1 files changed, 266 insertions, 0 deletions
diff --git a/lua/colorizer/buffer.lua b/lua/colorizer/buffer.lua
new file mode 100644
index 0000000..3b31daf
--- /dev/null
+++ b/lua/colorizer/buffer.lua
@@ -0,0 +1,266 @@
+---Helper functions to highlight buffer smartly
+--@module colorizer.buffer
+local api = vim.api
+local buf_set_virtual_text = api.nvim_buf_set_extmark
+local buf_get_lines = api.nvim_buf_get_lines
+local create_namespace = api.nvim_create_namespace
+local clear_namespace = api.nvim_buf_clear_namespace
+local set_highlight = api.nvim_set_hl
+
+local color = require "colorizer.color"
+local color_is_bright = color.is_bright
+
+local make_matcher = require("colorizer.matcher").make
+
+local sass = require "colorizer.sass"
+local sass_update_variables = sass.update_variables
+local sass_cleanup = sass.cleanup
+
+local tailwind = require "colorizer.tailwind"
+local tailwind_setup_lsp = tailwind.setup_lsp_colors
+local tailwind_cleanup = tailwind.cleanup
+
+local buffer = {}
+
+local HIGHLIGHT_NAME_PREFIX = "colorizer"
+local HIGHLIGHT_CACHE = {}
+
+--- Default namespace used in `highlight` and `colorizer.attach_to_buffer`.
+-- @see highlight
+-- @see colorizer.attach_to_buffer
+buffer.default_namespace = create_namespace "colorizer"
+
+--- Highlight mode which will be use to render the colour
+buffer.highlight_mode_names = {
+  background = "mb",
+  foreground = "mf",
+  virtualtext = "mv",
+}
+
+--- Clean the highlight cache
+function buffer.clear_hl_cache()
+  HIGHLIGHT_CACHE = {}
+end
+
+--- Make a deterministic name for a highlight given these attributes
+local function make_highlight_name(rgb, mode)
+  return table.concat({ HIGHLIGHT_NAME_PREFIX, buffer.highlight_mode_names[mode], rgb }, "_")
+end
+
+local function create_highlight(rgb_hex, mode)
+  mode = mode or "background"
+  -- TODO validate rgb format?
+  rgb_hex = rgb_hex:lower()
+  local cache_key = table.concat({ buffer.highlight_mode_names[mode], rgb_hex }, "_")
+  local highlight_name = HIGHLIGHT_CACHE[cache_key]
+
+  -- Look up in our cache.
+  if highlight_name then
+    return highlight_name
+  end
+
+  -- convert from #fff to #ffffff
+  if #rgb_hex == 3 then
+    rgb_hex = table.concat {
+      rgb_hex:sub(1, 1):rep(2),
+      rgb_hex:sub(2, 2):rep(2),
+      rgb_hex:sub(3, 3):rep(2),
+    }
+  end
+
+  -- Create the highlight
+  highlight_name = make_highlight_name(rgb_hex, mode)
+  if mode == "foreground" then
+    set_highlight(0, highlight_name, { fg = "#" .. rgb_hex })
+  else
+    local rr, gg, bb = rgb_hex:sub(1, 2), rgb_hex:sub(3, 4), rgb_hex:sub(5, 6)
+    local r, g, b = tonumber(rr, 16), tonumber(gg, 16), tonumber(bb, 16)
+    local fg_color
+    if color_is_bright(r, g, b) then
+      fg_color = "Black"
+    else
+      fg_color = "White"
+    end
+    set_highlight(0, highlight_name, { fg = fg_color, bg = "#" .. rgb_hex })
+  end
+  HIGHLIGHT_CACHE[cache_key] = highlight_name
+  return highlight_name
+end
+
+--- Create highlight and set highlights
+---@param buf number
+---@param ns number
+---@param line_start number
+---@param line_end number
+---@param data table: table output of `parse_lines`
+---@param options table: Passed in setup, mainly for `user_default_options`
+function buffer.add_highlight(buf, ns, line_start, line_end, data, options)
+  clear_namespace(buf, ns, line_start, line_end)
+
+  local mode = options.mode == "background" and "background" or "foreground"
+  if vim.tbl_contains({ "foreground", "background" }, options.mode) then
+    for linenr, hls in pairs(data) do
+      for _, hl in ipairs(hls) do
+        local hlname = create_highlight(hl.rgb_hex, mode)
+        api.nvim_buf_add_highlight(buf, ns, hlname, linenr, hl.range[1], hl.range[2])
+      end
+    end
+  elseif options.mode == "virtualtext" then
+    for linenr, hls in pairs(data) do
+      for _, hl in ipairs(hls) do
+        local hlname = create_highlight(hl.rgb_hex, mode)
+        buf_set_virtual_text(0, ns, linenr, hl.range[2], {
+          end_col = hl.range[2],
+          virt_text = { { options.virtualtext or "■", hlname } },
+        })
+      end
+    end
+  end
+end
+
+--- Highlight the buffer region.
+-- Highlight starting from `line_start` (0-indexed) for each line described by `lines` in the
+-- buffer `buf` and attach it to the namespace `ns`.
