#!/usr/bin/env lua

-- Monkey patch Luacheck (tested against version 0.23.0) to support Candran files
local candran = require("candran")

local function pattern(token)
	return "()"..token:gsub("[^%w]", "%%%0").."()"
end

local tokenAlias = {
	["self"] = { "@", ":" }
}

-- Patch checker
local oldCheck = require("luacheck.check")
local function check(can)
	local lua, err = candran.make(can)
	if lua then
		local r = oldCheck(lua)
		-- Calculate Candran file position.
		if #r.warnings > 0 then
			local lua_lines = {}
			for l in (lua.."\n"):gmatch("([^\n]*)\n") do
				table.insert(lua_lines, l)
			end
			local can_lines = {}
			for l in (can.."\n"):gmatch("([^\n]*)\n") do
				table.insert(can_lines, l)
			end
			for _, warning in ipairs(r.warnings) do
				-- candran line
				local lua_line = lua_lines[warning.line]
				warning.can_line = tonumber(lua_line:match(".*%-%- .-%:(%d+)$"))

				-- candran column
				local can_line = can_lines[warning.can_line]
				local lua_token = lua_line:sub(warning.column, warning.end_column)
				local token_pattern = pattern(lua_token) -- token finding pattern
				-- the warning happens on the n-th instance of lua_token on this line
				local lua_n = 1
				for start in lua_line:gmatch(token_pattern) do
					if start >= warning.column then
						break
					end
					lua_n = lua_n + 1
				end
				-- Find associated candran token. If lua_n > can_nmax, the last found lua_token is used.
				-- This approximation should work in like, 90% of cases.
				local can_n = 1
				local pos = 1
				while can_n <= lua_n do
					-- find first token or alias of this token
					local start, stop = can_line:match(token_pattern, pos)
					if tokenAlias[lua_token] then
						for _, token in ipairs(tokenAlias[lua_token]) do
							local nstart, nstop = can_line:match(pattern(token), pos)
							if nstart and (not start or nstart < start) then
								start, stop = nstart, nstop
							end
						end
					end
					-- found
					if start then
						pos = stop
						warning.can_column, warning.can_end_column = start, stop
						can_n = can_n + 1
					else
						break
					end
				end
			end
		end
		return r
	else
		local line, column, msg = err:match(":(%d+):(%d+):%s*(.*)$")
		local syntax_error = {
			code = "011",
			line = line,
			column = column,
			end_column = column,
			msg = msg
		}
		return {
			warnings = {syntax_error},
			inline_options = {},
			line_lengths = {},
			line_endings = {}
		}
	end
end
package.loaded["luacheck.check"] = check

-- Patch formatter
local format = require("luacheck.format")
local function format_location(file, location, opts)
   local res = ("%s:%d:%d"):format(file, location.can_line or location.line, location.can_column or location.column)
   if opts.ranges then
      res = ("%s-%d"):format(res, location.can_end_column or location.end_column)
   end
   return res
end
local function setupvalue(fn, val, name, ...)
	for i=1, debug.getinfo(fn, "u").nups do
		local n, v = debug.getupvalue(fn, i)
		if n == name then
			if not ... then
				debug.setupvalue(fn, i, val)
			else
				setupvalue(v, val, ...)
			end
		end
	end
end
setupvalue(format.builtin_formatters.plain, format_location, "format_event", "format_location")

require("luacheck.main")