package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io/ioutil"
	"os"
	"strconv"
	"strings"

	"github.com/BurntSushi/toml"
)

type AppConfig struct {
	StorageDir string `toml:"storage_dir"`
	ApiToken   string `toml:"api_token"`
	ApiSecret  string `toml:"api_secret"`
	AppToken   string `toml:"app_token"`
	AppSecret  string `toml:"app_secret"`

	PullCount     int  `toml:"-"`
	ForceDownload bool `toml:"-"`
	Verbose       bool `toml:"-"`
}

func NewAppConfig(args []string) (*AppConfig, error) {
	fmt.Println("Initializing App...")
	c := &AppConfig{}
	if err := c.ProcessArgs(args); err != nil {
		return nil, err
	}
	if err := c.Load(); err != nil {
		return nil, err
	}
	return c, c.VerifyConfig()
}

func (c *AppConfig) ProcessArgs(args []string) error {
	var err error
	for _, arg := range args {
		var k, v string
		if strings.ContainsRune(arg, '=') {
			k = arg[:strings.Index(arg, "=")]
			v = arg[strings.Index(arg, "=")+1:]
		} else {
			k = arg
		}
		switch k {
		case "-count", "-c":
			c.PullCount, err = strconv.Atoi(v)
			if err != nil {
				return fmt.Errorf("Invalid Count (%s): %w", v, err)
			}
			fmt.Printf("Pulling %d tweets", c.PullCount)
		case "-force", "-f":
			c.ForceDownload = true
			fmt.Println("Forcing Downloads")
		case "-help", "-h":
			PrintUsageAndExit()
		case "-verbose", "-v":
			c.Verbose = true
		}
	}
	return nil
}

func (c *AppConfig) Load() error {
	cfgPath := AppName + ".conf"
	tomlData, err := ioutil.ReadFile(cfgPath)
	if err != nil {
		if err = c.Save(); err != nil {
			return err
		}
	}
	if _, err := toml.Decode(string(tomlData), &c); err != nil {
		return err
	}
	return nil
}

func (c *AppConfig) Save() error {
	buf := new(bytes.Buffer)
	cfgPath := AppName + ".conf"
	if err := toml.NewEncoder(buf).Encode(c); err != nil {
		return err
	}
	return ioutil.WriteFile(cfgPath, buf.Bytes(), 0644)
}

func (c *AppConfig) VerifyConfig() error {
	configChanged := false
	if c.ApiToken == "" {
		c.ApiToken = GetDataFromUser("API Token")
		configChanged = true
	}
	if c.ApiSecret == "" {
		c.ApiSecret = GetDataFromUser("API Secret")
		configChanged = true
	}
	if c.AppToken == "" {
		c.AppToken = GetDataFromUser("App Token")
		configChanged = true
	}
	if c.AppSecret == "" {
		c.AppSecret = GetDataFromUser("App Secret")
		configChanged = true
	}
	exist, err := FileExists(c.StorageDir)
	for c.StorageDir == "" || err != nil || !exist {
		// Check if the storage directory exists
		c.StorageDir = GetDataFromUser("Image Download Directory")
		configChanged = true
		exist, err = FileExists(c.StorageDir)
	}
	if configChanged {
		return c.Save()
	}
	fmt.Println("Screenshot Directory:", c.StorageDir)
	return nil
}

func (c *AppConfig) GetFilePath(filename string) string {
	return c.StorageDir + string(os.PathSeparator) + filename
}

func GetDataFromUser(label string) string {
	reader := bufio.NewReader(os.Stdin)
	var res string
	for res == "" {
		fmt.Println(label + ": ")
		res, _ = reader.ReadString('\n')
		res = strings.TrimSpace(res)
		if res == "" {
			fmt.Println("Non-empty response is required")
		}
	}
	return res
}

func FileExists(path string) (bool, error) {
	_, err := os.Stat(path)
	if err == nil {
		return true, nil
	}
	if os.IsNotExist(err) {
		return false, nil
	}
	return true, err
}