#!/usr/bin/env lua

--[[
Based on luacheck: https://github.com/luarocks/luacheck

The MIT License (MIT)

Copyright (c) 2014 - 2018 Peter Melnichenko

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
]]

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

-- set a function upvalues (if several names are given, will go up the upvalue chain)
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

-- escape a string to be used as a pattern
local function escape(str)
	return str:gsub("[^%w]", "%%%0")
end

-- returns a pattern that find start and stop position of a token
local function pattern(token)
	return "()"..escape(token).."()"
end

-- token aliases
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

					-- Errors codes highlighting a identifier (alphanumeric+underscore not starting with a number):
					-- 1xx: global variables
					-- 2xx: unused variables
					-- 3xx: unused values
					-- 4xx: shadowing delarations
					local isIdentifier = tonumber(warning.code) >= 100 and tonumber(warning.code) < 500

					-- 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
						-- for non aliases token that are identifier, check if match is a full identifier
						-- (avoid things like `let e` matching the e in let)
						elseif start and isIdentifier then
							local prev = can_line:sub(start-1, start-1)
							local next = can_line:sub(stop, stop)
							if prev:match("[%w_]") or next:match("[%w_]") then
								can_n = can_n - 1 -- skip this match
							end
						end
						-- found
						if start then
							pos = stop
							warning.can_column, warning.can_end_column = start, stop-1
							can_n = can_n + 1
						else
							break
						end
					end

					-- AFAIK, prev_column and prev_end_column 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
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