From a803be7b83df742e66ab4f61ce134c721e51cef2 Mon Sep 17 00:00:00 2001
From: Max <max.heinzer397@gmx.ch>
Date: Sun, 23 Jun 2024 21:06:33 +0200
Subject: [PATCH] feat(lua): add vim.keymap.get

---
 runtime/doc/lua.txt        |  23 ++++++++
 runtime/lua/vim/keymap.lua | 108 +++++++++++++++++++++++++++++++++++++
 2 files changed, 131 insertions(+)

diff --git a/runtime/doc/lua.txt b/runtime/doc/lua.txt
index dfaf666874..0909fd72fc 100644
--- a/runtime/doc/lua.txt
+++ b/runtime/doc/lua.txt
@@ -2803,6 +2803,29 @@ vim.keymap.del({modes}, {lhs}, {opts})                      *vim.keymap.del()*
     See also: ~
       • |vim.keymap.set()|
 
+vim.keymap.get({modes}, {opts})                             *vim.keymap.get()*
+    Gets mappings in a format easily usable for vim.keymap.set Examples: >lua
+        -- Gets all normal mode keymaps
+        vim.keymap.get('n')
+
+        -- Gets a mapping which maps to a certain rhs
+        vim.keymap.get('n', { rhs = "<Plug>(MyAmazingFunction)" })
+<
+
+    Parameters: ~
+      • {modes}  (`string|string[]`)
+      • {opts}   (`table?`) A table with the following fields:
+                 • {lhs}? (`string`) Lhs of mapping
+                 • {rhs}? (`string`) Patter to match against rhs of mapping
+                 • {buffer}? (`integer|boolean`) Get a mapping for a certain
+                   buffer
+
+    Return: ~
+        (`table[]`) A list of objects with the following fields:
+        • {lhs} (`string`) Lhs of mapping
+        • {rhs} (`string|function`) Rhs of mapping (can be callback)
+        • {opts}? (`integer|boolean`) Get a mapping for a certain buffer
+
 vim.keymap.set({mode}, {lhs}, {rhs}, {opts})                *vim.keymap.set()*
     Adds a new |mapping|. Examples: >lua
         -- Map to a Lua function:
diff --git a/runtime/lua/vim/keymap.lua b/runtime/lua/vim/keymap.lua
index ec00c56c7a..7efa1e9e56 100644
--- a/runtime/lua/vim/keymap.lua
+++ b/runtime/lua/vim/keymap.lua
@@ -135,4 +135,112 @@ function keymap.del(modes, lhs, opts)
   end
 end
 
+--- @class vim.keymap.get.Opts
+--- @inlinedoc
+---
+--- Lhs of mapping
+--- @field lhs? string
+---
+--- Patter to match against rhs of mapping
+--- @field rhs? string
+---
+--- Get a mapping for a certain buffer
+--- @field buffer? integer|boolean
+
+--- @class vim.keymap.get.Return.Opts
+--- @inlinedoc
+---
+--- If they mapping is an expr mapping
+--- @field expr boolean
+---
+--- If they mapping is a buffer-local mapping
+--- @field buffer boolean
+---
+--- Description of the mapping
+--- @field desc? string
+
+--- @class vim.keymap.get.Return
+--- @inlinedoc
+---
+--- Lhs of mapping
+--- @field lhs string
+---
+--- Rhs of mapping (can be callback)
+--- @field rhs string|function
+---
+--- Get a mapping for a certain buffer
+--- @field opts? integer|boolean
+
+--- Gets mappings in a format easily usable for vim.keymap.set
+--- Examples:
+---
+--- ```lua
+--- -- Gets all normal mode keymaps
+--- vim.keymap.get('n')
+---
+--- -- Gets a mapping which maps to a certain rhs
+--- vim.keymap.get('n', { rhs = "<Plug>(MyAmazingFunction)" })
+--- ```
+---
+---@param modes string|string[]
+---@param opts? vim.keymap.get.Opts
+---@return vim.keymap.get.Return[]
+function keymap.get(modes, opts)
+  vim.validate({
+    mode = { modes, { 's', 't' } },
+    opts = { opts, 't', true },
+  })
+
+  opts = opts or {}
+  modes = type(modes) == 'string' and { modes } or modes
+  --- @cast modes string[]
+
+  local keymaps = {}
+  for _, mode in ipairs(modes) do
+    if opts.buffer then
+      table.insert(
+        keymaps,
+        ---@diagnostic disable-next-line: param-type-mismatch
+        vim.api.nvim_buf_get_keymap(opts.buffer == true and 0 or opts.buffer, mode)
+      )
+    else
+      table.insert(keymaps, vim.api.nvim_get_keymap(mode))
+    end
+  end
+
+  local function matches(mapping)
+    local match = true
+    if opts.lhs then
+      opts.lhs = opts.lhs:gsub('<leader>', vim.g.mapleader or '')
+      opts.lhs = opts.lhs:gsub('<localleader>', vim.g.maplocaleader or '')
+      match = match and opts.lhs == mapping.lhs
+    end
+    if opts.rhs then
+      opts.rhs = opts.rhs:gsub('<leader>', vim.g.mapleader or '')
+      opts.rhs = opts.rhs:gsub('<localleader>', vim.g.maplocaleader or '')
+      match = match and string.match(mapping.rhs, opts.rhs)
+    end
+    return match
+  end
+  return vim
+    .iter(keymaps)
+    :flatten()
+    :filter(function(mapping)
+      return matches(mapping)
+    end)
+    :map(function(mapping)
+      return {
+        lhs = mapping.lhs,
+        rhs = mapping.callback or mapping.rhs,
+        mode = mapping.mode,
+        opts = {
+          desc = mapping.desc,
+          buffer = mapping.buffer == 1,
+          expr = mapping.buffer == 1,
+        },
+      }
+    end)
+    :totable()
+end
+
 return keymap