+---@param buf number: buffer id
+---@param ns number: The namespace id. Default is DEFAULT_NAMESPACE. Create it with `vim.api.nvim_create_namespace`
+---@param line_start number: line_start should be 0-indexed
+---@param line_end number: Last line to highlight
+---@param options table: Configuration options as described in `setup`
+---@param options_local table: Buffer local variables
+---@return nil|boolean|number,table
+function buffer.highlight(buf, ns, line_start, line_end, options, options_local)
+  local returns = { detach = { ns = {}, functions = {} } }
+  if buf == 0 or buf == nil then
+    buf = api.nvim_get_current_buf()
+  end
+
+  local lines = buf_get_lines(buf, line_start, line_end, false)
+
+  ns = ns or buffer.default_namespace
+
+  -- only update sass varibles when text is changed
+  if options_local.__event ~= "WinScrolled" and options.sass and options.sass.enable then
+    table.insert(returns.detach.functions, sass_cleanup)
+    sass_update_variables(buf, 0, -1, nil, make_matcher(options.sass.parsers or { css = true }), options, options_local)
+  end
+
+  local data = buffer.parse_lines(buf, lines, line_start, options) or {}
+  buffer.add_highlight(buf, ns, line_start, line_end, data, options)
+
+  if options.tailwind == "lsp" or options.tailwind == "both" then
+    tailwind_setup_lsp(buf, options, options_local, buffer.add_highlight)
+    table.insert(returns.detach.functions, tailwind_cleanup)
+  end
+
+  return true, returns
+end
+
+--- Parse the given lines for colors and return a table containing
+-- rgb_hex and range per line
+---@param buf number
+---@param lines table
+---@param line_start number: This is the buffer line number, from where to start highlighting
+---@param options table: Passed in `colorizer.setup`, Only uses `user_default_options`
+---@return table|nil
+function buffer.parse_lines(buf, lines, line_start, options)
+  local loop_parse_fn = make_matcher(options)
+  if not loop_parse_fn then
+    return
+  end
+
+  local data = {}
+  for current_linenum, line in ipairs(lines) do
+    current_linenum = current_linenum - 1 + line_start
+    data[current_linenum] = data[current_linenum] or {}
+
+    -- Upvalues are options and current_linenum
+    local i = 1
+    while i < #line do
+      local length, rgb_hex = loop_parse_fn(line, i, buf)
+      if length and rgb_hex then
+        table.insert(data[current_linenum], { rgb_hex = rgb_hex, range = { i - 1, i + length - 1 } })
+        i = i + length
+      else
+        i = i + 1
+      end
+    end
+  end
+
+  return data
+end
+
+-- gets used in rehighlight function only
+local BUFFER_LINES = {}
+-- get the amount lines to highlight
+local function getrow(buf)
+  if not BUFFER_LINES[buf] then
+    BUFFER_LINES[buf] = {}
+  end
+
+  local a = api.nvim_buf_call(buf, function()
+    return {
+      vim.fn.line "w0",
+      vim.fn.line "w$",
+    }
+  end)
+  local min, max
+  local new_min, new_max = a[1] - 1, a[2]
+  local old_min, old_max = BUFFER_LINES[buf]["min"], BUFFER_LINES[buf]["max"]
+
+  if old_min and old_max then
+    -- Triggered for TextChanged autocmds
+    -- TODO: Find a way to just apply highlight to changed text lines
+    if (old_max == new_max) or (old_min == new_min) then
+      min, max = new_min, new_max
+    -- Triggered for WinScrolled autocmd - Scroll Down
+    elseif old_max < new_max then
+      min = old_max
+      max = new_max
+    -- Triggered for WinScrolled autocmd - Scroll Up
+    elseif old_max > new_max then
+      min = new_min
+      max = new_min + (old_max - new_max)
+    end
+    -- just in case a long jump was made
+    if max - min > new_max - new_min then
+      min = new_min
+      max = new_max
+    end
+  end
+  min = min or new_min
+  max = max or new_max
+  -- store current window position to be used later to incremently highlight
+  BUFFER_LINES[buf]["max"] = new_max
+  BUFFER_LINES[buf]["min"] = new_min
+  return min, max
+end
+
+--- Rehighlight the buffer if colorizer is active
+---@param buf number: Buffer number
+---@param options table: Buffer options
+---@param options_local table|nil: Buffer local variables
+---@param use_local_lines boolean|nil Whether to use lines num range from options_local
+---@return nil|boolean|number,table
+function buffer.rehighlight(buf, options, options_local, use_local_lines)
+  if buf == 0 or buf == nil then
+    buf = api.nvim_get_current_buf()
+  end
+
+  local ns = buffer.default_namespace
+
+  local min, max
+  if use_local_lines and options_local then
+    min, max = options_local.__startline or 0, options_local.__endline or -1
+  else
+    min, max = getrow(buf)
+  end
+
+  local bool, returns = buffer.highlight(buf, ns, min, max, options, options_local or {})
+  table.insert(returns.detach.functions, function()
+    BUFFER_LINES[buf] = nil
+  end)
+
+  return bool, returns
+end
+
+return buffer