-- IMPORTANT: for distribution the first 10 lines are changed to:
--   local fennel = mod
-- Initial setup for development:
--   Enables Fennel for Lisp-Lua embeded compatibility
--   Cfr. https://fennel-lang.org
local src_root = pandoc.path.directory(PANDOC_SCRIPT_FILE)
local fennel_lua = pandoc.path.join({src_root, "../opt/fennel.lua"})
package.path = package.path .. ";" .. fennel_lua
local fennel = require("fennel")
-- IMPORTANT: code for distribution starts after this line.
--[[
-- Lua LPeg shortcuts
local P, S, R, Cf, Cc, Ct, V, Cs, Cg, Cb, B, C, Cmt =
  lpeg.P, lpeg.S, lpeg.R, lpeg.Cf, lpeg.Cc, lpeg.Ct, lpeg.V,
  lpeg.Cs, lpeg.Cg, lpeg.Cb, lpeg.B, lpeg.C, lpeg.Cmt

-- Lexical elements
local space = S(" \t\r\n")
local lbracket = P"("
local rbracket = P")"
local word = (1 - (space + lbracket + rbracket))

-- Grammar for Pandoc parser that converts:
-- Lisp expression => pandoc.Plain
-- Lisp list => pandoc.Span
-- Lisp atom => pandoc.Str
G = P{
  "Doc";
  Doc = space^0 * Ct(V"SExpr"^0) * space^0 / pandoc.Pandoc; 
  SExpr = (V"List" + V"Atom");
  List = lbracket * V"SExpr"^0 * rbracket / embed;
  Atom = space + V"Word";
  Word = word^1 / pandoc.Str;
}
]]--

-- Evals Lisp code
-- @param code string: code to evaluate
-- @return table: evaluation result as {bool, string, string, string}
local function eval(code)
  is_passed, out = pcall (
    function () return fennel.eval(code) end,
    function (e) return e end
  )
  lua = ""
  out = tostring(out)
  preview = out:gsub("\n.*", "")
  if is_passed then
    lua = fennel.compileString(code)
  end
  return {is_passed = is_passed, preview = preview, out = out, lua = lua}
end

return {
  {
    CodeBlock = function (block)
      if block.classes:includes("eval") then
        local raw = block.text
        print("⚙️ ", raw)
        local res = eval(raw)
        print("", res["is_passed"], "→", res["preview"])
        if block.classes:includes("replace") then
          return pandoc.CodeBlock(res["out"], {code=raw})
        end
      end
    end,
  }
}