-- https://github.com/jagt/pprint.lua
--[[
Chen Tao - jagttt@gmail.com

This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or
distribute this software, either in source code form or as a compiled
binary, for any purpose, commercial or non-commercial, and by any
means.

In jurisdictions that recognize copyright laws, the author or authors
of this software dedicate any and all copyright interest in the
software to the public domain. We make this dedication for the benefit
of the public at large and to the detriment of our heirs and
successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to <http://unlicense.org/>
--]]
local pprint = { VERSION = '0.1' }

local depth = 1

pprint.defaults = {
    -- If set to number N, then limit table recursion to N deep.
    depth_limit = false,
    -- type display trigger, hide not useful datatypes by default
    -- custom types are treated as table
    show_nil = true,
    show_boolean = true,
    show_number = true,
    show_string = true,
    show_table = true,
    show_function = false,
    show_thread = false,
    show_userdata = false,
    -- additional display trigger
    show_metatable = false,     -- show metatable
    show_all = false,           -- override other show settings and show everything
    use_tostring = false,       -- use __tostring to print table if available
    filter_function = nil,      -- called like callback(value[,key, parent]), return truty value to hide
    object_cache = 'local',     -- cache blob and table to give it a id, 'local' cache per print, 'global' cache
                                -- per process, falsy value to disable (might cause infinite loop)
    -- format settings
    indent_size = 2,            -- indent for each nested table level
    level_width = 80,           -- max width per indent level
    wrap_string = true,         -- wrap string when it's longer than level_width
    wrap_array = true,         -- wrap every array elements
    sort_keys = true,           -- sort table keys
}

local TYPES = {
    ['nil'] = 1, ['boolean'] = 2, ['number'] = 3, ['string'] = 4, 
    ['table'] = 5, ['function'] = 6, ['thread'] = 7, ['userdata'] = 8
}

-- seems this is the only way to escape these, as lua don't know how to map char '\a' to 'a'
local ESCAPE_MAP = {
    ['\a'] = '\\a', ['\b'] = '\\b', ['\f'] = '\\f', ['\n'] = '\\n', ['\r'] = '\\r',
    ['\t'] = '\\t', ['\v'] = '\\v', ['\\'] = '\\\\',
}

-- generic utilities
local function escape(s)
    s = s:gsub('([%c\\])', ESCAPE_MAP)
    local dq = s:find('"') 
    local sq = s:find("'")
    if dq and sq then
        return s:gsub('"', '\\"'), '"'
    elseif sq then
        return s, '"'
    else
        return s, "'"
    end
end

local function is_plain_key(key)
    return type(key) == 'string' and key:match('^[%a_][%a%d_]*$')
end

local CACHE_TYPES = {
    ['table'] = true, ['function'] = true, ['thread'] = true, ['userdata'] = true
}

-- cache would be populated to be like:
-- {
--     function = { `fun1` = 1, _cnt = 1 }, -- object id
--     table = { `table1` = 1, `table2` = 2, _cnt = 2 },
--     visited_tables = { `table1` = 7, `table2` = 8  }, -- visit count
-- }
-- use weakrefs to avoid accidentall adding refcount
local function cache_apperance(obj, cache, option)
    if not cache.visited_tables then
        cache.visited_tables = setmetatable({}, {__mode = 'k'})
    end
    local t = type(obj)

    -- TODO can't test filter_function here as we don't have the ix and key,
    -- might cause different results?
    -- respect show_xxx and filter_function to be consistent with print results
    if (not TYPES[t] and not option.show_table)
        or (TYPES[t] and not option['show_'..t]) then
        return
    end

    if CACHE_TYPES[t] or TYPES[t] == nil then
        if not cache[t] then
            cache[t] = setmetatable({}, {__mode = 'k'})
            cache[t]._cnt = 0
        end
        if not cache[t][obj] then
            cache[t]._cnt = cache[t]._cnt + 1
            cache[t][obj] = cache[t]._cnt
        end
    end
    if t == 'table' or TYPES[t] == nil then
        if cache.visited_tables[obj] == false then
            -- already printed, no need to mark this and its children anymore
            return
        elseif cache.visited_tables[obj] == nil then
            cache.visited_tables[obj] = 1
        else
            -- visited already, increment and continue
            cache.visited_tables[obj] = cache.visited_tables[obj] + 1
            return
        end
        for k, v in pairs(obj) do
            cache_apperance(k, cache, option)
            cache_apperance(v, cache, option)
        end
        local mt = getmetatable(obj)
        if mt and option.show_metatable then
            cache_apperance(mt, cache, option)
        end
    end
end

