package beachcomber_test

import (
	"context"
	"fmt"
	"slices"
	"strconv"
	"strings"
	"sync"
	"testing"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/beachcomber"
	"git.golem15.com/golem15/summercms/modules/compass"
	"git.golem15.com/golem15/summercms/modules/lagoon"
	"gorm.io/gorm"
)

// Post is the acme.blog post model. It implements beachcomber.Searchable
// without importing beachcomber.
type Post struct {
	ID        uint   `gorm:"column:id;primaryKey"`
	BlogID    uint   `gorm:"column:blog_id"`
	Title     string `gorm:"column:title"`
	Published bool   `gorm:"column:published"`
}

func (Post) TableName() string { return "acme_blog_posts" }

// SearchableAs is the index name, before search.prefix.
func (Post) SearchableAs() string { return "acme_blog_posts" }

// ShouldBeSearchable keeps drafts out of the index.
func (p *Post) ShouldBeSearchable() bool { return p.Published }

// ToSearchableArray builds the document from the committed row.
func (p *Post) ToSearchableArray(ctx context.Context, db *gorm.DB) (map[string]any, error) {
	return map[string]any{
		"id":      strconv.FormatUint(uint64(p.ID), 10),
		"blog_id": int64(p.BlogID),
		"title":   p.Title,
	}, nil
}

// memoryEngine is a toy engine: it matches Q against the title and ignores
// FilterBy, so its answers are loose candidates, as a stale index's are.
type memoryEngine struct {
	mu   sync.Mutex
	docs map[string]map[string]map[string]any // index -> id -> document
}

func (e *memoryEngine) Name() string     { return "acme-memory" }
func (e *memoryEngine) Configured() bool { return true }

func (e *memoryEngine) Upsert(ctx context.Context, index string, schema map[string]any, docs []map[string]any) error {
	e.mu.Lock()
	defer e.mu.Unlock()
	if e.docs[index] == nil {
		e.docs[index] = map[string]map[string]any{}
	}
	for _, d := range docs {
		e.docs[index][fmt.Sprint(d["id"])] = d
	}
	return nil
}

func (e *memoryEngine) Delete(ctx context.Context, index string, ids []string) error {
	e.mu.Lock()
	defer e.mu.Unlock()
	for _, id := range ids {
		delete(e.docs[index], id)
	}
	return nil
}

func (e *memoryEngine) Flush(ctx context.Context, index string) error {
	e.mu.Lock()
	defer e.mu.Unlock()
	delete(e.docs, index)
	return nil
}

func (e *memoryEngine) SearchIDs(ctx context.Context, index string, q beachcomber.Query) ([]string, error) {
	e.mu.Lock()
	defer e.mu.Unlock()
	ids := []string{}
	for id, d := range e.docs[index] {
		if strings.Contains(strings.ToLower(fmt.Sprint(d["title"])), strings.ToLower(q.Q)) {
			ids = append(ids, id)
		}
	}
	slices.Sort(ids)
	return ids, nil
}

var memory = &memoryEngine{docs: map[string]map[string]map[string]any{}}

func ExampleFrom() {
	cfg, err := compass.Open(compass.Options{Dir: "config", Env: "development", Environ: []string{}})
	if err != nil {
		fmt.Println(err)
		return
	}
	_ = cfg.Set("search.prefix", "staging_")
	svc, err := beachcomber.From(backpack.New(cfg)) // search.driver defaults to null
	if err != nil {
		fmt.Println(err)
		return
	}
	fmt.Println(svc.Engine().Name(), svc.Engine().Configured(), svc.IndexName(&Post{}))
	ids, err := svc.Engine().SearchIDs(context.Background(), svc.IndexName(&Post{}), beachcomber.Query{Q: "go"})
	fmt.Println(ids, err)

	_ = cfg.Set("search.driver", "elastic")
	_, err = beachcomber.From(backpack.New(cfg))
	fmt.Println(err != nil)
	// Output:
	// null false staging_acme_blog_posts
	// [] <nil>
	// true
}

// installGate turns search sync on only while the blog's search setting is
// on; a failed read counts as off.
func installGate(svc *beachcomber.Service) {
	// docs:start gate
	svc.SetGate(beachcomber.GateFunc(func(ctx context.Context, db *gorm.DB) bool {
		var enabled bool
		err := db.WithContext(ctx).Raw(`SELECT search_enabled FROM acme_blog_settings WHERE id = 1`).Scan(&enabled).Error
		return err == nil && enabled
	}))
	// docs:end gate
}

