// Copyright 2024 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package embeddocs

import (
	"context"
	"fmt"
	"testing"

	"golang.org/x/oscar/internal/docs"
	"golang.org/x/oscar/internal/llm"
	"golang.org/x/oscar/internal/storage"
	"golang.org/x/oscar/internal/testutil"
)

var texts = []string{
	"for loops",
	"for all time, always",
	"break statements",
	"breakdancing",
	"forever could never be long enough for me",
	"the macarena",
}

func checker(t *testing.T) func(error) {
	return func(err error) {
		if err != nil {
			t.Helper()
			t.Fatal(err)
		}
	}
}

var ctx = context.Background()

func TestSync(t *testing.T) {
	check := testutil.Checker(t)
	lg := testutil.Slogger(t)
	db := storage.MemDB()
	vdb := storage.MemVectorDB(db, lg, "step1")
	dc := docs.New(lg, db)
	for i, text := range texts {
		dc.Add(fmt.Sprintf("URL%d", i), "", text)
	}

	check(Sync(ctx, lg, vdb, llm.QuoteEmbedder(), dc))
	for i, text := range texts {
		vec, ok := vdb.Get(fmt.Sprintf("URL%d", i))
		if !ok {
			t.Errorf("URL%d missing from vdb", i)
			continue
		}
		vtext := llm.UnquoteVector(vec)
		if vtext != text {
			t.Errorf("URL%d decoded to %q, want %q", i, vtext, text)
		}
	}

	for i, text := range texts {
		dc.Add(fmt.Sprintf("rot13%d", i), "", testutil.Rot13(text))
	}
	vdb2 := storage.MemVectorDB(db, lg, "step2")
	check(Sync(ctx, lg, vdb2, llm.QuoteEmbedder(), dc))
	for i, text := range texts {
		vec, ok := vdb2.Get(fmt.Sprintf("URL%d", i))
		if ok {
			t.Errorf("URL%d written during second sync: %q", i, llm.UnquoteVector(vec))
			continue
		}

		vec, ok = vdb2.Get(fmt.Sprintf("rot13%d", i))
		vtext := llm.UnquoteVector(vec)
		if vtext != testutil.Rot13(text) {
			t.Errorf("rot13%d decoded to %q, want %q", i, vtext, testutil.Rot13(text))
		}
	}
}

func TestBigSync(t *testing.T) {
	const N = 10000

	check := testutil.Checker(t)
	lg := testutil.Slogger(t)
	db := storage.MemDB()
	vdb := storage.MemVectorDB(db, lg, "vdb")
	dc := docs.New(lg, db)
	for i := range N {
		dc.Add(fmt.Sprintf("URL%d", i), "", fmt.Sprintf("Text%d", i))
	}

	check(Sync(ctx, lg, vdb, llm.QuoteEmbedder(), dc))
	for i := range N {
		vec, ok := vdb.Get(fmt.Sprintf("URL%d", i))
		if !ok {
			t.Errorf("URL%d missing from vdb", i)
			continue
		}
		text := fmt.Sprintf("Text%d", i)
		vtext := llm.UnquoteVector(vec)
		if vtext != text {
			t.Errorf("URL%d decoded to %q, want %q", i, vtext, text)
		}
	}
}

func TestBadEmbedders(t *testing.T) {
	const N = 150
	lg := testutil.Slogger(t)
	db := storage.MemDB()
	dc := docs.New(lg, db)
	for i := range N {
		dc.Add(fmt.Sprintf("URL%03d", i), "", fmt.Sprintf("Text%d", i))
	}

	db = storage.MemDB()
	vdb := storage.MemVectorDB(db, lg, "vdb")
	if err := Sync(ctx, lg, vdb, tooManyEmbed{}, dc); err == nil {
		t.Errorf("tooManyEmbed did not report error")
	}

	db = storage.MemDB()
	vdb = storage.MemVectorDB(db, lg, "vdb")
	if err := Sync(ctx, lg, vdb, embedErr{}, dc); err == nil {
		t.Errorf("embedErr did not report error")
	}
	if _, ok := vdb.Get("URL001"); !ok {
		t.Errorf("Sync did not write URL001 after embedErr")
	}

	db = storage.MemDB()
	vdb = storage.MemVectorDB(db, lg, "vdb")
	if err := Sync(ctx, lg, vdb, embedHalf{}, dc); err == nil {
		t.Errorf("embedHalf did not report error")
	}
	if _, ok := vdb.Get("URL001"); !ok {
		t.Errorf("Sync did not write URL001 after embedHalf")
	}
}

type tooManyEmbed struct{}

func (tooManyEmbed) EmbedDocs(ctx context.Context, docs []llm.EmbedDoc) ([]llm.Vector, error) {
	vec, _ := llm.QuoteEmbedder().EmbedDocs(ctx, docs)
	vec = append(vec, vec...)
	return vec, nil
}

type embedErr struct{}

func (embedErr) EmbedDocs(ctx context.Context, docs []llm.EmbedDoc) ([]llm.Vector, error) {
	vec, _ := llm.QuoteEmbedder().EmbedDocs(ctx, docs)
	return vec, fmt.Errorf("EMBED ERROR")
}

type embedHalf struct{}

func (embedHalf) EmbedDocs(ctx context.Context, docs []llm.EmbedDoc) ([]llm.Vector, error) {
	vec, _ := llm.QuoteEmbedder().EmbedDocs(ctx, docs)
	vec = vec[:len(vec)/2]
	return vec, nil
}