-- Convenience Lua functions that can be used within rpm macros

-- Set a spec variable

-- Echo the result if verbose

local function explicitset(rpmvar,value,verbose)

  local value = value

  if (value == nil) or (value == "") then

    value = "%{nil}"

  end

  rpm.define(rpmvar .. " " .. value)

  if verbose then

    rpm.expand("%{echo:Setting %%{" .. rpmvar .. "} = " .. value .. "}")

  end

end

-- Unset a spec variable if it is defined

-- Echo the result if verbose

local function explicitunset(rpmvar,verbose)

  if (rpm.expand("%{" .. rpmvar .. "}") ~= "%{" .. rpmvar .. "}") then

    rpm.define(rpmvar .. " %{nil}")

    if verbose then

      rpm.expand("%{echo:Unsetting %%{" .. rpmvar .. "}}")

    end

  end

end

-- Set a spec variable, if not already set

-- Echo the result if verbose

local function safeset(rpmvar,value,verbose)

  if (rpm.expand("%{" .. rpmvar .. "}") == "%{" .. rpmvar .. "}") then

    explicitset(rpmvar,value,verbose)

  end

end

-- Alias a list of rpm variables to the same variables suffixed with 0 (and vice versa)

-- Echo the result if verbose

local function zalias(rpmvars,verbose)

  for _, sfx in ipairs({{"","0"},{"0",""}}) do

    for _, rpmvar in ipairs(rpmvars) do

      local toalias = "%{?" .. rpmvar .. sfx[1] .. "}"

      if (rpm.expand(toalias) ~= "") then

        safeset(rpmvar .. sfx[2], toalias, verbose)

      end

    end

  end

end

-- Echo the list of rpm variables, with suffix, if set

local function echovars(rpmvars, suffix)

  for _, rpmvar in ipairs(rpmvars) do

    rpmvar = rpmvar .. suffix

    local header = string.sub("  " .. rpmvar .. ":                                               ",1,21)

    rpm.expand("%{?" .. rpmvar .. ":%{echo:" .. header .. "%{?" .. rpmvar .. "}}}")

  end

end

-- Returns an array, indexed by suffix, containing the non-empy values of

-- <rpmvar><suffix>, with suffix an integer string or the empty string

local function getsuffixed(rpmvar)

  local suffixes = {}

  zalias({rpmvar})

  for suffix=0,9999 do

    local value = rpm.expand("%{?" .. rpmvar .. suffix .. "}")

    if (value ~= "") then

      suffixes[tostring(suffix)] = value

    end

  end

  -- rpm convention is to alias no suffix to zero suffix

  -- only add no suffix if zero suffix is different

  local value = rpm.expand("%{?" .. rpmvar .. "}")

  if (value ~= "") and (value ~= suffixes["0"]) then

     suffixes[""] = value

  end

  return suffixes

end

-- Returns the list of suffixes, including the empty string, for which

-- <rpmvar><suffix> is set to a non empty value

local function getsuffixes(rpmvar)

  suffixes = {}

  for suffix in pairs(getsuffixed(rpmvar)) do

    table.insert(suffixes,suffix)

  end

  table.sort(suffixes,

             function(a,b) return (tonumber(a) or 0) < (tonumber(b) or 0) end)

  return suffixes

end

-- Returns the suffix for which <rpmvar><suffix> has a non-empty value that

-- matches best the beginning of the value string

local function getbestsuffix(rpmvar, value)

  local best         = nil

  local currentmatch = ""

  for suffix, setvalue in pairs(getsuffixed(rpmvar)) do

  if (string.len(setvalue) > string.len(currentmatch)) and

     (string.find(value, "^" .. setvalue)) then

      currentmatch = setvalue

      best         = suffix

    end

  end

  return best

end

return {

  explicitset   = explicitset,

  explicitunset = explicitunset,

  safeset       = safeset,

  zalias        = zalias,

  echovars      = echovars,

  getsuffixed   = getsuffixed,

  getsuffixes   = getsuffixes,

  getbestsuffix = getbestsuffix,

}