// Copyright 2017 CoreOS, Inc.
//
// 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 analyze

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

func minFloat64(a, b float64) float64 {
	if a < b {
		return a
	}
	return b
}

func maxFloat64(a, b float64) float64 {
	if a > b {
		return a
	}
	return b
}

func makeHeader(column string, tag string) string {
	return fmt.Sprintf("%s-%s", column, tag)
}

// converts unix nanoseconds to unix second.
func convertUnixNano(ts int64) int64 {
	return int64(ts / 1e9)
}

func openToRead(fpath string) (*os.File, error) {
	f, err := os.OpenFile(fpath, os.O_RDONLY, 0444)
	if err != nil {
		return nil, err
	}
	return f, nil
}

func openToAppend(fpath string) (*os.File, error) {
	f, err := os.OpenFile(fpath, os.O_RDWR|os.O_APPEND|os.O_CREATE, 0777)
	if err != nil {
		return nil, err
	}
	return f, nil
}

func openToOverwrite(fpath string) (*os.File, error) {
	f, err := os.OpenFile(fpath, os.O_RDWR|os.O_TRUNC|os.O_CREATE, 0777)
	if err != nil {
		return nil, err
	}
	return f, nil
}

func toFile(txt, fpath string) error {
	f, err := openToOverwrite(fpath)
	if err != nil {
		f, err = os.Create(fpath)
		if err != nil {
			return err
		}
	}
	defer f.Close()
	_, err = f.WriteString(txt)
	return err
}

func copyFile(src, dst string) error {
	if err := os.MkdirAll(filepath.Dir(dst), 0755); err != nil {
		return fmt.Errorf("copy: mkdirall: %v", err)
	}

	r, err := os.Open(src)
	if err != nil {
		return fmt.Errorf("copy: open(%q): %v", src, err)
	}
	defer r.Close()

	w, err := os.Create(dst)
	if err != nil {
		return fmt.Errorf("copy: create(%q): %v", dst, err)
	}
	defer w.Close()

	// func Copy(dst Writer, src Reader) (written int64, err error)
	if _, err = io.Copy(w, r); err != nil {
		return err
	}
	if err := w.Sync(); err != nil {
		return err
	}
	if _, err := w.Seek(0, 0); err != nil {
		return err
	}
	return nil
}