refactor: improve diff handling implementation

lua/CopilotChat/chat.lua

@@ -32,6 +32,7 @@ end
 
 local Chat = class(function(self, help, on_buf_create)
   self.header_ns = vim.api.nvim_create_namespace('copilot-chat-headers')
+  self.name = 'copilot-chat'
   self.help = help
   self.on_buf_create = on_buf_create
   self.bufnr = nil
@@ -43,12 +44,12 @@ local Chat = class(function(self, help, on_buf_create)
   self.highlight_headers = true
   self.layout = nil
 
-  vim.treesitter.language.register('markdown', 'copilot-chat')
+  vim.treesitter.language.register('markdown', self.name)
 
   self.buf_create = function()
     local bufnr = vim.api.nvim_create_buf(false, true)
-    vim.api.nvim_buf_set_name(bufnr, 'copilot-chat')
-    vim.bo[bufnr].filetype = 'copilot-chat'
+    vim.api.nvim_buf_set_name(bufnr, self.name)
+    vim.bo[bufnr].filetype = self.name
     vim.bo[bufnr].syntax = 'markdown'
     vim.bo[bufnr].textwidth = 0
     local ok, parser = pcall(vim.treesitter.get_parser, bufnr, 'markdown')

lua/CopilotChat/diff.lua

@@ -0,0 +1,105 @@
+---@class CopilotChat.Diff
+---@field bufnr number
+---@field show fun(self: CopilotChat.Diff, change: string, reference: string, start_line: number?, end_line: number?, filetype: string, winnr: number)
+---@field restore fun(self: CopilotChat.Diff, winnr: number, bufnr: number)
+---@field delete fun(self: CopilotChat.Diff)
+---@field get_diff fun(self: CopilotChat.Diff): string, string, number?, number?
+
+local Overlay = require('CopilotChat.overlay')
+local utils = require('CopilotChat.utils')
+local class = utils.class
+
+local Diff = class(function(self, help, on_buf_create)
+  self.hl_ns = vim.api.nvim_create_namespace('copilot-chat-highlights')
+  vim.api.nvim_set_hl(
+    self.hl_ns,
+    '@diff.plus',
+    { bg = utils.blend_color_with_neovim_bg('DiffAdd', 20) }
+  )
+  vim.api.nvim_set_hl(
+    self.hl_ns,
+    '@diff.minus',
+    { bg = utils.blend_color_with_neovim_bg('DiffDelete', 20) }
+  )
+  vim.api.nvim_set_hl(
+    self.hl_ns,
+    '@diff.delta',
+    { bg = utils.blend_color_with_neovim_bg('DiffChange', 20) }
+  )
+
+  self.name = 'copilot-diff'
+  self.help = help
+  self.on_buf_create = on_buf_create
+  self.bufnr = nil
+  self.change = nil
+  self.reference = nil
+  self.start_line = nil
+  self.end_line = nil
+  self.filetype = nil
+
+  self.buf_create = function()
+    local bufnr = vim.api.nvim_create_buf(false, true)
+    vim.api.nvim_buf_set_name(bufnr, self.name)
+    vim.bo[bufnr].filetype = self.name
+    return bufnr
+  end
+end, Overlay)
+
+function Diff:show(change, reference, start_line, end_line, filetype, winnr)
+  self.change = change
+  self.reference = reference
+  self.start_line = start_line
+  self.end_line = end_line
+  self.filetype = filetype
+
+  self:validate()
+  vim.api.nvim_win_set_hl_ns(winnr, self.hl_ns)
+
+  -- mini.diff integration (unfinished)
+  -- local diff_found, diff = pcall(require, 'mini.diff')
+  -- if diff_found then
+  --   diff.disable(self.bufnr)
+  --   Overlay.show(self, change, filetype, winnr)
+  --
+  --   vim.b[self.bufnr].minidiff_config = {
+  --     source = {
+  --       name = self.name,
+  --       attach = function(bufnr)
+  --         diff.set_ref_text(bufnr, reference)
+  --         diff.toggle_overlay(bufnr)
+  --       end,
+  --     },
+  --   }
+  --
+  --   diff.enable(self.bufnr)
+  --   return
+  -- end
+
+  Overlay.show(
+    self,
+    tostring(vim.diff(reference, change, {
+      result_type = 'unified',
+      ignore_blank_lines = true,
+      ignore_whitespace = true,
+      ignore_whitespace_change = true,
+      ignore_whitespace_change_at_eol = true,
+      ignore_cr_at_eol = true,
+      algorithm = 'myers',
+      ctxlen = #reference,
+    })),
+    filetype,
+    winnr,
+    'diff'
+  )
+end
+
+function Diff:restore(winnr, bufnr)
+  Overlay.restore(self, winnr, bufnr)
+  vim.api.nvim_win_set_hl_ns(winnr, 0)
+end
+
+function Diff:get_diff()
+  return self.change, self.reference, self.start_line, self.end_line, self.filetype
+end
+
+return Diff