package jscriptx_test

import (
	"context"
	"errors"
	"fmt"
	"strings"
	"sync"
	"testing"
	"time"

	"git.fsdpf.net/go/jscriptx"
	"git.fsdpf.net/go/jscriptx/internal/testext"
)

const objScript = `
export default class DeviceHandler {
	constructor(deviceId, model) {
		this.deviceId = deviceId
		this.model = model
		this.count = 0
	}
	info() { return this.deviceId + "/" + this.model }
	onMessage(payload) { this.count++; return this.count }
	spin() { while (true) {} }
}
`

// constructor 抛异常要在 New 就报出来，不用等到第一次调用。
func TestInstance_构造失败当场报错(t *testing.T) {
	e := newEngine(t)
	s := mustCompile(t, e, "bad.js", `
		export default class H {
			constructor(cfg) {
				if (!cfg) { throw new Error("缺少配置") }
			}
			run() { return 1 }
		}
	`)

	_, err := s.New(context.Background()) // 故意不传构造参数
	if err == nil {
		t.Fatal("New 就该报错")
	}
	var jsErr *jscriptx.Error
	if !errors.As(err, &jsErr) {
		t.Fatalf("错误类型不对: %T", err)
	}
	if jsErr.Func != "constructor" || !strings.Contains(jsErr.Msg, "缺少配置") {
		t.Errorf("错误信息不对: %+v", jsErr)
	}
	t.Logf("%v", err)
}

func TestInstance_Close后拒绝调用(t *testing.T) {
	e := newEngine(t)
	s := mustCompile(t, e, "device.js", objScript)
	ctx := context.Background()

	obj, _ := s.New(ctx, "dev-1", "温控器")
	if _, err := obj.Call(ctx, "info"); err != nil {
		t.Fatal(err)
	}
	obj.Close()
	if _, err := obj.Call(ctx, "info"); !errors.Is(err, jscriptx.ErrClosed) {
		t.Errorf("want ErrClosed, got %v", err)
	}
	obj.Close() // 重复关闭不该 panic
}

func TestInstance_Has(t *testing.T) {
	e := newEngine(t)
	s := mustCompile(t, e, "device.js", objScript)
	obj, _ := s.New(context.Background(), "d", "m")
	defer obj.Close()

	if !obj.Has("onMessage") || !obj.Has("info") {
		t.Error("Has 认不出实例方法")
	}
	if obj.Has("nope") {
		t.Error("Has 不该认出不存在的方法")
	}
}

// 实例独占 VM，this.xxx 在它活着期间跨调用保持。
func TestInstance_状态跨调用保持(t *testing.T) {
	e := newEngine(t)
	s := mustCompile(t, e, "device.ts", deviceScript)
	ctx := context.Background()

	obj, err := s.New(ctx, "device-A", "温控器")
	if err != nil {
		t.Fatal(err)
	}
	defer obj.Close()

	for i, want := range []string{"device-A#1:m1", "device-A#2:m2", "device-A#3:m3"} {
		got, err := obj.Call(ctx, "onMessage", fmt.Sprintf("m%d", i+1))
		if err != nil {
			t.Fatalf("第 %d 条失败: %v", i+1, err)
		}
		if got != want {
			t.Errorf("第 %d 条 = %#v, want %q", i+1, got, want)
		}
	}
}

// 不同实例互不相干，这是并发的基础。
func TestInstance_互相隔离(t *testing.T) {
	e := newEngine(t)
	s := mustCompile(t, e, "device.ts", deviceScript)
	ctx := context.Background()

	a, _ := s.New(ctx, "device-A", "型号A")
	defer a.Close()
	b, _ := s.New(ctx, "device-B", "型号B")
	defer b.Close()

	a.Call(ctx, "onMessage", "x")
	a.Call(ctx, "onMessage", "x")
	got, err := b.Call(ctx, "onMessage", "x")
	if err != nil {
		t.Fatal(err)
	}
	if got != "device-B#1:x" {
		t.Errorf("B 被 A 污染: %#v", got)
	}
}

