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

--[[ldx--
<p>Regimes take care of converting the input characters into
<l n='utf'/> sequences. The conversion tables are loaded at
runtime.</p>
--ldx]]--

local commands, context = commands, context

local utfchar = utf.char
local P, Cs, lpegmatch = lpeg.P, lpeg.Cs, lpeg.match
local char, gsub, format, gmatch, byte, match = string.char, string.gsub, string.format, string.gmatch, string.byte, string.match
local next = next
local insert, remove, fastcopy = table.insert, table.remove, table.fastcopy
local concat = table.concat
local totable = string.totable

local allocate          = utilities.storage.allocate
local sequencers        = utilities.sequencers
local textlineactions   = resolvers.openers.helpers.textlineactions
local setmetatableindex = table.setmetatableindex

--[[ldx--
<p>We will hook regime handling code into the input methods.</p>
--ldx]]--

local trace_translating = false  trackers.register("regimes.translating", function(v) trace_translating = v end)

local report_loading     = logs.reporter("regimes","loading")
local report_translating = logs.reporter("regimes","translating")

regimes        = regimes or { }
local regimes  = regimes

local mapping  = allocate {
    utf = false
}

local backmapping = allocate {
}

-- regimes.mapping  = mapping

local synonyms = { -- backward compatibility list

    ["windows-1250"] = "cp1250",
    ["windows-1251"] = "cp1251",
    ["windows-1252"] = "cp1252",
    ["windows-1253"] = "cp1253",
    ["windows-1254"] = "cp1254",
    ["windows-1255"] = "cp1255",
    ["windows-1256"] = "cp1256",
    ["windows-1257"] = "cp1257",
    ["windows-1258"] = "cp1258",

    ["il1"]          = "8859-1",
    ["il2"]          = "8859-2",
    ["il3"]          = "8859-3",
    ["il4"]          = "8859-4",
    ["il5"]          = "8859-9",
    ["il6"]          = "8859-10",
    ["il7"]          = "8859-13",
    ["il8"]          = "8859-14",
    ["il9"]          = "8859-15",
    ["il10"]         = "8859-16",

    ["iso-8859-1"]   = "8859-1",
    ["iso-8859-2"]   = "8859-2",
    ["iso-8859-3"]   = "8859-3",
    ["iso-8859-4"]   = "8859-4",
    ["iso-8859-9"]   = "8859-9",
    ["iso-8859-10"]  = "8859-10",
    ["iso-8859-13"]  = "8859-13",
    ["iso-8859-14"]  = "8859-14",
    ["iso-8859-15"]  = "8859-15",
    ["iso-8859-16"]  = "8859-16",

    ["latin1"]       = "8859-1",
    ["latin2"]       = "8859-2",
    ["latin3"]       = "8859-3",
    ["latin4"]       = "8859-4",
    ["latin5"]       = "8859-9",
    ["latin6"]       = "8859-10",
    ["latin7"]       = "8859-13",
    ["latin8"]       = "8859-14",
    ["latin9"]       = "8859-15",
    ["latin10"]      = "8859-16",

    ["utf-8"]        = "utf",
    ["utf8"]         = "utf",
    [""]             = "utf",

    ["windows"]      = "cp1252",

}

local currentregime = "utf"

local function loadregime(mapping,regime)
    local name = resolvers.findfile(format("regi-%s.lua",regime)) or ""
    local data = name ~= "" and dofile(name)
    if data then
        vector = { }
        for eightbit, unicode in next, data do
            vector[char(eightbit)] = utfchar(unicode)
        end
        report_loading("vector %a is loaded",regime)
    else
        vector = false
        report_loading("vector %a is unknown",regime)
    end
    mapping[regime] = vector
    return vector
end

local function loadreverse(t,k)
    local t = { }
    for k, v in next, mapping[k] do
        t[v] = k
    end
    backmapping[k] = t
    return t
end

setmetatableindex(mapping,    loadregime)
setmetatableindex(backmapping,loadreverse)

local function translate(line,regime)
    if line and #line > 0 then
        local map = mapping[regime and synonyms[regime] or regime or currentregime]
        if map then
            line = gsub(line,".",map)
        end
    end
    return line
end

-- local remappers = { }
--
-- local function toregime(vector,str,default) -- toregime('8859-1',"abcde Ä","?")
--     local t = backmapping[vector]
--     local remapper = remappers[vector]
--     if not remapper then
--         remapper = utf.remapper(t)
--         remappers[t] = remapper
--     end
--     local m = getmetatable(t)
--     setmetatableindex(t, function(t,k)
--         local v = default or "?"
--         t[k] = v
--         return v
--     end)
--     str = remapper(str)
--     setmetatable(t,m)
--     return str
-- end
--
-- -- much faster (but only matters when we have > 10K calls

local cache = { } -- if really needed we can copy vectors and hash defaults

setmetatableindex(cache, function(t,k)
    local v = { remappers = { } }
    t[k] = v
    return v
end)

