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 ListeningMode int64

func (lm ListeningMode) String() string {
	mapping := map[ListeningMode]string{
		ModeNet:  "net",
		ModeUnix: "unix",
	}
	val := mapping[lm]
	return val
}

func listeningModeFromString(rawVal string) (ListeningMode, error) {
	mapping := map[string]ListeningMode{
		"unix": ModeUnix,
		"net":  ModeNet,
	}
	if typedVal, ok := mapping[rawVal]; !ok {
		return ModeNet, fmt.Errorf("invalid listening mode %s", rawVal)
	} else {
		return typedVal, nil
	}
}

const (
	ModeUnix ListeningMode = iota
	ModeNet
)

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

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

type jsonConf struct {
	Log struct {
		Level string `json:"level"`
	} `json:"log"`
	Server struct {
		Host     string `json:"host"`
		Port     int    `json:"port"`
		Mode     string `json:"mode"`
		SockPath string `json:"sock"`
	} `json:"server"`
	OpenConnectConfig *OpenConnectConfig `json:"openconnect"`
}

type AppConfig struct {
	LogLevel          logrus.Level
	ServerMode        ListeningMode
	Host              string
	Port              int
	SockPath          string
	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.LogLevel = parseLevel(jsonConf.Log.Level)

	lm, err := listeningModeFromString(jsonConf.Server.Mode)
	if err != nil {
		return fmt.Errorf("failed to parse server listening mode: %w", err)
	}

	ac.ServerMode = lm
	ac.SockPath = jsonConf.Server.SockPath
	ac.Host = jsonConf.Server.Host
	ac.Port = jsonConf.Server.Port
	ac.OpenConnectConfig = jsonConf.OpenConnectConfig
	return nil
}

var defaultConfig AppConfig = AppConfig{
	LogLevel:   logrus.InfoLevel,
	ServerMode: ModeNet,
	Host:       "0.0.0.0",
	Port:       5000,
}

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