if not modules then modules = { } end modules ['lpdf-fmt'] = {
    version   = 1.001,
    comment   = "companion to lpdf-ini.mkiv",
    author    = "Peter Rolf and Hans Hagen",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files",
}

-- Thanks to Luigi and Steffen for testing.

-- context --directives="backend.format=PDF/X-1a:2001" --trackers=backend.format yourfile

local tonumber = tonumber
local lower, gmatch, format, find, gsub, tohex, pack = string.lower, string.gmatch, string.format, string.find, string.gsub, string.tohex, string.pack
local concat, serialize, sortedhash = table.concat, table.serialize, table.sortedhash
local setmetatableindex = table.setmetatableindex

local trace_format    = false  trackers.register("backend.format",    function(v) trace_format    = v end)
local trace_variables = false  trackers.register("backend.variables", function(v) trace_variables = v end)

local report_backend = logs.reporter("backend","profiles")

local pdfbackend               = backends.registered.pdf
----- nodeinjections           = pdfbackend.nodeinjections
local codeinjections           = pdfbackend.codeinjections

local variables                = interfaces.variables
local viewerlayers             = attributes.viewerlayers
local colors                   = attributes.colors
local transparencies           = attributes.transparencies

local lpdf                     = lpdf
local pdfdictionary            = lpdf.dictionary
local pdfarray                 = lpdf.array
local pdfconstant              = lpdf.constant
local pdfreference             = lpdf.reference
local pdfflushobject           = lpdf.flushobject
local pdfstring                = lpdf.string
local pdfverbose               = lpdf.verbose
local pdfflushstreamfileobject = lpdf.flushstreamfileobject

local addtoinfo                = lpdf.addtoinfo
local injectxmpinfo            = lpdf.injectxmpinfo
local insertxmpinfo            = lpdf.insertxmpinfo
local replacexmpinfo           = lpdf.replacexmpinfo

local settings_to_array        = utilities.parsers.settings_to_array
local settings_to_hash         = utilities.parsers.settings_to_hash

--[[
    Comments by Peter:

    output intent       : only one profile per color space (and device class)
    default color space : (theoretically) several profiles per color space possible

    The default color space profiles define the current gamuts (part of/all the
    colors we have in the document), while the output intent profile declares the
    gamut of the output devices (the colors that we get normally a printer or
    monitor).

    Example:

    I have two RGB pictures (both 'painted' in /DeviceRGB) and I declare sRGB as
    default color space for one picture and AdobeRGB for the other. As output
    intent I use ISO_coated_v2_eci.icc.

    If I had more than one output intent profile for the combination CMYK/printer I
    can't decide which one to use. But it is no problem to use several default color
    space profiles for the same color space as it's just a different color
    transformation. The relation between picture and profile is clear.
]]--

local channels = {
    gray = 1,
    grey = 1,
    rgb  = 3,
    cmyk = 4,
}

local prefixes = {
    gray = "DefaultGray",
    grey = "DefaultGray",
    rgb  = "DefaultRGB",
    cmyk = "DefaultCMYK",
}

local formatspecification = nil
local formatname          = nil
local pdfformats          = { }

local formats = utilities.storage.allocate {
    version = {
        external     = 1.4, -- 'p' in name; URL reference of output intent
        jbig2        = 1.4,
        jpeg2000     = 1.5, -- not supported yet
        nchannel     = 1.6, -- 'n' in name; n-channel colorspace support
        prepress     = 1.3, -- 'g' in name; reference to external graphics
        layers       = 1.5,
        transparency = 1.4,
        compression  = 1.5,
        attachments  = 1.7,
    },
    default = {
        version      = 1.7,  -- todo: block tex primitive
        format       = "default",
        xmpfile      = "lpdf-pdx.xml",
        gray         = true,
        cmyk         = true,
        rgb          = true,
        spot         = true,
        calibrated   = true,  -- rgb colors, not used
        cielab       = true,  -- unknown
        nchannel     = true,  -- unknown
        internal     = true,  -- controls profile inclusion
        external     = true,  -- controls profile inclusion
        intents      = true,
        prepress     = true,  -- unknown
        layers       = true,  -- todo: block at lua level
        transparency = true,  -- todo: block at lua level
        jbig2        = true,  -- todo: block at lua level (dropped anyway)
        jpeg2000     = true,  -- todo: block at lua level (dropped anyway)
        cidsets      = false, -- only some standards
        charsets     = true,  -- not used
        procsets     = false, -- also version driven
        info         = true,
        acrobat      = true,
        attachments  = true,
        compression  = false, -- object compression
        tagging      = false,
        forms        = false,
        metadata     = { },
    },
    data = pdfformats,
}

