package main

// This file builds the four built-in IM channel adapters from environment
// configuration. The config package carries no channel block, so credentials are
// read from CHANNEL_<NAME>_* env vars here and injected into each adapter's
// concrete Config. Adapters whose construction fails are skipped rather than
// aborting boot, matching the "no credentials → warn and continue" contract of
// the channel bridge.

import (
	"fmt"
	"log/slog"
	"os"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/channel/adapter"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/config"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/logger"
	"git.yeij.top/AskaEth/Cyrene_v2/plugins/channels/kook"
	"git.yeij.top/AskaEth/Cyrene_v2/plugins/channels/qq_obv11"
	"git.yeij.top/AskaEth/Cyrene_v2/plugins/channels/telegram"
	"git.yeij.top/AskaEth/Cyrene_v2/plugins/channels/webhook"
	"git.yeij.top/AskaEth/Cyrene_v2/plugins/channels/weixin_ilink"
)

// buildChannelAdapters constructs the four channel adapters from environment
// configuration and returns the successfully built subset. Adapter construction
// never dials the network; actual connection happens in the channel bridge.
func buildChannelAdapters(log *slog.Logger) []adapter.PlatformAdapter {
	qq := qq_obv11.NewAdapter(qq_obv11.Config{
		Mode:        envString("CHANNEL_QQ_OBV11_MODE", "server"),
		ListenAddr:  os.Getenv("CHANNEL_QQ_OBV11_LISTEN_ADDR"),
		RemoteURL:   os.Getenv("CHANNEL_QQ_OBV11_REMOTE_URL"),
		AccessToken: os.Getenv("CHANNEL_QQ_OBV11_ACCESS_TOKEN"),
		SelfID:      os.Getenv("CHANNEL_QQ_OBV11_SELF_ID"),
		Logger:      log,
	})

	weixin, werr := weixin_ilink.New(weixin_ilink.Config{
		BaseURL:    os.Getenv("CHANNEL_WEIXIN_ILINK_BASE_URL"),
		CDNBaseURL: os.Getenv("CHANNEL_WEIXIN_ILINK_CDN_BASE_URL"),
		BotToken:   os.Getenv("CHANNEL_WEIXIN_ILINK_BOT_TOKEN"),
		BotID:      os.Getenv("CHANNEL_WEIXIN_ILINK_BOT_ID"),
		OwnerID:    os.Getenv("CHANNEL_WEIXIN_ILINK_OWNER_ID"),
	}, nil, log)
	if werr != nil {
		// A blank config defaults to a valid base URL, so this only fires on an
		// explicitly invalid one; skip the channel rather than fail startup.
		log.Warn("weixin-ilink adapter build skipped", "error", werr)
		weixin = nil
	}

	tg := telegram.New(telegram.Config{
		BotToken:   os.Getenv("CHANNEL_TELEGRAM_BOT_TOKEN"),
		WebhookURL: os.Getenv("CHANNEL_TELEGRAM_WEBHOOK_URL"),
	}, telegram.WithLogger(log))

	kook := kook.New(kook.Config{
		BotToken: os.Getenv("CHANNEL_KOOK_TOKEN"),
		BaseURL:  os.Getenv("CHANNEL_KOOK_BASE_URL"),
	}, kook.WithLogger(log))

	// webhook.WithLogger does not tag provenance, so wrap base with the module
	// source here to satisfy the logging rule.
	wh := webhook.New(
		webhook.WithConfig(webhook.Config{
			EndpointPath:    os.Getenv("CHANNEL_WEBHOOK_ENDPOINT_PATH"),
			ChannelID:       os.Getenv("CHANNEL_WEBHOOK_CHANNEL_ID"),
			ChannelName:     os.Getenv("CHANNEL_WEBHOOK_CHANNEL_NAME"),
			Secret:          os.Getenv("CHANNEL_WEBHOOK_SECRET"),
			SignatureHeader: os.Getenv("CHANNEL_WEBHOOK_SIGNATURE_HEADER"),
		}),
		webhook.WithLogger(logger.WithSource(log, "plugins/channels/webhook")),
	)

	out := []adapter.PlatformAdapter{qq, tg, wh, kook}
	if weixin != nil {
		out = append(out, weixin)
	}

	// design/16 §4.6 §5: a platform may carry multiple access configs (multiple
	// accounts) via CHANNELS_JSON. Each account becomes its own adapter instance
	// (named platform:confID) with independent session/account and its own allow/deny
	// black-or-white lists. An empty CHANNELS_JSON adds nothing, so the single-account
	// env path above is unchanged.
	if accounts, err := config.ParseChannelAccounts(os.Getenv("CHANNELS_JSON")); err == nil {
		for platform, accts := range accounts {
			for _, acct := range accts {
				built, berr := buildAccountAdapter(platform, acct, log)
				if berr != nil {
					log.Warn("channel account build skipped", "platform", platform, "account", acct.ID, "error", berr)
					continue
				}
				out = append(out, built)
			}
		}
	} else {
		log.Warn("CHANNELS_JSON parse failed, ignoring multi-account config", "error", err)
	}
	return out
}

