package correctioncsv_test

import (
	"bytes"
	"encoding/csv"
	"encoding/json"
	"os"
	"path/filepath"
	"testing"
	"time"
	"voicesnap/internal/correctioncsv"
	"voicesnap/internal/history"
	"voicesnap/internal/userdict"
)

func TestCorrectionCSVEndToEndPreviewThenAppend(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	t.Setenv("XDG_CONFIG_HOME", filepath.Join(home, ".config"))

	store := userdict.New()
	if _, err := store.AppendNewReplacements([]userdict.Replacement{
		{From: "点 CSV", To: ".csv"},
		{From: "麦克", To: "Mac"},
	}); err != nil {
		t.Fatal(err)
	}

	exported, err := correctioncsv.BuildHistoryCSV([]history.Entry{
		{Timestamp: time.Date(2026, 5, 30, 13, 9, 0, 0, time.UTC).UnixMilli(), Text: "普通中文句子"},
		{Timestamp: time.Date(2026, 5, 30, 13, 10, 0, 0, time.UTC).UnixMilli(), Text: "CSV 2026, \"quoted\"\nnext"},
		{Timestamp: time.Date(2026, 5, 30, 13, 11, 0, 0, time.UTC).UnixMilli(), Text: "已经后处理的最终文本"},
	}, time.UTC)
	if err != nil {
		t.Fatal(err)
	}

	records := readCSV(t, exported)
	if len(records) != 5 {
		t.Fatalf("expected header, example, and 3 history rows, got %d rows", len(records))
	}
	records[2][3] = "点 PDF"
	records[2][4] = ".pdf"
	records[2][5] = "点 CSV"
	records[2][6] = ".csv"
	records[2][7] = "麦克"
	records[2][8] = "Mike"
	records[3][3] = "换\n行"
	records[3][4] = "换行词"

	importData := writeCSV(t, records)
	before := readUserDictFile(t, store.Path())

	preview, err := correctioncsv.ParseAndPreviewCSV(importData, store.GetAll(), correctioncsv.Options{})
	if err != nil {
		t.Fatal(err)
	}
	afterPreview := readUserDictFile(t, store.Path())
	if !bytes.Equal(before, afterPreview) {
		t.Fatal("preview changed userdict.json before confirmation")
	}

	if preview.Summary.New != 2 {
		t.Fatalf("expected 2 new rules, got %+v", preview.Summary)
	}
	if preview.Summary.DictDuplicate != 1 {
		t.Fatalf("expected 1 dictionary duplicate, got %+v", preview.Summary)
	}
	if preview.Summary.Conflict != 1 {
		t.Fatalf("expected 1 conflict, got %+v", preview.Summary)
	}

	added, err := store.AppendNewReplacements(toReplacements(preview.NewRules))
	if err != nil {
		t.Fatal(err)
	}
	if len(added) != 2 {
		t.Fatalf("expected 2 appended rules, got %d", len(added))
	}
	if got := store.Apply("点 PDF 和 换 行 和 点 CSV 和 麦克"); got != ".pdf 和 换行词 和 .csv 和 Mac" {
		t.Fatalf("unexpected applied text: %q", got)
	}
}

func toReplacements(rules []correctioncsv.Rule) []userdict.Replacement {
	replacements := make([]userdict.Replacement, 0, len(rules))
	for _, rule := range rules {
		replacements = append(replacements, userdict.Replacement{From: rule.From, To: rule.To})
	}
	return replacements
}

func readCSV(t *testing.T, data []byte) [][]string {
	t.Helper()
	reader := csv.NewReader(bytes.NewReader(bytes.TrimPrefix(data, []byte{0xEF, 0xBB, 0xBF})))
	records, err := reader.ReadAll()
	if err != nil {
		t.Fatal(err)
	}
	return records
}

func writeCSV(t *testing.T, records [][]string) []byte {
	t.Helper()
	var buf bytes.Buffer
	writer := csv.NewWriter(&buf)
	for _, row := range records {
		if err := writer.Write(row); err != nil {
			t.Fatal(err)
		}
	}
	writer.Flush()
	if err := writer.Error(); err != nil {
		t.Fatal(err)
	}
	return buf.Bytes()
}

func readUserDictFile(t *testing.T, path string) []byte {
	t.Helper()
	data, err := os.ReadFile(path)
	if err != nil {
		t.Fatal(err)
	}
	var parsed any
	if err := json.Unmarshal(data, &parsed); err != nil {
		t.Fatal(err)
	}
	return data
}