setmetatableindex(pdfformats,function(t,k)
    k = lower(k)
    k = gsub(k,"^pdf","")
    k = gsub(k,"[^a-z0-9]+","")
    local v = rawget(t,k)
    if not v then
        local filename = "lpdf-fmt-imp-" .. k .. ".lmt"
        local fullname = resolvers.findfile(filename) or ""
        if fullname ~= "" then
            v = dofile(fullname)
            if v then
                v = v.features
            end
            if v then
                setmetatableindex(v,formats.default)
            else
                v = false
            end
            t[k] = v
        end
    end
    return v
end)

lpdf.formats = formats -- it does not hurt to have this one visible

formatspecification = formats.default

function lpdf.getformatoption(key)
    return formatspecification and formatspecification[key]
end

-- function codeinjections.getformatspecification()
--     return formatspecification
-- end

function lpdf.supportedformats()
    local found = resolvers.findfile("lpdf-fmt-imp-a4.lmt")
    if found then
        local pattern = gsub(found,"a4.lmt", "*.lmt")
        local list    = dir.glob(pattern)
        local count   = 0
        for i=1,#list do
            local n = gsub(file.nameonly(list[i]),"lpdf.fmt.imp.","")
            local d = pdfformats[n]
        end
    end
    return table.sortedkeys(pdfformats)
end

codeinjections.getformatoption  = lpdf.getformatoption
codeinjections.supportedformats = lpdf.supportedformats

-- When we have an URL we can assume that embedding is not needed.

local filenames = {
    "colorprofiles.xml",
    "colorprofiles.lua",
}

local function locatefile(filename)
    local fullname = resolvers.findfile(filename,"icc",1,true)
    if not fullname or fullname == "" then
        fullname = resolvers.finders.byscheme("loc",filename) -- could be specific to the project
    end
    return fullname or ""
end

local internalprofiles = { }
local externalprofiles = { }
local defaultprofiles  = { }
local loadeddefaults   = { }
local loadedprofiles   = { }

local function loadprofile(name,filename)
    local profile = loadedprofiles[name]
    if profile ~= nil then
        return profile
    end
    local databases = filename and filename ~= "" and settings_to_array(filename) or filenames
    for i=1,#databases do
        local filename = locatefile(databases[i])
        if filename and filename ~= "" then
            local suffix = file.suffix(filename)
            local lname = lower(name)
            if suffix == "xml" then
                local xmldata = xml.load(filename) -- no need for caching it
                if xmldata then
                    profile = xml.filter(xmldata,format('xml://profiles/profile/(info|filename)[lower(text())=="%s"]/../table()',lname))
                end
            elseif suffix == "lua" then
                local luadata = loadfile(filename)
                luadata = ludata and luadata()
                if luadata then
                    profile = luadata[name] or luadata[lname] -- hashed
                    if not profile then
                        for i=1,#luadata do
                            local li = luadata[i]
                            if lower(li.info) == lname then -- indexed
                                profile = li
                                break
                            end
                        end
                    end
                end
            end
            if profile then
                if not next(profile) then
                    profile = false
                end
                loadedprofiles[name] = profile
                if profile then
                    report_backend("profile specification %a loaded from %a",name,filename)
                elseif trace_format then
                    report_backend("profile specification %a loaded from %a but empty",name,filename)
                end
                return profile
            end
        end
    end
    report_backend("profile specification %a not found in %a",name,concat(filenames, ", "))
end

local function profilename(filename)
    return lower(file.basename(filename))
end