// searchPosts answers a search in one blog.
func searchPosts(ctx context.Context, svc *beachcomber.Service, db *gorm.DB, blogID uint, term string) ([]Post, error) {
	// docs:start search
	ids, err := svc.Engine().SearchIDs(ctx, svc.IndexName(&Post{}), beachcomber.Query{
		Q:        term,
		QueryBy:  []string{"title"},
		FilterBy: "blog_id:=" + strconv.FormatUint(uint64(blogID), 10),
	})
	if err != nil {
		return nil, err
	}
	// The ids are candidates from an index that may be stale or loosely
	// filtered: re-check every one in SQL before exposing a row.
	var posts []Post
	err = db.WithContext(ctx).
		Where("id IN ? AND blog_id = ? AND published", ids, blogID).
		Order("id").
		Find(&posts).Error
	return posts, err
	// docs:end search
}

// TestDocsSearch runs the gate and search regions of the Search page on the
// package's Postgres harness.
func TestDocsSearch(t *testing.T) {
	app, db := beachcomber.DocsApp(t, nil)
	for _, stmt := range []string{
		`CREATE TABLE acme_blog_posts (id SERIAL PRIMARY KEY, blog_id INTEGER NOT NULL, title TEXT NOT NULL, published BOOLEAN NOT NULL DEFAULT FALSE)`,
		`CREATE TABLE acme_blog_settings (id INTEGER PRIMARY KEY, search_enabled BOOLEAN NOT NULL)`,
		`INSERT INTO acme_blog_settings VALUES (1, TRUE)`,
	} {
		if err := db.Exec(stmt).Error; err != nil {
			t.Fatal(err)
		}
	}
	svc, err := beachcomber.From(app)
	if err != nil {
		t.Fatal(err)
	}
	// An application selects a registered engine with search.driver; the
	// test installs the toy engine directly, so the global engine list the
	// package's own tests check stays unchanged.
	beachcomber.DocsUseEngine(svc, memory)
	installGate(svc)
	ctx := t.Context()
	indexed := func() int {
		memory.mu.Lock()
		defer memory.mu.Unlock()
		return len(memory.docs[svc.IndexName(&Post{})])
	}

	// A committed write is indexed after commit; a rolled-back one never is.
	create := func(p *Post, fail bool) error {
		return lagoon.Transaction(ctx, db, func(ctx context.Context, tx *gorm.DB) error {
			if err := tx.Create(p).Error; err != nil {
				return err
			}
			if fail {
				return fmt.Errorf("rolled back")
			}
			return nil
		})
	}
	hello := &Post{BlogID: 7, Title: "Hello Go", Published: true}
	if err := create(hello, false); err != nil {
		t.Fatal(err)
	}
	if err := create(&Post{BlogID: 7, Title: "Go rolled back", Published: true}, true); err == nil {
		t.Fatal("rolled-back create succeeded")
	}
	if err := create(&Post{BlogID: 8, Title: "Go elsewhere", Published: true}, false); err != nil {
		t.Fatal(err)
	}
	if n := indexed(); n != 2 {
		t.Fatalf("indexed %d documents, want 2", n)
	}

	// The engine answers both blogs; SQL keeps blog 7's post only.
	posts, err := searchPosts(ctx, svc, db, 7, "go")
	if err != nil {
		t.Fatal(err)
	}
	if len(posts) != 1 || posts[0].ID != hello.ID {
		t.Fatalf("search = %+v", posts)
	}

	// A write in a plain GORM transaction is not synced, so the index keeps
	// the stale document; the SQL re-check still hides the draft.
	if err := db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		return tx.Model(hello).Update("published", false).Error
	}); err != nil {
		t.Fatal(err)
	}
	if n := indexed(); n != 2 {
		t.Fatalf("indexed %d documents after an unsynced write, want 2", n)
	}
	if posts, err = searchPosts(ctx, svc, db, 7, "go"); err != nil || len(posts) != 0 {
		t.Fatalf("search after unpublish = %+v, %v", posts, err)
	}

	// With the gate off nothing is sent.
	if err := db.Exec(`UPDATE acme_blog_settings SET search_enabled = FALSE`).Error; err != nil {
		t.Fatal(err)
	}
	if err := create(&Post{BlogID: 7, Title: "Go quietly", Published: true}, false); err != nil {
		t.Fatal(err)
	}
	if n := indexed(); n != 2 {
		t.Fatalf("indexed %d documents with the gate off, want 2", n)
	}
}

// TestDocsDeclarations checks the Searchable methods the Search page shows.
func TestDocsDeclarations(t *testing.T) {
	var _ beachcomber.Searchable = &Post{}
	p := &Post{ID: 5, BlogID: 7, Title: "Hello", Published: true}
	if p.SearchableAs() != "acme_blog_posts" || !p.ShouldBeSearchable() {
		t.Fatalf("SearchableAs %q, ShouldBeSearchable %v", p.SearchableAs(), p.ShouldBeSearchable())
	}
	doc, err := p.ToSearchableArray(t.Context(), nil)
	if err != nil || doc["id"] != "5" || doc["blog_id"] != int64(7) {
		t.Fatalf("ToSearchableArray = %v, %v", doc, err)
	}
}