package zk

import (
	"fmt"
	"os"
	"path/filepath"

	"github.com/mickael-menu/zk/util/errors"
)

const defaultConfig = `
# Test
test = thing
`

// Open locates a slip box at the given path and parses its configuration.
func Open(path string) error {
	wrap := errors.Wrapper("open failed")

	path, err := filepath.Abs(path)
	if err != nil {
		return wrap(err)
	}
	_, err = locateRoot(path)
	return wrap(err)
}

// Create initializes a new slip box at the given path.
func Create(path string) error {
	wrap := errors.Wrapper("init failed")

	path, err := filepath.Abs(path)
	if err != nil {
		return wrap(err)
	}

	if existingPath, err := locateRoot(path); err == nil {
		return wrap(fmt.Errorf("a slip box already exists in %v", existingPath))
	}

	// Create .zk and .zk/templates directories.
	err = os.MkdirAll(filepath.Join(path, ".zk/templates"), os.ModePerm)
	if err != nil {
		return wrap(err)
	}

	// Write default config.toml.
	f, err := os.Create(filepath.Join(path, ".zk/config.toml"))
	if err != nil {
		return wrap(err)
	}
	_, err = f.WriteString(defaultConfig)
	if err != nil {
		return wrap(err)
	}

	return nil
}

// locate finds the root of the slip box containing the given path.
func locateRoot(path string) (string, error) {
	if !filepath.IsAbs(path) {
		panic("absolute path expected")
	}

	var locate func(string) (string, error)
	locate = func(currentPath string) (string, error) {
		if currentPath == "/" || currentPath == "." {
			return "", fmt.Errorf("no slip box found in %v or a parent directory", path)
		}
		if dotPath := filepath.Join(currentPath, ".zk"); dirExists(dotPath) {
			return currentPath, nil
		}

		return locate(filepath.Dir(currentPath))
	}

	return locate(path)
}

func dirExists(path string) bool {
	fi, err := os.Stat(path)
	if err != nil {
		return false
	}
	switch mode := fi.Mode(); {
	case mode.IsDir():
		return true
	default:
		return false
	}
}