1 files changed, 110 insertions, 0 deletions
diff --git a/lua/colorizer/parser/hsl.lua b/lua/colorizer/parser/hsl.lua
new file mode 100644
index 0000000..cb6a19d
--- /dev/null
+++ b/lua/colorizer/parser/hsl.lua
@@ -0,0 +1,110 @@
+---Helper function to parse argb
+local count = require("colorizer.utils").count
+local floor = math.floor
+
+local hsl_to_rgb = require("colorizer.color").hsl_to_rgb
+
+local parser = {}
+
+local CSS_HSLA_FN_MINIMUM_LENGTH = #"hsla(0,0%,0%)" - 1
+local CSS_HSL_FN_MINIMUM_LENGTH = #"hsl(0,0%,0%)" - 1
+---Parse for hsl() hsla() css function and return rgb hex.
+-- For more info: https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/hsl
+---@param line string: Line to parse
+---@param i number: Index of line from where to start parsing
+---@param opts table: Values passed from matchers like prefix
+---@return number|nil: Index of line where the hsla/hsl function ended
+---@return string|nil: rgb hex value
+function parser.hsl_function_parser(line, i, opts)
+  local min_len = CSS_HSLA_FN_MINIMUM_LENGTH
+  local min_commas, min_spaces = 2, 2
+  local pattern = "^"
+    .. opts.prefix
+    .. "%(%s*([.%d]+)([deg]*)([turn]*)(%s?)%s*(,?)%s*(%d+)%%(%s?)%s*(,?)%s*(%d+)%%%s*(/?,?)%s*([.%d]*)([%%]?)%s*%)()"
+
+  if opts.prefix == "hsl" then
+    min_len = CSS_HSL_FN_MINIMUM_LENGTH
+  end
+
+  if #line < i + min_len then
+    return
+  end
+
+  local h, deg, turn, ssep1, csep1, s, ssep2, csep2, l, sep3, a, percent_sign, match_end = line:sub(i):match(pattern)
+  if not match_end then
+    return
+  end
+  if a == "" then
+    a = nil
+  else
+    min_commas = min_commas + 1
+  end
+
+  -- the text after hue should be either deg or empty
+  if not ((deg == "") or (deg == "deg") or (turn == "turn")) then
+    return
+  end
+
+  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
+
+  if not a then
+    a = 1
+  else
+    a = tonumber(a)
+    -- if percentage, then convert to decimal
+    if percent_sign == "%" 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
+
+  h = tonumber(h) or 1
+  -- single turn is 360
+  if turn == "turn" then
+    h = 360 * h
+  end
+
+  -- if hue angle if greater than 360, then calculate the hue within 360
+  if h > 360 then
+    local turns = h / 360
+    h = 360 * (turns - floor(turns))
+  end
+
+  -- if saturation or luminance percentage is  greater than 100 then reset it to 100
+  s = tonumber(s)
+  if s > 100 then
+    s = 100
+  end
+  l = tonumber(l)
+  if l > 100 then
+    l = 100
+  end
+
+  local r, g, b = hsl_to_rgb(h / 360, s / 100, l / 100)
+  if r == nil or g == nil or b == nil then
+    return
+  end
+  local rgb_hex = string.format("%02x%02x%02x", r * a, g * a, b * a)
+  return match_end - 1, rgb_hex
+end
+
+return parser.hsl_function_parser