package postgres

import (
	"database/sql"
	"errors"
	"os"
	"sync"
	"testing"
	"time"

	"gardomatic.kleiax.de/internal/storage"
)

func TestGeneratedTaskInsertIsIdempotentUnderConcurrency(t *testing.T) {
	dsn := os.Getenv("GARDOMATIC_TEST_DB_DSN")
	if dsn == "" {
		t.Skip("set GARDOMATIC_TEST_DB_DSN to run PostgreSQL integration tests")
	}
	db, err := sql.Open("postgres", dsn)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { _ = db.Close() })
	if err := db.Ping(); err != nil {
		t.Fatal(err)
	}
	var userID, gardenID, speciesID, plantID, templateID int
	if err := db.QueryRow(`INSERT INTO users (name, email, password_hash, activated) VALUES ('Generator integration', $1, 'hash', true) RETURNING id`, "generator-"+time.Now().Format("150405.000000000")+"@example.com").Scan(&userID); err != nil {
		t.Fatal(err)
	}
	if err := db.QueryRow(`INSERT INTO gardens (name) VALUES ('Generator integration') RETURNING id`).Scan(&gardenID); err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() {
		_, _ = db.Exec(`DELETE FROM gardens WHERE id = $1`, gardenID)
		_, _ = db.Exec(`DELETE FROM users WHERE id = $1`, userID)
	})
	if err := db.QueryRow(`INSERT INTO species (garden_id, common_name) VALUES ($1, 'Parallelrose') RETURNING id`, gardenID).Scan(&speciesID); err != nil {
		t.Fatal(err)
	}
	if err := db.QueryRow(`INSERT INTO plants (garden_id, species_id, name) VALUES ($1, $2, 'Rose') RETURNING id`, gardenID, speciesID).Scan(&plantID); err != nil {
		t.Fatal(err)
	}
	if err := db.QueryRow(`INSERT INTO species_task_templates (species_id, title, trigger_type, month_from, month_to) VALUES ($1, 'Schneiden', 'month_of_year', 2, 3) RETURNING id`, speciesID).Scan(&templateID); err != nil {
		t.Fatal(err)
	}

	generatedFor := time.Date(2026, 2, 1, 0, 0, 0, 0, time.UTC)
	dueStart, dueEnd := generatedFor, time.Date(2026, 3, 31, 23, 59, 59, 0, time.UTC)
	model := TaskModel{DB: db}
	const workers = 12
	results := make(chan error, workers)
	var wg sync.WaitGroup
	for range workers {
		wg.Add(1)
		go func() {
			defer wg.Done()
			_, err := model.Insert(storage.Task{GardenID: gardenID, PlantID: &plantID, TemplateID: &templateID, Title: "Schneiden", DueAtStart: &dueStart, DueAtEnd: &dueEnd, GeneratedFor: &generatedFor, CreatedBy: userID})
			results <- err
		}()
	}
	wg.Wait()
	close(results)
	successes, conflicts := 0, 0
	for err := range results {
		if err == nil {
			successes++
		} else if errors.Is(err, storage.ErrConflict) {
			conflicts++
		} else {
			t.Fatalf("insert error: %v", err)
		}
	}
	if successes != 1 || conflicts != workers-1 {
		t.Fatalf("successes=%d conflicts=%d", successes, conflicts)
	}
	var count int
	if err := db.QueryRow(`SELECT count(*) FROM tasks WHERE plant_id = $1 AND template_id = $2 AND generated_for = $3`, plantID, templateID, generatedFor).Scan(&count); err != nil || count != 1 {
		t.Fatalf("count=%d err=%v", count, err)
	}
}