// Copyright © 2014 Steve Francia <spf@spf13.com>.

//

// Use of this source code is governed by an MIT-style

// license that can be found in the LICENSE file.

// Viper is a application configuration system.

// It believes that applications can be configured a variety of ways

// via flags, ENVIRONMENT variables, configuration files retrieved

// from the file system, or a remote key/value store.

package viper

import (

	"fmt"

	"os"

	"path/filepath"

	"runtime"

	"strings"

	"unicode"

	"github.com/spf13/cast"

)

// ConfigParseError denotes failing to parse configuration file.

type ConfigParseError struct {

	err error

}

// Error returns the formatted configuration error.

func (pe ConfigParseError) Error() string {

	return fmt.Sprintf("While parsing config: %s", pe.err.Error())

}

// toCaseInsensitiveValue checks if the value is a  map;

// if so, create a copy and lower-case the keys recursively.

func toCaseInsensitiveValue(value interface{}) interface{} {

	switch v := value.(type) {

	case map[interface{}]interface{}:

		value = copyAndInsensitiviseMap(cast.ToStringMap(v))

	case map[string]interface{}:

		value = copyAndInsensitiviseMap(v)

	}

	return value

}

// copyAndInsensitiviseMap behaves like insensitiviseMap, but creates a copy of

// any map it makes case insensitive.

func copyAndInsensitiviseMap(m map[string]interface{}) map[string]interface{} {

	nm := make(map[string]interface{})

	for key, val := range m {

		lkey := strings.ToLower(key)

		switch v := val.(type) {

		case map[interface{}]interface{}:

			nm[lkey] = copyAndInsensitiviseMap(cast.ToStringMap(v))

		case map[string]interface{}:

			nm[lkey] = copyAndInsensitiviseMap(v)

		default:

			nm[lkey] = v

		}

	}

	return nm

}

func insensitiviseMap(m map[string]interface{}) {

	for key, val := range m {

		lower := strings.ToLower(key)

		if key != lower {

			// remove old key (not lower-cased)

			delete(m, key)

		}

		// update map

		m[lower] = val

	}

}

func absPathify(logger Logger, inPath string) string {

	logger.Info("trying to resolve absolute path", "path", inPath)

	if inPath == "$HOME" || strings.HasPrefix(inPath, "$HOME"+string(os.PathSeparator)) {

		inPath = userHomeDir() + inPath[5:]

	}

	inPath = os.ExpandEnv(inPath)

	if filepath.IsAbs(inPath) {

		return filepath.Clean(inPath)

	}

	p, err := filepath.Abs(inPath)

	if err == nil {

		return filepath.Clean(p)

	}

	logger.Error(fmt.Errorf("could not discover absolute path: %w", err).Error())

	return ""

}

func stringInSlice(a string, list []string) bool {

	for _, b := range list {

		if b == a {

			return true

		}

	}

	return false

}

func userHomeDir() string {

	if runtime.GOOS == "windows" {

		home := os.Getenv("HOMEDRIVE") + os.Getenv("HOMEPATH")

		if home == "" {

			home = os.Getenv("USERPROFILE")

		}

		return home

	}

	return os.Getenv("HOME")

}

func safeMul(a, b uint) uint {

	c := a * b

	if a > 1 && b > 1 && c/b != a {

		return 0

	}

	return c

}

// parseSizeInBytes converts strings like 1GB or 12 mb into an unsigned integer number of bytes

func parseSizeInBytes(sizeStr string) uint {

	sizeStr = strings.TrimSpace(sizeStr)

	lastChar := len(sizeStr) - 1

	multiplier := uint(1)

	if lastChar > 0 {

		if sizeStr[lastChar] == 'b' || sizeStr[lastChar] == 'B' {

			if lastChar > 1 {

				switch unicode.ToLower(rune(sizeStr[lastChar-1])) {

				case 'k':

					multiplier = 1 << 10

					sizeStr = strings.TrimSpace(sizeStr[:lastChar-1])

				case 'm':

					multiplier = 1 << 20

					sizeStr = strings.TrimSpace(sizeStr[:lastChar-1])

				case 'g':

					multiplier = 1 << 30

					sizeStr = strings.TrimSpace(sizeStr[:lastChar-1])

				default:

					multiplier = 1

					sizeStr = strings.TrimSpace(sizeStr[:lastChar])

				}

			}

		}

	}

	size := cast.ToInt(sizeStr)

	if size < 0 {

		size = 0

	}

	return safeMul(uint(size), multiplier)

}

// deepSearch scans deep maps, following the key indexes listed in the

// sequence "path".

// The last value is expected to be another map, and is returned.

//

// In case intermediate keys do not exist, or map to a non-map value,

// a new map is created and inserted, and the search continues from there:

// the initial map "m" may be modified!

func deepSearch(m map[string]interface{}, path []string) map[string]interface{} {

	for _, k := range path {

		m2, ok := m[k]

		if !ok {

			// intermediate key does not exist

			// => create it and continue from there

			m3 := make(map[string]interface{})

			m[k] = m3

			m = m3

			continue

		}

		m3, ok := m2.(map[string]interface{})

		if !ok {

			// intermediate key is a value

			// => replace with a new map

			m3 = make(map[string]interface{})

			m[k] = m3

		}

		// continue search from here

		m = m3

	}

	return m

}