local M = {}

local fm, md

local function ensure_deps()
    if not fm then
        fm = dofile(engine.module.dir_of("lib-management.launcher") .. "/frontmatter.lua")
    end
    if not md then
        md = dofile(engine.module.dir_of("lib-management.launcher") .. "/markdown.lua")
    end
end

-- Returns:
--   meta = { summary, description_md, author, tags, teaser_images,
--            carousel_interval_seconds, ... }
--   body_blocks = output of markdown.parse(body) — pre-parsed for cache reuse
-- On any failure (file missing, parse error): meta = {}, body_blocks = {}.
function M.load_for(module_id)
    ensure_deps()
    local content, err = engine.module.read_file(module_id, "manifest.launcher.md")
    if not content then
        return { _missing = true, _err = err }, {}
    end
    local meta, body, perr = fm.parse(content)
    if not meta then
        return { _missing = false, _err = perr }, {}
    end
    local blocks = md.parse(body)
    return meta, blocks
end

return M