package buildstep

import (
	"context"
	"strings"
	"sync"
	"time"

	"git.novox.be/novox/mesh-sdk/go/delivery"
)

// **A running ask says its phases** (issue 1890, 2026-10-26 19:09: a mesh-catalog try's step on shanks ran 30 minutes
// and its module's journal held no line naming its ask, so nobody could tell whether it fetched, linted or tested). The
// puller hands every ask's run a phase reporter in its context; RunAsk and a module's own step bodies call Phase as they
// move (fetch and merge, a level's digest, lint, a level's tests), and each phase is logged with the ask's id and its
// time since the start, and written to the ask's running step key (delivery.Step.Phase), so its asker and the delivery
// view read where it stands from the bus.

type phaseKey struct{}

// Phase says that the ask whose run ctx belongs to entered phase; nothing outside an ask's run (a tool called by hand).
func Phase(ctx context.Context, phase string) {
	if r, ok := ctx.Value(phaseKey{}).(*phases); ok && r != nil {
		r.enter(strings.TrimSpace(phase))
	}
}

// phases is one running ask's reporter: it writes the step key again with each new phase until the step ends.
type phases struct {
	mu     sync.Mutex
	put    Put
	key    string
	step   delivery.Step
	ended  bool
	logf   func(format string, args ...any)
	prefix string
}

func (r *phases) enter(phase string) {
	if phase == "" {
		return
	}
	r.mu.Lock()
	defer r.mu.Unlock()
	if r.ended || phase == r.step.Phase {
		return
	}
	at := now().UTC()
	r.step.Phase, r.step.PhaseAt = phase, at
	if r.logf != nil {
		r.logf("%s: %s, %s after its start", r.prefix, phase, at.Sub(r.step.Started).Round(time.Second))
	}
	if r.put == nil {
		return
	}
	if err := write(r.put, r.key, r.step); err != nil && r.logf != nil {
		r.logf("%s: the phase %s could not be written to %s: %v", r.prefix, phase, r.key, err)
	}
}

// end stops the writes (the step's end is written after it) and answers the step with its last phase, for the end.
func (r *phases) end() delivery.Step {
	r.mu.Lock()
	defer r.mu.Unlock()
	r.ended = true
	return r.step
}