local guide = require 'parser.guide'
local vm    = require 'vm'

local function mergeTypesInLibrary(types)
    if type(types) == 'table' then
        return table.concat(types, '|')
    else
        return types or 'any'
    end
end

local function asLibrary(source, oop)
    if not source.args then
        return ''
    end
    local start = 1
    local methodDef
    local parent = source.parent
    if parent and parent.type == 'setmethod' then
        methodDef = true
    end
    if not methodDef and oop then
        start = 2
    end
    local args = {}
    local afterCount = 0
    for i = start, #source.args do
        local buf = {}
        local arg = source.args[i]
        local name = arg.name
        if arg.optional then
            if i == start then
                buf[#buf+1] = '['
            else
                buf[#buf+1] = ' ['
            end
        end
        if i > start then
            buf[#buf+1] = ', '
        end
        if name then
            buf[#buf+1] = ('%s: %s'):format(name, mergeTypesInLibrary(arg.type))
        else
            buf[#buf+1] = ('%s'):format(mergeTypesInLibrary(arg.type))
        end
        if arg.optional == 'after' then
            afterCount = afterCount + 1
        elseif arg.optional == 'self' then
            buf[#buf+1] = ']'
        end
        if i == #source.args and afterCount > 0 then
            buf[#buf+1] = (']'):rep(afterCount)
        end
        args[#args+1] = table.concat(buf)
    end
    return table.concat(args)
end

local function asFunction(source, oop)
    if not source.args then
        return ''
    end
    local args = {}
    for i = 1, #source.args do
        local arg = source.args[i]
        local name = arg.name or guide.getName(arg)
        if name then
            args[i] = ('%s: %s'):format(name, vm.getInferType(arg))
        else
            args[i] = ('%s'):format(vm.getInferType(arg))
        end
    end
    local methodDef
    local parent = source.parent
    if parent and parent.type == 'setmethod' then
        methodDef = true
    end
    if not methodDef and oop then
        return table.concat(args, ', ', 2)
    else
        return table.concat(args, ', ')
    end
end

return function (source, oop)
    if source.type == 'library' then
        return asLibrary(source.value, oop)
    elseif source.library then
        return asLibrary(source, oop)
    end
    if source.type == 'function' then
        return asFunction(source, oop)
    end
    return ''
end