package core

import (
	"fmt"
	"math/rand"
	"path/filepath"
	"testing"

	"git.ycl.pub/yl32940/TsDB2/DB/core/page"
	"git.ycl.pub/yl32940/TsDB2/DB/core/types"
)

// TestRandomOpsAgainstModel 模糊测试: 随机插入/更新/删除 (含整表删空再灌),
// 每步与一个内存模型比对; 最后关库重开, 全量校验持久化结果。
// 固定种子 → 失败可复现。这是对抗"人工审计想不到的序列"的主要手段。
func TestRandomOpsAgainstModel(t *testing.T) {
	seeds := []int64{1, 42, 1337, 20240927, 777, 90091}
	for _, seed := range seeds {
		t.Run(fmt.Sprintf("seed-%d", seed), func(t *testing.T) {
			path := filepath.Join(t.TempDir(), "fuzz.db")
			db, err := Open(path)
			if err != nil {
				t.Fatalf("open: %v", err)
			}
			db.SetAutoCommitDelay(0)

			tbl, err := db.CreateTable("t", []types.FieldInfo{
				{FieldType: types.FieldType_Uint64, FieldName: []byte("id")},
				{FieldType: types.FieldType_Int64, FieldName: []byte("a")},
				{FieldType: types.FieldType_Int64, FieldName: []byte("b")},
			})
			if err != nil {
				t.Fatalf("建表: %v", err)
			}
			if _, err := tbl.CreateIndex("pk", page.IndexTypePrimary, []byte{0}); err != nil {
				t.Fatalf("建主键索引: %v", err)
			}
			if _, err := tbl.CreateIndex("idx_a", page.IndexTypeBTree, []byte{1}); err != nil {
				t.Fatalf("建二级索引: %v", err)
			}

			rng := rand.New(rand.NewSource(seed))
			model := map[uint64][2]int64{}
			ids := []uint64{} // 存活 id 池 (用于随机改/删)
			nextID := uint64(1)

			insert := func(id uint64, a, b int64) {
				if _, err := tbl.InsertRowWithID(id, []types.FieldValue{
					{FieldName: []byte("id"), Value: id},
					{FieldName: []byte("a"), Value: a},
					{FieldName: []byte("b"), Value: b},
				}); err != nil {
					t.Fatalf("插入 id=%d: %v", id, err)
				}
			}
			remove := func(id uint64) {
				if err := tbl.DeleteRowByPK(id); err != nil {
					t.Fatalf("删除 id=%d: %v", id, err)
				}
			}

			for op := 0; op < 8000; op++ {
				roll := rng.Intn(100)
				switch {
				case roll < 34: // 插入
					id := nextID
					nextID++
					a := int64(rng.Intn(20))
					b := int64(rng.Intn(7))
					insert(id, a, b)
					model[id] = [2]int64{a, b}
					ids = append(ids, id)
				case roll < 62 && len(ids) > 0: // 更新 (整行覆盖)
					k := rng.Intn(len(ids))
					id := ids[k]
					a := int64(rng.Intn(20))
					b := int64(rng.Intn(7))
					if err := tbl.UpdateRowByPK(id, []types.FieldValue{
						{FieldName: []byte("a"), Value: a},
						{FieldName: []byte("b"), Value: b},
					}); err != nil {
						t.Fatalf("更新 id=%d: %v", id, err)
					}
					model[id] = [2]int64{a, b}
				case roll < 88 && len(ids) > 0: // 删除
					k := rng.Intn(len(ids))
					id := ids[k]
					ids = append(ids[:k], ids[k+1:]...)
					remove(id)
					delete(model, id)
				case roll < 90: // 整表删空 (制造删空页 + 空闲页复用)
					for id := range model {
						remove(id)
					}
					model = map[uint64][2]int64{}
					ids = nil
				default: // 提交
					if err := db.Commit(); err != nil {
						t.Fatalf("commit: %v", err)
					}
				}
			}
			if err := db.Commit(); err != nil {
				t.Fatalf("final commit: %v", err)
			}

			verify := func(phase string) {
				// 行数
				if c, _ := tbl.Query().Count(); c != int64(len(model)) {
					t.Fatalf("%s: count=%d, 模型 %d", phase, c, len(model))
				}
				// 全量逐行比对
				seen := map[uint64][2]int64{}
				err := tbl.Query().ScanWithPKID(func(pkID uint64, row []types.FieldValue) bool {
					var pair [2]int64
					for _, fv := range row {
						switch string(fv.FieldName) {
						case "a":
							pair[0] = fv.Value.(int64)
						case "b":
							pair[1] = fv.Value.(int64)
						}
					}
					seen[pkID] = pair
					return true
				})
				if err != nil {
					t.Fatalf("%s: scan: %v", phase, err)
				}
				if len(seen) != len(model) {
					t.Fatalf("%s: 扫到 %d 行, 模型 %d 行", phase, len(seen), len(model))
				}
				for id, want := range model {
					got, ok := seen[id]
					if !ok || got != want {
						t.Fatalf("%s: id=%d 得到 %+v (存在=%v), 模型 %+v", phase, id, got, ok, want)
					}
				}
				// 二级索引等值计数与模型交叉验证
				for a := int64(0); a < 20; a++ {
					wantN := int64(0)
					for _, pair := range model {
						if pair[0] == a {
							wantN++
						}
					}
					if n, _ := tbl.Query().Where(Eq("a", a, 0)).Count(); n != wantN {
						t.Fatalf("%s: a=%d 索引 count=%d, 模型 %d", phase, a, n, wantN)
					}
				}
			}

			verify("关库前")
			if err := db.Close(); err != nil {
				t.Fatalf("close: %v", err)
			}

			// 重开: 持久化校验
			db2, err := Open(path)
			if err != nil {
				t.Fatalf("重开: %v", err)
			}
			defer db2.Close()
			tbl2, ok := db2.FindTable("t")
			if !ok {
				t.Fatalf("重开找不到表")
			}
			tbl = tbl2
			verify("重开后")
		})
	}
}