// 同一个实例的调用串行，保护 this.xxx 不错乱。
func TestInstance_调用串行(t *testing.T) {
	e := newEngine(t)
	s := mustCompile(t, e, "counter.ts", `
		export default class C {
			constructor() { this.n = 0 }
			bump() { this.n++; return this.n }
			total() { return this.n }
		}
	`)

	obj, err := s.New(context.Background())
	if err != nil {
		t.Fatal(err)
	}
	defer obj.Close()

	const goroutines, per = 8, 100
	var wg sync.WaitGroup
	for g := 0; g < goroutines; g++ {
		wg.Add(1)
		go func() {
			defer wg.Done()
			for i := 0; i < per; i++ {
				if _, err := obj.Call(context.Background(), "bump"); err != nil {
					t.Errorf("%v", err)
					return
				}
			}
		}()
	}
	wg.Wait()

	got, _ := obj.Call(context.Background(), "total")
	if got.(int64) != goroutines*per {
		t.Errorf("串行保证失效, total = %#v, want %d", got, goroutines*per)
	}
}

// 多个实例并发跑，各自的状态正确。
func TestInstance_多实例并发(t *testing.T) {
	e := newEngine(t)
	s := mustCompile(t, e, "device.ts", deviceScript)

	const devices, messages = 16, 30
	var wg sync.WaitGroup
	for d := 0; d < devices; d++ {
		id := fmt.Sprintf("device-%d", d)
		wg.Add(1)
		go func(id string) {
			defer wg.Done()
			obj, err := s.New(context.Background(), id, "型号")
			if err != nil {
				t.Errorf("%v", err)
				return
			}
			defer obj.Close()
			for m := 0; m < messages; m++ {
				got, err := obj.Call(context.Background(), "onMessage", "m")
				if err != nil {
					t.Errorf("%s: %v", id, err)
					return
				}
				want := fmt.Sprintf("%s#%d:m", id, m+1)
				if got != want {
					t.Errorf("%s 第 %d 条 = %#v, want %q", id, m+1, got, want)
					return
				}
			}
		}(id)
	}
	wg.Wait()
}

// 脚本出错会丢 this 上的状态，但扩展里的东西还在。
func TestInstance_出错后状态归零(t *testing.T) {
	e := newEngine(t, jscriptx.WithTimeout(80*time.Millisecond))
	s := mustCompile(t, e, "mix.ts", `
		export default class M {
			constructor() { this.n = 0 }
			bump() { store.Incr("kept", 1); return ++this.n }
			spin() { while (true) {} }
		}
	`)

	st := testext.New()
	ctx := jscriptx.WithScope(context.Background(), jscriptx.ScopeExtensions(st))
	obj, err := s.New(ctx)
	if err != nil {
		t.Fatal(err)
	}
	defer obj.Close()

	obj.Call(ctx, "bump")
	obj.Call(ctx, "bump")

	if _, err := obj.Call(ctx, "spin"); !errors.Is(err, jscriptx.ErrTimeout) {
		t.Fatalf("want ErrTimeout, got %v", err)
	}
	if obj.Resets() != 1 {
		t.Errorf("Resets = %d, want 1", obj.Resets())
	}

	got, err := obj.Call(ctx, "bump")
	if err != nil {
		t.Fatal(err)
	}
	if got.(int64) != 1 {
		t.Errorf("this 上的状态应该归零, got %#v", got)
	}
	// 扩展在 Go 侧，不受 VM 重建影响
	if n := toNumber(t, st.Get("kept")); n != 3 {
		t.Errorf("扩展里的状态不该丢, got %v want 3", n)
	}
}

// 脚本关闭后实例失效。
func TestInstance_脚本关闭后失效(t *testing.T) {
	e := newEngine(t)
	s := mustCompile(t, e, "device.ts", deviceScript)
	obj, _ := s.New(context.Background(), "d", "m")

	s.Close()
	if _, err := obj.Call(context.Background(), "onMessage", "x"); !errors.Is(err, jscriptx.ErrClosed) {
		t.Errorf("want ErrClosed, got %v", err)
	}
}