converge

type Batch struct {
	Number     int
	MergedAt   time.Time
	Rounds     int
	HaveRounds bool
}

type Field struct {
	Key   string
	Value string
}

type Forge interface {
	// OpenPRs is every pull request open right now.
	OpenPRs(ctx context.Context) ([]PR, error)
	// ClosedSince is every pull request closed or merged at or after `since`.
	ClosedSince(ctx context.Context, since time.Time) ([]PR, error)
}

type GH struct {
	Repo    string
	Timeout time.Duration
	// Bin is the gh executable, "gh" unless a caller names another. A test
	// names a fake; nothing here searches a path of its own.
	Bin string
}

type Git interface {
	// RevBefore is the last commit on the current branch at or before t.
	RevBefore(ctx context.Context, t time.Time) (string, error)
	// Show is one path's content at one revision.
	Show(ctx context.Context, rev, path string) (string, error)
}

type JSON struct {
	At          string       `json:"at"`
	Since       string       `json:"since"`
	Streams     []StreamJSON `json:"streams"`
	Verdict     string       `json:"verdict"`
	Measured    int          `json:"streams_measured"`
	Contracting int          `json:"contracting"`
	Widening    []string     `json:"widening"`
	Absent      []string     `json:"absent"`
}

type Options struct {
	Repo        string
	LedgerPath  string
	ReceiptsDir string
	RetiredPath string

	BinDir       string // SCRIPTS
	RepoDir      string // CLASSES
	BatchLogs    string // LANDING's second source for rounds
	VersionsPath string // FLEET
	CertsPath    string // FLEET's certified fraction

	By []string

	Since time.Time
	Now   time.Time

	Forge Forge
	Git   Git // nil when --repo-dir was not given
}

type PR struct {
	Number    int
	Title     string
	Body      string
	Merged    bool
	CreatedAt time.Time
	ClosedAt  time.Time
}

type RealGit struct {
	Dir     string
	Timeout time.Duration
	// Bin is the git executable, "git" unless a caller names another.
	Bin string
}

type Report struct {
	Streams []Stream
}

type RetiredRow struct {
	Script   string
	Date     time.Time
	HaveDate bool
}

type State struct {
	Streams map[string]StreamState `json:"streams"`
}

type Stream struct {
	Name    string // LANDING, CLASSES, SCRIPTS, PRS, EDGES, FLEET, LEDGER
	Measure string // what the number counts, printed as measure=

	Now    float64
	Before float64

	HaveNow    bool
	HaveBefore bool

	// Lower is true when fewer is converging. CLASSES is the one stream where
	// it is false: a class made mechanical cannot come back, so more entries is
	// the family contracting, not widening.
	Lower bool

	// Want is the flag that would have fed this stream, on an absent one.
	Want string

	// BeforeFrom names where `before` came from when it was not read from a
	// source of its own: `state` for the two streams a single photograph cannot
	// give a history.
	BeforeFrom string

	Extra []Field
}

type StreamJSON struct {
	Name    string            `json:"stream"`
	Measure string            `json:"measure"`
	Now     *float64          `json:"now"`
	Before  *float64          `json:"before"`
	Ratio   *float64          `json:"ratio"`
	Trend   string            `json:"trend"`
	Want    string            `json:"source,omitempty"`
	Extra   map[string]string `json:"extra,omitempty"`
}

type StreamState struct {
	Now      float64 `json:"now"`
	At       string  `json:"at"`
	Widening int     `json:"widening_ticks"`
}

type Trend string

type VersionRow struct {
	Unit  string
	Stamp string
}