package suggestions

import (
	"encoding/json"
	"net/http"
	"testing"

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

// The offline rule pack and the LLM now share the collocation family, which is
// the point: the writer sees one rail and is never told which engine spoke. What
// makes that safe is `source` — each pass replaces only its own rows. These tests
// pin the two ways that could go wrong, both of which the old type-scoped DELETEs
// would have hit.

// pendingOfType counts the pending rows of one family in a response body.
func pendingOfType(got []db.Suggestion, typ string) []db.Suggestion {
	var out []db.Suggestion
	for _, s := range got {
		if s.Type == typ {
			out = append(out, s)
		}
	}
	return out
}

// TestOfflineCollocationFilesAsCollocation proves a miscollocation the rule pack
// found is stored in the collocation family (so accepting it plants a garden
// card, exactly as the coach's would) while still being marked as locally found.
func TestOfflineCollocationFilesAsCollocation(t *testing.T) {
	srv, docID, _ := newTestServer(t, &stubClient{response: `{"suggestions":[]}`})

	got := postMechanics(t, srv, docID, `[
		{"from":0,"to":13,"original":"do a decision","replacement":"make a decision","explanation":"pairing","type":"collocation"},
		{"from":20,"to":27,"original":"the the","replacement":"the","explanation":"doubled word","type":"mechanics"}
	]`)
	if len(got) != 2 {
		t.Fatalf("want both findings, got %+v", got)
	}
	coll := pendingOfType(got, db.SuggestionTypeCollocation)
	if len(coll) != 1 {
		t.Fatalf("want 1 collocation, got %+v", got)
	}
	if coll[0].Source != db.SuggestionSourceLocal {
		t.Errorf("offline finding should be source=local, got %q", coll[0].Source)
	}
	if mech := pendingOfType(got, db.SuggestionTypeMechanics); len(mech) != 1 {
		t.Fatalf("want 1 mechanics finding, got %+v", got)
	}
}

// TestUnknownLocalTypeFallsBackToMechanics: a family the offline pass isn't
// allowed to claim (or an older client sending none at all) must land in
// mechanics. Otherwise a stray label would smuggle a row into an LLM family,
// where nothing would ever replace it.
func TestUnknownLocalTypeFallsBackToMechanics(t *testing.T) {
	srv, docID, _ := newTestServer(t, &stubClient{response: `{"suggestions":[]}`})

	got := postMechanics(t, srv, docID, `[
		{"from":0,"to":5,"original":"aaaaa","replacement":"bbbbb","explanation":"x","type":"voice"},
		{"from":6,"to":11,"original":"ccccc","replacement":"ddddd","explanation":"y"}
	]`)
	if len(got) != 2 {
		t.Fatalf("want 2 findings, got %+v", got)
	}
	for _, s := range got {
		if s.Type != db.SuggestionTypeMechanics {
			t.Errorf("offline finding claimed family %q; only mechanics/collocation are allowed", s.Type)
		}
	}
}

// TestCoachDoesNotWipeOfflineCollocations is the collision the source column
// exists for: the LLM collocation pass replaces the collocation family, and the
// rule pack's share of that family has to survive it. Before `source`, running
// the coach silently deleted every offline chunk on the page.
func TestCoachDoesNotWipeOfflineCollocations(t *testing.T) {
	client := &stubClient{response: `{"suggestions":[
		{"original":"apple","replacement":"an apple","explanation":"article","type":"collocation"}
	]}`}
	srv, docID, _ := newTestServer(t, client)

	// The seeded doc is "I has two apple." — the coach's flag anchors on "apple"
	// at [10,15], so the offline finding is given a span well clear of it. Two
	// findings fighting over the same characters is a different rule (see
	// TestOfflineCardWinsSpanCollision); this test is about the DELETE.
	postMechanics(t, srv, docID, `[
		{"from":0,"to":5,"original":"do a decision","replacement":"make a decision","explanation":"pairing","type":"collocation"}
	]`)

	rec := do(t, srv, http.MethodPost, "/docs/"+docID+"/collocation", "")
	if rec.Code != http.StatusOK {
		t.Fatalf("collocation pass: code=%d body=%s", rec.Code, rec.Body)
	}
	var got []db.Suggestion
	if err := json.Unmarshal(rec.Body.Bytes(), &got); err != nil {
		t.Fatalf("decode: %v", err)
	}

	var local, llm int
	for _, s := range pendingOfType(got, db.SuggestionTypeCollocation) {
		if s.Source == db.SuggestionSourceLocal {
			local++
		} else {
			llm++
		}
	}
	if local != 1 {
		t.Errorf("the coach wiped the offline collocation: local=%d, got %+v", local, got)
	}
	if llm != 1 {
		t.Errorf("want the coach's own flag alongside it: llm=%d, got %+v", llm, got)
	}
}

