package config

import (
	"encoding/json"
	"errors"
	"fmt"
	"io/fs"
	"os"

	"github.com/dexidp/dex/connector/oidc"
	"github.com/dexidp/dex/storage"
	"github.com/sirupsen/logrus"
)

type envVar string

const (
	varLogLevel envVar = "LOG_LEVEL"

	varServerMode   envVar = "SERVER_MODE"
	varServerHost   envVar = "SERVER_HOST"
	varServerPort   envVar = "SERVER_PORT"
	varServerSocket envVar = "SERVER_SOCK_PATH"

	varStorageType      envVar = "STORAGE_TYPE"
	varStorageFile      envVar = "STORAGE_FILEPATH"
	varStorageHost      envVar = "STORAGE_HOST"
	varStoragePort      envVar = "STORAGE_PORT"
	varStorageDB        envVar = "STORAGE_DB"
	varStorageUser      envVar = "STORAGE_USER"
	varStoragePassword  envVar = "STORAGE_PASSWORD"
	varStorageSSLMode   envVar = "STORAGE_SSL_MODE"
	varStorageSSLCaFile envVar = "STORAGE_SSL_CA_FILE"
)

type ListeningMode string

const (
	ModeUnix ListeningMode = "unix"
	ModeNet  ListeningMode = "net"
)

type BackendConfigType string

const (
	Memory BackendConfigType = "memory"
	SQLite BackendConfigType = "sqlite"
)

const (
	defaultLogLevel = logrus.InfoLevel

	defaultServerMode   = ModeNet
	defaultServerHost   = "0.0.0.0"
	defaultServerPort   = 5000
	defaultServerSocket = ""

	defaultStorageType      = Memory
	defaultStorageFile      = "./polyculeconnect.db"
	defaultStorageHost      = "127.0.0.1"
	defaultStoragePort      = 5432
	defaultStorageDB        = "polyculeconnect"
	defaultStorageUser      = "polyculeconnect"
	defaultStoragePassword  = "polyculeconnect"
	defaultStorageSSLMode   = "disable"
	defaultStorageSSLCaFile = ""
)

type BackendConfig struct {
	Config *oidc.Config      `json:"config"`
	Name   string            `json:"name"`
	ID     string            `json:"ID"`
	Type   BackendConfigType `json:"type"`
	Local  bool              `json:"local"`
}

type OpenConnectConfig struct {
	ClientConfigs  []*storage.Client `json:"clients"`
	BackendConfigs []*BackendConfig  `json:"backends"`
	Issuer         string            `json:"issuer"`
}

type StorageConfig struct {
	File     string
	Host     string
	Port     int
	Database string
	User     string
	Password string
	Ssl      struct {
		Mode   string
		CaFile string
	}
}

type jsonConf struct {
	OpenConnectConfig *OpenConnectConfig `json:"openconnect"`
}

type AppConfig struct {
	LogLevel          logrus.Level
	ServerMode        ListeningMode
	Host              string
	Port              int
	SockPath          string
	StorageType       string
	StorageConfig     *StorageConfig
	OpenConnectConfig *OpenConnectConfig
}

func parseLevel(lvlStr string) logrus.Level {
	for _, lvl := range logrus.AllLevels {
		if lvl.String() == lvlStr {
			return lvl
		}
	}
	return logrus.InfoLevel
}

func (ac *AppConfig) UnmarshalJSON(data []byte) error {
	var jsonConf jsonConf
	if err := json.Unmarshal(data, &jsonConf); err != nil {
		return fmt.Errorf("failed to read JSON: %w", err)
	}
	ac.OpenConnectConfig = jsonConf.OpenConnectConfig
	return nil
}

func (ac *AppConfig) getConfFromEnv() {
	ac.LogLevel = parseLevel(getStringFromEnv(varLogLevel, defaultLogLevel.String()))

	ac.ServerMode = ListeningMode(getStringFromEnv(varServerMode, string(defaultServerMode)))
	ac.Host = getStringFromEnv(varServerHost, defaultServerHost)
	ac.Port = getIntFromEnv(varServerPort, defaultServerPort)
	ac.SockPath = getStringFromEnv(varServerSocket, defaultServerSocket)

	ac.StorageType = getStringFromEnv(varStorageType, string(defaultStorageType))
	ac.StorageConfig.Database = getStringFromEnv(varStorageDB, defaultStorageDB)
	ac.StorageConfig.File = getStringFromEnv(varStorageFile, defaultStorageFile)
	ac.StorageConfig.Host = getStringFromEnv(varStorageHost, defaultStorageHost)
	ac.StorageConfig.Port = getIntFromEnv(varStoragePort, defaultStoragePort)
	ac.StorageConfig.User = getStringFromEnv(varStorageUser, defaultStorageUser)
	ac.StorageConfig.Password = getStringFromEnv(varStoragePassword, defaultStoragePassword)
	ac.StorageConfig.Ssl.CaFile = getStringFromEnv(varStorageSSLCaFile, defaultStorageSSLCaFile)
	ac.StorageConfig.Ssl.Mode = getStringFromEnv(varStorageSSLMode, defaultStorageSSLMode)
}

func New(filepath string) (*AppConfig, error) {
	var conf AppConfig
	conf.StorageConfig = &StorageConfig{}
	content, err := os.ReadFile(filepath)
	if err != nil {
		if !errors.Is(err, fs.ErrNotExist) {
			return nil, fmt.Errorf("failed to read config file %q: %w", filepath, err)
		}
	} else {
		if err := json.Unmarshal(content, &conf); err != nil {
			return nil, fmt.Errorf("failed to parse config file: %w", err)
		}
	}
	conf.getConfFromEnv()
	return &conf, nil
}