-- Copyright (c) 2026 Progmasoft.
-- SPDX-License-Identifier: MPL-2.0 WITH AdditionRef-Progmasoft-Exception-2.0

-- Materialize the checked-in CMake template of the engine's configuration
-- header for non-CMake build tools.
-- Keeping the template as the source of truth avoids maintaining a second
-- copy of upstream configuration declarations under a different license.
local M = {}

local function read_file(file_path)
    local file = assert(io.open(file_path, "rb"), "cannot read " .. file_path)
    local contents = file:read("*a")
    file:close()
    return contents
end

local function write_file(file_path, contents)
    local file = assert(io.open(file_path, "wb"), "cannot write " .. file_path)
    file:write(contents)
    file:close()
end

--- Generates the default user configuration header under output_root.
--- The generated path is output_root/Progmasoft/Catch3/UserConfig.hpp.
function M.generate(output_root, repository_root)
    local template_path = repository_root .. "/src/Progmasoft/Catch3/UserConfig.hpp.in"
    local template = read_file(template_path)

    -- Neither Xmake nor Premake interprets CMake's #cmakedefine directives;
    -- every feature toggle stays at its default.
    local configured = template:gsub(
        "#cmakedefine%s+([%w_]+)%s*([^\r\n]*)",
        function(name)
            return "/* #undef " .. name .. " */"
        end
    )
    configured = configured:gsub("@CATCH_CONFIG_FALLBACK_STRINGIFIER@", "")

    local output_dir = output_root .. "/Progmasoft/Catch3"
    os.mkdir(output_dir)
    write_file(output_dir .. "/UserConfig.hpp", configured)
end

-- Xmake imports call the module's main entry point; Premake can use generate.
function main(output_root, repository_root)
    return M.generate(output_root, repository_root)
end

return M