// TestOfflinePassReplacesItsOwnCollocations is the mirror: the rule pack
// recomputes the whole document every run, so a chunk the current text no longer
// warrants must go — and the coach's flags must stay. Scoping the offline DELETE
// by type instead of source would have stranded the first row forever.
func TestOfflinePassReplacesItsOwnCollocations(t *testing.T) {
	client := &stubClient{response: `{"suggestions":[
		{"original":"apple","replacement":"an apple","explanation":"article","type":"collocation"}
	]}`}
	srv, docID, _ := newTestServer(t, client)

	// A coach flag, then an offline chunk, then a rerun that no longer finds it.
	do(t, srv, http.MethodPost, "/docs/"+docID+"/collocation", "")
	postMechanics(t, srv, docID, `[
		{"from":0,"to":13,"original":"do a decision","replacement":"make a decision","explanation":"pairing","type":"collocation"}
	]`)
	got := postMechanics(t, srv, docID, `[]`)

	for _, s := range got {
		if s.Source == db.SuggestionSourceLocal {
			t.Errorf("stale offline finding survived a recompute: %+v", s)
		}
	}
	if len(pendingOfType(got, db.SuggestionTypeCollocation)) != 1 {
		t.Fatalf("the coach's own flag should be untouched, got %+v", got)
	}
}

// TestOfflineCollocationPlantsOnAccept closes the loop the family split was for:
// a chunk the rule pack found, accepted, becomes a vocabulary-garden card — with
// no model involved anywhere in the path.
func TestOfflineCollocationPlantsOnAccept(t *testing.T) {
	srv, docID, h := newTestServer(t, &stubClient{response: `{"suggestions":[]}`})
	if _, err := h.DB.Exec(
		`UPDATE documents SET content_text = ? WHERE id = ?`,
		"I had to do a decision about the job.", docID,
	); err != nil {
		t.Fatalf("set content: %v", err)
	}

	got := postMechanics(t, srv, docID, `[
		{"from":9,"to":22,"original":"do a decision","replacement":"make a decision","explanation":"pairing","type":"collocation"}
	]`)
	if len(got) != 1 {
		t.Fatalf("want the offline chunk, got %+v", got)
	}
	if rec := do(t, srv, http.MethodPost, "/suggestions/"+got[0].ID+"/accept", ""); rec.Code != http.StatusNoContent {
		t.Fatalf("accept: code=%d body=%s", rec.Code, rec.Body)
	}

	cards := gardenCards(t, h)
	if len(cards) != 1 || cards[0].word != "make a decision" {
		t.Fatalf("want a planted phrase card, got %+v", cards)
	}
	// The example is the corrected sentence — the phrasing she kept, not the one
	// she just left behind.
	if cards[0].example != "I had to make a decision about the job." {
		t.Errorf("example should be the corrected sentence, got %q", cards[0].example)
	}
}

// TestOfflineCardWinsSpanCollision: the tiebreak is by engine, not by family. An
// offline miscollocation has an exact span; the coach's overlapping flag is only
// advisory, so it is the one that goes.
func TestOfflineCardWinsSpanCollision(t *testing.T) {
	client := &stubClient{response: `{"suggestions":[
		{"original":"do a decision about","replacement":"decide about","explanation":"wordy","type":"collocation"}
	]}`}
	srv, docID, h := newTestServer(t, client)
	if _, err := h.DB.Exec(
		`UPDATE documents SET content_text = ? WHERE id = ?`,
		"I had to do a decision about the job.", docID,
	); err != nil {
		t.Fatalf("set content: %v", err)
	}

	do(t, srv, http.MethodPost, "/docs/"+docID+"/collocation", "")
	got := postMechanics(t, srv, docID, `[
		{"from":9,"to":22,"original":"do a decision","replacement":"make a decision","explanation":"pairing","type":"collocation"}
	]`)

	if len(got) != 1 {
		t.Fatalf("want the overlapping coach flag dropped, got %+v", got)
	}
	if got[0].Source != db.SuggestionSourceLocal {
		t.Errorf("the exact offline card should own the span, got %+v", got[0])
	}
}