// Package testutil provides shared helpers for Silo tests.
package testutil

import (
	"context"
	"fmt"
	"os"
	"path/filepath"
	"sort"
	"testing"

	"github.com/jackc/pgx/v5/pgxpool"
)

// MustConnectTestPool connects to a test database using TEST_DATABASE_URL.
// If the env var is unset the test is skipped. Migrations are applied and
// all data tables are truncated before returning. The pool is closed
// automatically when the test finishes.
func MustConnectTestPool(t *testing.T) *pgxpool.Pool {
	t.Helper()

	dsn := os.Getenv("TEST_DATABASE_URL")
	if dsn == "" {
		t.Skip("TEST_DATABASE_URL not set, skipping integration test")
	}

	pool, err := pgxpool.New(context.Background(), dsn)
	if err != nil {
		t.Fatalf("connecting to test database: %v", err)
	}
	if err := pool.Ping(context.Background()); err != nil {
		pool.Close()
		t.Fatalf("pinging test database: %v", err)
	}
	t.Cleanup(func() { pool.Close() })

	RunMigrations(t, pool)
	TruncateAll(t, pool)

	return pool
}

// RunMigrations applies all SQL migration files from the migrations/
// directory. It walks upward from the current working directory to find
// the project root (containing go.mod).
func RunMigrations(t *testing.T, pool *pgxpool.Pool) {
	t.Helper()

	root := findProjectRoot(t)
	migDir := filepath.Join(root, "migrations")
	entries, err := os.ReadDir(migDir)
	if err != nil {
		t.Fatalf("reading migrations directory: %v", err)
	}

	// Sort by filename to apply in order.
	sort.Slice(entries, func(i, j int) bool {
		return entries[i].Name() < entries[j].Name()
	})

	for _, e := range entries {
		if e.IsDir() || filepath.Ext(e.Name()) != ".sql" {
			continue
		}
		sql, err := os.ReadFile(filepath.Join(migDir, e.Name()))
		if err != nil {
			t.Fatalf("reading migration %s: %v", e.Name(), err)
		}
		if _, err := pool.Exec(context.Background(), string(sql)); err != nil {
			// Migrations may contain IF NOT EXISTS / CREATE OR REPLACE,
			// so most "already exists" errors are fine. Log and continue.
			t.Logf("migration %s: %v (may be OK if already applied)", e.Name(), err)
		}
	}
}

// TruncateAll removes all data from tables, leaving schema intact.
func TruncateAll(t *testing.T, pool *pgxpool.Pool) {
	t.Helper()

	_, err := pool.Exec(context.Background(), `
		TRUNCATE
			settings_overrides, module_state,
			job_log, jobs, job_definitions, runners,
			dag_cross_edges, dag_edges, dag_nodes,
			audit_log, sync_log, api_tokens, sessions, item_files,
			item_projects, relationships, revisions, inventory, items,
			projects, sequences_by_name, users, property_migrations
		CASCADE
	`)
	if err != nil {
		t.Fatalf("truncating tables: %v", err)
	}
}

// findProjectRoot walks upward from cwd to find the directory containing go.mod.
func findProjectRoot(t *testing.T) string {
	t.Helper()

	dir, err := os.Getwd()
	if err != nil {
		t.Fatalf("getting working directory: %v", err)
	}

	for {
		if _, err := os.Stat(filepath.Join(dir, "go.mod")); err == nil {
			return dir
		}
		parent := filepath.Dir(dir)
		if parent == dir {
			t.Fatalf("could not find project root (go.mod)")
		}
		dir = parent
	}

	panic(fmt.Sprintf("unreachable"))
}