// Copyright (c) 2026 Charles KWON OhJun (charleskwonohjun@gmail.com)
// All rights reserved.

// CDX engine test — reads CDX files created by Harbour.

package cdx

import (
	"os"
	"testing"
)

const testCDX = "/mnt/d/charles/five/dbf/cdxtest.cdx"

func TestCDXOpen(t *testing.T) {
	if _, err := os.Stat(testCDX); err != nil {
		t.Skip("cdxtest.cdx not found — run Harbour to create it first")
	}

	idx, err := OpenIndex(testCDX)
	if err != nil {
		t.Fatalf("OpenIndex: %v", err)
	}
	defer idx.Close()

	t.Logf("CDX opened: %d tags", idx.TagCount())
	if idx.TagCount() < 1 {
		t.Fatal("Expected at least 1 tag")
	}

	for i := 0; i < idx.TagCount(); i++ {
		tag := idx.GetTag(i)
		if tag != nil {
			t.Logf("  Tag %d: name=%q", i, tag.Name)
		}
	}
}

func TestCDXFindTag(t *testing.T) {
	if _, err := os.Stat(testCDX); err != nil {
		t.Skip("cdxtest.cdx not found")
	}

	idx, err := OpenIndex(testCDX)
	if err != nil {
		t.Fatalf("OpenIndex: %v", err)
	}
	defer idx.Close()

	tag := idx.FindTag("NAME")
	if tag == nil {
		// Try without prefix
		for i := 0; i < idx.TagCount(); i++ {
			tg := idx.GetTag(i)
			t.Logf("Available tag: %q", tg.Name)
		}
		t.Fatal("Tag BYNAME not found")
	}
	t.Logf("Found tag BYNAME")
}

func TestCDXGoTop(t *testing.T) {
	if _, err := os.Stat(testCDX); err != nil {
		t.Skip("cdxtest.cdx not found")
	}

	idx, err := OpenIndex(testCDX)
	if err != nil {
		t.Fatalf("OpenIndex: %v", err)
	}
	defer idx.Close()

	tag := idx.FindTag("NAME")
	if tag == nil {
		// Try first tag
		if idx.TagCount() > 0 {
			tag = idx.GetTag(0)
			t.Logf("Using first tag: %q", tag.Name)
		} else {
			t.Skip("No tags found")
		}
	}

	ok := tag.GoTop()
	t.Logf("GoTop: ok=%v, recNo=%d, key=%q, eof=%v", ok, tag.CurRecNo(), string(tag.CurKey()), tag.IsEOF())

	if tag.IsEOF() {
		t.Error("GoTop resulted in EOF")
	}

	// First by name should be "Cho" (Harbour verified)
	key := string(tag.CurKey())
	t.Logf("First key: %q", key)
}

func TestCDXTraverse(t *testing.T) {
	if _, err := os.Stat(testCDX); err != nil {
		t.Skip("cdxtest.cdx not found")
	}

	idx, err := OpenIndex(testCDX)
	if err != nil {
		t.Fatalf("OpenIndex: %v", err)
	}
	defer idx.Close()

	tag := idx.FindTag("NAME")
	if tag == nil && idx.TagCount() > 0 {
		tag = idx.GetTag(0)
	}
	if tag == nil {
		t.Skip("No tags")
	}

	tag.GoTop()
	count := 0
	prev := ""
	for !tag.IsEOF() {
		key := string(tag.CurKey())
		if key < prev {
			t.Errorf("Not sorted: %q < %q at %d", key, prev, count)
			break
		}
		prev = key
		count++
		if count > 200 {
			t.Error("Too many iterations, possible infinite loop")
			break
		}
		tag.SkipNext()
	}
	t.Logf("Traversed %d keys", count)
	if count != 100 {
		t.Errorf("Expected 100 keys, got %d", count)
	}
}

func TestCDXSeek(t *testing.T) {
	if _, err := os.Stat(testCDX); err != nil {
		t.Skip("cdxtest.cdx not found")
	}

	idx, err := OpenIndex(testCDX)
	if err != nil {
		t.Fatalf("OpenIndex: %v", err)
	}
	defer idx.Close()

	tag := idx.FindTag("NAME")
	if tag == nil && idx.TagCount() > 0 {
		tag = idx.GetTag(0)
	}
	if tag == nil {
		t.Skip("No tags")
	}

	// Seek "Park" — should find it
	searchKey := make([]byte, 20)
	copy(searchKey, []byte("Park"))
	for i := 4; i < 20; i++ {
		searchKey[i] = ' '
	}

	recNo, found := tag.Seek(searchKey)
	t.Logf("Seek 'Park': found=%v recNo=%d", found, recNo)
	if !found {
		t.Error("Expected to find 'Park'")
	}
}

func TestCDXGoBottom(t *testing.T) {
	if _, err := os.Stat(testCDX); err != nil {
		t.Skip("cdxtest.cdx not found")
	}

	idx, err := OpenIndex(testCDX)
	if err != nil {
		t.Fatalf("OpenIndex: %v", err)
	}
	defer idx.Close()

	tag := idx.FindTag("NAME")
	if tag == nil && idx.TagCount() > 0 {
		tag = idx.GetTag(0)
	}
	if tag == nil {
		t.Skip("No tags")
	}

	tag.GoBottom()
	t.Logf("GoBottom: recNo=%d key=%q", tag.CurRecNo(), string(tag.CurKey()))

	// Last by name should be "Yoon" (Harbour verified)
	key := string(tag.CurKey())
	if len(key) >= 4 && key[:4] != "Yoon" {
		t.Errorf("Last key = %q, expected 'Yoon...'", key)
	}
}

func TestCDXCityTag(t *testing.T) {
	if _, err := os.Stat(testCDX); err != nil {
		t.Skip("cdxtest.cdx not found")
	}

	idx, err := OpenIndex(testCDX)
	if err != nil {
		t.Fatalf("OpenIndex: %v", err)
	}
	defer idx.Close()

	tag := idx.FindTag("CITY")
	if tag == nil {
		t.Skip("BYCITY tag not found")
	}

	tag.GoTop()
	t.Logf("City GoTop: recNo=%d key=%q", tag.CurRecNo(), string(tag.CurKey()))

	// First by city should be "London" (Harbour verified)
	key := string(tag.CurKey())
	if len(key) >= 6 && key[:6] != "London" {
		t.Logf("First city key = %q (expected 'London...')", key)
	}
}