// Package wire is the protocol: the JSON shapes a Gitea instance sends and
// takes, the identifiers that address them, and nothing else.
//
// It is a package because two layers need the same vocabulary and neither may
// import the other. internal/gitea is the transport — HTTP verbs, pagination,
// status codes, credentials — and internal/mapping is the bridge — md <-> JSON,
// pure functions, no network. Both have to name a Gitea issue, and when each
// named it with a struct of its own, every command written on top of the two
// would have had to copy a payload field by field from one spelling into the
// other. Two copies of a shape also drift: the first field only one of them
// learns is a field the other silently drops.
//
// THIS PACKAGE IMPORTS THE STANDARD LIBRARY AND NOTHING ELSE — no HTTP, no
// filesystem, no configuration, and above all not internal/issue. That is what
// lets the transport and the bridge share it without either one landing inside
// the other's layer, and layering_test.go fails the moment it stops being true.
//
// Structs and not map[string]any, because the two representations disagreeing
// is the failure this vocabulary exists to make debuggable: a typo in a key is
// a compile error here and a silently dropped field there. Anything Gitea sends
// that is not named below is not read by anybody — decoding is lossy on
// purpose, since the tracker is not the record for anything the domain owns.
package wire

// User is whoever wrote or was assigned something.
//
// Only the login crosses this boundary — it is the one field of a Gitea user
// that means anything to a command, it is what `assignees:` holds, and a
// display name is not an identity anything can be pushed against. A transport
// that carries the rest invites somebody to use it.
type User struct {
	Login string `json:"login"`
}

// Label as the tracker holds it.
//
// Color is hex. Gitea returns it without the leading `#` (`ee0701`) and accepts
// it either way; both spellings are the same color, so a comparison has to
// strip before it compares.
type Label struct {
	ID          int64  `json:"id"`
	Name        string `json:"name"`
	Color       string `json:"color"`
	Description string `json:"description"`
	Exclusive   bool   `json:"exclusive"`
}

// Milestone as the tracker holds it. The domain carries its title; the id
// exists only long enough to be sent back.
type Milestone struct {
	ID          int64  `json:"id"`
	Title       string `json:"title"`
	State       string `json:"state"`
	Description string `json:"description"`
}

// RepoRef is the repository an issue payload says it belongs to. Present on a
// dependency listing, where the answer may well be another repository.
type RepoRef struct {
	Owner    string `json:"owner"`
	Name     string `json:"name"`
	FullName string `json:"full_name"`
}

// PullRequest is non-nil on a row that is a pull request rather than an issue.
// Gitea's issue endpoints return both, and `type=issues` is a filter the server
// has been known to ignore — which is why every listing re-checks it.
type PullRequest struct {
	Merged  bool   `json:"merged"`
	HTMLURL string `json:"html_url"`
}

// Issue is a tracker row: a Gitea issue as the API reports it.
//
// Timestamps stay strings. They are written into an issue's metadata verbatim
// and compared as opaque values; parsing them here would mean formatting them
// back, and a round trip through a time package is a chance to hand the store a
// different string than the tracker sent.
type Issue struct {
	Number int    `json:"number"`
	Title  string `json:"title"`
	Body   string `json:"body"`
	State  string `json:"state"`
	// Ref is the branch the issue is pinned to.
	Ref string `json:"ref"`
	// HTMLURL and UpdatedAt are the tracker's own bookkeeping and land in the
	// domain's Extra untouched.
	HTMLURL string `json:"html_url"`
	// Comments is a count, not a thread: the thread is fetched separately and
	// parked beside the issue as a sidecar.
	Comments    int          `json:"comments"`
	Labels      []Label      `json:"labels"`
	Assignees   []User       `json:"assignees"`
	Milestone   *Milestone   `json:"milestone"`
	Repository  *RepoRef     `json:"repository"`
	PullRequest *PullRequest `json:"pull_request"`
	CreatedAt   string       `json:"created_at"`
	UpdatedAt   string       `json:"updated_at"`
}

// IsPullRequest reports whether this row is a pull request.
func (i *Issue) IsPullRequest() bool { return i.PullRequest != nil }

// LabelNames are the label names, in the order the tracker listed them.
func (i *Issue) LabelNames() []string {
	out := make([]string, 0, len(i.Labels))
	for _, l := range i.Labels {
		out = append(out, l.Name)
	}
	return out
}

// AssigneeLogins are the assignees, as logins.
func (i *Issue) AssigneeLogins() []string {
	out := make([]string, 0, len(i.Assignees))
	for _, a := range i.Assignees {
		out = append(out, a.Login)
	}
	return out
}

// MilestoneTitle is the milestone's title, or "" when there is none.
func (i *Issue) MilestoneTitle() string {
	if i.Milestone == nil {
		return ""
	}
	return i.Milestone.Title
}

// KeyIn is this issue's cross-repo handle. The payload's own repository wins
// when it carries one — a dependency listing answers with issues from other
// repositories — and fallback is the repository that was asked.
func (i *Issue) KeyIn(fallback Repo) Key {
	repo := fallback
	if i.Repository != nil {
		if r, err := ParseRepo(i.Repository.FullName); err == nil {
			repo = r
		}
	}
	return Key{Repo: repo, Number: i.Number}
}

// Comment is one entry in an issue's thread.
//
// Read only, in practice: a thread is flattened to markdown for a reader and
// nothing writes that markdown back, which is why the rendering may be as lossy
// as a reader needs.
type Comment struct {
	ID        int64  `json:"id"`
	Body      string `json:"body"`
	HTMLURL   string `json:"html_url"`
	User      User   `json:"user"`
	CreatedAt string `json:"created_at"`
	UpdatedAt string `json:"updated_at"`
}