package main

// This file builds the four built-in IM channel adapters from the runtime-editable
// configuration. The effective source is channels.json when it is present and
// valid (design/04 §3.1); otherwise it falls back to the env channel block
// (CHANNELS_JSON multi-account + the single-account CHANNEL_<NAME>_* vars), which
// stays the final fallback so a bare install boots without any config file.
//
// Each account becomes its own adapter instance. A single-account env adapter is
// named after the bare platform (e.g. "kook"); a multi-account entry is named
// "kook:confID" and wrapped in a namedAdapter that surfaces its allow/deny lists
// through Config() for the channel bridge's black-or-white gate (design/16 §4.6
// §5-6). The channelFactory lets the bridge hot-replace a platform's adapters when
// the panel saves a new config (Bridge.Reload), so a token/address/rate change
// takes effect without a restart.

import (
	"fmt"
	"log/slog"
	"net/http"
	"os"
	"strings"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/channel/adapter"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/config"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/config/runtimeconfig"
	"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 every channel adapter from the effective
// account config (channels.json → env fallback) and returns the successfully
// built subset. Adapter construction never dials the network; actual connection
// happens in the channel bridge. f holds the path/fallback/logger so boot and the
// reload factory read the same source.
func buildChannelAdapters(f *channelFactory) []adapter.PlatformAdapter {
	accounts, warn := runtimeconfig.LoadChannels(f.path, f.fallback)
	if warn != nil {
		f.log.Warn("channels.json load fell back to env", "error", warn)
	}
	out := make([]adapter.PlatformAdapter, 0)
	for platform, accts := range accounts {
		out = append(out, buildPlatformAdapters(platform, accts, f.log)...)
	}
	return out
}

// channelFactory is the channelbridge.PlatformFactory wired into the bridge. It
// rebuilds a platform's adapters from the CURRENT effective config (file → env),
// so a panel save followed by Bridge.Reload(platform) picks the new config up
// without a restart.
type channelFactory struct {
	path     string
	fallback map[string][]config.ChannelAccount
	log      *slog.Logger
}

// Build returns the adapters for a platform from its effective account config.
func (f *channelFactory) Build(platform string) ([]adapter.PlatformAdapter, error) {
	accounts, warn := runtimeconfig.LoadChannels(f.path, f.fallback)
	if warn != nil {
		f.log.Warn("channels.json reload fell back to env", "error", warn)
	}
	return buildPlatformAdapters(platform, accounts[platform], f.log), nil
}

// Persona returns the role bound to one channel account of a platform (design/22
// §2 方案 b). It reads the same effective config Build does — channels.json wins,
// env is the fallback — so the panel's save plus the bridge's hot reload stay the
// single update path, and it is called once per adapter connect rather than per
// message. An unknown platform/account, or an account without a personaId, returns
// "" (no channel-level binding: the session binding or the global default applies).
func (f *channelFactory) Persona(platform, accountID string) string {
	accounts, warn := runtimeconfig.LoadChannels(f.path, f.fallback)
	if warn != nil {
		f.log.Warn("channels.json persona lookup fell back to env", "error", warn)
	}
	for _, acct := range accounts[platform] {
		if strings.TrimSpace(acct.ID) == strings.TrimSpace(accountID) {
			return strings.TrimSpace(acct.PersonaID)
		}
	}
	return ""
}

// buildPlatformAdapters builds every account of one platform into an adapter
// instance. A failed account build is skipped with a warn (never fatal), matching
// the "no credentials → warn and continue" contract of the bridge.
func buildPlatformAdapters(platform string, accts []config.ChannelAccount, log *slog.Logger) []adapter.PlatformAdapter {
	out := make([]adapter.PlatformAdapter, 0, len(accts))
	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)
	}
	return out
}