local function includeprofile(s)
    local filename   = s.filename   or ""
    local colorspace = s.colorspace or ""
    local colorspace = lower(colorspace)
    local channel    = channels[colorspace] or nil
    if filename == "" or colorspace == "" then
        report_backend("error in profile specification: %s",serialize(s,false))
    else
        local tag     = profilename(filename)
        local profile = internalprofiles[tag] or externalprofiles[tag]
        if not profile then
            -- We check if the profile has an id other than "custom". If so, we
            -- don't embed it but create a reference.
            local id = s.id
            if id and lower(id) ~= "custom" then
                local name = s.info or s.filename or ""
                local d = pdfdictionary {
                    ProfileName = name ~= "" and name or nil,
                    ProfileCS   = colorspace,
                    URLs        = urls(s.url or ""),
                }
                profile = pdfflushobject(d)
                externalprofiles[tag] = profile
             -- defaultprofiles[channel] = profile
            end
        end
        if not profile then
            local fullname   = locatefile(filename)
            if fullname == "" then
                fullname = locatefile("colo-imp-" .. filename)
            end
            if fullname == "" then
                report_backend("error, couldn't locate profile %a",filename)
            elseif not channel then
                report_backend("error, couldn't resolve channel entry for colorspace %a",colorspace)
            else
                profile = pdfflushstreamfileobject(fullname,pdfdictionary{ N = channel },false) -- uncompressed
                internalprofiles[tag]    = profile
                defaultprofiles[channel] = profile
                if trace_format then
                    report_backend("including %a color profile from %a",colorspace,fullname)
                end
            end
        end
        return profile
    end
end

function codeinjections.defaultprofile(channel)
 -- print("get profile",channel,defaultprofiles[channel])
    return defaultprofiles[channel]
end

local function urls(url)
    if not url or url == "" then
        return nil
    else
        local u = pdfarray()
        for url in gmatch(url,"([^, ]+)") do
            if find(url,"^http") then
                u[#u+1] = pdfdictionary {
                    FS = pdfconstant("URL"),
                    F  = pdfstring(url),
                }
            end
        end
        return u
    end
end

local function processprofile(s,spec) -- specification
    local filename   = s.filename or ""
    local colorspace = lower(s.colorspace or "")
    if filename == "" or colorspace == "" then
        report_backend("error in default profile specification: %s",serialize(s,false))
    elseif not loadeddefaults[colorspace] then
        local tag = profilename(filename)
        local n   = internalprofiles[tag] or externalprofiles[tag]
        if n == true then -- not internalized
            report_backend("no default profile %a for colorspace %a",filename,colorspace)
        elseif n then
            local a = pdfarray {
                pdfconstant("ICCBased"),
                pdfreference(n),
            }
             -- used in page /Resources, so this must be inserted at runtime
            lpdf.adddocumentcolorspace(prefixes[colorspace],pdfreference(pdfflushobject(a)))
            loadeddefaults[colorspace] = true
            report_backend("setting %a as default %a color space",filename,colorspace)
        else
            report_backend("no default profile %a for colorspace %a",filename,colorspace)
        end
    elseif trace_format then
        report_backend("a default %a colorspace is already in use",colorspace)
    end
end

-- pdfa  sRGB  GTS_PDFA1
-- pdfx  CMYK  GTS_PDFX
-- pdfe        ISO_PDFE1

-- OutputCondition           : optional, meant for user interfacing
-- OutputConditionIdentifier : mandate, something official

-- sRGB v4 Preference
-- PSOuncoated_v3_FOGRA52.icc  (european)

local loadedintents = { }
local intents       = pdfarray()

