package main

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"sync/atomic"
	"testing"
	"time"

	"gcy_hpc_server/internal/handler"
	"gcy_hpc_server/internal/model"
	"gcy_hpc_server/internal/server"
	"gcy_hpc_server/internal/service"
	"gcy_hpc_server/internal/slurm"
	"gcy_hpc_server/internal/store"

	"go.uber.org/zap"
	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"gorm.io/gorm/logger"
)

func newTaskTestDB(t *testing.T) *gorm.DB {
	t.Helper()
	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{Logger: logger.Default.LogMode(logger.Silent)})
	if err != nil {
		t.Fatalf("open sqlite: %v", err)
	}
	sqlDB, _ := db.DB()
	sqlDB.SetMaxOpenConns(1)
	db.AutoMigrate(
		&model.Application{},
		&model.File{},
		&model.FileBlob{},
		&model.Task{},
	)
	t.Cleanup(func() {
		sqlDB.Close()
	})
	return db
}

type mockSlurmHandler struct {
	submitFn func(w http.ResponseWriter, r *http.Request)
}

func newMockSlurmServer(t *testing.T, h *mockSlurmHandler) *httptest.Server {
	t.Helper()
	mux := http.NewServeMux()
	mux.HandleFunc("/slurm/v0.0.40/job/submit", func(w http.ResponseWriter, r *http.Request) {
		if h != nil && h.submitFn != nil {
			h.submitFn(w, r)
			return
		}
		w.Header().Set("Content-Type", "application/json")
		fmt.Fprint(w, `{"job_id": 42, "step_id": "0", "result": {"job_id": 42, "step_id": "0"}}`)
	})
	mux.HandleFunc("/slurm/v0.0.40/jobs", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{"jobs": []interface{}{}})
	})
	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		json.NewEncoder(w).Encode(map[string]interface{}{})
	})
	srv := httptest.NewServer(mux)
	t.Cleanup(srv.Close)
	return srv
}

func setupTaskTestServer(t *testing.T) (*httptest.Server, *store.TaskStore, func()) {
	t.Helper()
	return setupTaskTestServerWithSlurm(t, nil)
}

func setupTaskTestServerWithSlurm(t *testing.T, slurmHandler *mockSlurmHandler) (*httptest.Server, *store.TaskStore, func()) {
	t.Helper()

	db := newTaskTestDB(t)
	slurmSrv := newMockSlurmServer(t, slurmHandler)

	client, err := slurm.NewClientWithOpts(slurmSrv.URL, slurm.WithHTTPClient(slurmSrv.Client()))
	if err != nil {
		t.Fatalf("slurm client: %v", err)
	}

	log := zap.NewNop()
	jobSvc := service.NewJobService(client, log)
	appStore := store.NewApplicationStore(db)
	taskStore := store.NewTaskStore(db)

	tmpDir, err := os.MkdirTemp("", "task-test-workdir-*")
	if err != nil {
		t.Fatalf("temp dir: %v", err)
	}

	taskSvc := service.NewTaskService(
		taskStore, appStore,
		nil, nil, nil,
		jobSvc,
		tmpDir,
		log,
	)

	ctx, cancel := context.WithCancel(context.Background())
	taskSvc.StartProcessor(ctx)

	appSvc := service.NewApplicationService(appStore, jobSvc, tmpDir, log, taskSvc)
	appH := handler.NewApplicationHandler(appSvc, log)
	taskH := handler.NewTaskHandler(taskSvc, log)

	router := server.NewRouter(
		handler.NewJobHandler(jobSvc, log),
		handler.NewClusterHandler(service.NewClusterService(client, log), log),
		appH,
		nil, nil, nil,
		taskH,
		log,
	)

	httpSrv := httptest.NewServer(router)
	cleanup := func() {
		taskSvc.StopProcessor()
		cancel()
		httpSrv.Close()
		os.RemoveAll(tmpDir)
	}

	return httpSrv, taskStore, cleanup
}

func createTestApp(t *testing.T, srvURL string) int64 {
	t.Helper()
	body := `{"name":"test-app","script_template":"#!/bin/bash\necho {{.np}}","parameters":[{"name":"np","type":"string","default":"1"}]}`
	resp, err := http.Post(srvURL+"/api/v1/applications", "application/json", bytes.NewReader([]byte(body)))
	if err != nil {
		t.Fatalf("create app: %v", err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusCreated {
		b, _ := io.ReadAll(resp.Body)
		t.Fatalf("create app: status %d, body %s", resp.StatusCode, b)
	}
	var result struct {
		Data struct {
			ID int64 `json:"id"`
		} `json:"data"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		t.Fatalf("decode app response: %v", err)
	}
	return result.Data.ID
}