// channelAccountsFromEnv synthesizes the env fallback: the single-account
// CHANNEL_<NAME>_* adapters plus any CHANNELS_JSON multi-account entries. It is
// the .env fallback passed to runtimeconfig.LoadChannels when channels.json is
// absent or invalid. .env only carries the necessary connection fallback
// (token/base_url/...); business and advanced per-account fields (receive_mode,
// webhook path/verify_token/encrypt_key, allow/deny lists, rate limits) are
// configured in the panel's channel management and live in channels.json, never
// in .env.
//
// A token-requiring platform (kook/telegram/weixin-ilink) is synthesized only
// when its token env var is set; with an unset token there is no account at all,
// so an empty-token placeholder never claims the bare platform name. qq-obv11 and
// webhook are always present (they do not need a token; the bridge's configured()
// gate decides whether to dial) so the channel list stays stable.
func channelAccountsFromEnv() map[string][]config.ChannelAccount {
	out := map[string][]config.ChannelAccount{}
	// KOOK: only the necessary connection fields. receive_mode / webhook_path /
	// webhook_verify_token / webhook_encrypt_key are business·advanced fields that
	// go to channels.json via the panel — .env does not fall back on them.
	if tok := os.Getenv("CHANNEL_KOOK_TOKEN"); tok != "" {
		out["kook"] = append(out["kook"], config.ChannelAccount{Config: map[string]any{
			"bot_token": tok,
			"base_url":  os.Getenv("CHANNEL_KOOK_BASE_URL"),
		}})
	}
	// Telegram: token (necessary) + optional webhook_url (connection). Business
	// tuning goes to channels.json.
	if tok := os.Getenv("CHANNEL_TELEGRAM_BOT_TOKEN"); tok != "" {
		out["telegram"] = append(out["telegram"], config.ChannelAccount{Config: map[string]any{
			"bot_token":   tok,
			"webhook_url": os.Getenv("CHANNEL_TELEGRAM_WEBHOOK_URL"),
		}})
	}
	// qq-obv11 的四个端（裁决 1.4）：transport(ws|http) × mode(client|server)。
	// 默认 transport=ws、mode=server，与改造前的行为完全一致（保守：不改变已部署
	// 现状）；listen_addr 是 server 端的显式监听地址，留空即不开端口（AGENTS §9）。
	out["qq-obv11"] = append(out["qq-obv11"], config.ChannelAccount{Config: map[string]any{
		"transport":    envString("CHANNEL_QQ_OBV11_TRANSPORT", "ws"),
		"mode":         envString("CHANNEL_QQ_OBV11_MODE", "server"),
		"listen_addr":  os.Getenv("CHANNEL_QQ_OBV11_LISTEN_ADDR"),
		"remote_url":   os.Getenv("CHANNEL_QQ_OBV11_REMOTE_URL"),
		"api_base_url": os.Getenv("CHANNEL_QQ_OBV11_API_BASE_URL"),
		"report_path":  os.Getenv("CHANNEL_QQ_OBV11_REPORT_PATH"),
		"access_token": os.Getenv("CHANNEL_QQ_OBV11_ACCESS_TOKEN"),
		"self_id":      os.Getenv("CHANNEL_QQ_OBV11_SELF_ID"),
	}})
	out["webhook"] = append(out["webhook"], config.ChannelAccount{Config: map[string]any{
		"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"),
	}})
	if tok := os.Getenv("CHANNEL_WEIXIN_ILINK_BOT_TOKEN"); tok != "" {
		out["weixin-ilink"] = append(out["weixin-ilink"], config.ChannelAccount{Config: map[string]any{
			"base_url":     os.Getenv("CHANNEL_WEIXIN_ILINK_BASE_URL"),
			"cdn_base_url": os.Getenv("CHANNEL_WEIXIN_ILINK_CDN_BASE_URL"),
			"bot_token":    tok,
			"bot_id":       os.Getenv("CHANNEL_WEIXIN_ILINK_BOT_ID"),
			"owner_id":     os.Getenv("CHANNEL_WEIXIN_ILINK_OWNER_ID"),
		}})
	}
	if raw := os.Getenv("CHANNELS_JSON"); raw != "" {
		if accounts, err := config.ParseChannelAccounts(raw); err == nil {
			for platform, accts := range accounts {
				out[platform] = append(out[platform], accts...)
			}
		}
	}
	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
}

// InboundHandler forwards to the inner adapter when it exposes an inbound HTTP
// callback; the bridge type-asserts the wrapper and mounts the handler at
// WebhookPath. It returns nil for a non-webhook inner adapter.
func (n *namedAdapter) InboundHandler() http.Handler {
	if inner, ok := n.PlatformAdapter.(interface{ InboundHandler() http.Handler }); ok {
		return inner.InboundHandler()
	}
	return nil
}

// WebhookPath forwards the inner adapter's webhook route, returning "" when the
// inner adapter does not expose one (so the bridge skips it).
func (n *namedAdapter) WebhookPath() string {
	if inner, ok := n.PlatformAdapter.(interface{ WebhookPath() string }); ok {
		return inner.WebhookPath()
	}
	return ""
}

// 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)
		}
		if strings.TrimSpace(cfg.BotToken) == "" {
			return nil, fmt.Errorf("%s: missing bot token", platform)
		}
		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)
		}
		// A weixin-ilink account may carry an empty bot_token: it is a pending
		// scan-login account the panel drives via the login-qr/login-status admin
		// endpoints (design/08 §4). The bridge's configured() gate skips it until
		// the scan confirms and the token is persisted, so an empty token here is
		// legitimate — build the adapter (disconnected) rather than dropping it.
		w, err := weixin_ilink.New(cfg, nil, logger.WithSource(log, "plugins/channels/weixin_ilink"))
		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)
		}
		if strings.TrimSpace(cfg.BotToken) == "" {
			return nil, fmt.Errorf("%s: missing bot token", platform)
		}
		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
}