package httpapi

import (
	"textmachine/platform/internal/ingest"
	"textmachine/platform/internal/pgstore"
)

// project.go: the read model as the contract's shapes.
//
// Everything here is a TRANSLATION and not a forwarding. Three vocabularies meet at this line — the
// engine's, the platform's own and the contract's — and the rule is the same for all three: what
// leaves is the contract's, and a value this build cannot map leaves as `null` rather than as a word
// a generated client's union does not contain.

func projectBook(b pgstore.Book) wireBook {
	out := wireBook{
		ID: b.ID, Revision: b.Revision, Title: b.Title,
		SourceLang: b.SourceLang, TargetLang: b.TargetLang,
		Status:           b.Status,
		StructureVersion: b.StructureVersion,
		ChapterCount:     b.ChapterCount,
		ChaptersDone:     b.ChaptersDone,
		AddedAt:          b.AddedAt,
		NoteCount:        b.NoteCount,
	}
	// `null` while the book is still arriving: the size is counted as the bytes go past, so a book
	// that is still on the wire has no size yet — which is a different fact from "zero characters".
	if b.Status != "uploading" {
		count := b.CharacterCount
		out.CharacterCount = &count
	}
	if reason := ingest.ContractRejectReason(b.RejectReason); reason != "" {
		out.RejectReason = &reason
	}
	return out
}

func projectRun(r pgstore.Run) wireRun {
	out := wireRun{
		ID: r.ID, BookID: r.BookID, Revision: r.Revision, Status: r.Status,
		// ⚠ The wire name is the product's and the column's is the engine flag's (`--verify-bank`).
		// They are deliberately different words for the same bit: what the user chose is "stop so I
		// can look at the terms", and the flag is how that reaches the engine.
		StopForSigning: r.VerifyBank,
		// The user's own click, which no `status` answers: a stop asked for mid-translation can meet
		// the run reaching the bank signature, and `awaiting_bank` then offers to continue on a click
		// that meant "stop". REQUIRED and never omitted — no stop is `false`, and an absent field
		// would be a second way of writing the same fact.
		StopRequested:   r.StopRequested,
		CeilingChapters: r.CeilingChapters,
		Progress: wireProgress{
			Done: r.Progress.Done, Total: r.Progress.Total, Stage: r.Progress.Stage,
			ETASeconds: r.Progress.ETASeconds,
		},
		StartedAt: r.StartedAt, FinishedAt: r.FinishedAt,
	}
	if reason := ingest.ContractPausedReason(r.PausedReason); reason != "" {
		out.PausedReason = &reason
	}
	if r.FailureReason != "" {
		out.FailureReason = &r.FailureReason
	}
	return out
}

func projectChapter(c pgstore.Chapter) wireChapter {
	return wireChapter{
		ID: c.ID, Number: c.Number,
		// ⚠ ALWAYS `null` today, and that is the contract being obeyed rather than a hole. The engine's
		// manifest carries a `heading`, and it is a deterministic render of the pair's heading rule
		// («Глава N») — the engine's own comment forbids presenting it as a label carried by the book,
		// and the canon forbids a deployment to put a rendered ordinal in this field. A client with no
		// label renders its own ordinal, in the language of ITS interface, which the server does not
		// know. Real labels need a producer that does not exist yet (engine backlog row 160).
		Heading:    nil,
		UnitsTotal: c.UnitsTotal,
		UnitsDone:  c.UnitsDone,
		NoteCount:  c.NoteCount,
	}
}

func projectUnit(u pgstore.Unit) wireUnit {
	out := wireUnit{
		ID: u.ID, Source: u.Source, Target: u.Target, State: u.State,
		Notes: make([]wireNote, 0, len(u.Notes)),
	}
	for _, n := range u.Notes {
		out.Notes = append(out.Notes, projectNote(n))
	}
	return out
}

func projectNote(n pgstore.Note) wireNote {
	code, severity := ingest.NoteCode(n.Reason)
	out := wireNote{
		ID: n.ID, CreatedAt: n.CreatedAt, Severity: severity, Code: code, ChapterID: n.ChapterID,
	}
	if n.UnitID != "" {
		out.UnitID = &n.UnitID
	}
	return out
}

func projectTerm(t pgstore.BankTerm) wireTerm {
	out := wireTerm{
		ID: t.ID, Src: t.Src, Dst: t.Dst, Status: t.Status, Origin: t.Origin, Sense: t.Sense,
		SinceChapter: t.Since, UntilChapter: t.Until,
	}
	if t.Kind != "" {
		kind := t.Kind
		out.Kind = &kind
	}
	return out
}