package backend

import (
	"flag"
	"fmt"
	"io/fs"
	"os"
	"path/filepath"
	"strings"

	"github.com/BurntSushi/toml"
)

type Config struct {
	AESKeyFile      string
	ArticleDir      string
	ConfigFile      string
	DBName          string
	Description     string
	Domain          string
	AtomFile        string
	FirebaseKey     string
	GOBKeyFile      string
	Link            string
	LogFile         string
	PDFDir          string
	PicsDir         string
	Port            string
	Title           string
	Version         string
	WebDir          string
	MaxBannerHeight int
	MaxBannerWidth  int
	MaxImgHeight    int
	MaxImgWidth     int
}

func newConfig() *Config {
	return &Config{
		AESKeyFile:      "/var/www/cpolis/aes.key",
		ArticleDir:      "/var/www/cpolis/articles",
		AtomFile:        "/var/www/cpolis/cpolis.atom",
		ConfigFile:      "/etc/cpolis/config.toml",
		DBName:          "cpolis",
		FirebaseKey:     "/var/www/cpolis/serviceAccountKey.json",
		GOBKeyFile:      "/var/www/cpolis/gob.key",
		LogFile:         "/var/log/cpolis.log",
		MaxBannerHeight: 1080,
		MaxBannerWidth:  1920,
		MaxImgHeight:    1080,
		MaxImgWidth:     1920,
		PDFDir:          "/var/www/cpolis/pdfs",
		PicsDir:         "/var/www/cpolis/pics",
		Port:            ":8080",
		Version:         "v0.13.2",
		WebDir:          "/var/www/cpolis/web",
	}
}

func mkDir(path string, perm fs.FileMode) (string, error) {
	var err error

	stringSlice := strings.Split(path, "/")
	name := stringSlice[len(stringSlice)-1]

	path, err = filepath.Abs(path)
	if err != nil {
		return "", fmt.Errorf("error finding absolute path for %v directory: %v", name, err)
	}
	if err = os.MkdirAll(path, perm); err != nil {
		return "", fmt.Errorf("error creating %v directory: %v", name, err)
	}

	return path, nil
}

func mkFile(path string, filePerm, dirPerm fs.FileMode) (string, error) {
	var err error

	path, err = filepath.Abs(path)
	if err != nil {
		return "", fmt.Errorf("error finding absolute path for %v: %v", path, err)
	}

	stringSlice := strings.Split(path, "/")
	_, err = os.Stat(path)
	if os.IsNotExist(err) {
		dir := strings.Join(stringSlice[:len(stringSlice)-1], "/")
		if err = os.MkdirAll(dir, dirPerm); err != nil {
			return "", fmt.Errorf("error creating %v: %v", dir, err)
		}

		fileName := stringSlice[len(stringSlice)-1]
		file, err := os.Create(dir + "/" + fileName)
		if err != nil {
			return "", fmt.Errorf("error creating %v: %v", fileName, err)
		}
		defer file.Close()
		if err = file.Chmod(filePerm); err != nil {
			return "", fmt.Errorf("error setting permissions for %v: %v", fileName, err)
		}
	}

	return path, nil
}

func (c *Config) handleCliArgs() error {
	var port int
	var err error

	flag.StringVar(&c.AESKeyFile, "aes", c.AESKeyFile, "aes key file")
	flag.StringVar(&c.ArticleDir, "articles", c.ArticleDir, "articles directory")
	flag.StringVar(&c.AtomFile, "feed", c.AtomFile, "atom feed file")
	flag.StringVar(&c.ConfigFile, "config", c.ConfigFile, "config file")
	flag.StringVar(&c.DBName, "db", c.DBName, "DB name")
	flag.StringVar(&c.Description, "desc", c.Description, "channel description")
	flag.StringVar(&c.Domain, "domain", c.Domain, "domain name")
	flag.StringVar(&c.FirebaseKey, "firebase", c.FirebaseKey, "Firebase service account key file")
	flag.StringVar(&c.GOBKeyFile, "gob", c.GOBKeyFile, "gob key file")
	flag.StringVar(&c.Link, "link", c.Link, "channel Link")
	flag.StringVar(&c.LogFile, "log", c.LogFile, "log file")
	flag.StringVar(&c.PDFDir, "pdfs", c.PDFDir, "pdf directory")
	flag.StringVar(&c.PicsDir, "pics", c.PicsDir, "pictures directory")
	flag.StringVar(&c.Title, "title", c.Title, "channel title")
	flag.StringVar(&c.WebDir, "web", c.WebDir, "web directory")
	flag.IntVar(&c.MaxBannerHeight, "banner-height", c.MaxBannerHeight, "maximum banner height")
	flag.IntVar(&c.MaxBannerWidth, "banner-width", c.MaxBannerWidth, "maximum banner width")
	flag.IntVar(&c.MaxImgHeight, "img-height", c.MaxImgHeight, "maximum image height")
	flag.IntVar(&c.MaxImgWidth, "img-width", c.MaxImgWidth, "maximum image width")
	flag.IntVar(&port, "port", port, "port")
	flag.Parse()

	if port != 0 {
		c.Port = fmt.Sprint(":", port)
	}

	c.ConfigFile, err = mkFile(c.ConfigFile, 0600, 0700)
	if err != nil {
		return fmt.Errorf("error setting up file: %v", err)
	}

