feat(clipboard): initial support (#279)

Signed-off-by: Aaron Pham <contact@aarnphm.xyz>

lua/avante/clipboard/linux.lua

@@ -0,0 +1,59 @@
+local Utils = require("avante.utils")
+
+---@class AvanteClipboard
+local M = {}
+
+M.clip_cmd = nil
+
+M.get_clip_cmd = function()
+  if M.clip_cmd then
+    return M.clip_cmd
+  end
+  -- Wayland
+  if os.getenv("WAYLAND_DISPLAY") ~= nil and vim.fn.executable("wl-paste") == 1 then
+    M.clip_cmd = "wl-paste"
+  -- X11
+  elseif os.getenv("DISPLAY") ~= nil and vim.fn.executable("xclip") == 1 then
+    M.clip_cmd = "xclip"
+  end
+  return M.clip_cmd
+end
+
+M.has_content = function()
+  local cmd = M.get_clip_cmd()
+  ---@type vim.SystemCompleted
+  local output
+
+  -- X11
+  if cmd == "xclip" then
+    output = Utils.shell_run("xclip -selection clipboard -t TARGETS -o")
+    return output.code == 0 and output.stdout:find("image/png") ~= nil
+  elseif cmd == "wl-paste" then
+    output = Utils.shell_run("wl-paste --list-types")
+    return output.code == 0 and output.stdout:find("image/png") ~= nil
+  end
+
+  Utils.warn("Failed to validate clipboard content", { title = "Avante" })
+  return false
+end
+
+M.get_content = function()
+  local cmd = M.get_clip_cmd()
+  ---@type vim.SystemCompleted
+  local output
+
+  if cmd == "xclip" then
+    output = Utils.shell_run("xclip -selection clipboard -o -t image/png | base64 | tr -d '\n'")
+    if output.code == 0 then
+      return output.stdout
+    end
+  elseif cmd == "osascript" then
+    output = Utils.shell_run("wl-paste --type image/png | base64 | tr -d '\n'")
+    if output.code == 0 then
+      return output.stdout
+    end
+  end
+  error("Failed to get clipboard content")
+end
+
+return M