-- makes 'foo2' < 'foo100000'. string.sub makes substring anyway, no need to use index based method
local function str_natural_cmp(lhs, rhs)
    while #lhs > 0 and #rhs > 0 do
        local lmid, lend = lhs:find('%d+')
        local rmid, rend = rhs:find('%d+')
        if not (lmid and rmid) then return lhs < rhs end

        local lsub = lhs:sub(1, lmid-1)
        local rsub = rhs:sub(1, rmid-1)
        if lsub ~= rsub then
            return lsub < rsub
        end
        
        local lnum = tonumber(lhs:sub(lmid, lend))
        local rnum = tonumber(rhs:sub(rmid, rend))
        if lnum ~= rnum then
            return lnum < rnum
        end

        lhs = lhs:sub(lend+1)
        rhs = rhs:sub(rend+1)
    end
    return lhs < rhs
end

local function cmp(lhs, rhs)
    local tleft = type(lhs)
    local tright = type(rhs)
    if tleft == 'number' and tright == 'number' then return lhs < rhs end
    if tleft == 'string' and tright == 'string' then return str_natural_cmp(lhs, rhs) end
    if tleft == tright then return str_natural_cmp(tostring(lhs), tostring(rhs)) end

    -- allow custom types
    local oleft = TYPES[tleft] or 9
    local oright = TYPES[tright] or 9
    return oleft < oright
end

-- setup option with default
local function make_option(option)
    if option == nil then
        option = {}
    end
    for k, v in pairs(pprint.defaults) do
        if option[k] == nil then
            option[k] = v
        end
        if option.show_all then
            for t, _ in pairs(TYPES) do
                option['show_'..t] = true
            end
            option.show_metatable = true
        end
    end
    return option
end

-- override defaults and take effects for all following calls
function pprint.setup(option)
    pprint.defaults = make_option(option)
end

-- format lua object into a string
function pprint.pformat(obj, option, printer)
    option = make_option(option)
    local buf = {}
    local function default_printer(s)
        table.insert(buf, s)
    end
    printer = printer or default_printer

    local cache
    if option.object_cache == 'global' then
        -- steal the cache into a local var so it's not visible from _G or anywhere
        -- still can't avoid user explicitly referentce pprint._cache but it shouldn't happen anyway
        cache = pprint._cache or {}
        pprint._cache = nil
    elseif option.object_cache == 'local' then
        cache = {}
    end

    local last = '' -- used for look back and remove trailing comma
    local status = {
        indent = '', -- current indent
        len = 0,     -- current line length
    }

    local wrapped_printer = function(s)
        printer(last)
        last = s
    end

    local function _indent(d)
        status.indent = string.rep(' ', d + #(status.indent))
    end

    local function _n(d)
        wrapped_printer('\n')
        wrapped_printer(status.indent)
        if d then
            _indent(d)
        end
        status.len = 0
        return true -- used to close bracket correctly
    end

    local function _p(s, nowrap)
        status.len = status.len + #s
        if not nowrap and status.len > option.level_width then
            _n()
            wrapped_printer(s)
            status.len = #s
        else
            wrapped_printer(s)
        end
    end

    local formatter = {}
    local function format(v)
        local f = formatter[type(v)]
        f = f or formatter.table -- allow patched type()
        if option.filter_function and option.filter_function(v, nil, nil) then
            return ''
        else
            return f(v)
        end
    end

    local function tostring_formatter(v)
        return tostring(v)
    end

    local function number_formatter(n)
        return n == math.huge and '[[math.huge]]' or tostring(n)
    end

    local function nop_formatter(v)
        return ''
    end

    local function make_fixed_formatter(t, has_cache)
        if has_cache then
            return function (v)
                return string.format('[[%s %d]]', t, cache[t][v])
            end
        else
            return function (v)
                return '[['..t..']]'
            end
        end
    end

    local function string_formatter(s, force_long_quote)
        local s, quote = escape(s)
        local quote_len = force_long_quote and 4 or 2
        if quote_len + #s + status.len > option.level_width then
            _n()
            -- only wrap string when is longer than level_width
            if option.wrap_string and #s + quote_len > option.level_width then
                -- keep the quotes together
                _p('[[')
                while #s + status.len >= option.level_width do
                    local seg = option.level_width - status.len
                    _p(string.sub(s, 1, seg), true)
                    _n()
                    s = string.sub(s, seg+1)
                end
                _p(s) -- print the remaining parts
                return ']]' 
            end
        end

        return force_long_quote and '[['..s..']]' or quote..s..quote
    end

    local function table_formatter(t)
        if option.use_tostring then
            local mt = getmetatable(t)
            if mt and mt.__tostring then
                return string_formatter(tostring(t), true)
            end
        end

        local print_header_ix = nil
        local ttype = type(t)
        if option.object_cache then
            local cache_state = cache.visited_tables[t]
            local tix = cache[ttype][t]
            -- FIXME should really handle `cache_state == nil`
            -- as user might add things through filter_function
            if cache_state == false then
                -- already printed, just print the the number
                return string_formatter(string.format('%s %d', ttype, tix), true)
            elseif cache_state > 1 then
                -- appeared more than once, print table header with number
                print_header_ix = tix
                cache.visited_tables[t] = false
            else
                -- appeared exactly once, print like a normal table
            end
        end

