package cache

import (
	"context"
	"errors"
	"fuj-management/go/internal/io/drive"
	"os"
	"testing"
	"time"
)

func TestGet_FreshFetch(t *testing.T) {
	dir := t.TempDir()
	d := &drive.Fake{Times: map[string]string{"sheet1": "2026-01-01T00:00:00Z"}}
	fc := New(d, dir, map[string]string{"mykey": "sheet1"}, time.Minute, time.Minute)

	calls := 0
	got, err := Get(context.Background(), fc, "mykey", func(_ context.Context) ([]string, error) {
		calls++
		return []string{"a", "b"}, nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if len(got) != 2 || got[0] != "a" {
		t.Errorf("unexpected: %v", got)
	}
	if calls != 1 {
		t.Errorf("want 1 fetch call, got %d", calls)
	}
}

func TestGet_CacheHit(t *testing.T) {
	dir := t.TempDir()
	d := &drive.Fake{Times: map[string]string{"sheet1": "2026-01-01T00:00:00Z"}}
	fc := New(d, dir, map[string]string{"mykey": "sheet1"}, time.Minute, time.Minute)

	fetch := func(_ context.Context) ([]string, error) { return []string{"a"}, nil }
	if _, err := Get(context.Background(), fc, "mykey", fetch); err != nil {
		t.Fatal(err)
	}

	// Second call — modifiedTime unchanged, should hit cache
	calls := 0
	got, err := Get(context.Background(), fc, "mykey", func(_ context.Context) ([]string, error) {
		calls++
		return []string{"SHOULD_NOT_CALL"}, nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if got[0] != "a" {
		t.Errorf("want cache hit with 'a', got %q", got[0])
	}
	if calls != 0 {
		t.Errorf("want 0 fetch calls on hit, got %d", calls)
	}
}

func TestGet_CacheMiss_OnModifiedTimeChange(t *testing.T) {
	dir := t.TempDir()
	d := &drive.Fake{Times: map[string]string{"sheet1": "2026-01-01T00:00:00Z"}}
	// No TTL guards so we always hit Drive
	fc := New(d, dir, map[string]string{"mykey": "sheet1"}, 0, 0)

	fetch := func(_ context.Context) ([]string, error) { return []string{"v1"}, nil }
	if _, err := Get(context.Background(), fc, "mykey", fetch); err != nil {
		t.Fatal(err)
	}

	// Sheet updated — change modifiedTime
	d.Times["sheet1"] = "2026-02-01T00:00:00Z"
	got, err := Get(context.Background(), fc, "mykey", func(_ context.Context) ([]string, error) {
		return []string{"v2"}, nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if got[0] != "v2" {
		t.Errorf("want v2 after sheet update, got %q", got[0])
	}
}

func TestGet_DriveFailureFallback(t *testing.T) {
	dir := t.TempDir()
	d := &drive.Fake{Err: errors.New("drive down")}
	fc := New(d, dir, nil, 0, 0)

	calls := 0
	_, err := Get(context.Background(), fc, "mykey", func(_ context.Context) ([]string, error) {
		calls++
		return []string{"fallback"}, nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if calls != 1 {
		t.Errorf("want 1 fetch call, got %d", calls)
	}
}

func TestFlush(t *testing.T) {
	dir := t.TempDir()
	d := &drive.Fake{Times: map[string]string{"sheet1": "t1"}}
	fc := New(d, dir, map[string]string{"k": "sheet1"}, 0, 0)

	if _, err := Get(context.Background(), fc, "k", func(_ context.Context) (int, error) { return 42, nil }); err != nil {
		t.Fatal(err)
	}

	n, err := fc.Flush()
	if err != nil {
		t.Fatal(err)
	}
	if n != 1 {
		t.Errorf("want 1 deleted file, got %d", n)
	}
	// Cache dir should be empty of _cache.json files
	entries, _ := os.ReadDir(dir)
	for _, e := range entries {
		if e.Name() != "" {
			t.Errorf("expected empty dir after flush, found %s", e.Name())
		}
	}
}