package lua

import (
	"fmt"
	"sort"
	"strings"

	golua "github.com/aarzilli/golua/lua"
)

// Package lua — Lua 绑定：凭据保险库 + 内核动作面
//
// 这两个全局把"插件自己主导链接认证"所需的两块补齐：
//
//	__llmsproxy_secrets  —— 安全存放 OAuth token / session / 设备指纹
//	__llmsproxy_kernel   —— 触发内核动作（注册源、探测、清冷却、改链路…）
//
// 注册点与 __llmsproxy_http 相同：只在 PLUGIN 的 bootPluginState 里装，
// 因为适配器共用 setupGlobals 而不该拿到这些能力。
//
// 两张表都用 buildJSONTable 的既有写法（NewTable + PushGoClosure + SetField），
// 该写法在 json 表上长期稳定，也是内核自己的用法。

// secretGlobal 是凭据保险库的 Lua 名字。
const secretGlobal = "__llmsproxy_secrets"

// kernelGlobal 是内核动作面的 Lua 名字。
const kernelGlobal = "__llmsproxy_kernel"

// registerSecretBridge installs the credential vault onto a plugin's state.
//
// The plugin name is bound HERE, at boot, rather than read from the Lua state at
// call time. That is what makes "a plugin can only read its OWN credentials" a
// mechanism instead of a convention: a shard or any other holder of the compiled
// script cannot pass a different name.
func registerSecretBridge(L *golua.State, ps *Plugins, name string) {
	L.NewTable()
	L.PushGoClosure(luaSecretSet(ps, name))
	L.SetField(-2, "set")
	L.PushGoClosure(luaSecretGet(ps, name))
	L.SetField(-2, "get")
	L.PushGoClosure(luaSecretDelete(ps, name))
	L.SetField(-2, "delete")
	L.PushGoClosure(luaSecretKeys(ps, name))
	L.SetField(-2, "keys")
	L.SetGlobal(secretGlobal)
}

// luaSecretSet: set(key, value) -> (true, nil) | (nil, err)
func luaSecretSet(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		key := L.ToString(1)
		val := L.ToString(2)
		if err := ps.SetSecret(name, key, val); err != nil {
			L.PushNil()
			L.PushString(err.Error())
			return 2
		}
		L.PushBoolean(true)
		L.PushNil()
		return 2
	}
}

// luaSecretGet: get(key) -> (value, nil) | (nil, err). A missing key yields
// (nil, nil) so a plugin can test `if tok == nil then login() end` — the "no
// credential stored yet" case is the common one for a fresh install, and making
// it an error would force every caller to string-match on a message.
func luaSecretGet(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		key := L.ToString(1)
		v, ok, err := ps.GetSecret(name, key)
		if err != nil {
			L.PushNil()
			L.PushString(err.Error())
			return 2
		}
		if !ok {
			L.PushNil()
			L.PushNil()
			return 2
		}
		L.PushString(v)
		L.PushNil()
		return 2
	}
}

// luaSecretDelete: delete(key) -> (true, nil) | (nil, err)
func luaSecretDelete(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		key := L.ToString(1)
		if err := ps.DeleteSecret(name, key); err != nil {
			L.PushNil()
			L.PushString(err.Error())
			return 2
		}
		L.PushBoolean(true)
		L.PushNil()
		return 2
	}
}

// luaSecretKeys: keys() -> (array of key names, nil). Names only — a plugin can
// render "which accounts are configured" without ever echoing token bytes.
func luaSecretKeys(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		keys, err := ps.SecretKeys(name)
		if err != nil {
			L.PushNil()
			L.PushString(err.Error())
			return 2
		}
		L.NewTable()
		for i, k := range keys {
			L.PushString(k)
			L.RawSeti(-2, i+1)
		}
		L.PushNil()
		return 2
	}
}

// registerKernelBridge installs the kernel action surface onto a plugin's state.
func registerKernelBridge(L *golua.State, ps *Plugins, name string) {
	L.NewTable()
	L.PushGoClosure(luaKernelActions(ps, name))
	L.SetField(-2, "actions")
	L.PushGoClosure(luaKernelCall(ps, name))
	L.SetField(-2, "call")
	L.SetGlobal(kernelGlobal)
}

