Implement DistantOpen autocomplete (#143)

* Implement 'complete' field for DistantCommand
* Implement autocomplete for DistantOpen

lua/distant/commands/distant_open.lua

@@ -1,6 +1,8 @@
 local plugin = require('distant')
 local utils = require('distant.commands.utils')
 
+local parent_path = require('distant-core.utils').parent_path
+
 --- DistantOpen path [opt1=... opt2=...]
 --- @param cmd NvimCommand
 local function command(cmd)
@@ -38,12 +40,58 @@ local function command(cmd)
     plugin.editor.open(opts)
 end
 
+local function completion(ArgLead,_,_)
+    local seperator = require('distant-core.utils').seperator()
+
+    -- Helper: Get the last component of a path
+    local function last_component(path)
+        local parts = vim.split(path, seperator)
+        return parts[#parts]
+    end
+
+    local path = ArgLead
+    if path == nil or path == '' then
+        path = "."
+    end
+
+    local component
+    if not vim.endswith(path, seperator) and path ~= "." then
+        component = last_component(path)
+        path = parent_path(path)
+    end
+
+    local err, payload = plugin.api().read_dir({
+        path = path,
+        depth = 1,
+        absolute = true,
+        canonicalize = true,
+    })
+
+    assert(not err, err)
+    assert(payload)
+
+    local results = {}
+
+    for _, entry in ipairs(payload.entries) do
+        if component == nil or string.match(entry.path, component) then
+            local ending_sep = ""
+            if entry.file_type == 'dir' then
+                ending_sep = seperator
+            end
+            table.insert(results, entry.path .. ending_sep)
+        end
+    end
+
+    return results
+end
+
 --- @type DistantCommand
 local COMMAND = {
     name        = 'DistantOpen',
     description = 'Open a file or directory on the remote machine',
     command     = command,
     bang        = true,
     nargs       = '*',
+    complete    = completion,
 }
 return COMMAND

lua/distant/commands/init.lua

@@ -19,6 +19,7 @@
 --- @field bang? boolean
 --- @field force? boolean
 --- @field nargs? integer|'*'
+--- @field complete? fun(string,string,_):string[]
 
 local log      = require('distant-core').log
 
@@ -58,11 +59,24 @@ local function _initialize()
             table.insert(names, name)
         end
 
+        local complete
+        if cmd.complete then
+            -- Register a global function 
+            local func_name = "DistantCommandComplete_" .. cmd.name
+
+            _G[func_name] = function(ArgLead, CmdLine, CursorPos)
+                return table.concat(cmd.complete(ArgLead, CmdLine, CursorPos), "\n")
+            end
+            -- completion config is a string with name of the global function
+            complete = "custom,v:lua." .. func_name
+        end
+
         for _, name in ipairs(names) do
             vim.api.nvim_create_user_command(name, cmd.command, {
                 desc = cmd.description,
                 bang = cmd.bang,
                 nargs = cmd.nargs,
+                complete = complete,
             })
         end
     end