local function toregime(vector,str,default) -- toregime('8859-1',"abcde Ä","?")
    local d = default or "?"
    local c = cache[vector].remappers
    local r = c[d]
    if not r then
        local t = fastcopy(backmapping[vector])
        setmetatableindex(t, function(t,k)
            local v = d
            t[k] = v
            return v
        end)
        r = utf.remapper(t)
        c[d]  = r
    end
    return r(str)
end

local function disable()
    currentregime = "utf"
    sequencers.disableaction(textlineactions,"regimes.process")
end

local function enable(regime)
    regime = synonyms[regime] or regime
    if mapping[regime] == false then
        disable()
    else
        currentregime = regime
        sequencers.enableaction(textlineactions,"regimes.process")
    end
end

regimes.toregime  = toregime
regimes.translate = translate
regimes.enable    = enable
regimes.disable   = disable

-- The following function can be used when we want to make sure that
-- utf gets passed unharmed. This is needed for modules.

local level = 0

function regimes.process(str,filename,currentline,noflines,coding)
    if level == 0 and coding ~= "utf-8" then
        str = translate(str,currentregime)
        if trace_translating then
            report_translating("utf: %s",str)
        end
    end
    return str
end

local function push()
    level = level + 1
    if trace_translating then
        report_translating("pushing level %s",level)
    end
end

local function pop()
    if level > 0 then
        if trace_translating then
            report_translating("popping level %s",level)
        end
        level = level - 1
    end
end

regimes.push = push
regimes.pop  = pop

sequencers.prependaction(textlineactions,"system","regimes.process")
sequencers.disableaction(textlineactions,"regimes.process")

-- interface:

commands.enableregime  = enable
commands.disableregime = disable

commands.pushregime    = push
commands.popregime     = pop

function commands.currentregime()
    context(currentregime)
end

local stack = { }

function commands.startregime(regime)
    insert(stack,currentregime)
    if trace_translating then
        report_translating("start using %a",regime)
    end
    enable(regime)
end

function commands.stopregime()
    if #stack > 0 then
        local regime = remove(stack)
        if trace_translating then
            report_translating("stop using %a",regime)
        end
        enable(regime)
    end
end

-- Next we provide some hacks. Unfortunately we run into crappy encoded
-- (read : mixed) encoded xml files that have these ë ä ö ü sequences
-- instead of ë ä ö ü

local patterns = { }

-- function regimes.cleanup(regime,str)
--     local p = patterns[regime]
--     if p == nil then
--         regime = regime and synonyms[regime] or regime or currentregime
--         local vector = regime ~= "utf" and mapping[regime]
--         if vector then
--             local list = { }
--             for k, uchar in next, vector do
--                 local stream = totable(uchar)
--                 for i=1,#stream do
--                     stream[i] = vector[stream[i]]
--                 end
--                 list[concat(stream)] = uchar
--             end
--             p = lpeg.append(list,nil,true)
--             p = Cs((p+1)^0)
--          -- lpeg.print(p) -- size 1604
--         else
--             p = false
--         end
--         patterns[vector] = p
--     end
--     return p and lpegmatch(p,str) or str
-- end
--
-- twice as fast and much less lpeg bytecode

function regimes.cleanup(regime,str)
    local p = patterns[regime]
    if p == nil then
        regime = regime and synonyms[regime] or regime or currentregime
        local vector = regime ~= "utf" and mapping[regime]
        if vector then
            local utfchars = { }
            local firsts = { }
            for k, uchar in next, vector do
                local stream = { }
                local split = totable(uchar)
                local nofsplits = #split
                if nofsplits > 1 then
                    local first
                    for i=1,nofsplits do
                        local u = vector[split[i]]
                        if not first then
                            first = firsts[u]
                            if not first then
                                first = { }
                                firsts[u] = first
                            end
                        end
                        stream[i] = u
                    end
                    local nofstream = #stream
                    if nofstream > 1 then
                        first[#first+1] = concat(stream,2,nofstream)
                        utfchars[concat(stream)] = uchar
                    end
                end
            end
            p = P(false)
            for k, v in next, firsts do
                local q = P(false)
                for i=1,#v do
                    q = q + P(v[i])
                end
                p = p + P(k) * q
            end
            p = Cs(((p+1)/utfchars)^1)
         -- lpeg.print(p) -- size: 1042
        else
            p = false
        end
        patterns[regime] = p
    end
    return p and lpegmatch(p,str) or str
end

-- local map = require("regi-cp1252")
-- local old = [[test ë ä ö ü crap]]
-- local new = correctencoding(map,old)
--
-- print(old,new)

-- obsolete:
--
-- function regimes.setsynonym(synonym,target)
--     synonyms[synonym] = target
-- end
--
-- function regimes.truename(regime)
--     return regime and synonyms[regime] or regime or currentregime
-- end
--
-- commands.setregimesynonym = regimes.setsynonym
--
-- function commands.trueregimename(regime)
--     context(regimes.truename(regime))
-- end
--
-- function regimes.load(regime)
--     return mapping[synonyms[regime] or regime]
-- end