// luaKernelActions: actions() -> (array of {name,title,danger,description,params,
// granted}, nil)
//
// It reports GRANTED alongside each action so a plugin can degrade gracefully
// (skip the part that needs a permission it does not have) instead of
// discovering it by hitting an error mid-operation.
func luaKernelActions(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		perm := ps.PluginKernelPermission(name)
		L.NewTable()
		for i, a := range KernelActions() {
			L.NewTable()
			L.PushString(a.Name)
			L.SetField(-2, "name")
			L.PushString(a.Title)
			L.SetField(-2, "title")
			L.PushString(a.Danger)
			L.SetField(-2, "danger")
			L.PushString(a.Description)
			L.SetField(-2, "description")
			L.PushBoolean(perm.allows(a))
			L.SetField(-2, "granted")
			L.NewTable()
			for j, p := range a.Params {
				L.PushString(p)
				L.RawSeti(-2, j+1)
			}
			L.SetField(-2, "params")
			L.RawSeti(-2, i+1)
		}
		L.PushNil()
		return 2
	}
}

// luaKernelCall: call(name, args) -> (result, nil) | (nil, err)
//
// One entry point rather than a function per action: the action set will change,
// and a table field per action would mean editing bootPluginState — the exact
// place that produced a cgo crash during earlier work.
func luaKernelCall(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		action := L.ToString(1)
		args := map[string]interface{}{}
		if L.Type(2) == golua.LUA_TTABLE {
			var raw interface{}
			if err := luaToJSON(L, 2, &raw); err == nil {
				if m, ok := raw.(map[string]interface{}); ok {
					args = m
				}
			}
		}
		v, err := ps.callKernel(name, action, args)
		if err != nil {
			L.PushNil()
			L.PushString(err.Error())
			return 2
		}
		if v == nil {
			L.PushNil()
		} else {
			pushGoValue(L, v)
		}
		L.PushNil()
		return 2
	}
}

// readPluginKernelDeclared reads `plugin.kernel`, the actions a plugin asks for.
//
// The shape is a list of names:
//
//	plugin.kernel = { "status", "reset_health" }
//
// Unknown names are kept rather than dropped so the settings page can show a
// typo as "requested but not a real action" — silently discarding it would make
// a plugin's intent invisible at exactly the moment the operator is deciding
// what to grant.
func readPluginKernelDeclared(L *golua.State) []string {
	raw, ok := pluginFieldValue(L, "kernel")
	if !ok {
		return nil
	}
	items, isList := raw.([]interface{})
	if !isList {
		if one, isTable := raw.(map[string]interface{}); isTable {
			// A single string field or a set-style table; accept both spellings.
			if v, ok := one["actions"].([]interface{}); ok {
				items = v
			} else {
				return nil
			}
		} else {
			return nil
		}
	}
	out := make([]string, 0, len(items))
	seen := map[string]bool{}
	for _, it := range items {
		name, ok := it.(string)
		if !ok {
			continue
		}
		name = strings.TrimSpace(name)
		if name == "" || seen[name] {
			continue
		}
		seen[name] = true
		out = append(out, name)
	}
	sort.Strings(out)
	return out
}

// loginGlobal is the Lua name of the login-session bridge.
const loginGlobal = "__llmsproxy_login"

// registerLoginBridge installs the login session API.
//
// A plugin drives the whole flow itself (it knows the platform's endpoints) and
// the kernel only owns the session lifecycle: create, poll, resolve, cancel.
// That split is what lets one kernel serve OAuth, device-code, QR and paste
// flows without containing any platform knowledge.
func registerLoginBridge(L *golua.State, ps *Plugins, name string) {
	L.NewTable()
	L.PushGoClosure(luaLoginBegin(ps, name))
	L.SetField(-2, "begin")
	L.PushGoClosure(luaLoginGet(ps, name))
	L.SetField(-2, "get")
	L.PushGoClosure(luaLoginResolve(ps, name))
	L.SetField(-2, "resolve")
	L.PushGoClosure(luaLoginList(ps, name))
	L.SetField(-2, "list")
	L.PushGoClosure(luaLoginCancel(ps, name))
	L.SetField(-2, "cancel")
	// 服务端浏览器（回环类登录的唯一自动化路径）。与登录会话同一张表，
	// 因为它就是登录的一种流程，而不是独立能力。
	L.PushGoClosure(luaBrowserStart(ps, name))
	L.SetField(-2, "start_browser")
	L.PushGoClosure(luaBrowserGet(ps, name))
	L.SetField(-2, "get_browser")
	L.PushGoClosure(luaBrowserStop(ps, name))
	L.SetField(-2, "stop_browser")
	L.SetGlobal(loginGlobal)
}

