package oauth

import (
	"cs-bridge/internal/auth"
	"cs-bridge/pkg/lua"
	"fmt"

	lua2 "github.com/yuin/gopher-lua"
)

type LuaProvider struct {
	model       ProviderModel
	engine      *lua.Engine
	redirectURI string
}

// NewLuaProvider creates a new Lua-based provider
func NewLuaProvider(model ProviderModel, redirectURI, scriptPath string) (*LuaProvider, error) {
	engine := lua.New()

	// Register all API modules (http, json, log, util)
	engine.RegisterAPI()

	// Load the Lua script
	if err := engine.LoadFile(scriptPath); err != nil {
		engine.Close()
		return nil, err
	}

	return &LuaProvider{
		model:       model,
		engine:      engine,
		redirectURI: redirectURI,
	}, nil
}

// Close cleans up the Lua engine
func (p *LuaProvider) Close() {
	p.engine.Close()
}

// Name implements [Provider].
func (p *LuaProvider) Name() string {
	return p.model.Name
}

// luaConfig constructs the config table passed to Lua functions
func (p *LuaProvider) luaConfig() *lua2.LTable {
	L := p.engine.L
	config := L.NewTable()
	config.RawSetString("client_id", lua2.LString(p.model.ClientID))
	config.RawSetString("client_secret", lua2.LString(p.model.ClientSecret))
	config.RawSetString("base_url", lua2.LString(p.model.BaseURL))
	config.RawSetString("authorize_url", lua2.LString(p.model.AuthorizeURL))
	config.RawSetString("token_url", lua2.LString(p.model.TokenURL))
	config.RawSetString("user_url", lua2.LString(p.model.UserURL))
	config.RawSetString("redirect_uri", lua2.LString(p.redirectURI))
	return config
}

// AuthURL implements [Provider].
func (p *LuaProvider) AuthURL(state string) (string, error) {
	cfg := p.luaConfig()
	return p.engine.CallString("auth_url", cfg, lua2.LString(state))
}

// Exchange implements [Provider].
func (p *LuaProvider) Exchange(code string) (string, error) {
	cfg := p.luaConfig()
	return p.engine.CallString("exchange", cfg, lua2.LString(code))
}

// UserInfo implements [Provider].
func (p *LuaProvider) UserInfo(token string) (auth.Identify, error) {
	cfg := p.luaConfig()

	var userInfo auth.Identify
	if err := p.engine.CallStruct("user_info", &userInfo, cfg, lua2.LString(token)); err != nil {
		return auth.Identify{}, fmt.Errorf("failed to get user info: %w", err)
	}

	// Set the provider name
	userInfo.Provider = p.model.Name

	return userInfo, nil
}