// Package fpm implements the Pipe interface providing FPM bindings.
package fpm

import (
	"fmt"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"strings"

	"github.com/apex/log"
	"github.com/pkg/errors"
	"golang.org/x/sync/errgroup"

	"github.com/goreleaser/goreleaser/context"
	"github.com/goreleaser/goreleaser/internal/artifact"
	"github.com/goreleaser/goreleaser/internal/filenametemplate"
	"github.com/goreleaser/goreleaser/internal/linux"
	"github.com/goreleaser/goreleaser/pipeline"
)

// ErrNoFPM is shown when fpm cannot be found in $PATH
var ErrNoFPM = errors.New("fpm not present in $PATH")

const (
	defaultNameTemplate = "{{ .ProjectName }}_{{ .Version }}_{{ .Os }}_{{ .Arch }}{{ if .Arm }}v{{ .Arm }}{{ end }}"
	// path to gnu-tar on macOS when installed with homebrew
	gnuTarPath = "/usr/local/opt/gnu-tar/libexec/gnubin"
)

// Pipe for fpm packaging
type Pipe struct{}

func (Pipe) String() string {
	return "creating Linux packages with fpm"
}

// Default sets the pipe defaults
func (Pipe) Default(ctx *context.Context) error {
	var fpm = &ctx.Config.FPM
	if fpm.Bindir == "" {
		fpm.Bindir = "/usr/local/bin"
	}
	if fpm.NameTemplate == "" {
		fpm.NameTemplate = defaultNameTemplate
	}
	return nil
}

// Run the pipe
func (Pipe) Run(ctx *context.Context) error {
	if len(ctx.Config.FPM.Formats) == 0 {
		return pipeline.Skip("no output formats configured")
	}
	_, err := exec.LookPath("fpm")
	if err != nil {
		return ErrNoFPM
	}
	return doRun(ctx)
}

func doRun(ctx *context.Context) error {
	var g errgroup.Group
	sem := make(chan bool, ctx.Parallelism)
	for _, format := range ctx.Config.FPM.Formats {
		for platform, artifacts := range ctx.Artifacts.Filter(
			artifact.And(
				artifact.ByType(artifact.Binary),
				artifact.ByGoos("linux"),
			),
		).GroupByPlatform() {
			sem <- true
			format := format
			arch := linux.Arch(platform)
			artifacts := artifacts
			g.Go(func() error {
				defer func() {
					<-sem
				}()
				return create(ctx, format, arch, artifacts)
			})
		}
	}
	return g.Wait()
}

func create(ctx *context.Context, format, arch string, binaries []artifact.Artifact) error {
	name, err := filenametemplate.Apply(
		ctx.Config.FPM.NameTemplate,
		filenametemplate.NewFields(ctx, ctx.Config.FPM.Replacements, binaries...),
	)
	if err != nil {
		return err
	}
	var path = filepath.Join(ctx.Config.Dist, name)
	var file = path + "." + format
	var log = log.WithField("format", format).WithField("arch", arch)
	dir, err := ioutil.TempDir("", "fpm")
	if err != nil {
		return err
	}
	log.WithField("file", file).WithField("workdir", dir).Info("creating fpm archive")
	var options = basicOptions(ctx, dir, format, arch, file)

	for _, binary := range binaries {
		// This basically tells fpm to put the binary in the bindir, e.g. /usr/local/bin
		// binary=/usr/local/bin/binary
		log.WithField("path", binary.Path).
			WithField("name", binary.Name).
			Debug("added binary to fpm package")
		options = append(options, fmt.Sprintf(
			"%s=%s",
			binary.Path,
			filepath.Join(ctx.Config.FPM.Bindir, binary.Name),
		))
	}

	for src, dest := range ctx.Config.FPM.Files {
		log.WithField("src", src).
			WithField("dest", dest).
			Debug("added an extra file to the fpm package")
		options = append(options, fmt.Sprintf(
			"%s=%s",
			src,
			dest,
		))
	}

	log.WithField("args", options).Debug("creating fpm package")
	if out, err := cmd(ctx, options).CombinedOutput(); err != nil {
		return errors.Wrap(err, string(out))
	}
	ctx.Artifacts.Add(artifact.Artifact{
		Type:   artifact.LinuxPackage,
		Name:   name + "." + format,
		Path:   file,
		Goos:   binaries[0].Goos,
		Goarch: binaries[0].Goarch,
		Goarm:  binaries[0].Goarm,
	})
	return nil
}

func cmd(ctx *context.Context, options []string) *exec.Cmd {
	/* #nosec */
	var cmd = exec.CommandContext(ctx, "fpm", options...)
	cmd.Env = []string{fmt.Sprintf("PATH=%s:%s", gnuTarPath, os.Getenv("PATH"))}
	for _, env := range os.Environ() {
		if strings.HasPrefix(env, "PATH=") {
			continue
		}
		cmd.Env = append(cmd.Env, env)
	}
	return cmd
}

func basicOptions(ctx *context.Context, workdir, format, arch, file string) []string {
	var options = []string{
		"--input-type", "dir",
		"--output-type", format,
		"--name", ctx.Config.ProjectName,
		"--version", ctx.Version,
		"--architecture", arch,
		"--package", file,
		"--force",
		"--workdir", workdir,
	}

	if ctx.Debug {
		options = append(options, "--debug")
	}

	if ctx.Config.FPM.Vendor != "" {
		options = append(options, "--vendor", ctx.Config.FPM.Vendor)
	}
	if ctx.Config.FPM.Homepage != "" {
		options = append(options, "--url", ctx.Config.FPM.Homepage)
	}
	if ctx.Config.FPM.Maintainer != "" {
		options = append(options, "--maintainer", ctx.Config.FPM.Maintainer)
	}
	if ctx.Config.FPM.Description != "" {
		options = append(options, "--description", ctx.Config.FPM.Description)
	}
	if ctx.Config.FPM.License != "" {
		options = append(options, "--license", ctx.Config.FPM.License)
	}
	for _, dep := range ctx.Config.FPM.Dependencies {
		options = append(options, "--depends", dep)
	}
	for _, conflict := range ctx.Config.FPM.Conflicts {
		options = append(options, "--conflicts", conflict)
	}

	// FPM requires --rpm-os=linux if your rpm target is linux
	if format == "rpm" {
		options = append(options, "--rpm-os", "linux")
	}
	return options
}