// luaBrowserStart: start_browser({platform, start_url, callback_port}) ->
//
//	({view_url, id, callback_port}, nil) | (nil, err)
//
// The plugin gets a VIEW URL, never a browser-control handle. That is the
// deliberate boundary: a plugin that could drive the browser arbitrarily could
// read every tab's cookies, and the browser is logged into the OPERATOR's
// third-party accounts, not the plugin's own.
func luaBrowserStart(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		args, err := luaTableArg(L, 1)
		if err != nil {
			L.PushNil()
			L.PushString("__llmsproxy_login.start_browser: " + err.Error())
			return 2
		}
		port := 0
		if n, ok := asFloat(args["callback_port"]); ok {
			port = int(n)
		}
		sess, err := ps.StartBrowserSession(name, asString(args["platform"]),
			asString(args["start_url"]), port)
		if err != nil {
			L.PushNil()
			L.PushString(err.Error())
			return 2
		}
		pushGoValue(L, browserToLua(*sess))
		L.PushNil()
		return 2
	}
}

// luaBrowserGet: get_browser(id) -> (session, nil) | (nil, nil)
func luaBrowserGet(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		id := L.ToString(1)
		s, ok := ps.GetBrowserSession(id)
		if !ok || s.Plugin != name {
			L.PushNil()
			L.PushNil()
			return 2
		}
		pushGoValue(L, browserToLua(*s))
		L.PushNil()
		return 2
	}
}

// luaBrowserStop: stop_browser(id) -> (true, nil)
func luaBrowserStop(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		id := L.ToString(1)
		if s, ok := ps.GetBrowserSession(id); ok && s.Plugin == name {
			ps.StopBrowserSession(id)
		}
		L.PushBoolean(true)
		L.PushNil()
		return 2
	}
}

// browserToLua renders a browser session for Lua. The CDP/debug ports are NOT
// included: the plugin receives what it needs to display the viewer and read the
// captured code, and nothing that would let it drive the browser.
func browserToLua(s BrowserSession) map[string]interface{} {
	return map[string]interface{}{
		"id":            s.ID,
		"platform":      s.Platform,
		"view_url":      s.ViewURL,
		"callback_port": s.CallbackPort,
		"captured_code": s.CapturedCode,
		"state":         s.CapturedState,
		"error":         s.Error,
		"started_at":    s.StartedAt.Unix(),
		"expires_at":    s.ExpiresAt.Unix(),
	}
}

// luaLoginBegin: begin({platform, flow, url, user_code}) -> (session, nil) | (nil, err)
func luaLoginBegin(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		args, err := luaTableArg(L, 1)
		if err != nil {
			L.PushNil()
			L.PushString("__llmsproxy_login.begin: " + err.Error())
			return 2
		}
		s := LoginSession{
			Plugin:   name,
			Platform: asString(args["platform"]),
			Flow:     LoginFlow(asString(args["flow"])),
			URL:      asString(args["url"]),
			UserCode: asString(args["user_code"]),
		}
		out, err := ps.BeginLogin(s)
		if err != nil {
			L.PushNil()
			L.PushString(err.Error())
			return 2
		}
		pushGoValue(L, sessionToLua(*out, true))
		L.PushNil()
		return 2
	}
}

// luaLoginGet: get(id) -> (session, nil) | (nil, err)
func luaLoginGet(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		id := L.ToString(1)
		s, ok := ps.GetLogin(id)
		if !ok {
			L.PushNil()
			L.PushNil() // absent is not an error; the plugin tests for nil
			return 2
		}
		if s.Plugin != name {
			// Another plugin's session is indistinguishable from a missing one.
			// Reporting "not yours" would confirm the id exists.
			L.PushNil()
			L.PushNil()
			return 2
		}
		pushGoValue(L, sessionToLua(*s, false))
		L.PushNil()
		return 2
	}
}

