if not modules then modules = { } end modules ['spac-pas'] = {
    version   = 1.001,
    comment   = "companion to spac-pas.mkxl",
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

local rawget, tonumber = rawget, tonumber

local report         = logs.reporter("break quality")

local integer_value  = tokens.values.integer
local currentfile    = luatex.currentfile

local toobad         = 20
local tracing        = false
local details        = false

-- builders.passnames   = utilities.storage.mark(builders.passnames or { })
-- local passnames      = builders.passnames
-- local nofidentifiers = #passnames
--
-- storage.register("builders/passnames", passnames, "builders.passnames")

local passnames      = { }
local nofidentifiers = 0

table.setmetatableindex(passnames,function(t,k)
    if type(k) == "number" and k >= 0 then
        return k
    else
        nofidentifiers = nofidentifiers - 1
        t[k] = nofidentifiers
        t[nofidentifiers] = k
        return nofidentifiers
    end
end)

interfaces.implement {
    name      = "parpassidentifier",
    public    = true,
    usage     = "value",
    arguments = "string",
    actions   = function(s)
        return integer_value, passnames[s]
    end,
}

local function linebreak_quality_console(id,line,pass,subpass,subpasses,overfull,underfull,badness,classes)
    local filename = currentfile()
    local passname = passnames[id]
    if pass == 1 then
        if details then
            report("file %a, line %i, pass 1",filename,line)
        end
    elseif overfull ~= 0 then
        if subpass > 0 then
            report("file %a, line %i, pass %i, subpass %i of %i, overfull %p, classes 0x%02X, id %a",filename,line,pass,subpass,subpasses,overfull,classes,passname)
        else
            report("file %a, line %i, pass %i, classes 0x%02X, overfull %p",filename,line,pass,classes,overfull)
        end
    elseif underfull ~= 0 then
        if subpass > 0 then
            report("file %a, line %i, pass %i, subpass %i of %i, underfull %p, classes 0x%02X, id %a",filename,line,pass,subpass,subpasses,underfull,classes,passname)
        else
            report("file %a, line %i, pass %i, classes 0x%02X, underfull %p",filename,line,pass,classes,underfull)
        end
    elseif badness > toobad then
        if subpass > 0 then
            report("file %a, line %i, pass %i, subpass %i of %i, badness %s, classes 0x%02X, id %a",filename,line,pass,subpass,subpasses,badness,classes,passname)
        else
            report("file %a, line %i, classes 0x%02X, badness %i, okay",filename,line,pass,classes,badness)
        end
    else
        if subpass > 0 then
            report("file %a, line %i, pass %i, subpass %i of %i, okay, classes 0x%02X, id %a",filename,line,pass,subpass,subpasses,classes,passname)
        elseif details then
            report("file %a, line %i, okay",filename,line,pass)
        end
    end
end

local collected    = table.setmetatableindex("table")
local noffirst     = 0
local nofsecond    = 0
local nofthird     = 0
local nofsubpasses = 0
local nofsubdone   = 0
local nofoverfull  = 0
local nofunderfull = 0
local nofbadness   = 0

local function linebreak_quality_summary(id,line,pass,subpass,subpasses,overfull,underfull,badness,classes)
    if pass == 1 then
     -- t = { pass = 1, line = line }
        noffirst = noffirst + 1
    else
        if pass == 2 then
            nofsecond = nofsecond + 1
        else
            nofthird = nofthird + 1
        end
        local o = overfull  ~= 0
        local u = underfull ~= 0
        local b = badness    > toobad
        local s = subpass    > 0
        if o then
            nofoverfull = nofoverfull + 1
        end
        if u then
            nofunderfull = nofunderfull + 1
        end
        if b then
            nofbadness = nofbadness + 1
        end
        if s then
            nofsubpasses = nofsubpasses + 1
            nofsubdone   = nofsubdone   + subpass
        end
        if o then
            local c = collected[currentfile()]
            c[#c+1] = {
                pass      = pass,
                line      = line,
                subpass   = subpass,
                subpasses = subpasses,
                overfull  = overfull,
                classes   = classes,
                id        = passnames[id],
            }
        elseif b then
            local c = collected[currentfile()]
            c[#c+1] = {
                pass      = pass,
                line      = line,
                subpass   = subpass,
                subpasses = subpasses,
                badness   = badness,
                classes   = classes,
                id        = passnames[id],
            }
        end
    end
end

logs.registerfinalactions(function()
    if tracing and next(collected) then
        logs.startfilelogging(report,"overfull lines")
        for filename, list in table.sortedhash(collected) do
            for i=1,#list do
                local t = list[i]
                local b = t.badness
                local o = t.overfull
                if b then
                    report("  file %a, line %i, pass %i, subpass %i of %i, classes 0x%02X, badness %i", filename,t.line,t.pass,t.subpass,t.subpasses,t.classes,b)
                elseif o then
                    report("  file %a, line %i, pass %i, subpass %i of %i, classes 0x%02X, overfull %p",filename,t.line,t.pass,t.subpass,t.subpasses,t.classes,o)
                end
            end
        end
        logs.stopfilelogging()
    end
end)

statistics.register("linebreak quality",function()
    if tracing then
        return string.formatters["%i first, %i second, %i third, %i subpasses, %i subruns, %i overfull, %i underfull, %i badness"](
            noffirst, nofsecond, nofthird,
            nofsubpasses, nofsubdone,
            nofoverfull, nofunderfull,
            nofbadness
        )
    end
end)

local registercallback = callback.register

trackers.register("paragraphs.passes", function(v)
    details = false
    if not v then
        tracing = nil
    elseif v == "summary" then
        tracing = linebreak_quality_summary
    elseif v == "details" then
        details = true
        tracing = linebreak_quality_console
    else
        tracing = linebreak_quality_console
    end
    registercallback("linebreak_quality",tracing)
end)

-- -- -- --

local nuts    = nodes.nuts
local tonut   = nodes.tonut
local setprop = nuts.setprop
local getprop = nuts.getprop

local trace_callbacks = false

trackers.register("paragraphs.passes.callbacks", function(v)
    trace_callbacks = v
end)

local actions     = { }
local identifiers = table.setmetatableindex(function(t,k)
    local v = #t + 1
    local s = tostring(k) -- no number
    t[s] = v
    t[v] = s
    return v
end)

callback.register("paragraph_pass", function(
        head,identifier,callback,
        overfull,underfull,verdict,classified,
        threshold,badness,classes
    )
    local action = actions[callback]
    if action then
        local head = tonut(head)
        local step = getprop(head,"par_pass_done") or 1
        setprop(head,"par_pass_done",step+1)
        local result, again = action(
            head,rawget(identifiers,identifier) or identifier,callback,step,
            overfull,underfull,verdict,classified,
            threshold,badness,classes
        )
        if trace_callbacks then
            if type(result) == "table" then
                report("subpass identifier %a, callback %a, %s",identifier,callback,"process with data")
            elseif result then
                report("subpass identifier %a, callback %a, %s",identifier,callback,"process")
            else
                report("subpass identifier %a, callback %a, %s",identifier,callback,"quit")
            end
        end
        return result, again
    else
        report("subpass identifier %a, unknown callback %a",identifier,callback)
        return false
    end
end)

function builders.registerpaspasscallback(identifier,action)
    local index = identifiers[identifier]
    actions[index] = action
    return index
end

interfaces.implement {
    name      = "parpasscallback",
    public    = true,
    usage     = "value",
    arguments = "string",
    actions   = function(s)
        return integer_value, identifiers[s]
    end,
}