package loopd

import (
	"fmt"
	"os"
	"path/filepath"

	"github.com/btcsuite/btcutil"
	"github.com/lightninglabs/loop/lsat"
	"github.com/lightningnetwork/lnd/lncfg"
)

var (
	loopDirBase = btcutil.AppDataDir("loop", false)

	defaultNetwork     = "mainnet"
	defaultLogLevel    = "info"
	defaultLogDirname  = "logs"
	defaultLogFilename = "loopd.log"
	defaultLogDir      = filepath.Join(loopDirBase, defaultLogDirname)
	defaultConfigFile  = filepath.Join(
		loopDirBase, defaultNetwork, defaultConfigFilename,
	)

	defaultMaxLogFiles     = 3
	defaultMaxLogFileSize  = 10
	defaultLoopOutMaxParts = uint32(5)
)

type lndConfig struct {
	Host        string `long:"host" description:"lnd instance rpc address"`
	MacaroonDir string `long:"macaroondir" description:"Path to the directory containing all the required lnd macaroons"`
	TLSPath     string `long:"tlspath" description:"Path to lnd tls certificate"`
}

type loopServerConfig struct {
	Host  string `long:"host" description:"Loop server address host:port"`
	Proxy string `long:"proxy" description:"The host:port of a SOCKS proxy through which all connections to the loop server will be established over"`

	NoTLS   bool   `long:"notls" description:"Disable tls for communication to the loop server [testing only]"`
	TLSPath string `long:"tlspath" description:"Path to loop server tls certificate [testing only]"`
}

type viewParameters struct{}

type Config struct {
	ShowVersion bool   `long:"version" description:"Display version information and exit"`
	Network     string `long:"network" description:"network to run on" choice:"regtest" choice:"testnet" choice:"mainnet" choice:"simnet"`
	RPCListen   string `long:"rpclisten" description:"Address to listen on for gRPC clients"`
	RESTListen  string `long:"restlisten" description:"Address to listen on for REST clients"`
	CORSOrigin  string `long:"corsorigin" description:"The value to send in the Access-Control-Allow-Origin header. Header will be omitted if empty."`

	LoopDir        string `long:"loopdir" description:"The directory for all of loop's data."`
	ConfigFile     string `long:"configfile" description:"Path to configuration file."`
	DataDir        string `long:"datadir" description:"Directory for loopdb."`
	LogDir         string `long:"logdir" description:"Directory to log output."`
	MaxLogFiles    int    `long:"maxlogfiles" description:"Maximum logfiles to keep (0 for no rotation)"`
	MaxLogFileSize int    `long:"maxlogfilesize" description:"Maximum logfile size in MB"`

	DebugLevel  string `long:"debuglevel" description:"Logging level for all subsystems {trace, debug, info, warn, error, critical} -- You may also specify <subsystem>=<level>,<subsystem2>=<level>,... to set the log level for individual subsystems -- Use show to list available subsystems"`
	MaxLSATCost uint32 `long:"maxlsatcost" description:"Maximum cost in satoshis that loopd is going to pay for an LSAT token automatically. Does not include routing fees."`
	MaxLSATFee  uint32 `long:"maxlsatfee" description:"Maximum routing fee in satoshis that we are willing to pay while paying for an LSAT token."`

	LoopOutMaxParts uint32 `long:"loopoutmaxparts" description:"The maximum number of payment parts that may be used for a loop out swap."`

	Lnd *lndConfig `group:"lnd" namespace:"lnd"`

	Server *loopServerConfig `group:"server" namespace:"server"`

	View viewParameters `command:"view" alias:"v" description:"View all swaps in the database. This command can only be executed when loopd is not running."`
}

const (
	mainnetServer = "swap.lightning.today:11010"
	testnetServer = "test.swap.lightning.today:11010"
)

// DefaultConfig returns all default values for the Config struct.
func DefaultConfig() Config {
	return Config{
		Network:    defaultNetwork,
		RPCListen:  "localhost:11010",
		RESTListen: "localhost:8081",
		Server: &loopServerConfig{
			NoTLS: false,
		},
		LoopDir:         loopDirBase,
		ConfigFile:      defaultConfigFile,
		DataDir:         loopDirBase,
		LogDir:          defaultLogDir,
		MaxLogFiles:     defaultMaxLogFiles,
		MaxLogFileSize:  defaultMaxLogFileSize,
		DebugLevel:      defaultLogLevel,
		MaxLSATCost:     lsat.DefaultMaxCostSats,
		MaxLSATFee:      lsat.DefaultMaxRoutingFeeSats,
		LoopOutMaxParts: defaultLoopOutMaxParts,
		Lnd: &lndConfig{
			Host: "localhost:10009",
		},
	}
}

// Validate cleans up paths in the config provided and validates it.
func Validate(cfg *Config) error {
	// Cleanup any paths before we use them.
	cfg.LoopDir = lncfg.CleanAndExpandPath(cfg.LoopDir)
	cfg.DataDir = lncfg.CleanAndExpandPath(cfg.DataDir)
	cfg.LogDir = lncfg.CleanAndExpandPath(cfg.LogDir)

	// Since our loop directory overrides our log/data dir values, make sure
	// that they are not set when loop dir is set. We hard here rather than
	// overwriting and potentially confusing the user.
	logDirSet := cfg.LogDir != defaultLogDir
	dataDirSet := cfg.DataDir != loopDirBase
	loopDirSet := cfg.LoopDir != loopDirBase

	if loopDirSet {
		if logDirSet {
			return fmt.Errorf("loopdir overwrites logdir, please " +
				"only set one value")
		}

		if dataDirSet {
			return fmt.Errorf("loopdir overwrites datadir, please " +
				"only set one value")
		}

		// Once we are satisfied that neither config value was set, we
		// replace them with our loop dir.
		cfg.DataDir = cfg.LoopDir
		cfg.LogDir = filepath.Join(cfg.LoopDir, defaultLogDirname)
	}

	// Append the network type to the data and log directory so they are
	// "namespaced" per network.
	cfg.DataDir = filepath.Join(cfg.DataDir, cfg.Network)
	cfg.LogDir = filepath.Join(cfg.LogDir, cfg.Network)

	// If either of these directories do not exist, create them.
	if err := os.MkdirAll(cfg.DataDir, os.ModePerm); err != nil {
		return err
	}

	if err := os.MkdirAll(cfg.LogDir, os.ModePerm); err != nil {
		return err
	}

	return nil
}