package suggestions

import (
	"net/http"
	"testing"

	"gitea.parodia.dev/drwily/petal/internal/db"
)

// seedSuggestion writes one pending suggestion against the seeded doc, after
// replacing the doc's text so the sentence around `original` is under the test's
// control.
func seedSuggestion(t *testing.T, h *Handler, docID, text, sType, original, replacement, explanation string) string {
	t.Helper()
	if _, err := h.DB.Exec(`UPDATE documents SET content_text = ? WHERE id = ?`, text, docID); err != nil {
		t.Fatalf("set content: %v", err)
	}
	var id string
	err := h.DB.QueryRow(
		`INSERT INTO suggestions (doc_id, from_pos, to_pos, original, replacement, explanation, type, status)
		 VALUES (?, 0, 0, ?, ?, ?, ?, 'pending') RETURNING id`,
		docID, original, replacement, explanation, sType,
	).Scan(&id)
	if err != nil {
		t.Fatalf("seed suggestion: %v", err)
	}
	return id
}

type card struct {
	word, definition, example string
	interval                  int
}

func gardenCards(t *testing.T, h *Handler) []card {
	t.Helper()
	rows, err := h.DB.Query(
		`SELECT word, definition, example, interval_days FROM vocab_words WHERE user_id = ? ORDER BY word`,
		db.LocalUserID,
	)
	if err != nil {
		t.Fatalf("read garden: %v", err)
	}
	defer rows.Close()
	var out []card
	for rows.Next() {
		var c card
		if err := rows.Scan(&c.word, &c.definition, &c.example, &c.interval); err != nil {
			t.Fatalf("scan: %v", err)
		}
		out = append(out, c)
	}
	return out
}

// TestAcceptedCollocationIsPlanted walks the whole hand-over: a collocation the
// writer accepts becomes a phrase card whose example is the *corrected*
// sentence, so the flashcard quizzes the phrasing she kept.
func TestAcceptedCollocationIsPlanted(t *testing.T) {
	srv, docID, h := newTestServer(t, &stubClient{})
	id := seedSuggestion(t, h, docID,
		"Yesterday was hard. I had to do a decision about the job. Then I slept.",
		db.SuggestionTypeCollocation, "do a decision", "make a decision",
		"English pairs “make” with “decision”.")

	if rec := do(t, srv, http.MethodPost, "/suggestions/"+id+"/accept", ""); rec.Code != http.StatusNoContent {
		t.Fatalf("accept: got %d, want 204", rec.Code)
	}

	cards := gardenCards(t, h)
	if len(cards) != 1 {
		t.Fatalf("garden has %d cards, want 1: %+v", len(cards), cards)
	}
	got := cards[0]
	if got.word != "make a decision" {
		t.Errorf("word = %q, want %q", got.word, "make a decision")
	}
	if got.example != "I had to make a decision about the job." {
		t.Errorf("example = %q — want the corrected sentence, bounded to its own sentence", got.example)
	}
	if got.definition != "English pairs “make” with “decision”." {
		t.Errorf("definition = %q, want the explanation", got.definition)
	}
	if got.interval != 1 {
		t.Errorf("interval_days = %d, want 1 (due tomorrow, like a fresh capture)", got.interval)
	}
}

// TestOnlyCollocationsArePlanted: the other families correct this sentence and
// hand over nothing reusable. A dismissed collocation is not a lesson either.
func TestOnlyCollocationsArePlanted(t *testing.T) {
	srv, docID, h := newTestServer(t, &stubClient{})

	grammar := seedSuggestion(t, h, docID, "I has two apples.",
		db.SuggestionTypeGrammar, "I has", "I have", "Subject–verb agreement.")
	if rec := do(t, srv, http.MethodPost, "/suggestions/"+grammar+"/accept", ""); rec.Code != http.StatusNoContent {
		t.Fatalf("accept grammar: got %d", rec.Code)
	}

	dismissed := seedSuggestion(t, h, docID, "We must take a photo of it.",
		db.SuggestionTypeCollocation, "do a photo", "take a photo", "Photos are taken.")
	if rec := do(t, srv, http.MethodPost, "/suggestions/"+dismissed+"/dismiss", ""); rec.Code != http.StatusNoContent {
		t.Fatalf("dismiss: got %d", rec.Code)
	}

	if cards := gardenCards(t, h); len(cards) != 0 {
		t.Fatalf("garden grew %d card(s) from a grammar fix and a dismissal: %+v", len(cards), cards)
	}
}

// TestPlantingIsIdempotentAndNeverResets: accepting the same chunk again is
// evidence it's still being learned — the worst possible response is to wipe the
// card's first context and the schedule it has been climbing.
func TestPlantingIsIdempotentAndNeverResets(t *testing.T) {
	srv, docID, h := newTestServer(t, &stubClient{})
	first := seedSuggestion(t, h, docID, "I had to do a decision.",
		db.SuggestionTypeCollocation, "do a decision", "make a decision", "First explanation.")
	if rec := do(t, srv, http.MethodPost, "/suggestions/"+first+"/accept", ""); rec.Code != http.StatusNoContent {
		t.Fatalf("accept: got %d", rec.Code)
	}
	// The card climbs a little.
	if _, err := h.DB.Exec(
		`UPDATE vocab_words SET reps = 3, interval_days = 7 WHERE user_id = ? AND word = 'make a decision'`,
		db.LocalUserID,
	); err != nil {
		t.Fatalf("advance card: %v", err)
	}