	return nil
}

func (c *Config) handleFile(configFile string) error {
	_, err := toml.DecodeFile(configFile, c)
	if err != nil {
		return fmt.Errorf("error reading config file: %v", err)
	}

	return nil
}

func (c *Config) setupConfig(cliConfig *Config) error {
	var err error
	defaultConfig := newConfig()

	if cliConfig.AESKeyFile != defaultConfig.AESKeyFile {
		c.AESKeyFile = cliConfig.AESKeyFile
	}
	c.AESKeyFile, err = mkFile(c.AESKeyFile, 0600, 0700)
	if err != nil {
		return fmt.Errorf("error setting up file: %v", err)
	}

	if cliConfig.ArticleDir != defaultConfig.ArticleDir {
		c.ArticleDir = cliConfig.ArticleDir
	}
	c.ArticleDir, err = mkDir(c.ArticleDir, 0700)
	if err != nil {
		return fmt.Errorf("error setting up directory: %v", err)
	}

	if cliConfig.DBName != defaultConfig.DBName {
		c.DBName = cliConfig.DBName
	}

	if cliConfig.Description != defaultConfig.Description {
		c.Description = cliConfig.Description
	}

	if cliConfig.Domain != defaultConfig.Domain {
		c.Domain = cliConfig.Domain
	}
	domainStrings := strings.Split(c.Domain, "/")
	if domainStrings[0] != "http:" && domainStrings[0] != "https:" {
		c.Domain = "https://" + c.Domain
	}

	if cliConfig.AtomFile != defaultConfig.AtomFile {
		c.AtomFile = cliConfig.AtomFile
	}
	c.AtomFile, err = mkFile(c.AtomFile, 0644, 0744)
	if err != nil {
		return fmt.Errorf("error setting up file: %v", err)
	}

	if cliConfig.FirebaseKey != defaultConfig.FirebaseKey {
		c.FirebaseKey = cliConfig.FirebaseKey
	}
	c.FirebaseKey, err = mkFile(c.FirebaseKey, 0600, 0700)
	if err != nil {
		return fmt.Errorf("error setting up file: %v", err)
	}

	if cliConfig.GOBKeyFile != defaultConfig.GOBKeyFile {
		c.GOBKeyFile = cliConfig.GOBKeyFile
	}
	c.GOBKeyFile, err = mkFile(c.GOBKeyFile, 0600, 0700)
	if err != nil {
		return fmt.Errorf("error setting up file: %v", err)
	}

	if cliConfig.Link != defaultConfig.Link {
		c.Link = cliConfig.Link
	}

	if cliConfig.LogFile != defaultConfig.LogFile {
		c.LogFile = cliConfig.LogFile
	}
	c.LogFile, err = mkFile(c.LogFile, 0600, 0700)
	if err != nil {
		return fmt.Errorf("error setting up file: %v", err)
	}

	if cliConfig.MaxBannerHeight != defaultConfig.MaxBannerHeight {
		c.MaxBannerHeight = cliConfig.MaxBannerHeight
	}

	if cliConfig.MaxBannerWidth != defaultConfig.MaxBannerWidth {
		c.MaxBannerWidth = cliConfig.MaxBannerWidth
	}

	if cliConfig.MaxImgHeight != defaultConfig.MaxImgHeight {
		c.MaxImgHeight = cliConfig.MaxImgHeight
	}

	if cliConfig.MaxImgWidth != defaultConfig.MaxImgWidth {
		c.MaxImgWidth = cliConfig.MaxImgWidth
	}

	if cliConfig.PDFDir != defaultConfig.PDFDir {
		c.PDFDir = cliConfig.PDFDir
	}
	c.PDFDir, err = mkDir(c.PDFDir, 0700)
	if err != nil {
		return fmt.Errorf("error setting up directory: %v", err)
	}

	if cliConfig.PicsDir != defaultConfig.PicsDir {
		c.PicsDir = cliConfig.PicsDir
	}
	c.PicsDir, err = mkDir(c.PicsDir, 0700)
	if err != nil {
		return fmt.Errorf("error setting up directory: %v", err)
	}

	if cliConfig.Port != defaultConfig.Port {
		c.Port = cliConfig.Port
	}

	if cliConfig.Title != defaultConfig.Title {
		c.Title = cliConfig.Title
	}

	if cliConfig.WebDir != defaultConfig.WebDir {
		c.WebDir = cliConfig.WebDir
	}
	c.WebDir, err = mkDir(c.WebDir, 0700)
	if err != nil {
		return fmt.Errorf("error setting up directory: %v", err)
	}

	return nil
}

func HandleConfig() (*Config, error) {
	config := newConfig()
	cliConfig := newConfig()

	if err := cliConfig.handleCliArgs(); err != nil {
		return nil, fmt.Errorf("error handling cli arguments: %v", err)
	}

	err := config.handleFile(cliConfig.ConfigFile)
	if err != nil {
		return nil, fmt.Errorf("error reading configuration file: %v", err)
	}

	if err = config.setupConfig(cliConfig); err != nil {
		return nil, fmt.Errorf("error setting up files: %v", err)
	}

	return config, nil
}