f = {
    args_default = {
        bracket_left = "",
        bracket_right = "",
        bracket_year_left = "",
        bracket_year_right = "",
        postscript = "",
        page = "",
        pages = "",
        location = "",
        page_sep = "، صفحة ",
        pages_sep = "، صفحات ",
        ref = "",
        P1 = "",
        P2 = "",
        P3 = "",
        P4 = "",
        P5 = ""
    }
};
      
function trim( str )
    if str == nil then
        return nil;
    end
    return str:match( "^%s*(.-)%s*$");
end    
      
function core( args )
    local result;
    
    if args.P5 ~= "" then
        result = args.P1 .. ' et al. ' .. args.bracket_year_left .. args.P5 .. 
            args.bracket_year_right;
    elseif args.P4 ~= "" then
        result = args.P1 .. ', ' .. args.P2 .. ' & ' .. args.P3 .. ' ' .. 
            args.bracket_year_left .. args.P4 .. args.bracket_year_right;
    elseif args.P3 ~= "" then
        result = args.P1 .. ' & ' .. args.P2 .. ' ' .. args.bracket_year_left .. 
            args.P3 .. args.bracket_year_right;
    else
        result = trim( args.P1 .. ' ' .. args.bracket_year_left .. args.P2 .. 
            args.bracket_year_right )
    end
    
    if args.ref ~= 'none' then
        if args.ref ~= "" then
            result = "[[#" .. args.ref .. "|" .. result .. "]]";
        else
            result = "[[#CITEREF" .. args.P1 .. args.P2 .. args.P3 .. args.P4 .. args.P5 .. "|" .. result .. "]]";
        end
    end
    
    if args.page ~= "" then
        result = result .. args.page_sep .. args.page;
    elseif args.pages ~= "" then
        result = result .. args.pages_sep .. args.pages;
    end      
    
    if args.location ~= "" then
        result = result .. "، " .. args.location;
    end
    
    result = args.bracket_left .. result .. args.bracket_right .. args.postscript;
    return result;
end

function f.harvard_core( frame )
    local args = {};
    local pframe = frame:getParent();
    
    args.bracket_left = pframe.args.BracketLeft or "";
    args.bracket_right = pframe.args.BracketRight or "";
    args.bracket_year_left = pframe.args.BracketYearLeft or "";
    args.bracket_year_right = pframe.args.BracketYearRight or "";
    args.postscript = pframe.args.Postscript or "";
    args.page = pframe.args.Page or "";
    args.pages = pframe.args.Pages or "";
    args.location = pframe.args.Location or "";
    args.page_sep = pframe.args.PageSep or "";
    args.pages_sep = pframe.args.PagesSep or "";
    args.ref = pframe.args.REF or "{{{REF}}}";
    args.P1 = trim( pframe.args.P1 ) or "";
    args.P2 = trim( pframe.args.P2 ) or "";
    args.P3 = trim( pframe.args.P3 ) or "";
    args.P4 = trim( pframe.args.P4 ) or "";
    args.P5 = trim( pframe.args.P5 ) or "";
    
    return core( args );
end

function f.harvard_citation( frame )
    local args = f.args_default;
    pframe = frame:getParent();
    
    args.bracket_left = "(";
    args.bracket_right = ")";
    args.page = pframe.args.p or pframe.args.page or "";
    args.pages = pframe.args.pp or pframe.args.pages or "";
    args.location = pframe.args.loc or "";
    args.ref = pframe.args.ref or pframe.args.Ref or "";
    args.P1 = trim( pframe.args[1] ) or "";
    args.P2 = trim( pframe.args[2] ) or "";
    args.P3 = trim( pframe.args[3] ) or "";
    args.P4 = trim( pframe.args[4] ) or "";
    args.P5 = trim( pframe.args[5] ) or "";
    
    return core( args );
end
    
function f.harvard_citation_no_bracket( frame )
    local args = f.args_default;
    pframe = frame:getParent();
    
    args.page = pframe.args.p or pframe.args.page or "";
    args.pages = pframe.args.pp or pframe.args.pages or "";
    args.location = pframe.args.loc or "";
    args.ref = pframe.args.ref or pframe.args.Ref or "";
    args.P1 = trim( pframe.args[1] ) or "";
    args.P2 = trim( pframe.args[2] ) or "";
    args.P3 = trim( pframe.args[3] ) or "";
    args.P4 = trim( pframe.args[4] ) or "";
    args.P5 = trim( pframe.args[5] ) or "";
    
    return core( args );
end

function f.sfn( frame )
    local args = f.args_default;
    pframe = frame:getParent();
    
    args.postscript = pframe.args.postscript or pframe.args.ps or ".";
    args.page = pframe.args.p or pframe.args.page or "";
    args.pages = pframe.args.pp or pframe.args.pages or "";
    args.location = pframe.args.loc or "";
    args.ref = pframe.args.ref or pframe.args.Ref or "";
    args.P1 = trim( pframe.args[1] ) or "";
    args.P2 = trim( pframe.args[2] ) or "";
    args.P3 = trim( pframe.args[3] ) or "";
    args.P4 = trim( pframe.args[4] ) or "";
    args.P5 = trim( pframe.args[5] ) or "";
    
    local result = core( args );
    local name = "FOOTNOTE" .. args.P1 .. args.P2 .. 
        args.P3 .. args.P4 .. args.P5 .. args.page .. args.pages .. args.location;
    
    result = frame:extensionTag{ name = "ref", args = {name=name}, content=result };
        
    return result;
end

return f;