package logging

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

func TestCompressDayAndPurge(t *testing.T) {
	dir := t.TempDir()
	loc := time.FixedZone("Asia/Shanghai", 8*60*60)
	w := newDailyWriter(dir, "app", loc, 2)

	// 准备三天明文日志
	days := []string{"2026-07-01", "2026-07-10", "2026-07-11"}
	for _, day := range days {
		path := filepath.Join(dir, "app-"+day+".log")
		if err := os.WriteFile(path, []byte(`{"msg":"hello `+day+`"}`+"\n"), 0o644); err != nil {
			t.Fatalf("write log: %v", err)
		}
	}

	// 压缩 7-10
	if err := w.compressDay("2026-07-10"); err != nil {
		t.Fatalf("compressDay: %v", err)
	}
	if _, err := os.Stat(filepath.Join(dir, "app-2026-07-10.log")); !os.IsNotExist(err) {
		t.Fatalf("plain log should be removed after gzip, err=%v", err)
	}
	if _, err := os.Stat(filepath.Join(dir, "app-2026-07-10.log.gz")); err != nil {
		t.Fatalf("gzip missing: %v", err)
	}

	// 以 7-12 为「现在」，保留 2 天（7-11、7-12），删除 7-11 之前。
	now := time.Date(2026, 7, 12, 12, 0, 0, 0, loc)
	if err := w.purgeOlderThan(now); err != nil {
		t.Fatalf("purgeOlderThan: %v", err)
	}
	if _, err := os.Stat(filepath.Join(dir, "app-2026-07-01.log")); !os.IsNotExist(err) {
		t.Fatal("expired log should be purged")
	}
	if _, err := os.Stat(filepath.Join(dir, "app-2026-07-10.log.gz")); !os.IsNotExist(err) {
		t.Fatalf("expired gzip should be purged, err=%v", err)
	}
	// 7-11 仍应存在（cutoff 当天起保留）
	if _, err := os.Stat(filepath.Join(dir, "app-2026-07-11.log")); err != nil {
		t.Fatalf("recent plain should remain: %v", err)
	}
}

func TestCompressDayReplacesCorruptedGzip(t *testing.T) {
	dir := t.TempDir()
	w := newDailyWriter(dir, "app", time.UTC, 0)
	sourcePath := filepath.Join(dir, "app-2026-07-11.log")
	gzipPath := sourcePath + ".gz"
	if err := os.WriteFile(sourcePath, []byte("important log\n"), 0o600); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(gzipPath, []byte("broken"), 0o600); err != nil {
		t.Fatal(err)
	}

	if err := w.compressDay("2026-07-11"); err != nil {
		t.Fatal(err)
	}
	if err := validateGzip(gzipPath); err != nil {
		t.Fatalf("gzip should be valid: %v", err)
	}
	if _, err := os.Stat(sourcePath); !os.IsNotExist(err) {
		t.Fatalf("source should be removed after successful compression, err=%v", err)
	}
}

func TestCompressDayIdempotent(t *testing.T) {
	dir := t.TempDir()
	loc := time.UTC
	w := newDailyWriter(dir, "app", loc, 0)
	path := filepath.Join(dir, "app-2026-07-11.log")
	if err := os.WriteFile(path, []byte("line\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	if err := w.compressDay("2026-07-11"); err != nil {
		t.Fatal(err)
	}
	if err := w.compressDay("2026-07-11"); err != nil {
		t.Fatalf("second compress should be no-op: %v", err)
	}
}