local function processoutputintent(s,spec)
    local url             = s.url or ""
    local filename        = s.filename or ""
    local name            = s.info or filename
    local id              = s.id or ""
    local outputcondition = s.outputcondition or ""
    local info            = s.info or ""
    if name == "" or id == "" then
        report_backend("error in output intent specification: %s",serialize(s,false))
    elseif not loadedintents[name] then
        local tag      = profilename(filename)
        local internal = internalprofiles[tag]
        local external = externalprofiles[tag]
        --
        -- The OutputConditionIdentifier is mandate and can be an officially registered
        -- one. When we have an unofficial one, we need to provide DestOutputProfile
        -- but DestOutputProfileRef i soptional and can best be omitted.
        --
        -- We can use <id>Custom</id> as indicator for a to be embedded profile and
        -- thereby play safe. In that case <info>whatever</info> also makes sense.
        --
        if internal or external then
            local d = {
                Type                      = pdfconstant("OutputIntent"),
                -- mandate
                S                         = pdfconstant(spec.intent or "GTS_PDFX"),
                OutputConditionIdentifier = id,
            }
            if internal then
                -- optional
                d.RegistryName      = url
                d.OutputCondition   = outputcondition
                d.Info              = info
                -- needed
                d.DestOutputProfile = pdfreference(internal)
            else
                -- an external one mandates a known id to be used
            end
            intents[#intents+1] = pdfreference(pdfflushobject(pdfdictionary(d)))
         -- if trace_format then
                report_backend("setting output intent to %a with id %a for entry %a",name,id,#intents)
         -- end
        else
            report_backend("invalid output intent %a",name)
        end
        loadedintents[name] = true
    elseif trace_format then
        report_backend("an output intent with name %a is already in use",name)
    end
end

-- In order to get a bit more reliable validation we made some choices. A mix of
-- internal and external profiles gives a mess so we can best only handle embeded
-- ones and just include the smallest possible set. Users who deal with real complex
-- icc profiles (likely cmyk) will embed these anyway. For a previous implementation
-- one can look in the archives (ok mkiv). We kind of assume PDF/A-4 to be used.

local function handleiccprofile(message,spec,name,filename,dowithprofile)
    -- name is an intent or profile list
    if name and name ~= "" then
        local list = settings_to_array(name)
        for i=1,#list do
            local name    = list[i]
            local profile = loadprofile(name,filename)
            if trace_format then
                report_backend("handling %s %a",message,name)
            end
            --
            if not profile and file.suffix(name) == "icc" then
                -- so we have no description ... we can create a bogus entry:
                profile = {
                    filename   = name,
                    id         = "Custom",
                    colorspace = find(lower(name),"rgb") and "RGB" or "CMYK",
                }
                if trace_format then
                    report_backend("forcing internal profiles %a",name)
                end
            end
            --
            if profile then
                if formatspecification.cmyk then
                    profile.colorspace = profile.colorspace or "CMYK"
                else
                    profile.colorspace = profile.colorspace or "RGB"
                end
                if trace_format then
                    report_backend("handling internal profiles cf. %a",name)
                end
                includeprofile(profile)
                dowithprofile(profile,spec)
            elseif trace_format then
                report_backend("unknown profile %a",name)
            end
        end
        return list[1]
    end
end

local function flushoutputintents()
    if #intents > 0 then
        lpdf.addtocatalog("OutputIntents",pdfreference(pdfflushobject(intents)))
    end
end

lpdf.registerdocumentfinalizer(flushoutputintents,2,"output intents")