	second := seedSuggestion(t, h, docID, "Later I must do a decision again.",
		db.SuggestionTypeCollocation, "do a decision", "make a decision", "Second explanation.")
	if rec := do(t, srv, http.MethodPost, "/suggestions/"+second+"/accept", ""); rec.Code != http.StatusNoContent {
		t.Fatalf("accept again: got %d", rec.Code)
	}

	cards := gardenCards(t, h)
	if len(cards) != 1 {
		t.Fatalf("garden has %d cards, want 1 (one chunk, one card)", len(cards))
	}
	if cards[0].definition != "First explanation." {
		t.Errorf("definition = %q — the existing card should win", cards[0].definition)
	}
	if cards[0].example != "I had to make a decision." {
		t.Errorf("example = %q — the first context should survive", cards[0].example)
	}
	if cards[0].interval != 7 {
		t.Errorf("interval_days = %d, want 7 — progress must not be reset", cards[0].interval)
	}
}

// TestSentenceRewriteIsNotAPhraseCard: a "collocation" long enough to be a
// rewritten sentence makes a miserable flashcard, so it is dropped rather than
// planted — and the accept still succeeds.
func TestSentenceRewriteIsNotAPhraseCard(t *testing.T) {
	srv, docID, h := newTestServer(t, &stubClient{})
	long := "I would like to take this opportunity to thank you for everything"
	id := seedSuggestion(t, h, docID, "I want thank you for everything.",
		db.SuggestionTypeCollocation, "I want thank you for everything", long, "More natural.")
	if rec := do(t, srv, http.MethodPost, "/suggestions/"+id+"/accept", ""); rec.Code != http.StatusNoContent {
		t.Fatalf("accept: got %d, want 204 — a skipped card must never fail the accept", rec.Code)
	}
	if cards := gardenCards(t, h); len(cards) != 0 {
		t.Fatalf("planted a sentence as a phrase card: %+v", cards)
	}
}

func TestCorrectedSentence(t *testing.T) {
	const text = "One thing. I had to do a decision fast! Another thing."
	cases := []struct {
		name, original, replacement, want string
	}{
		{"bounded to its sentence", "do a decision", "make a decision", "I had to make a decision fast!"},
		{"original no longer present", "do a choice", "make a choice", ""},
		{"empty original", "", "make a decision", ""},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			if got := correctedSentence(text, tc.original, tc.replacement); got != tc.want {
				t.Errorf("correctedSentence = %q, want %q", got, tc.want)
			}
		})
	}
	// A document with no terminator at all is one sentence, and still works.
	if got := correctedSentence("i had to do a decision", "do a decision", "make a decision"); got != "i had to make a decision" {
		t.Errorf("unterminated doc: got %q", got)
	}
}

// TestPlantedPhraseCarriesTheDocumentLanguage: a chunk planted out of a document
// written in her own language is a card in that language. The collocation pass
// itself deliberately did not flip in Phase 28 — its prompt is per-language
// knowledge, not framing — but the phrase it hands over is still lifted from her
// prose, so the card has to know what language that prose was in or the garden
// will read it aloud in the wrong voice.
func TestPlantedPhraseCarriesTheDocumentLanguage(t *testing.T) {
	srv, docID, h := newTestServer(t, &stubClient{})
	if _, err := h.DB.Exec(`UPDATE documents SET doc_lang = 'pair' WHERE id = ?`, docID); err != nil {
		t.Fatalf("set doc_lang: %v", err)
	}
	id := seedSuggestion(t, h, docID,
		"Ontem foi difícil. Tive de tomar uma decisão sobre o trabalho.",
		db.SuggestionTypeCollocation, "tomar uma decisão", "tomar uma decisão",
		"Em português diz-se “tomar” uma decisão.")

	if rec := do(t, srv, http.MethodPost, "/suggestions/"+id+"/accept", ""); rec.Code != http.StatusNoContent {
		t.Fatalf("accept: got %d, want 204", rec.Code)
	}

	var lang string
	if err := h.DB.QueryRow(
		`SELECT lang FROM vocab_words WHERE user_id = ? AND word = ?`,
		db.LocalUserID, "tomar uma decisão",
	).Scan(&lang); err != nil {
		t.Fatalf("read planted card: %v", err)
	}
	if lang != "pair" {
		t.Fatalf("planted card lang = %q, want pair", lang)
	}
}

// TestPlantedPhraseOnAnEnglishDocumentIsUnchanged is the other half, and the one
// every account is on today: an English document plants an English card, and the
// empty backfill and 'en' both mean that.
func TestPlantedPhraseOnAnEnglishDocumentIsUnchanged(t *testing.T) {
	srv, docID, h := newTestServer(t, &stubClient{})
	id := seedSuggestion(t, h, docID, "I had to do a decision about the job.",
		db.SuggestionTypeCollocation, "do a decision", "make a decision",
		"English pairs “make” with “decision”.")

	if rec := do(t, srv, http.MethodPost, "/suggestions/"+id+"/accept", ""); rec.Code != http.StatusNoContent {
		t.Fatalf("accept: got %d, want 204", rec.Code)
	}

	var lang string
	if err := h.DB.QueryRow(
		`SELECT lang FROM vocab_words WHERE user_id = ? AND word = ?`,
		db.LocalUserID, "make a decision",
	).Scan(&lang); err != nil {
		t.Fatalf("read planted card: %v", err)
	}
	if lang == "pair" {
		t.Fatalf("planted card lang = %q on an English document, want en or empty", lang)
	}
}