package main

// release.go — the `release` command: tag a commit and publish it as a release
// on the public mirror servers.
//
//	release [@name ...] <tag> [notes]
//
// It does the whole chain in one step, because doing it in two is where the
// second half gets forgotten: create the annotated tag, push it to the internal
// git server, then push it to each selected mirror target and turn it into a
// release object there via the provider's REST API.
//
// Release notes come from the text after the tag; without it, from the tag's own
// annotation, and failing that from the commit subjects since the previous tag.
//
// Binary assets are deliberately not supported: Gitea uploads them to the
// release, GitHub to a separate host, and GitLab does not host them at all but
// wants a link into its package registry. A source release with notes is what
// this needs; assets would be three implementations instead of one.

import (
	"encoding/json"
	"fmt"
	"net/url"
	"regexp"
	"strconv"
	"strings"
)

// preReleaseRe marks a tag as a pre-release by its usual suffixes.
var preReleaseRe = regexp.MustCompile(`(?i)-(rc|alpha|beta|pre)[.\-0-9]*$`)

// maxAutoNotes caps generated release notes, so a first release on a long
// history does not paste the entire log into the release body.
const maxAutoNotes = 50

// release is one release as mgsh publishes it.
type release struct {
	Tag        string
	Name       string
	Body       string
	Prerelease bool
}

// releasePath is the API path of a repository's release collection.
func (r *remoteAPI) releasePath(owner, repo string) string {
	return r.repoPath(owner, repo) + "/releases"
}

// releaseByTagPath addresses one existing release: Gitea and GitHub look it up
// under .../releases/tags/<tag>, GitLab directly under .../releases/<tag>.
func (r *remoteAPI) releaseByTagPath(owner, repo, tag string) string {
	if r.kind == kindGitLab {
		return r.releasePath(owner, repo) + "/" + url.PathEscape(tag)
	}
	return r.releasePath(owner, repo) + "/tags/" + url.PathEscape(tag)
}

// findRelease returns the provider's id for the release of tag and whether it
// exists at all. GitLab addresses releases by tag, so there the tag is the id.
func (r *remoteAPI) findRelease(owner, repo, tag string) (id string, found bool, err error) {
	code, data, err := r.do("GET", r.releaseByTagPath(owner, repo, tag), nil)
	if err != nil {
		return "", false, err
	}
	switch code {
	case 404:
		return "", false, nil
	case 200:
		if r.kind == kindGitLab {
			return tag, true, nil
		}
		var res struct {
			ID int64 `json:"id"`
		}
		json.Unmarshal(data, &res)
		return strconv.FormatInt(res.ID, 10), true, nil
	default:
		return "", false, fmt.Errorf("checking release failed (HTTP %d): %s", code, firstLine(data))
	}
}

// createRelease publishes a new release for an already pushed tag.
func (r *remoteAPI) createRelease(owner, repo string, rel release) error {
	code, data, err := r.do("POST", r.releasePath(owner, repo), r.releaseBody(rel, true))
	if err != nil {
		return err
	}
	if code != 200 && code != 201 {
		return fmt.Errorf("creating release failed (HTTP %d): %s", code, firstLine(data))
	}
	return nil
}

// updateRelease rewrites the name and notes of an existing release. Gitea and
// GitHub patch it by numeric id, GitLab puts it by tag.
func (r *remoteAPI) updateRelease(owner, repo, id string, rel release) error {
	method, ep := "PATCH", r.releasePath(owner, repo)+"/"+id
	if r.kind == kindGitLab {
		method, ep = "PUT", r.releaseByTagPath(owner, repo, rel.Tag)
	}
	code, data, err := r.do(method, ep, r.releaseBody(rel, false))
	if err != nil {
		return err
	}
	if code != 200 && code != 201 {
		return fmt.Errorf("updating release failed (HTTP %d): %s", code, firstLine(data))
	}
	return nil
}

// releaseBody maps a release onto the provider's field names. GitLab calls the
// notes "description" and has no pre-release flag; the tag is only sent when
// creating, since none of the three lets an existing release change tags.
func (r *remoteAPI) releaseBody(rel release, create bool) map[string]any {
	body := map[string]any{"name": rel.Name}
	if r.kind == kindGitLab {
		body["description"] = rel.Body
	} else {
		body["body"] = rel.Body
		body["prerelease"] = rel.Prerelease
	}
	if create {
		body["tag_name"] = rel.Tag
	}
	return body
}

