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
	AtomFeed     string
	FirebaseKey  string
	KeyFile      string
	Link         string
	LogFile      string
	PDFDir       string
	PicsDir      string
	Port         string
	RSSFile      string
	Title        string
	WebDir       string
	MaxImgHeight int
	MaxImgWidth  int
}

func newConfig() *Config {
	return &Config{
		ArticleDir:   "/var/www/cpolis/articles",
		ConfigFile:   "/etc/cpolis/config.toml",
		DBName:       "cpolis",
		AtomFeed:     "/var/www/cpolis/cpolis.atom",
		FirebaseKey:  "/var/www/cpolis/serviceAccountKey.json",
		KeyFile:      "/var/www/cpolis/cpolis.key",
		LogFile:      "/var/log/cpolis.log",
		MaxImgHeight: 1080,
		MaxImgWidth:  1920,
		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.AtomFeed, "feed", c.AtomFeed, "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.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(&c.MaxImgHeight, "height", c.MaxImgHeight, "maximum image height")
	flag.IntVar(&c.MaxImgWidth, "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.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.AtomFeed != defaultConfig.AtomFeed {
		c.AtomFeed = cliConfig.AtomFeed
	}
	c.AtomFeed, err = mkFile(c.AtomFeed, 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.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.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.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
}