package main

import (
	"os"
	"path/filepath"
	"testing"
)

func newTestStore(t *testing.T) *Store {
	t.Helper()
	s, err := NewStore(filepath.Join(t.TempDir(), "test.db"))
	if err != nil {
		t.Fatalf("NewStore() failed: %v", err)
	}
	t.Cleanup(func() { s.Close() })
	return s
}

func TestStore_CreateAndFindByCode(t *testing.T) {
	s := newTestStore(t)

	originalURL := "https://example.com/create-and-find"

	if err := s.Create("testabc", originalURL); err != nil {
		t.Fatalf("Create() failed: %v", err)
	}

	rec, err := s.FindByCode("testabc")
	if err != nil {
		t.Fatalf("FindByCode() failed: %v", err)
	}
	if rec == nil {
		t.Fatal("FindByCode() returned nil, expected a record")
	}
	if rec.OriginalURL != originalURL {
		t.Fatalf("expected OriginalURL %q, got %q", originalURL, rec.OriginalURL)
	}
	if rec.Code != "testabc" {
		t.Fatalf("expected Code %q, got %q", "testabc", rec.Code)
	}
}

func TestStore_FindByCode_NonExistent(t *testing.T) {
	s := newTestStore(t)

	rec, err := s.FindByCode("nonexist")
	if err != nil {
		t.Fatalf("FindByCode() for non-existent code failed: %v", err)
	}
	if rec != nil {
		t.Fatal("expected nil for non-existent code, got a record")
	}
}

func TestStore_Create_Duplicate(t *testing.T) {
	s := newTestStore(t)

	url := "https://example.com/dup"
	if err := s.Create("dupcode", url); err != nil {
		t.Fatalf("first Create() failed: %v", err)
	}
	if err := s.Create("dupcode", url); err == nil {
		t.Fatal("second Create() with same code should fail")
	}
}

func TestStore_Persistence(t *testing.T) {
	tmpFile, err := os.CreateTemp("", "shortlink-*.json")
	if err != nil {
		t.Fatal(err)
	}
	tmpPath := tmpFile.Name()
	tmpFile.Close()
	defer os.Remove(tmpPath)

	s1, err := NewStore(tmpPath)
	if err != nil {
		t.Fatalf("NewStore() failed: %v", err)
	}
	s1.Create("persist", "https://example.com/persist")
	s1.Close()

	s2, err := NewStore(tmpPath)
	if err != nil {
		t.Fatalf("reopen store failed: %v", err)
	}
	defer s2.Close()

	rec, err := s2.FindByCode("persist")
	if err != nil {
		t.Fatalf("FindByCode() after reopen failed: %v", err)
	}
	if rec == nil {
		t.Fatal("expected record after reopening store")
	}
	if rec.OriginalURL != "https://example.com/persist" {
		t.Fatalf("unexpected OriginalURL: %q", rec.OriginalURL)
	}
}

func TestGenerateCode(t *testing.T) {
	seen := make(map[string]bool)
	for i := 0; i < 100; i++ {
		code, err := generateCode()
		if err != nil {
			t.Fatalf("generateCode() failed: %v", err)
		}
		if len(code) != codeLength {
			t.Fatalf("expected code length %d, got %d: %q", codeLength, len(code), code)
		}
		for _, c := range code {
			if !((c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')) {
				t.Fatalf("invalid character %c in code %q", c, code)
			}
		}
		if seen[code] {
			t.Fatal("unexpected collision: duplicate code generated")
		}
		seen[code] = true
	}
}