// Copyright 2023 Google LLC
//
// 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 execv provides a wrapper around exec.Cmd for debugging purposes.
package execv

import (
	"io/fs"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
)

// CmdWrapper is a wrapper around exec.Cmd for debugging purposes.
type CmdWrapper struct {
	*exec.Cmd
}

// Command wraps a exec.Command to add some logging about commands being run.
// The commands stdout/stderr default to os.Stdout/os.Stderr respectfully.
func Command(name string, arg ...string) *CmdWrapper {
	c := &CmdWrapper{exec.Command(name, arg...)}
	c.Stderr = os.Stderr
	c.Stdin = os.Stdin
	return &CmdWrapper{exec.Command(name, arg...)}
}

// Run a command.
func (c *CmdWrapper) Run() error {
	b, err := c.Output()
	if len(b) > 0 {
		log.Printf("Command Output: %s", b)
	}
	return err
}

// Output a command.
func (c *CmdWrapper) Output() ([]byte, error) {
	log.Printf("[%s] >>>> %v <<<<", c.Dir, strings.Join(c.Args, " "))
	b, err := c.Cmd.Output()
	if err != nil {
		if ee, ok := err.(*exec.ExitError); ok {
			log.Println(string(ee.Stderr))
		}
	}
	return b, err
}

// ForEachMod runs the given function with the directory of
// every non-internal module.
func ForEachMod(rootDir string, fn func(dir string) error) error {
	return filepath.WalkDir(rootDir, func(path string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if strings.Contains(path, "internal") {
			return filepath.SkipDir
		}
		if d.Name() != "go.mod" {
			return nil
		}
		// process Go module directory.
		return fn(filepath.Dir(path))
	})
}