function codeinjections.setformat(s)
    local format   = s.format or ""
    local intent   = s.intent  or ""
    local profile  = s.profile or ""
    local option   = s.option  or ""
    local filename = s.file    or "" -- profile databases
    local level    = tonumber(s.level)
    --
    if format ~= "" then
        local spec = pdfformats[format]
        if spec then
            formatspecification = spec
            formatname = spec.format
            report_backend("setting format %a to %a",format,formatname)
            local xmpfile = formatspecification.xmpfile or ""
            if xmpfile == "" then
                -- weird error
            else
                codeinjections.setxmpfile(xmpfile)
            end
            if profile == "" then
                if intent == variables.default or intent == variables.rgb then
                    intent  = "sRGB-v4.icc"
                    profile = "sRGB-v4.icc,CGATS001Compat-v2-micro.icc,sGrey-v4.icc"
                elseif intent == variables.cmyk then
                    intent  = "CGATS001Compat-v2-micro.icc"
                    profile = "sRGB-v4.icc,CGATS001Compat-v2-micro.icc"
                else
                    goto SKIP
                end
                report_backend("using color intent %a",intent)
                report_backend("using icc profiles %a",profile)
              ::SKIP::
            elseif intent == variables.default or intent == variables.rgb or intent == variables.cmyk then
                -- these are non existent
                intent = ""
            end
            if not level then
                level = 3 -- good compromise, default anyway
            end
            local pdfversion          = spec.version * 10
            local injectmetadata      = spec.metadata
         -- local injectconformance   = spec.conformance
            local majorversion        = math.floor(math.div(pdfversion,10))
            local minorversion        = math.floor(math.mod(pdfversion,10))
            local objectcompression   = spec.compression and pdfversion >= 15
            local compresslevel       = level or lpdf.compresslevel() -- keep default
            local objectcompresslevel = (objectcompression and (level or lpdf.objectcompresslevel())) or 0
            lpdf.setcompression(compresslevel,objectcompresslevel)
            lpdf.setversion(majorversion,minorversion)
            if objectcompression then
                report_backend("forcing pdf version %s.%s, compression level %s, object compression level %s",
                    majorversion,minorversion,compresslevel,objectcompresslevel)
            elseif compresslevel > 0 then
                report_backend("forcing pdf version %s.%s, compression level %s, object compression disabled",
                    majorversion,minorversion,compresslevel)
            else
                report_backend("forcing pdf version %s.%s, compression disabled",
                    majorversion,minorversion)
            end
            --
            -- maybe block by pdf version
            --
            codeinjections.settaggingsupport(formatspecification.tagging)
            codeinjections.setattachmentsupport(formatspecification.attachments)
            --
            -- context.setupcolors { -- not this way
            --     cmyk = spec.cmyk and variables.yes or variables.no,
            --     rgb  = spec.rgb  and variables.yes or variables.no,
            -- }
            --
            local rgb = spec.rgb  and variables.yes or variables.no
            local cmy = spec.cmyk and variables.yes or variables.no
            report_backend("permitted colorspaces: rgb %a, cmyk %a",rgb,cmy)
         -- token.expandmacro ("colo_force_colormodel",true,rgb,true,cmy)
            --
            colors.forcesupport(
                spec.gray     or false,
                spec.rgb      or false,
                spec.cmyk     or false,
                spec.spot     or false,
                spec.nchannel or false
            )
            transparencies.forcesupport(
                spec.transparency or false
            )
            viewerlayers.forcesupport(
                spec.layers or false
            )
            viewerlayers.setfeatures(
                spec.has_order or false -- new
            )
            --
            -- spec.jbig2    : todo, block in image inclusion
            -- spec.jpeg2000 : todo, block in image inclusion
            --
            if type(injectmetadata) == "function" then
                injectmetadata()
            elseif type(injectmetadata) == "table" then
                for i=1,#injectmetadata do
                    local entry  = injectmetadata[i]
                    local action = lpdf[entry[1]]
                    if action then
                        action(entry[2],entry[3],entry[4])
                    end
                end
            end
            --
            -- If needed we can make a dedicated imp file for this but currently we
            -- consider this not that useful, so we go for less code instead.
            --
         -- if type(injectconformance) == "function" then
         --     injectconformance(environment.arguments.wtpdf)
         -- elseif type(injectconformance) == "table" then
         --     for i=1,#injectconformance do
         --         local entry  = injectconformance[i]
         --         local action = lpdf[entry[1]]
         --         if action then
         --             action(entry[2],entry[3],entry[4])
         --         end
         --     end
         -- end
            --
            local first = handleiccprofile("color profile",spec,profile,filename,processprofile)
            if intent == "" then
                intent = first
            end
            handleiccprofile("output intent",spec,intent,filename,processoutputintent)
            --
            if trace_variables then
                for k, v in sortedhash(formats.default) do
                    local v = formatspecification[k]
                    if type(v) ~= "function" then
                        report_backend("%a = %a",k,v or false)
                    end
                end
            end
            function codeinjections.setformat(noname)
                if trace_format then
                    report_backend("error, format is already set to %a, ignoring %a",formatname,noname.format)
                end
            end
        else
            report_backend("error, format %a is not supported, valid formats: % | t",
                format,table.sortedkeys(formats.data))
        end
    elseif level then
        lpdf.setcompression(level,level)
    else
        -- we ignore this as we hook it in \everysetupbackend
    end
end

directives.register("backend.format", function(v) -- table !
    local tv = type(v)
    if tv == "table" then
        codeinjections.setformat(v)
    elseif tv == "string" then
        codeinjections.setformat { format = v }
    end
end)

interfaces.implement {
    name      = "setformat",
    actions   = codeinjections.setformat,
    arguments = { { "*" } }
}