// luaLoginResolve: resolve(id, state, account, message) -> (true, nil) | (nil, err)
func luaLoginResolve(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		id := L.ToString(1)
		state := LoginSessionState(L.ToString(2))
		account := L.ToString(3)
		message := L.ToString(4)
		s, ok := ps.GetLogin(id)
		if !ok || s.Plugin != name {
			L.PushNil()
			L.PushString("no such login session")
			return 2
		}
		if err := ps.ResolveLogin(id, state, account, message); err != nil {
			L.PushNil()
			L.PushString(err.Error())
			return 2
		}
		L.PushBoolean(true)
		L.PushNil()
		return 2
	}
}

// luaLoginList: list() -> (array of sessions, nil)
func luaLoginList(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		sessions := ps.ListLogins(name)
		L.NewTable()
		for i, s := range sessions {
			pushGoValue(L, sessionToLua(s, false))
			L.RawSeti(-2, i+1)
		}
		L.PushNil()
		return 2
	}
}

// luaLoginCancel: cancel(id) -> (true, nil)
func luaLoginCancel(ps *Plugins, name string) golua.LuaGoFunction {
	return func(L *golua.State) int {
		id := L.ToString(1)
		s, ok := ps.GetLogin(id)
		if ok && s.Plugin == name {
			_ = ps.ResolveLogin(id, LoginCancelled, "", "cancelled by the plugin")
		}
		L.PushBoolean(true)
		L.PushNil()
		return 2
	}
}

// sessionToLua renders a session for Lua. The nonce is included ONLY on begin
// (the plugin needs it to build its redirect_uri); subsequent reads omit it so a
// plugin that logs or forwards a session cannot leak the CSRF token.
func sessionToLua(s LoginSession, includeNonce bool) map[string]interface{} {
	out := map[string]interface{}{
		"id":         s.ID,
		"platform":   s.Platform,
		"flow":       string(s.Flow),
		"state":      string(s.State),
		"url":        s.URL,
		"user_code":  s.UserCode,
		"message":    s.Message,
		"account":    s.Account,
		"created_at": s.CreatedAt.Unix(),
		"expires_at": s.ExpiresAt.Unix(),
	}
	if includeNonce {
		out["nonce"] = s.Nonce
	}
	return out
}

// luaTableArg decodes a Lua table argument into a Go map, reporting a clear error
// when the caller passed something else (a common mistake that would otherwise
// surface as a silent zero value).
func luaTableArg(L *golua.State, idx int) (map[string]interface{}, error) {
	if L.Type(idx) != golua.LUA_TTABLE {
		return nil, fmt.Errorf("expected a table argument, got %s", normalizeString(L, idx))
	}
	var raw interface{}
	if err := luaToJSON(L, idx, &raw); err != nil {
		return nil, err
	}
	m, ok := raw.(map[string]interface{})
	if !ok {
		return nil, fmt.Errorf("argument must be a keyed table")
	}
	return m, nil
}

// readPluginAuthHosts reads `plugin.auth_hosts`, the login hosts a plugin needs.
//
//	plugin.auth_hosts = { "auth.example.com", "accounts.google.com" }
//
// A list of bare hostnames — not URLs — because the allowlist matches on host,
// and accepting full URLs would invite a plugin to smuggle a path or scheme that
// the operator did not read. Entries are normalised so the granted and declared
// forms always compare equal.
func readPluginAuthHosts(L *golua.State) []string {
	raw, ok := pluginFieldValue(L, "auth_hosts")
	if !ok {
		return nil
	}
	items, isList := raw.([]interface{})
	if !isList {
		if one, isTable := raw.(map[string]interface{}); isTable {
			if v, ok := one["hosts"].([]interface{}); ok {
				items = v
			} else {
				return nil
			}
		} else {
			return nil
		}
	}
	out := make([]string, 0, len(items))
	seen := map[string]bool{}
	for _, it := range items {
		s, ok := it.(string)
		if !ok {
			continue
		}
		h := normalizeHost(s)
		if h == "" || seen[h] {
			continue
		}
		seen[h] = true
		out = append(out, h)
	}
	sort.Strings(out)
	return out
}