package backend

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

	"github.com/BurntSushi/toml"
)

type Config struct {
	ArticleDir  string
	ConfigFile  string
	DBName      string
	Description string
	Domain      string
	FirebaseKey string
	KeyFile     string
	Link        string
	LogFile     string
	PDFDir      string
	PicsDir     string
	Port        string
	RSSFile     string
	Title       string
	WebDir      string
}

func newConfig() *Config {
	return &Config{
		ArticleDir:  "/var/www/cpolis/articles",
		ConfigFile:  "/etc/cpolis/config.toml",
		DBName:      "cpolis",
		FirebaseKey: "/var/www/cpolis/serviceAccountKey.json",
		KeyFile:     "/var/www/cpolis/cpolis.key",
		LogFile:     "/var/log/cpolis.log",
		PDFDir:      "/var/www/cpolis/pdfs",
		PicsDir:     "/var/www/cpolis/pics",
		Port:        ":8080",
		RSSFile:     "/var/www/cpolis/cpolis.rss",
		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.ArticleDir, "articles", c.ArticleDir, "articles directory")
	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.KeyFile, "key", c.KeyFile, "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.RSSFile, "rss", c.RSSFile, "RSS file")
	flag.StringVar(&c.Title, "title", c.Title, "channel title")
	flag.StringVar(&c.WebDir, "web", c.WebDir, "web directory")
	flag.IntVar(&port, "port", port, "port")
	flag.Parse()

	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.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
	}

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

	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
}