#!/usr/bin/env lua

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

local function escape(str)
	return str:gsub("[^%w]", "%%%0")
end

local function pattern(token)
	return "()"..escape(token).."()"
end

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

-- Patch checker
local oldCheck = require("luacheck.check")
local function check(can)
	local lua, err = candran.make(can, {chunkname="_luacheck_source"})
	-- Warnings
	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 i=#r.warnings, 1, -1 do
				local warning  = r.warnings[i]

				-- calculating candran line
				local lua_line = lua_lines[warning.line]

				local source, line = lua_line:match(".*%-%- (.-)%:(%d+)$")
				if source ~= "_luacheck_source" then -- line is from another file, discard
					table.remove(r.warnings, i)

				elseif source then
					warning.can_line = tonumber(line)

					-- do the same for prev_line
					if warning.prev_line then
						local s, l = lua_lines[warning.prev_line]:match(".*%-%- (.-)%:(%d+)$")
						if s ~= "_luacheck_source" then
							warning.prev_line = s..":"..l -- luacheck seems to do no validation on this, so we can redefine it to anything
						elseif l then
							warning.prev_line = l
						end
					end

					-- calculating 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

					-- AFAIK, prev_column and prev_column_end are not displayed in any warning so we don't need to recalculate them for Candran.
				end
			end
		end
		return r
	-- Syntax error
	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

local runner = require("luacheck.runner")
local oldRunner = runner.new
function runner.new(opts)
	-- Disable max line length checking (it is compiled code...)
	opts.max_line_length = false
	return oldRunner(opts)
end

-- 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")

-- Fix some Luacheck messages and run
local path = util.search("luacheck.main", {"lua"})
if path then
	local f = io.open(path, "r")
	local code = f:read("*a")
	f:close()

	code = code:gsub(escape(" bug (please report at https://github.com/mpeterv/luacheck/issues)"), ", patched for Candran "..candran.VERSION.." bug. Please DO NOT report this bug to Luacheck") -- error text
	           :gsub(escape("\"luacheck\","), "\"cancheck\",") -- command name
	           :gsub("a linter and a static analyzer for Lua%.", "a linter and a static analyzer for Lua, patched for Candran "..candran.VERSION..".") -- help text

	-- run
	return load(code)()
else
	io.stderr:write("can't find luacheck.main\n")
	os.exit(1)
end