feat: add-fuzzy-completion

lua/kubectl/utils/completion.lua

@@ -1,3 +1,4 @@
+local fzy = require("kubectl.utils.fzy")
 local M = {}
 
 local function set_prompt(bufnr, suggestion)
@@ -31,13 +32,16 @@ function M.with_completion(buf, data, callback, shortest)
       original_input = input
     end
 
+    local tbl_for_fzy = {}
+    for _, suggestion in pairs(data) do
+      table.insert(tbl_for_fzy, suggestion.name)
+    end
+
     -- Filter suggestions based on input
     local filtered_suggestions = {}
-
-    for _, suggestion in pairs(data) do
-      if suggestion.name:lower():sub(1, #original_input) == original_input then
-        table.insert(filtered_suggestions, suggestion.name)
-      end
+    local matches = fzy.filter(original_input, tbl_for_fzy)
+    for _, match in pairs(matches) do
+      table.insert(filtered_suggestions, tbl_for_fzy[match[1]])
     end
 
     -- Cycle through the suggestions

lua/kubectl/utils/fzy.lua

@@ -0,0 +1,257 @@
+-- The lua implementation of the fzy string matching algorithm
+-- Credit https://github.com/swarn/fzy-lua
+
+local SCORE_GAP_LEADING = -0.005
+local SCORE_GAP_TRAILING = -0.005
+local SCORE_GAP_INNER = -0.01
+local SCORE_MATCH_CONSECUTIVE = 1.0
+local SCORE_MATCH_SLASH = 0.9
+local SCORE_MATCH_WORD = 0.8
+local SCORE_MATCH_CAPITAL = 0.7
+local SCORE_MATCH_DOT = 0.6
+local SCORE_MAX = math.huge
+local SCORE_MIN = -math.huge
+local MATCH_MAX_LENGTH = 1024
+
+local fzy = {}
+
+--- Check if `needle` is a subsequence of the `haystack`.
+--- Usually called before `score` or `positions`.
+---@param needle (string)
+---@param haystack (string)
+---@param case_sensitive (boolean?)
+---@return boolean
+function fzy.has_match(needle, haystack, case_sensitive)
+  if not case_sensitive then
+    needle = string.lower(needle)
+    haystack = string.lower(haystack)
+  end
+
+  local j = 1
+  for i = 1, string.len(needle) do
+    local found_at = string.find(haystack, needle:sub(i, i), j, true)
+    if not found_at then
+      return false
+    else
+      j = found_at + 1
+    end
+  end
+
+  return true
+end
+
+local function is_lower(c)
+  return c:match("%l")
+end
+
+local function is_upper(c)
+  return c:match("%u")
+end
+
+-- Sort matches by score in descending order
+local function sort_by_score(matches)
+  table.sort(matches, function(a, b)
+    return a[3] > b[3] -- Compare scores (a[3] and b[3])
+  end)
+  return matches
+end
+
+local function precompute_bonus(haystack)
+  local match_bonus = {}
+
+  local last_char = "/"
+  for i = 1, string.len(haystack) do
+    local this_char = haystack:sub(i, i)
+    if last_char == "/" or last_char == "\\" then
+      match_bonus[i] = SCORE_MATCH_SLASH
+    elseif last_char == "-" or last_char == "_" or last_char == " " then
+      match_bonus[i] = SCORE_MATCH_WORD
+    elseif last_char == "." then
+      match_bonus[i] = SCORE_MATCH_DOT
+    elseif is_lower(last_char) and is_upper(this_char) then
+      match_bonus[i] = SCORE_MATCH_CAPITAL
+    else
+      match_bonus[i] = 0
+    end
+
+    last_char = this_char
+  end
+
+  return match_bonus
+end
+
+local function compute(needle, haystack, D, M, case_sensitive)
+  -- Note that the match bonuses must be computed before the arguments are
+  -- converted to lowercase, since there are bonuses for camelCase.
+  local match_bonus = precompute_bonus(haystack)
+  local n = string.len(needle)
+  local m = string.len(haystack)
+
+  if not case_sensitive then
+    needle = string.lower(needle)
+    haystack = string.lower(haystack)
+  end
+
+  -- Because lua only grants access to chars through substring extraction,
+  -- get all the characters from the haystack once now, to reuse below.
+  local haystack_chars = {}
+  for i = 1, m do
+    haystack_chars[i] = haystack:sub(i, i)
+  end
+
+  for i = 1, n do
+    D[i] = {}
+    M[i] = {}
+
+    local prev_score = SCORE_MIN
+    local gap_score = i == n and SCORE_GAP_TRAILING or SCORE_GAP_INNER
+    local needle_char = needle:sub(i, i)
+
+    for j = 1, m do
+      if needle_char == haystack_chars[j] then
+        local score = SCORE_MIN
+        if i == 1 then
+          score = ((j - 1) * SCORE_GAP_LEADING) + match_bonus[j]
+        elseif j > 1 then
+          local a = M[i - 1][j - 1] + match_bonus[j]
+          local b = D[i - 1][j - 1] + SCORE_MATCH_CONSECUTIVE
