From ebb03999a8cffcd927e36d54062d9d01e868992b Mon Sep 17 00:00:00 2001
From: akianonymus <anonymus.aki@gmail.com>
Date: Sun, 26 Feb 2023 23:12:48 +0530
Subject: feat: Support modern rgb/rgba syntax

https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/rgb
---
 lua/colorizer/color.lua | 126 ++++++++++++++++++++++++++++++------------------
 1 file changed, 80 insertions(+), 46 deletions(-)

(limited to 'lua/colorizer/color.lua')

diff --git a/lua/colorizer/color.lua b/lua/colorizer/color.lua
index fe3e15b..370131b 100644
--- a/lua/colorizer/color.lua
+++ b/lua/colorizer/color.lua
@@ -14,7 +14,6 @@ local byte_is_hex = utils.byte_is_hex
 local byte_is_valid_colorchar = utils.byte_is_valid_colorchar
 local count = utils.count
 local parse_hex = utils.parse_hex
-local percent_or_hex = utils.percent_or_hex
 
 local color = {}
 
@@ -298,76 +297,111 @@ function color.name_parser(line, i, opts)
   end
 end
 
+local CSS_RGBA_FN_MINIMUM_LENGTH = #"rgba(0,0,0)" - 1
 local CSS_RGB_FN_MINIMUM_LENGTH = #"rgb(0,0,0)" - 1
----Parse for rgb() css function and return rgb hex.
+---Parse for rgb() rgba() css function and return rgb hex.
+-- For more info: https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/rgb
 ---@param line string: Line to parse
 ---@param i number: Index of line from where to start parsing
----@return number|nil: Index of line where the rgb function ended
+---@param opts table: Values passed from matchers like prefix
+---@return number|nil: Index of line where the rgb/rgba function ended
 ---@return string|nil: rgb hex value
-function color.rgb_function_parser(line, i)
-  if #line < i + CSS_RGB_FN_MINIMUM_LENGTH then
-    return
-  end
-  local r, g, b, match_end = line:sub(i):match "^rgb%(%s*(%d+%%?)%s*,%s*(%d+%%?)%s*,%s*(%d+%%?)%s*%)()"
-  if not match_end then
-    r, g, b, match_end = line:sub(i):match "^rgb%(%s*(%d+%%?)%s+(%d+%%?)%s+(%d+%%?)%s*%)()"
-    if not match_end then
-      return
-    end
-  end
-  r = percent_or_hex(r)
-  if not r then
-    return
+function color.rgb_function_parser(line, i, opts)
+  local min_len = CSS_RGBA_FN_MINIMUM_LENGTH
+  local min_commas, min_spaces, min_percent = 2, 2, 3
+  local pattern = "^"
+    .. opts.prefix
+    .. "%(%s*([.%d]+)([%%]?)(%s?)%s*(,?)%s*([.%d]+)([%%]?)(%s?)%s*(,?)%s*([.%d]+)([%%]?)%s*(/?,?)%s*([.%d]*)([%%]?)%s*%)()"
+
+  if opts.prefix == "rgb" then
+    min_len = CSS_RGB_FN_MINIMUM_LENGTH
   end
-  g = percent_or_hex(g)
-  if not g then
+
+  if #line < i + min_len then
     return
   end
-  b = percent_or_hex(b)
-  if not b then
+
+  local r, unit1, ssep1, csep1, g, unit2, ssep2, csep2, b, unit3, sep3, a, unit_a, match_end =
+    line:sub(i):match(pattern)
+  if not match_end then
     return
   end
-  local rgb_hex = string.format("%02x%02x%02x", r, g, b)
-  return match_end - 1, rgb_hex
-end
 
-local CSS_RGBA_FN_MINIMUM_LENGTH = #"rgba(0,0,0,0)" - 1
----Parse for rgba() css function and return rgb hex.
--- Todo consider removing the regexes here
--- Todo this might not be the best approach to alpha channel.
--- Things like pumblend might be useful here.
----@param line string: Line to parse
----@param i number: Index of line from where to start parsing
----@return number|nil: Index of line where the rgba function ended
----@return string|nil: rgb hex value
-function color.rgba_function_parser(line, i)
-  if #line < i + CSS_RGBA_FN_MINIMUM_LENGTH then
-    return
+  if a == "" then
+    a = nil
+  else
+    min_commas = min_commas + 1
   end
-  local r, g, b, a, match_end =
-    line:sub(i):match "^rgba%(%s*(%d+%%?)%s*,%s*(%d+%%?)%s*,%s*(%d+%%?)%s*,%s*([.%d]+)%s*%)()"
-  if not match_end then
-    r, g, b, a, match_end = line:sub(i):match "^rgba%(%s*(%d+%%?)%s+(%d+%%?)%s+(%d+%%?)%s+([.%d]+)%s*%)()"
-    if not match_end then
+
+  local units = ("%s%s%s"):format(unit1, unit2, unit3)
+  if units:match "%%" then
+    if not ((count(units, "%%")) == min_percent) then
       return
     end
   end
-  a = tonumber(a)
-  if not a or a > 1 then
+
+  local c_seps = ("%s%s%s"):format(csep1, csep2, sep3)
+  local s_seps = ("%s%s"):format(ssep1, ssep2)
+  -- comma separator syntax
+  if c_seps:match "," then
+    if not (count(c_seps, ",") == min_commas) then
+      return
+    end
+    -- space separator syntax with decimal or percentage alpha
+  elseif count(s_seps, "%s") >= min_spaces then
+    if a then
+      if not (c_seps == "/") then
+        return
+      end
+    end
+  else
     return
   end
-  r = percent_or_hex(r)
+
+  if not a then
+    a = 1
+  else
+    a = tonumber(a)
+    -- if percentage, then convert to decimal
+    if unit_a == "%" then
+      a = a / 100
+    end
+    -- although alpha doesn't support larger values than 1, css anyways renders it at 1
+    if a > 1 then
+      a = 1
+    end
+  end
+
+  r = tonumber(r)
   if not r then
     return
   end
-  g = percent_or_hex(g)
+  g = tonumber(g)
   if not g then
     return
   end
-  b = percent_or_hex(b)
+  b = tonumber(b)
   if not b then
     return
   end
+
+  if unit1 == "%" then
+    r = r / 100 * 255
+    g = g / 100 * 255
+    b = b / 100 * 255
+  else
+    -- although r,g,b doesn't support larger values than 255, css anyways renders it at 255
+    if r > 255 then
+      r = 255
+    end
+    if g > 255 then
+      g = 255
+    end
+    if b > 255 then
+      b = 255
+    end
+  end
+
   local rgb_hex = string.format("%02x%02x%02x", r * a, g * a, b * a)
   return match_end - 1, rgb_hex
 end
-- 
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