func postTask(t *testing.T, srvURL string, body string) (*http.Response, map[string]interface{}) {
	t.Helper()
	resp, err := http.Post(srvURL+"/api/v1/tasks", "application/json", bytes.NewReader([]byte(body)))
	if err != nil {
		t.Fatalf("post task: %v", err)
	}
	defer resp.Body.Close()
	b, _ := io.ReadAll(resp.Body)
	var result map[string]interface{}
	json.Unmarshal(b, &result)
	return resp, result
}

func getTasks(t *testing.T, srvURL string, query string) (int, []interface{}) {
	t.Helper()
	url := srvURL + "/api/v1/tasks"
	if query != "" {
		url += "?" + query
	}
	resp, err := http.Get(url)
	if err != nil {
		t.Fatalf("get tasks: %v", err)
	}
	defer resp.Body.Close()
	b, _ := io.ReadAll(resp.Body)
	var result map[string]interface{}
	json.Unmarshal(b, &result)
	data, _ := result["data"].(map[string]interface{})
	items, _ := data["items"].([]interface{})
	total, _ := data["total"].(float64)
	return int(total), items
}

func TestTask_FullLifecycle(t *testing.T) {
	srv, _, cleanup := setupTaskTestServer(t)
	defer cleanup()

	appID := createTestApp(t, srv.URL)

	resp, result := postTask(t, srv.URL, fmt.Sprintf(
		`{"app_id":%d,"task_name":"lifecycle-test","values":{"np":"4"}}`, appID,
	))
	if resp.StatusCode != http.StatusCreated {
		t.Fatalf("expected 201, got %d: %v", resp.StatusCode, result)
	}

	data, _ := result["data"].(map[string]interface{})
	if data["id"] == nil {
		t.Fatal("expected id in response")
	}

	time.Sleep(300 * time.Millisecond)

	total, items := getTasks(t, srv.URL, "")
	if total < 1 {
		t.Fatalf("expected at least 1 task, got %d", total)
	}

	task := items[0].(map[string]interface{})
	if task["status"] == nil || task["status"] == "" {
		t.Error("expected non-empty status")
	}
	if task["task_name"] != "lifecycle-test" {
		t.Errorf("expected task_name=lifecycle-test, got %v", task["task_name"])
	}
	if task["app_id"] != float64(appID) {
		t.Errorf("expected app_id=%d, got %v", appID, task["app_id"])
	}
}

func TestTask_CreateWithMissingApp(t *testing.T) {
	srv, _, cleanup := setupTaskTestServer(t)
	defer cleanup()

	resp, result := postTask(t, srv.URL, `{"app_id":9999,"task_name":"no-app"}`)

	if resp.StatusCode != http.StatusNotFound {
		t.Fatalf("expected 404, got %d: %v", resp.StatusCode, result)
	}
}

func TestTask_CreateWithInvalidBody(t *testing.T) {
	srv, _, cleanup := setupTaskTestServer(t)
	defer cleanup()

	resp, result := postTask(t, srv.URL, `{}`)

	if resp.StatusCode != http.StatusBadRequest {
		t.Fatalf("expected 400, got %d: %v", resp.StatusCode, result)
	}
}

func TestTask_FileLimitExceeded(t *testing.T) {
	srv, _, cleanup := setupTaskTestServer(t)
	defer cleanup()

	appID := createTestApp(t, srv.URL)

	fileIDs := make([]int64, 101)
	for i := range fileIDs {
		fileIDs[i] = int64(i + 1)
	}
	idsJSON, _ := json.Marshal(fileIDs)

	body := fmt.Sprintf(`{"app_id":%d,"file_ids":%s}`, appID, string(idsJSON))
	resp, result := postTask(t, srv.URL, body)

	if resp.StatusCode != http.StatusBadRequest {
		t.Fatalf("expected 400 for file limit, got %d: %v", resp.StatusCode, result)
	}
}

func TestTask_RetryScenario(t *testing.T) {
	var failCount int32
	slurmH := &mockSlurmHandler{
		submitFn: func(w http.ResponseWriter, r *http.Request) {
			if atomic.AddInt32(&failCount, 1) <= 2 {
				w.WriteHeader(http.StatusInternalServerError)
				fmt.Fprint(w, `{"errors":[{"error":"internal error"}]}`)
				return
			}
			w.Header().Set("Content-Type", "application/json")
			fmt.Fprint(w, `{"job_id": 99, "step_id": "0", "result": {"job_id": 99, "step_id": "0"}}`)
		},
	}

	srv, taskStore, cleanup := setupTaskTestServerWithSlurm(t, slurmH)
	defer cleanup()