// handleRelease implements `release [@name ...] <tag> [notes]`.
func handleRelease(args string) {
	if !requireRepo() {
		return
	}
	names, rest := parsePushRemoteArgs(args)
	fields := strings.Fields(rest)
	if len(fields) == 0 {
		errorln("usage: release [@remote ...] <tag> [notes]")
		return
	}
	tag := fields[0]
	notes := strings.Join(fields[1:], " ")

	if !ensureTag(DIR, tag, notes) {
		return
	}
	if !gitOK(DIR, "push", "origin", tag) {
		return
	}

	targets, incomplete := cfg.mirrorTargets()
	for _, n := range incomplete {
		errorln("remote " + n + ": url or key missing — skipped")
	}
	targets = pickRemotes(targets, names)
	if len(targets) == 0 {
		if len(names) == 0 { // an unknown @name already reported itself
			errorln("release needs a mirror target — see 'config'")
		}
		return
	}

	body := notes
	if body == "" {
		body = releaseNotes(DIR, tag)
	}

	done := 0
	for _, t := range targets {
		if publishRelease(t, PRJ, tag, body) {
			done++
		}
	}
	if len(targets) > 1 {
		fmt.Printf("%s %d/%d remotes released\n", col(cGray, "release:"), done, len(targets))
	}
}

// ensureTag creates the annotated tag when it is missing. It refuses to move a
// tag that already points somewhere else: re-pointing a published tag is how
// the same version silently ends up meaning different things per server.
func ensureTag(dir, tag, message string) bool {
	if _, err := gitCapture(dir, "rev-parse", "--verify", "--quiet", "refs/tags/"+tag); err == nil {
		head, _ := gitCapture(dir, "rev-parse", "HEAD^{commit}")
		tagged, _ := gitCapture(dir, "rev-parse", tag+"^{commit}")
		if strings.TrimSpace(head) != strings.TrimSpace(tagged) {
			errorln("tag " + tag + " exists on another commit — publishing it would move it; pick a new tag")
			return false
		}
		return true // same commit: re-publishing an existing release is fine
	}
	msg := message
	if msg == "" {
		msg = tag
	}
	return gitOK(dir, "tag", "-a", tag, "-m", msg)
}

// releaseNotes builds the body for a release: the tag's own annotation when it
// carries more than the default (`tag add` annotates with the tag name), else
// the commit subjects since the previous tag.
func releaseNotes(dir, tag string) string {
	if out, err := gitCapture(dir, "tag", "-l",
		"--format=%(contents:subject)%0a%0a%(contents:body)", tag); err == nil {
		if msg := strings.TrimSpace(out); msg != "" && msg != tag {
			return msg
		}
	}

	rng := tag
	if prev, err := gitCapture(dir, "describe", "--tags", "--abbrev=0", tag+"^"); err == nil {
		if p := strings.TrimSpace(prev); p != "" {
			rng = p + ".." + tag
		}
	}
	out, err := gitCapture(dir, "log", "--reverse", "-n", strconv.Itoa(maxAutoNotes),
		"--format=- %s", rng)
	if err != nil {
		return ""
	}
	return strings.TrimSpace(out)
}

// publishRelease pushes the tag to one mirror target and turns it into a
// release there. It returns success, so one unreachable server does not stop
// the remaining ones.
func publishRelease(t RemoteTarget, repo, tag, body string) bool {
	api := newRemoteAPI(t.URL, t.Key, t.Type)

	owner, err := api.authUser()
	if err != nil {
		errorln(t.Name + ": " + err.Error())
		return false
	}
	exists, err := api.repoExists(owner, repo)
	if err != nil {
		errorln(t.Name + ": " + err.Error())
		return false
	}
	if !exists {
		errorln(t.Name + ": " + owner + "/" + repo + " does not exist there — run 'pushremote' first")
		return false
	}

	// a release refers to a tag, so the tag has to reach the server first
	ensureGitRemote(t.Name, api.repoWebURL(owner, repo))
	if !gitPushHeader(DIR, t.Name, api.pushHeader(owner), "tag", tag) {
		return false
	}

	rel := release{Tag: tag, Name: tag, Body: body, Prerelease: preReleaseRe.MatchString(tag)}
	id, found, err := api.findRelease(owner, repo, tag)
	if err != nil {
		errorln(t.Name + ": " + err.Error())
		return false
	}
	if found {
		if err := api.updateRelease(owner, repo, id, rel); err != nil {
			errorln(t.Name + ": " + err.Error())
			return false
		}
	} else if err := api.createRelease(owner, repo, rel); err != nil {
		errorln(t.Name + ": " + err.Error())
		return false
	}

	what := "released"
	if found {
		what = "updated release"
	}
	if rel.Prerelease {
		what += " (pre-release)"
	}
	fmt.Printf("%s %s %s %s\n", col(cGray, "remote"), col(cYellow, t.Name),
		col(cGreen, what), col(cCyan, api.repoWebURL(owner, repo)))
	return true
}