        local limit = tonumber(option.depth_limit)
        if limit and depth > limit then
           if print_header_ix then
              return string.format('[[%s %d]]...', ttype, print_header_ix)
           end
           return string_formatter(tostring(t), true)
        end

        local tlen = #t
        local wrapped = false
        _p('{')
        _indent(option.indent_size)
        _p(string.rep(' ', option.indent_size - 1))
        if print_header_ix then
            _p(string.format('--[[%s %d]] ', ttype, print_header_ix))
        end
        local wrap_array = option.wrap_array
        if wrap_array then
            local allvalues = true
            for ix = 1,tlen do
               local tp = type(t[ix])
               if tp ~= "string" and tp ~= "number" and tp ~= "boolean" then
                    allvalues = false
                    break
               end
            end
            if allvalues then
                wrap_array = false
            end
        end
        for ix = 1,tlen do
            local v = t[ix]
            if formatter[type(v)] == nop_formatter or 
               (option.filter_function and option.filter_function(v, ix, t)) then
               -- pass
            else
                if wrap_array then
                    wrapped = _n()
                end
                depth = depth+1
                _p(format(v)..', ')
                depth = depth-1
            end
        end

        -- hashmap part of the table, in contrast to array part
        local function is_hash_key(k)
            if type(k) ~= 'number' then
                return true
            end

            local numkey = math.floor(tonumber(k))
            if numkey ~= k or numkey > tlen or numkey <= 0 then
                return true
            end
        end

        local function print_kv(k, v, t)
            -- can't use option.show_x as obj may contain custom type
            if formatter[type(v)] == nop_formatter or
               formatter[type(k)] == nop_formatter or 
               (option.filter_function and option.filter_function(v, k, t)) then
                return
            end
            wrapped = _n()
            if is_plain_key(k) then
                _p(k, true)
            else
                _p('[')
                -- [[]] type string in key is illegal, needs to add spaces inbetween
                local k = format(k)
                if string.match(k, '%[%[') then
                    _p(' '..k..' ', true)
                else
                    _p(k, true)
                end
                _p(']')
            end
            _p(' = ', true)
            depth = depth+1
            _p(format(v), true)
            depth = depth-1
            _p(',', true)
        end

        if option.sort_keys then
            local keys = {}
            for k, _ in pairs(t) do
                if is_hash_key(k) then
                    table.insert(keys, k)
                end
            end
            table.sort(keys, cmp)
            for _, k in ipairs(keys) do
                print_kv(k, t[k], t)
            end
        else
            for k, v in pairs(t) do
                if is_hash_key(k) then
                    print_kv(k, v, t)
                end
            end
        end

        if option.show_metatable then
            local mt = getmetatable(t)
            if mt then
                print_kv('__metatable', mt, t)
            end
        end

        _indent(-option.indent_size)
        -- make { } into {}
        last = string.gsub(last, '^ +$', '')
        -- peek last to remove trailing comma
        last = string.gsub(last, ',%s*$', ' ')
        if wrapped then
            _n()
        end
        _p('}')

        return ''
    end

    -- set formatters
    formatter['nil'] = option.show_nil and tostring_formatter or nop_formatter
    formatter['boolean'] = option.show_boolean and tostring_formatter or nop_formatter
    formatter['number'] = option.show_number and number_formatter or nop_formatter -- need to handle math.huge
    formatter['function'] = option.show_function and make_fixed_formatter('function', option.object_cache) or nop_formatter
    formatter['thread'] = option.show_thread and make_fixed_formatter('thread', option.object_cache) or nop_formatter
    formatter['userdata'] = option.show_userdata and make_fixed_formatter('userdata', option.object_cache) or nop_formatter
    formatter['string'] = option.show_string and string_formatter or nop_formatter
    formatter['table'] = option.show_table and table_formatter or nop_formatter

    if option.object_cache then
        -- needs to visit the table before start printing
        cache_apperance(obj, cache, option)
    end

    _p(format(obj))
    printer(last) -- close the buffered one

    -- put cache back if global
    if option.object_cache == 'global' then
        pprint._cache = cache
    end

    return table.concat(buf)
end

-- pprint all the arguments
function pprint.pprint( ... )
    local args = {...}
    -- select will get an accurate count of array len, counting trailing nils
    local len = select('#', ...)
    for ix = 1,len do
        pprint.pformat(args[ix], nil, io.write)
        io.write('\n')
    end
end

setmetatable(pprint, {
    __call = function (_, ...)
        pprint.pprint(...)
    end
})

return pprint

