package main

import (
	"bufio"
	"errors"
	"fmt"
	"net/url"
	"os"
	"path/filepath"
	"strings"
	"syscall"

	"github.com/BurntSushi/toml"
)

type Config struct {
	DefaultScheme  string `toml:"default_scheme"`
	SoftWrap       int    `toml:"soft_wrap"`
	DownloadFolder string `toml:"download_folder"`
	VimKeys        bool   `toml:"vim_keys"`
}

func getConfig() (*Config, error) {
	home := os.Getenv("HOME")
	path := os.Getenv("XDG_CONFIG_HOME")
	if path == "" {
		path = filepath.Join(home, ".config")
	}
	path = filepath.Join(path, "x-1", "config.toml")

	if err := ensurePath(path); err != nil {
		return nil, err
	}

	c := Config{
		VimKeys:        true,
		DefaultScheme:  "gemini",
		SoftWrap:       80,
		DownloadFolder: home,
	}
	if _, err := toml.DecodeFile(path, &c); err != nil {
		return nil, err
	}
	if strings.HasPrefix(c.DownloadFolder, "~") {
		c.DownloadFolder = home + c.DownloadFolder[1:]
	}
	return &c, nil
}

func getMarks() (map[string]string, error) {
	path, err := marksFilePath()
	if err != nil {
		return nil, err
	}

	marks := make(map[string]string)

	f, err := os.Open(path)
	if err != nil {
		return nil, err
	}
	defer func() { _ = f.Close() }()

	rdr := bufio.NewScanner(f)
	for rdr.Scan() {
		line := rdr.Text()
		name, target, _ := strings.Cut(line, ":")
		marks[name] = target
	}
	if err := rdr.Err(); err != nil {
		return nil, err
	}

	return marks, nil
}

func saveMarks(marks map[string]string) error {
	path, err := marksFilePath()
	if err != nil {
		return err
	}

	f, err := os.OpenFile(path, os.O_WRONLY|os.O_TRUNC, 0o600)
	if err != nil {
		return err
	}
	defer func() { _ = f.Close() }()

	for name, target := range marks {
		_, err := fmt.Fprintf(f, "%s:%s\n", name, target)
		if err != nil {
			return err
		}
	}

	return nil
}

func marksFilePath() (string, error) {
	return dataFilePath("marks")
}

func getTours() (map[string]*Tour, error) {
	path, err := toursFilePath()
	if err != nil {
		return nil, err
	}

	tours := make(map[string]*Tour)
	var current Tour
	var currentName string

	f, err := os.Open(path)
	if err != nil {
		return nil, err
	}
	defer func() { _ = f.Close() }()

	rdr := bufio.NewScanner(f)
	for rdr.Scan() {
		line := rdr.Text()
		if strings.HasSuffix(line, ":") {
			if currentName != "" {
				tours[currentName] = &current
			}
			currentName = strings.TrimSuffix(line, ":")
			current = Tour{}
		} else {
			u, err := url.Parse(line)
			if err != nil {
				return nil, err
			}
			current.Links = append(current.Links, u)
		}
	}
	if err := rdr.Err(); err != nil {
		return nil, err
	}

	if currentName != "" {
		tours[currentName] = &current
	}

	return tours, nil
}

func saveTours(tours map[string]*Tour) error {
	path, err := toursFilePath()
	if err != nil {
		return err
	}

	f, err := os.OpenFile(path, os.O_WRONLY|os.O_TRUNC, 0o600)
	if err != nil {
		return err
	}
	defer func() { _ = f.Close() }()

	for name, tour := range tours {
		if len(tour.Links) == 0 {
			continue
		}

		if _, err := fmt.Fprintf(f, "%s:\n", name); err != nil {
			return err
		}

		for _, link := range tour.Links {
			if _, err := fmt.Fprintf(f, "%s\n", link.String()); err != nil {
				return err
			}
		}
	}

	return nil
}

func toursFilePath() (string, error) {
	return dataFilePath("tours")
}

func dataFilePath(filename string) (string, error) {
	home := os.Getenv("HOME")
	path := os.Getenv("XDG_DATA_HOME")
	if path == "" {
		path = filepath.Join(home, ".local", "share")
	}
	path = filepath.Join(path, "x-1", filename)

	if err := ensurePath(path); err != nil {
		return "", err
	}

	return path, nil
}

func ensurePath(fpath string) error {
	if _, err := os.Stat(fpath); errors.Is(err, syscall.ENOENT) {
		if err := os.MkdirAll(filepath.Dir(fpath), 0o700); err != nil {
			return err
		}
		f, err := os.OpenFile(fpath, os.O_RDWR|os.O_CREATE, 0o600)
		if err != nil {
			return err
		}
		_ = f.Close()
	}
	return nil
}