feat(snip): prepend to expanded lines (#15)

* changed add_to_newl behavior to auto-indent

* commented debug messages

* fixed dm inine according to into_newl change

* oops. no visual doubling with inline dm

* in theory indent and prepend block functionality...

* parameter switch

* comments

* added prepend parameters to intonewl

* refinement

* necessary changes for dm snippet

* backup in comment

* style: format code

* refactor: remove commented code

---------

Co-authored-by: Arne <73391160+arne314@users.noreply.github.com>

lua/typstar/autosnippets.lua

@@ -95,17 +95,100 @@ function M.start_snip(trigger, expand, insert, condition, priority, trigOptions)
     return M.snip('^(\\s*)' .. trigger, '<>' .. expand, { M.cap(1), unpack(insert) }, condition, priority, trigOptions)
 end
 
-function M.start_snip_in_newl(trigger, expand, insert, condition, priority, trigOptions)
+-- Allows to pass expand string and insert table to either indent each line
+-- dynamically of the captured group indent, and or prepend to each line after the indent
+-- For example prepend = '-- ' in lua.
+-- indent: boolean to turn off indenting (option can't be set off right now)
+-- prepend: prepend string
+function M.blocktransform(expand, insert, prepend, indent)
+    -- if idiomatic, skip
+    if indent ~= nil and not indent and not prepend then return expand, insert end
+
+    -- defaults / setup
+    if indent == nil then indent = true end
+    prepend = prepend or ''
+    local last_newl_index = 0
+    local modified_expand = expand
+    function shallowClone(original)
+        local copy = {}
+        for key, value in pairs(original) do
+            copy[key] = value
+        end
+        return copy
+    end
+
+    local modified_insert = shallowClone(insert)
+    local newl_count = 0
+    local offset = 0
+
+    -- logic
+    while true do
+        -- break if no \n anymore
+        local new_newl_index = string.find(expand, '\n', last_newl_index + 1)
+        if not new_newl_index then break end
+        newl_count = newl_count + 1
+
+        -- insert the prepend and newl at the correct position
+        local insert_pos = new_newl_index + offset + 1
+        modified_expand = string.sub(modified_expand, 1, insert_pos - 1)
+            .. (indent and '<>' or '')
+            .. prepend
+            .. string.sub(modified_expand, insert_pos)
+        offset = offset + (indent and 2 or 0) + #prepend
+
+        -- indent of course needs to be added as a dynamic function
+        if indent then
+            local substring = string.sub(modified_expand, 1, insert_pos + 1)
+            local count = 0
+
+            local _, occurrences = string.gsub(substring, '<>', '')
+            count = occurrences
+            table.insert(modified_insert, count, M.leading_white_spaces(1))
+        end
+
+        last_newl_index = new_newl_index
+    end
+    return modified_expand, modified_insert
+end
+
+function M.snip_after_transform(trigger, expand, insert, condition, priority, prependlines, trigOptions)
+    local expand, insert = M.blocktransform(expand, insert, prependlines, true)
     return M.snip(
-        '([^\\s]\\s+)' .. trigger,
-        '<>\n<>' .. expand,
-        { M.cap(1), M.leading_white_spaces(1), unpack(insert) },
+        trigger,
+        expand,
+        insert,
         condition,
         priority,
         vim.tbl_deep_extend('keep', { wordTrig = false }, trigOptions or {})
     )
 end
 
+function M.start_snip_in_newl(trigger, expand, insert, condition, priority, prepend, prependlines, trigOptions)
+    prepend = prepend or ''
+    return M.snip_after_transform(
+        '([^\\s]\\s+)' .. trigger,
+        '<><>\n' .. expand,
+        { M.cap(1), prepend, unpack(insert) },
+        condition,
+        priority,
+        prependlines,
+        trigOptions
+    )
+end
+
+function M.bulletpoint_snip(trigger, expand, insert, condition, priority, prepend, prependlines, trigOptions)
+    prepend = prepend or ''
+    return M.snip_after_transform(
+        '(^\\s*\\-\\s+.*\\s*)' .. trigger,
+        '<><>' .. expand,
+        { M.cap(1), prepend, unpack(insert) },
+        condition,
+        priority,
+        prependlines,
+        trigOptions
+    )
+end
+
 local alts_regex = '[\\[\\(](.*|.*)[\\)\\]]'
 
 function M.engine(trigger, opts)

lua/typstar/snippets/markup.lua

@@ -45,7 +45,8 @@ end
 
 return {
     start('dm', '$\n<>\n<>$', { indent_visual(1), cap(1) }, markup),
-    helper.start_snip_in_newl('dm', '$\n<>\n<>$', { indent_visual(1), helper.leading_white_spaces(1) }, markup),
+    helper.start_snip_in_newl('dm', '$\n\t<>\n$ <>', { helper.visual(1), i(2) }, markup, 999),
+    helper.bulletpoint_snip('dm', '\n$\n\t<>\n$ <>', { helper.visual(1), i(2) }, markup, 1001, '', '\t'),
     start('fla', '#flashcard(0)[<>][\n<>\n<>]', { i(1, 'flashcard'), indent_visual(2), cap(1) }, markup),
     start('flA', '#flashcard(0, "<>")[\n<>\n<>]', { i(1, 'flashcard'), indent_visual(2), cap(1) }, markup),
     snip('IMP', '$==>>$ ', {}, markup),