+          score = math.max(a, b)
+        end
+        D[i][j] = score
+        prev_score = math.max(score, prev_score + gap_score)
+        M[i][j] = prev_score
+      else
+        D[i][j] = SCORE_MIN
+        prev_score = prev_score + gap_score
+        M[i][j] = prev_score
+      end
+    end
+  end
+end
+
+--- Compute a matching score.
+---
+---@param needle (string): must be a subequence of `haystack`, or the result is undefined.
+---@param haystack (string)
+---@param case_sensitive (boolean?): defaults to false
+---@return number: higher scores indicate better matches. See also `get_score_min` and `get_score_max`.
+function fzy.score(needle, haystack, case_sensitive)
+  local n = string.len(needle)
+  local m = string.len(haystack)
+
+  if n == 0 or m == 0 or m > MATCH_MAX_LENGTH or n > m then
+    return SCORE_MIN
+  elseif n == m then
+    return SCORE_MAX
+  else
+    local D = {}
+    local M = {}
+    compute(needle, haystack, D, M, case_sensitive)
+    return M[n][m]
+  end
+end
+
+--- Compute the locations where fzy matches a string.
+---
+--- Determine where each character of the `needle` is matched to the `haystack`
+--- in the optimal match.
+---
+---@param needle (string): must be a subequence of `haystack`, or the result is undefined.
+---@param haystack (string)
+---@param case_sensitive (boolean?): defaults to false
+---
+---@return table<number> @indices, where `indices[n]` is the location of the `n`th character of `needle` in `haystack`.
+---@return number @the same matching score returned by `score`
+function fzy.positions(needle, haystack, case_sensitive)
+  local n = string.len(needle)
+  local m = string.len(haystack)
+
+  if n == 0 or m == 0 or m > MATCH_MAX_LENGTH or n > m then
+    return {}, SCORE_MIN
+  elseif n == m then
+    local consecutive = {}
+    for i = 1, n do
+      consecutive[i] = i
+    end
+    return consecutive, SCORE_MAX
+  end
+
+  local D = {}
+  local M = {}
+  compute(needle, haystack, D, M, case_sensitive)
+
+  local positions = {}
+  local match_required = false
+  local j = m
+  for i = n, 1, -1 do
+    while j >= 1 do
+      if D[i][j] ~= SCORE_MIN and (match_required or D[i][j] == M[i][j]) then
+        match_required = (i ~= 1) and (j ~= 1) and (M[i][j] == D[i - 1][j - 1] + SCORE_MATCH_CONSECUTIVE)
+        positions[i] = j
+        j = j - 1
+        break
+      else
+        j = j - 1
+      end
+    end
+  end
+
+  return positions, M[n][m]
+end
+
+-- Apply `has_match` and `positions` to an array of haystacks.
+---@param needle string
+---@param haystacks table<string>
+---@param case_sensitive boolean? @defaults to false
+---@return table<{idx: number, positions: table<number>, score: number}> @an array with one entry per matching line in `haystacks`, each entry giving the index of the line in `haystacks` as well as the equivalent to the return value of `positions` for that line.
+function fzy.filter(needle, haystacks, case_sensitive)
+  local result = {}
+
+  for i, line in ipairs(haystacks) do
+    if fzy.has_match(needle, line, case_sensitive) then
+      local p, s = fzy.positions(needle, line, case_sensitive)
+      table.insert(result, { i, p, s })
+    end
+  end
+
+  return sort_by_score(result)
+end
+
+-- The lowest value returned by `score`.
+--
+-- In two special cases:
+--  - an empty `needle`, or
+--  - a `needle` or `haystack` larger than than `get_max_length`,
+-- the `score` function will return this exact value, which can be used as a
+-- sentinel. This is the lowest possible score.
+function fzy.get_score_min()
+  return SCORE_MIN
+end
+
+-- The score returned for exact matches. This is the highest possible score.
+function fzy.get_score_max()
+  return SCORE_MAX
+end
+
+-- The maximum size for which `fzy` will evaluate scores.
+function fzy.get_max_length()
+  return MATCH_MAX_LENGTH
+end
+
+-- The minimum score returned for normal matches.
+--
+-- For matches that don't return `get_score_min`, their score will be greater
+-- than than this value.
+function fzy.get_score_floor()
+  return MATCH_MAX_LENGTH * SCORE_GAP_INNER
+end
+
+-- The maximum score for non-exact matches.
+--
+-- For matches that don't return `get_score_max`, their score will be less than
+-- this value.
+function fzy.get_score_ceiling()
+  return MATCH_MAX_LENGTH * SCORE_MATCH_CONSECUTIVE
+end
+
+return fzy