// Copyright 2015 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package android

import (
	"fmt"
	"regexp"
	"runtime"
	"sort"
	"strings"
)

// CopyOf returns a new slice that has the same contents as s.
func CopyOf(s []string) []string {
	return append([]string(nil), s...)
}

func JoinWithPrefix(strs []string, prefix string) string {
	if len(strs) == 0 {
		return ""
	}

	if len(strs) == 1 {
		return prefix + strs[0]
	}

	n := len(" ") * (len(strs) - 1)
	for _, s := range strs {
		n += len(prefix) + len(s)
	}

	ret := make([]byte, 0, n)
	for i, s := range strs {
		if i != 0 {
			ret = append(ret, ' ')
		}
		ret = append(ret, prefix...)
		ret = append(ret, s...)
	}
	return string(ret)
}

func sortedKeys(m map[string][]string) []string {
	s := make([]string, 0, len(m))
	for k := range m {
		s = append(s, k)
	}
	sort.Strings(s)
	return s
}

func IndexList(s string, list []string) int {
	for i, l := range list {
		if l == s {
			return i
		}
	}

	return -1
}

func InList(s string, list []string) bool {
	return IndexList(s, list) != -1
}

func PrefixInList(s string, list []string) bool {
	for _, prefix := range list {
		if strings.HasPrefix(s, prefix) {
			return true
		}
	}
	return false
}

func FilterList(list []string, filter []string) (remainder []string, filtered []string) {
	for _, l := range list {
		if InList(l, filter) {
			filtered = append(filtered, l)
		} else {
			remainder = append(remainder, l)
		}
	}

	return
}

func RemoveListFromList(list []string, filter_out []string) (result []string) {
	result = make([]string, 0, len(list))
	for _, l := range list {
		if !InList(l, filter_out) {
			result = append(result, l)
		}
	}
	return
}

func RemoveFromList(s string, list []string) (bool, []string) {
	i := IndexList(s, list)
	if i == -1 {
		return false, list
	}

	result := make([]string, 0, len(list)-1)
	result = append(result, list[:i]...)
	for _, l := range list[i+1:] {
		if l != s {
			result = append(result, l)
		}
	}
	return true, result
}

// FirstUniqueStrings returns all unique elements of a slice of strings, keeping the first copy of
// each.  It modifies the slice contents in place, and returns a subslice of the original slice.
func FirstUniqueStrings(list []string) []string {
	k := 0
outer:
	for i := 0; i < len(list); i++ {
		for j := 0; j < k; j++ {
			if list[i] == list[j] {
				continue outer
			}
		}
		list[k] = list[i]
		k++
	}
	return list[:k]
}

// LastUniqueStrings returns all unique elements of a slice of strings, keeping the last copy of
// each.  It modifies the slice contents in place, and returns a subslice of the original slice.
func LastUniqueStrings(list []string) []string {
	totalSkip := 0
	for i := len(list) - 1; i >= totalSkip; i-- {
		skip := 0
		for j := i - 1; j >= totalSkip; j-- {
			if list[i] == list[j] {
				skip++
			} else {
				list[j+skip] = list[j]
			}
		}
		totalSkip += skip
	}
	return list[totalSkip:]
}

// checkCalledFromInit panics if a Go package's init function is not on the
// call stack.
func checkCalledFromInit() {
	for skip := 3; ; skip++ {
		_, funcName, ok := callerName(skip)
		if !ok {
			panic("not called from an init func")
		}

		if funcName == "init" || strings.HasPrefix(funcName, "init·") ||
			strings.HasPrefix(funcName, "init.") {
			return
		}
	}
}

// A regex to find a package path within a function name. It finds the shortest string that is
// followed by '.' and doesn't have any '/'s left.
var pkgPathRe = regexp.MustCompile(`^(.*?)\.([^/]+)$`)

// callerName returns the package path and function name of the calling
// function.  The skip argument has the same meaning as the skip argument of
// runtime.Callers.
func callerName(skip int) (pkgPath, funcName string, ok bool) {
	var pc [1]uintptr
	n := runtime.Callers(skip+1, pc[:])
	if n != 1 {
		return "", "", false
	}

	f := runtime.FuncForPC(pc[0]).Name()
	s := pkgPathRe.FindStringSubmatch(f)
	if len(s) < 3 {
		panic(fmt.Errorf("failed to extract package path and function name from %q", f))
	}

	return s[1], s[2], true
}

func GetNumericSdkVersion(v string) string {
	if strings.Contains(v, "system_") {
		return strings.Replace(v, "system_", "", 1)
	}
	return v
}

// copied from build/kati/strutil.go
func substPattern(pat, repl, str string) string {
	ps := strings.SplitN(pat, "%", 2)
	if len(ps) != 2 {
		if str == pat {
			return repl
		}
		return str
	}
	in := str
	trimed := str
	if ps[0] != "" {
		trimed = strings.TrimPrefix(in, ps[0])
		if trimed == in {
			return str
		}
	}
	in = trimed
	if ps[1] != "" {
		trimed = strings.TrimSuffix(in, ps[1])
		if trimed == in {
			return str
		}
	}

	rs := strings.SplitN(repl, "%", 2)
	if len(rs) != 2 {
		return repl
	}
	return rs[0] + trimed + rs[1]
}

// copied from build/kati/strutil.go
func matchPattern(pat, str string) bool {
	i := strings.IndexByte(pat, '%')
	if i < 0 {
		return pat == str
	}
	return strings.HasPrefix(str, pat[:i]) && strings.HasSuffix(str, pat[i+1:])
}