.Count
+    for ($i = 0; $i -lt $elements.Count; $i++) {
+        $e = $elements[$i].Extent
+        if ($cursorPosition -ge $e.StartOffset -and $cursorPosition -le $e.EndOffset) {
+            $index = $i
+        }
+    }
+    $found = @(& meshbay-cli __complete powershell $index @words 2>$null)
+    $quote = {
+        param($s)
+        if ($s -match '[\s''"`$&|;(){}@,#]') { "'" + ($s -replace "'", "''") + "'" } else { $s }
+    }
+    $item = [System.Management.Automation.CompletionResult]
+    $results = @()
+    foreach ($c in $found) {
+        if ($c -eq '__files__') {
+            $sep = [IO.Path]::DirectorySeparatorChar
+            $typed = $wordToComplete.Trim([char[]]"'`"")
+            $dir = Split-Path -Path $typed -Parent
+            Get-ChildItem -Path "$typed*" -ErrorAction SilentlyContinue |
+                ForEach-Object {
+                    $p = if ($dir) { Join-Path $dir $_.Name } else { $_.Name }
+                    if ($_.PSIsContainer) { $p += $sep }
+                    $results += $item::new((& $quote $p), $p, 'ProviderItem', $p)
+                }
+            continue
+        }
+        $results += $item::new((& $quote $c), $c, 'ParameterValue', $c)
+    }
+    $results
+}
+'''
+
+SCRIPTS = {"bash": BASH, "powershell": POWERSHELL}
+
+
+def add_parser(sub, parent) -> None:
+    p = sub.add_parser("completion", parents=[parent], help=HELP, description=sentence(HELP)
+                       + '. bash: eval "$(meshbay-cli completion bash)" in ~/.bashrc; '
+                         "PowerShell: meshbay-cli completion powershell | Out-String | "
+                         "Invoke-Expression in $PROFILE.")
+    p.add_argument("shell", choices=tuple(SCRIPTS), help="the shell")
+
+
+async def run(ctx: Context) -> int:
+    script = SCRIPTS.get(ctx.args.shell)
+    if script is None:
+        raise CliError(USAGE, "bash or powershell.")
+    print(script, end="")
+    return 0