Add support for embeddings

Signed-off-by: Tomas Slusny <slusnucky@gmail.com>

.editorconfig

@@ -0,0 +1,2 @@
+[*.lua]
+indent_size = 2

lua/CopilotChat/context.lua

@@ -0,0 +1,121 @@
+local log = require('plenary.log')
+
+local M = {}
+
+local function_types = {
+  'function_definition',
+  'function_declaration',
+  'local_function',
+  'method_definition',
+  'method_declaration',
+  'constructor_declaration',
+  'function_item',
+  'arrow_function',
+}
+
+local function spatial_distance_cosine(a, b)
+  local dot_product = 0
+  local magnitude_a = 0
+  local magnitude_b = 0
+  for i = 1, #a do
+    dot_product = dot_product + a[i] * b[i]
+    magnitude_a = magnitude_a + a[i] * a[i]
+    magnitude_b = magnitude_b + b[i] * b[i]
+  end
+  magnitude_a = math.sqrt(magnitude_a)
+  magnitude_b = math.sqrt(magnitude_b)
+  return dot_product / (magnitude_a * magnitude_b)
+end
+
+local function data_ranked_by_relatedness(query, data, top_n)
+  local scores = {}
+  for i, item in pairs(data) do
+    scores[i] = { index = i, score = spatial_distance_cosine(item.embedding, query.embedding) }
+  end
+  table.sort(scores, function(a, b)
+    return a.score > b.score
+  end)
+  local result = {}
+  for i = 1, math.min(top_n, #scores) do
+    local srt = scores[i]
+    table.insert(result, vim.tbl_extend('keep', data[srt.index], { score = srt.score }))
+  end
+  return result
+end
+
+local function collect_inputs(bufnr)
+  local ft = vim.bo[bufnr].filetype
+  local name = vim.api.nvim_buf_get_name(bufnr)
+  local parser = vim.treesitter.get_parser(bufnr, ft)
+  if not parser then
+    return
+  end
+
+  local root = parser:parse()[1]:root()
+  local function get_functions(node, result)
+    if vim.tbl_contains(function_types, node:type()) then
+      table.insert(result, node)
+      return
+    end
+    for child in node:iter_children() do
+      get_functions(child, result)
+    end
+  end
+
+  local functions = {}
+  get_functions(root, functions)
+
+  local inputs = {}
+  for _, node in ipairs(functions) do
+    local start_row, start_col, end_row, end_col = node:range()
+    local lines = vim.api.nvim_buf_get_lines(bufnr, start_row, end_row + 1, false)
+    local body = table.concat(lines, '\n')
+
+    if vim.trim(body) ~= '' then
+      table.insert(inputs, {
+        content = body,
+        filename = name,
+        filetype = ft,
+      })
+    end
+  end
+
+  return inputs
+end
+
+function M.find_for_query(copilot, selection, bufnr, on_done)
+  local filetype = selection.filetype or vim.bo[bufnr].filetype
+  local filename = selection.filename or vim.api.nvim_buf_get_name(bufnr)
+
+  local inputs = collect_inputs(bufnr)
+  if #inputs > 0 then
+    copilot:embed(inputs, {
+      on_done = function(out)
+        log.debug(string.format('Got %s embeddings for file %s', #out, filename))
+
+        copilot:embed({
+          {
+            content = selection.lines,
+            filename = filename,
+            filetype = filetype,
+          },
+        }, {
+          on_done = function(query_out)
+            local query = query_out[1]
+            log.debug('Query:', query.content)
+            local data = data_ranked_by_relatedness(query, out, 10)
+            log.debug('Ranked data:', #data)
+            for i, item in ipairs(data) do
+              log.debug(
+                string.format('%s: %s - %s', i, item.score, vim.split(item.content, '\n')[1])
+              )
+            end
+            on_done(data)
+          end,
+        })
+      end,
+    })
+  end
+end
+
+return M