Module:BookTOC

local p = {}

function p.main(frame)
    local args = frame:getParent().args
    local items = {}
    local levels = {}
    
    -- Check if collapsed parameter is set
    local collapsed = args.collapsed == "true"
    
    -- Collect all TOC items and their levels
    local i = 1
    while args['item' .. i] do
        items[i] = args['item' .. i]
        levels[i] = tonumber(args['level' .. i]) or 2 -- Default to level 2
        i = i + 1
    end
    
    if #items == 0 then
        return ''
    end
    
    -- Find minimum level
    local min_level = math.min(unpack(levels))
    
    local list = {}
    
    for idx = 1, #items do
        local normalized_level = levels[idx] - min_level + 1
        local item = items[idx]
        
        -- Add list line
        table.insert(list, string.rep('#', normalized_level) .. ' ' .. item)
    end
    
    -- Add mw-collapsed class if collapsed=true
    local collapsible_class = "mw-collapsible mw-made-collapsible"
    if collapsed then
        collapsible_class = collapsible_class .. " mw-collapsed"
    end
    
    return '<div class="book-toc">\n' ..
       '<div class="toc-header">\n' ..
       '<strong>Table of contents</strong>\n' ..
       '</div>\n' ..
       '<div class="' .. collapsible_class .. '">\n' ..
       table.concat(list, '\n') .. '\n' ..
       '</div>\n' ..
       '</div>'
end

return p