package config

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

	"github.com/spf13/pflag"
	"github.com/spf13/viper"

	"github.com/stashapp/stash/pkg/fsutil"
	"github.com/stashapp/stash/pkg/logger"
)

type flagStruct struct {
	configFilePath string
	nobrowser      bool
}

var flags flagStruct

func init() {
	pflag.IP("host", net.IPv4(0, 0, 0, 0), "ip address for the host")
	pflag.Int("port", 9999, "port to serve from")
	pflag.StringVarP(&flags.configFilePath, "config", "c", "", "config file to use")
	pflag.BoolVar(&flags.nobrowser, "nobrowser", false, "Don't open a browser window after launch")
}

// Called at startup
func Initialize() (*Config, error) {
	cfg := &Config{
		main:      viper.New(),
		overrides: viper.New(),
	}

	cfg.initOverrides()

	err := cfg.initConfig()
	if err != nil {
		return nil, err
	}

	if cfg.isNewSystem {
		if cfg.Validate() == nil {
			// system has been initialised by the environment
			cfg.isNewSystem = false
		}
	}

	if !cfg.isNewSystem {
		cfg.setExistingSystemDefaults()

		err := cfg.SetInitialConfig()
		if err != nil {
			return nil, err
		}

		err = cfg.Write()
		if err != nil {
			return nil, err
		}

		err = cfg.Validate()
		if err != nil {
			return nil, err
		}
	}

	instance = cfg
	return instance, nil
}

// Called by tests to initialize an empty config
func InitializeEmpty() *Config {
	cfg := &Config{
		main:      viper.New(),
		overrides: viper.New(),
	}
	instance = cfg
	return instance
}

func bindEnv(v *viper.Viper, key string) {
	if err := v.BindEnv(key); err != nil {
		panic(fmt.Sprintf("unable to set environment key (%v): %v", key, err))
	}
}

func (i *Config) initOverrides() {
	v := i.overrides

	if err := v.BindPFlags(pflag.CommandLine); err != nil {
		logger.Infof("failed to bind flags: %v", err)
	}

	v.SetEnvPrefix("stash")     // will be uppercased automatically
	bindEnv(v, "host")          // STASH_HOST
	bindEnv(v, "port")          // STASH_PORT
	bindEnv(v, "external_host") // STASH_EXTERNAL_HOST
	bindEnv(v, "generated")     // STASH_GENERATED
	bindEnv(v, "metadata")      // STASH_METADATA
	bindEnv(v, "cache")         // STASH_CACHE
	bindEnv(v, "stash")         // STASH_STASH
}

func (i *Config) initConfig() error {
	v := i.main

	// The config file is called config.  Leave off the file extension.
	v.SetConfigName("config")

	v.AddConfigPath(".")                                // Look for config in the working directory
	v.AddConfigPath(filepath.FromSlash("$HOME/.stash")) // Look for the config in the home directory

	configFile := ""
	envConfigFile := os.Getenv("STASH_CONFIG_FILE")

	if flags.configFilePath != "" {
		configFile = flags.configFilePath
	} else if envConfigFile != "" {
		configFile = envConfigFile
	}

	if configFile != "" {
		v.SetConfigFile(configFile)

		// if file does not exist, assume it is a new system
		if exists, _ := fsutil.FileExists(configFile); !exists {
			i.isNewSystem = true

			// ensure we can write to the file
			if err := fsutil.Touch(configFile); err != nil {
				return fmt.Errorf(`could not write to provided config path "%s": %v`, configFile, err)
			} else {
				// remove the file
				os.Remove(configFile)
			}

			return nil
		}
	}

	err := v.ReadInConfig() // Find and read the config file
	// if not found, assume its a new system
	var notFoundErr viper.ConfigFileNotFoundError
	if errors.As(err, &notFoundErr) {
		i.isNewSystem = true
		return nil
	} else if err != nil {
		return err
	}

	return nil
}