-- This is a hack to get around the specifications "We can't expect an application
-- to keep track of nested H's (but otherwise expect very complex things things to
-- be properly dealt with)". A typical example of bugs becoming features, standards
-- being not really standards as they get adapted, etc. That said: it is up to the
-- user to decide what to do but don't blame us for the resulting less optimal
-- structure.
--
-- Because we don't want to spoil the otherwise rather clean structure in ConTeXt,
-- this kicks in very late in the backend. We might extend this hackery but there
-- are limits to what is desired. After all, in over a decade of pdf tagging nothing
-- significant happened (we're speaking 2024) nor proper viewer support showed up
-- and we can anyway expect LLM's to deal with proper tags anyway some day.
--
-- criterium : parent    : use parent "detail"
--             parents   : use first in parent "parents" list
--             otherwise : look at self "detail"
--
-- We need violate the proper structure by getting a Hn on the title so we
-- have to backtrack to what we're in, thereby also denying the proper
-- section instance. Don't ask. The plural "parents" will make sure we
-- consult the first in the chain and not the instance that is encoded in
-- "detail".

local level   = structures.tags.getoption("level")
local current = 0
local used    = 0

local function HN(bump)
    if bump then
        current = current + 1
        if current >= level then
            used = used + 1
        end
    end
    if used > 0 and used < 10 then
        return "H" .. used
    else
        return "NonStruct"
    end
end

return {

    name      = "basic pdf specific tagging",
    version   = "1.00",
    author    = "Hans Hagen & Mikael Sundqvist",
    copyright = "ConTeXt development team",

    mapping   = {

        sectionblock   = { pdf = "NonStruct" },

        -- 1.28.1 1.29.57 (otherwise complaints about P)

        section        = { pdf = "Sect" },
        sectioncaption = { pdf = "Div"  },
        sectiontitle   = { pdf = "Lbl"  }, -- Span is fragile
        sectionnumber  = { pdf = "Lbl"  }, -- Span is fragile
        sectioncontent = { pdf = "Div"  },

    },


    remapping = {

        { element = "sectioncaption", parent = "part",                            pdf = HN(true ) },
        { element = "sectioncaption", parent = "chapter",                         pdf = HN(true ) },
        { element = "sectioncaption", parent = "title",                           pdf = HN(false) },
        { element = "sectioncaption", parent = "section",                         pdf = HN(true ) },
        { element = "sectioncaption", parent = "subject",                         pdf = HN(false) },
        { element = "sectioncaption", parent = "subsection",                      pdf = HN(true ) },
        { element = "sectioncaption", parent = "subsubsubject",                   pdf = HN(false) },
        { element = "sectioncaption", parent = "subsubsection",                   pdf = HN(true ) },
        { element = "sectioncaption", parent = "subsubsubsubject",                pdf = HN(false) },
        { element = "sectioncaption", parent = "subsubsubsection",                pdf = HN(true ) },
        { element = "sectioncaption", parent = "subsubsubsubsubject",             pdf = HN(false) },
        { element = "sectioncaption", parent = "subsubsubsubsection",             pdf = HN(true ) },
        { element = "sectioncaption", parent = "subsubsubsubsubsubject",          pdf = HN(false) },
        { element = "sectioncaption", parent = "subsubsubsubsubsection",          pdf = HN(true ) },
        { element = "sectioncaption", parent = "subsubsubsubsubsubsubject",       pdf = HN(false) },
        { element = "sectioncaption", parent = "subsubsubsubsubsubsubsection",    pdf = HN(true ) },
        { element = "sectioncaption", parent = "subsubsubsubsubsubsubsubsubject", pdf = HN(false) },

        { element = "sectionblock",   pdf = "NonStruct" },

        { element = "section",        pdf = "Sect" },
        { element = "sectioncaption", pdf = "Div"  },
        { element = "sectiontitle",   pdf = "Lbl"  },
        { element = "sectionnumber",  pdf = "Lbl"  },
        { element = "sectioncontent", pdf = "Div"  },

    },

}