From 9828d7a97e61d79b8c796ae606be0e1eac652c10 Mon Sep 17 00:00:00 2001
From: Scott McKendry <39483124+scottmckendry@users.noreply.github.com>
Date: Mon, 15 Jul 2024 15:39:27 +1200
Subject: [PATCH] add custom telescope local diff keymap and util functions
 :mag:

---
 nvim/lua/core/keymaps.lua |  3 +++
 nvim/lua/core/utils.lua   | 26 ++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/nvim/lua/core/keymaps.lua b/nvim/lua/core/keymaps.lua
index 9fbde49..34cec5a 100644
--- a/nvim/lua/core/keymaps.lua
+++ b/nvim/lua/core/keymaps.lua
@@ -66,6 +66,9 @@ map("n", "<leader>ft", ":Telescope<cr>", { desc = "Other pickers..." })
 map("n", "<leader>fS", ":Telescope resession<cr>", { desc = "Find Session" })
 map("n", "<leader><leader>", ":Telescope smart_open<cr>", { desc = "Smart open" })
 map("n", "<leader>fh", ":Telescope help_tags<cr>", { desc = "Find help tags" })
+map("n", "<leader>fq", function()
+    require("core.utils").telescope_diff_file()
+end, { desc = "Find file to compare with current buffer" })
 
 -- Clear search with <esc>
 map("n", "<esc>", ":noh<cr><esc>", { desc = "Escape and clear hlsearch" })
diff --git a/nvim/lua/core/utils.lua b/nvim/lua/core/utils.lua
index 01d5c74..cfe9b01 100644
--- a/nvim/lua/core/utils.lua
+++ b/nvim/lua/core/utils.lua
@@ -103,4 +103,30 @@ function M.open_help(buf)
     end
 end
 
+--- Display a diff between the current buffer and a given file
+--- @param file string The file to diff against the current buffer
+function M.diff_file(file)
+    local current_file = vim.fn.expand("%:p")
+    vim.cmd("edit " .. file)
+    vim.cmd("vert diffsplit " .. current_file)
+end
+
+--- Open a telescope picker to select a file to diff against the current buffer
+function M.telescope_diff_file()
+    require("telescope.builtin").find_files({
+        prompt_title = "Select File to Compare",
+        attach_mappings = function(prompt_bufnr)
+            local actions = require("telescope.actions")
+            local action_state = require("telescope.actions.state")
+
+            actions.select_default:replace(function()
+                actions.close(prompt_bufnr)
+                local selection = action_state.get_selected_entry()
+                M.diff_file(selection.value)
+            end)
+            return true
+        end,
+    })
+end
+
 return M