package tdesktop

import (
	"net/netip"
	"time"

	"github.com/iamxvbaba/td/tg"

	"telesrv/internal/links"
)

// BuildConfig 构造 help.getConfig 返回的 tg.Config，含自建 DC 的 DCOptions。
//
// 字段值取 Telegram 常见默认；TDesktop 联调阶段按客户端实际需要微调
// （记录于 docs/compatibility-matrix.md）。
func BuildConfig(dc int, ip string, port int, now time.Time, publicBaseURL string) *tg.Config {
	// TELESRV_ADVERTISE_IP is validated during config loading. Parse again here
	// only to derive the wire ipv6 flag and to render IPv4-mapped addresses in
	// their canonical form. Keeping the advertised route in help.getConfig is a
	// protocol invariant: clients replace or persist this list for reconnects.
	addr, err := netip.ParseAddr(ip)
	if err == nil {
		addr = addr.Unmap()
		ip = addr.String()
	}
	meURLPrefix := links.NormalizeBaseURL(publicBaseURL) + "/"
	config := &tg.Config{
		Date:     int(now.Unix()),
		Expires:  int(now.Add(time.Hour).Unix()),
		TestMode: false,
		ThisDC:   dc,
		DCOptions: []tg.DCOption{{
			Ipv6:      addr.Is6(),
			ID:        dc,
			IPAddress: ip,
			Port:      port,
		}},
		ChatSizeMax:          200,
		MegagroupSizeMax:     200000,
		ForwardedCountMax:    100,
		OnlineUpdatePeriodMs: 120000,
		OfflineBlurTimeoutMs: 5000,
		OfflineIdleTimeoutMs: 30000,
		OnlineCloudTimeoutMs: 300000,
		NotifyCloudDelayMs:   30000,
		NotifyDefaultDelayMs: 1500,
		PushChatPeriodMs:     60000,
		PushChatLimit:        2,
		EditTimeLimit:        172800,
		// 官方现行 revoke 三元组：无时限 + 允许撤回对方发来的私聊消息。
		// TDesktop 的私聊 "Also delete for X" 复选框要求
		// revoke_pm_inbox=true 且 revoke_pm_time_limit=0x7FFFFFFF，
		// 否则双向删除 UI 永不出现。
		RevokeTimeLimit:      2147483647,
		RevokePmTimeLimit:    2147483647,
		RevokePmInbox:        true,
		RatingEDecay:         2419200,
		StickersRecentLimit:  200,
		CallReceiveTimeoutMs: 20000,
		CallRingTimeoutMs:    90000,
		CallConnectTimeoutMs: 30000,
		CallPacketTimeoutMs:  10000,
		MeURLPrefix:          meURLPrefix,
		CaptionLengthMax:     1024,
		MessageLengthMax:     4096,
		WebfileDCID:          dc,
	}
	config.SetReactionsDefault(&tg.ReactionEmoji{Emoticon: DefaultReactionEmoticon})
	// The GIF picker's trending/search panel reads this from help.getConfig's
	// typed Config (gifs_list_widget.cpp: session().serverConfig().gifSearchUsername)
	// -- NOT from help.getAppConfig's loose JSON blob, which is a separate RPC/
	// response entirely. Must match the built-in @gif system bot's username
	// (domain.GifBotUser().Username), whose inline results are served
	// synchronously in-process (see rpc.ServiceBotInlineResults).
	config.SetGifSearchUsername("gif")
	return config
}