// namedAdapter wraps a platform adapter so a multi-account instance gets a unique
// name (platform:confID) and surfaces its allow/deny lists through Config(), which
// the channel bridge reads to enforce the platform's black-or-white lists per
// account (design/16 §4.6 §5-6). Everything else delegates to the inner adapter.
type namedAdapter struct {
	adapter.PlatformAdapter
	name        string
	allowGroups []string
	denyGroups  []string
	allowUsers  []string
	denyUsers   []string
	// flow limits (design/12 §6 策略三/四). They are always surfaced through
	// Config() so the bridge can build a per-account ingress gate; the bridge maps
	// the zero default to the protective values and a negative value to "off".
	groupMsgPerMin int
	msgPerMin      int
	maxMessages    int
}

func (n *namedAdapter) Name() string { return n.name }

func (n *namedAdapter) Config() map[string]any {
	cfg := n.PlatformAdapter.Config()
	out := make(map[string]any, len(cfg)+7)
	for k, v := range cfg {
		out[k] = v
	}
	out["allowGroups"] = n.allowGroups
	out["denyGroups"] = n.denyGroups
	out["allowUsers"] = n.allowUsers
	out["denyUsers"] = n.denyUsers
	out["groupMsgPerMin"] = n.groupMsgPerMin
	out["msgPerMin"] = n.msgPerMin
	out["maxMessages"] = n.maxMessages
	return out
}

// buildAccountAdapter builds one account's adapter for a platform, decoding the
// account's generic Config map into the platform's typed config and wrapping it so
// the bridge sees a distinct account name and its allow/deny lists.
func buildAccountAdapter(platform string, acct config.ChannelAccount, log *slog.Logger) (adapter.PlatformAdapter, error) {
	name := platform
	if acct.ID != "" {
		name = platform + ":" + acct.ID
	}

	var inner adapter.PlatformAdapter
	switch barePlatform(platform) {
	case "telegram":
		var cfg telegram.Config
		if err := adapter.DecodeConfig(acct.Config, &cfg); err != nil {
			return nil, fmt.Errorf("decode telegram config: %w", err)
		}
		inner = telegram.New(cfg, telegram.WithLogger(log))
	case "weixin-ilink":
		var cfg weixin_ilink.Config
		if err := adapter.DecodeConfig(acct.Config, &cfg); err != nil {
			return nil, fmt.Errorf("decode weixin-ilink config: %w", err)
		}
		w, err := weixin_ilink.New(cfg, nil, log)
		if err != nil {
			return nil, fmt.Errorf("build weixin-ilink: %w", err)
		}
		inner = w
	case "qq-obv11":
		var cfg qq_obv11.Config
		if err := adapter.DecodeConfig(acct.Config, &cfg); err != nil {
			return nil, fmt.Errorf("decode qq-obv11 config: %w", err)
		}
		inner = qq_obv11.NewAdapter(cfg)
	case "kook":
		var cfg kook.Config
		if err := adapter.DecodeConfig(acct.Config, &cfg); err != nil {
			return nil, fmt.Errorf("decode kook config: %w", err)
		}
		inner = kook.New(cfg, kook.WithLogger(log))
	case "webhook":
		var cfg webhook.Config
		if err := adapter.DecodeConfig(acct.Config, &cfg); err != nil {
			return nil, fmt.Errorf("decode webhook config: %w", err)
		}
		inner = webhook.New(webhook.WithConfig(cfg), webhook.WithLogger(logger.WithSource(log, "plugins/channels/webhook")))
	default:
		return nil, fmt.Errorf("unknown platform %q", platform)
	}
	return &namedAdapter{
		PlatformAdapter: inner,
		name:            name,
		allowGroups:     acct.AllowGroups,
		denyGroups:      acct.DenyGroups,
		allowUsers:      acct.AllowUsers,
		denyUsers:       acct.DenyUsers,
		groupMsgPerMin:  acct.GroupMsgPerMin,
		msgPerMin:       acct.MsgPerMin,
		maxMessages:     acct.MaxMessages,
	}, nil
}

// barePlatform returns the platform name for a possibly-suffixed "platform:confID".
func barePlatform(name string) string {
	for i := 0; i < len(name); i++ {
		if name[i] == ':' {
			return name[:i]
		}
	}
	return name
}

// envString returns the value of key, or fallback when the variable is unset or
// blank.
func envString(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}