---@class ScraperTestCase
---@field input string
---@field expected string

---@class ScraperResult
---@field success boolean
---@field problem_id string
---@field url? string
---@field tests? ScraperTestCase[]
---@field error? string

local M = {}
local logger = require("cp.log")
local cache = require("cp.cache")

local function get_plugin_path()
	local plugin_path = debug.getinfo(1, "S").source:sub(2)
	return vim.fn.fnamemodify(plugin_path, ":h:h:h")
end

local function ensure_io_directory()
	vim.fn.mkdir("io", "p")
end

local function check_internet_connectivity()
	local result = vim.system({ "ping", "-c", "1", "-W", "3", "8.8.8.8" }, { text = true }):wait()
	return result.code == 0
end

local function setup_python_env()
	local plugin_path = get_plugin_path()
	local venv_dir = plugin_path .. "/.venv"

	if vim.fn.executable("uv") == 0 then
		logger.log(
			"uv is not installed. Install it to enable problem scraping: https://docs.astral.sh/uv/",
			vim.log.levels.WARN
		)
		return false
	end

	if vim.fn.isdirectory(venv_dir) == 0 then
		logger.log("setting up Python environment for scrapers...")
		local result = vim.system({ "uv", "sync" }, { cwd = plugin_path, text = true }):wait()
		if result.code ~= 0 then
			logger.log("failed to setup Python environment: " .. result.stderr, vim.log.levels.ERROR)
			return false
		end
		logger.log("python environment setup complete")
	end

	return true
end

---@param platform string
---@param contest_id string
---@return {success: boolean, problems?: table[], error?: string}
function M.scrape_contest_metadata(platform, contest_id)
	vim.validate({
		platform = { platform, "string" },
		contest_id = { contest_id, "string" },
	})

	cache.load()

	local cached_data = cache.get_contest_data(platform, contest_id)
	if cached_data then
		return {
			success = true,
			problems = cached_data.problems,
		}
	end

	if not check_internet_connectivity() then
		return {
			success = false,
			error = "No internet connection available",
		}
	end

	if not setup_python_env() then
		return {
			success = false,
			error = "Python environment setup failed",
		}
	end

	local plugin_path = get_plugin_path()
	local scraper_path = plugin_path .. "/scrapers/" .. platform .. ".py"

	local args
	if platform == "cses" then
		args = {
			"uv",
			"run",
			"--directory",
			plugin_path,
			scraper_path,
			"metadata",
		}
	else
		args = {
			"uv",
			"run",
			"--directory",
			plugin_path,
			scraper_path,
			"metadata",
			contest_id,
		}
	end

	local result = vim.system(args, {
		cwd = plugin_path,
		text = true,
		timeout = 30000,
	}):wait()

	if result.code ~= 0 then
		return {
			success = false,
			error = "Failed to run metadata scraper: " .. (result.stderr or "Unknown error"),
		}
	end

	local ok, data = pcall(vim.json.decode, result.stdout)
	if not ok then
		return {
			success = false,
			error = "Failed to parse metadata scraper output: " .. tostring(data),
		}
	end

	if not data.success then
		return data
	end

	local problems_list
	if platform == "cses" then
		problems_list = data.categories and data.categories["CSES Problem Set"] or {}
	else
		problems_list = data.problems or {}
	end

	cache.set_contest_data(platform, contest_id, problems_list)
	return {
		success = true,
		problems = problems_list,
	}
end

---@param ctx ProblemContext
---@return {success: boolean, problem_id: string, test_count?: number, test_cases?: ScraperTestCase[], url?: string, error?: string}
function M.scrape_problem(ctx)
	vim.validate({
		ctx = { ctx, "table" },
	})

	ensure_io_directory()

	if vim.fn.filereadable(ctx.input_file) == 1 and vim.fn.filereadable(ctx.expected_file) == 1 then
		local base_name = vim.fn.fnamemodify(ctx.input_file, ":r")
		local test_cases = {}
		local i = 1

		while true do
			local input_file = base_name .. "." .. i .. ".cpin"
			local expected_file = base_name .. "." .. i .. ".cpout"

			if vim.fn.filereadable(input_file) == 1 and vim.fn.filereadable(expected_file) == 1 then
				local input_content = table.concat(vim.fn.readfile(input_file), "\n")
				local expected_content = table.concat(vim.fn.readfile(expected_file), "\n")

				table.insert(test_cases, {
					index = i,
					input = input_content,
					output = expected_content,
				})
				i = i + 1
			else
				break
			end
		end

		return {
			success = true,
			problem_id = ctx.problem_name,
			test_count = #test_cases,
			test_cases = test_cases,
		}
	end

	if not check_internet_connectivity() then
		return {
			success = false,
			problem_id = ctx.problem_name,
			error = "No internet connection available",
		}
	end

	if not setup_python_env() then
		return {
			success = false,
			problem_id = ctx.problem_name,
			error = "Python environment setup failed",
		}
	end

	local plugin_path = get_plugin_path()
	local scraper_path = plugin_path .. "/scrapers/" .. ctx.contest .. ".py"

	local args
	if ctx.contest == "cses" then
		args = {
			"uv",
			"run",
			"--directory",
			plugin_path,
			scraper_path,
			"tests",
			ctx.contest_id,
		}
	else
		args = {
			"uv",
			"run",
			"--directory",
			plugin_path,
			scraper_path,
			"tests",
			ctx.contest_id,
			ctx.problem_id,
		}
	end

	local result = vim.system(args, {
		cwd = plugin_path,
		text = true,
		timeout = 30000,
	}):wait()

	if result.code ~= 0 then
		return {
			success = false,
			problem_id = ctx.problem_name,
			error = "Failed to run tests scraper: " .. (result.stderr or "Unknown error"),
		}
	end

	local ok, data = pcall(vim.json.decode, result.stdout)
	if not ok then
		return {
			success = false,
			problem_id = ctx.problem_name,
			error = "Failed to parse tests scraper output: " .. tostring(data),
		}
	end

	if not data.success then
		return data
	end

	if data.tests and #data.tests > 0 then
		local base_name = vim.fn.fnamemodify(ctx.input_file, ":r")

		for i, test_case in ipairs(data.tests) do
			local input_file = base_name .. "." .. i .. ".cpin"
			local expected_file = base_name .. "." .. i .. ".cpout"

			local input_content = test_case.input:gsub("\r", "")
			local expected_content = test_case.expected:gsub("\r", "")

			vim.fn.writefile(vim.split(input_content, "\n", true), input_file)
			vim.fn.writefile(vim.split(expected_content, "\n", true), expected_file)
		end

		local combined_input = table.concat(
			vim.tbl_map(function(tc)
				return tc.input
			end, data.tests),
			"\n"
		)
		local combined_output = table.concat(
			vim.tbl_map(function(tc)
				return tc.expected
			end, data.tests),
			"\n"
		)

		vim.fn.writefile(vim.split(combined_input, "\n", true), ctx.input_file)
		vim.fn.writefile(vim.split(combined_output, "\n", true), ctx.expected_file)
	end

	return {
		success = true,
		problem_id = ctx.problem_name,
		test_count = data.tests and #data.tests or 0,
		test_cases = data.tests,
		url = data.url,
	}
end

return M