// Package globals holds application-wide metadata (name, version,
// commit) that is populated at build time via linker flags, or from the
// build info Go records in the binary when the linker flags set none.
package globals

import (
	"regexp"
	"runtime/debug"
	"strings"
	"time"

	"golang.org/x/mod/module"
)

// Appname is the application name, populated from main().
var Appname = "vaultik" //nolint:gochecknoglobals // set via -ldflags at build time

// DevVersion is the version a binary reports when it was built without
// git metadata: script/version emits it outside a git checkout, and a
// binary keeps it when neither its linker flags nor its Go build info
// name a version. goreleaser's snapshot template stamps
// it followed by "-" and the commit it was built from. It is
// deliberately not a number.
const DevVersion = "dev"

// Unknown is what Commit and CommitDate hold when the build did not
// stamp them, and the version script/docker and script/cibuild stamp
// when the host has no git checkout.
const Unknown = "unknown"

// Version is the application version, populated from main().
var Version = DevVersion //nolint:gochecknoglobals // set via -ldflags at build time

// Commit is the git commit hash, populated from main().
var Commit = Unknown //nolint:gochecknoglobals // set via -ldflags at build time

// CommitDate is the ISO-8601 date of the commit, populated from main().
var CommitDate = Unknown //nolint:gochecknoglobals // set via -ldflags at build time

// develVersion is the main module version Go records when it cannot
// tell which version it built.
const develVersion = "(devel)"

// UseBuildInfo applies FromBuildInfo to Version, Commit and CommitDate,
// with the build info of the running binary.
func UseBuildInfo() {
	info, ok := debug.ReadBuildInfo()
	if !ok {
		return
	}

	Version, Commit, CommitDate = FromBuildInfo(
		info, Version, Commit, CommitDate)
}

// FromBuildInfo returns version, commit and commitDate, with each one
// the linker flags left unset taken from info. A `go install` of a tag
// sets no linker flags, but Go records the tag as the main module's
// version. Go records the commit and its time only when it builds from
// a git checkout. The time is cut to a date, as the Makefile stamps it.
func FromBuildInfo(
	info *debug.BuildInfo, version, commit, commitDate string,
) (string, string, string) {
	if (version == "" || version == DevVersion) &&
		info.Main.Version != "" && info.Main.Version != develVersion {
		version = info.Main.Version
	}

	for _, s := range info.Settings {
		switch s.Key {
		case "vcs.revision":
			if commit == Unknown {
				commit = s.Value
			}
		case "vcs.time":
			t, err := time.Parse(time.RFC3339, s.Value)
			if commitDate == Unknown && err == nil {
				commitDate = t.UTC().Format(time.DateOnly)
			}
		}
	}

	return version, commit, commitDate
}

// Author identifies the upstream author of vaultik.
const Author = "Jeffrey Paul <sneak@sneak.berlin>"

// Homepage is the canonical URL for vaultik.
const Homepage = "https://sneak.berlin/go/vaultik"

// ReleasesURL is where tagged release artifacts are published.
const ReleasesURL = "https://git.eeqj.de/sneak/vaultik/releases"

// License is the SPDX identifier for the project license.
const License = "MIT"

// Globals contains application-wide configuration and metadata.
type Globals struct {
	Appname    string
	Version    string
	Commit     string
	CommitDate string
	StartTime  time.Time
}

// New creates and returns a new Globals instance initialized with the
// package-level variables.
func New() (*Globals, error) {
	return &Globals{
		Appname:    Appname,
		Version:    Version,
		Commit:     Commit,
		CommitDate: CommitDate,
	}, nil
}

// IsDevVersion reports whether v names a development build rather than
// a release. "dev" and goreleaser's snapshot "dev-<sha>" count, and so
// does what `git describe --tags --always --dirty` gives a make or
// docker build of an untagged commit: the bare short commit, or
// tag-N-gHASH on a commit after a tag. A Go pseudo-version counts: Go
// records one for a build of an untagged commit without linker flags.
// Any version ending in "-dirty" or "+dirty" counts, a modified
// checkout of a tag ("v1.0.0-dirty", "v1.0.0+dirty") included.
// A plain tag such as "v1.0.0" or "1.0.0" is a release.
//
// The empty string counts too. Nothing that knows its version reports
// no version, so an empty Version means the stamping failed, and the
// safe reading of "we could not establish that this is a release" is
// that it is not one. The Makefile refuses to build at all in that
// case; this is the second line of defence, for a binary linked by
// something other than the Makefile. Unknown counts for the same
// reason.
func IsDevVersion(v string) bool {
	if v == "" || v == Unknown || v == DevVersion ||
		strings.HasPrefix(v, DevVersion+"-") ||
		strings.HasSuffix(v, "-dirty") || strings.HasSuffix(v, "+dirty") ||
		module.IsPseudoVersion(v) {
		return true
	}

	return regexp.MustCompile(`^(.+-[0-9]+-g)?[0-9a-f]+$`).MatchString(v)
}

// shortCommitLen is the number of commit-hash characters ShortCommit keeps.
const shortCommitLen = 12

// ShortCommit returns the first 12 chars of the commit hash, or the
// whole string if it's shorter (e.g. "unknown").
func (g *Globals) ShortCommit() string {
	if len(g.Commit) > shortCommitLen {
		return g.Commit[:shortCommitLen]
	}

	return g.Commit
}