	appID := createTestApp(t, srv.URL)

	resp, result := postTask(t, srv.URL, fmt.Sprintf(
		`{"app_id":%d,"task_name":"retry-test","values":{"np":"2"}}`, appID,
	))
	if resp.StatusCode != http.StatusCreated {
		t.Fatalf("expected 201, got %d: %v", resp.StatusCode, result)
	}

	taskID := int64(result["data"].(map[string]interface{})["id"].(float64))

	deadline := time.Now().Add(5 * time.Second)
	for time.Now().Before(deadline) {
		task, _ := taskStore.GetByID(context.Background(), taskID)
		if task != nil && task.Status == model.TaskStatusQueued {
			if task.SlurmJobID != nil && *task.SlurmJobID == 99 {
				return
			}
		}
		time.Sleep(100 * time.Millisecond)
	}

	task, _ := taskStore.GetByID(context.Background(), taskID)
	if task == nil {
		t.Fatalf("task %d not found after deadline", taskID)
	}
	t.Fatalf("task did not reach queued with slurm_job_id=99; status=%s retry_count=%d slurm_job_id=%v",
		task.Status, task.RetryCount, task.SlurmJobID)
}

// [已禁用] 前端已全部迁移到 POST /tasks 接口，旧 API 兼容性测试不再需要。
/*
func TestTask_OldAPICompatibility(t *testing.T) {
	srv, _, cleanup := setupTaskTestServer(t)
	defer cleanup()

	appID := createTestApp(t, srv.URL)

	body := `{"values":{"np":"8"}}`
	url := fmt.Sprintf("%s/api/v1/applications/%d/submit", srv.URL, appID)
	resp, err := http.Post(url, "application/json", bytes.NewReader([]byte(body)))
	if err != nil {
		t.Fatalf("post submit: %v", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusCreated {
		b, _ := io.ReadAll(resp.Body)
		t.Fatalf("expected 201, got %d: %s", resp.StatusCode, b)
	}

	var result map[string]interface{}
	json.NewDecoder(resp.Body).Decode(&result)

	data, _ := result["data"].(map[string]interface{})
	if data == nil {
		t.Fatal("expected data in response")
	}
	if data["job_id"] == nil {
		t.Errorf("expected job_id in old API response, got: %v", data)
	}
	jobID, ok := data["job_id"].(float64)
	if !ok || jobID == 0 {
		t.Errorf("expected non-zero job_id, got %v", data["job_id"])
	}
}
*/

func TestTask_ListWithFilters(t *testing.T) {
	srv, taskStore, cleanup := setupTaskTestServer(t)
	defer cleanup()

	appID := createTestApp(t, srv.URL)

	now := time.Now()
	taskStore.Create(context.Background(), &model.Task{
		TaskName: "task-completed", AppID: appID, AppName: "test-app",
		Status: model.TaskStatusCompleted, SubmittedAt: now,
	})
	taskStore.Create(context.Background(), &model.Task{
		TaskName: "task-failed", AppID: appID, AppName: "test-app",
		Status: model.TaskStatusFailed, ErrorMessage: "boom", SubmittedAt: now,
	})
	taskStore.Create(context.Background(), &model.Task{
		TaskName: "task-queued", AppID: appID, AppName: "test-app",
		Status: model.TaskStatusQueued, SubmittedAt: now,
	})

	total, items := getTasks(t, srv.URL, "status=completed")
	if total != 1 {
		t.Fatalf("expected 1 completed, got %d", total)
	}
	task := items[0].(map[string]interface{})
	if task["status"] != "completed" {
		t.Errorf("expected status=completed, got %v", task["status"])
	}

	total, items = getTasks(t, srv.URL, "status=failed")
	if total != 1 {
		t.Fatalf("expected 1 failed, got %d", total)
	}

	total, _ = getTasks(t, srv.URL, "")
	if total != 3 {
		t.Fatalf("expected 3 total, got %d", total)
	}
}

func TestTask_WorkDirCreated(t *testing.T) {
	srv, taskStore, cleanup := setupTaskTestServer(t)
	defer cleanup()

	appID := createTestApp(t, srv.URL)

	resp, result := postTask(t, srv.URL, fmt.Sprintf(
		`{"app_id":%d,"task_name":"workdir-test","values":{"np":"1"}}`, appID,
	))
	if resp.StatusCode != http.StatusCreated {
		t.Fatalf("expected 201, got %d: %v", resp.StatusCode, result)
	}

	taskID := int64(result["data"].(map[string]interface{})["id"].(float64))

	deadline := time.Now().Add(5 * time.Second)
	for time.Now().Before(deadline) {
		task, _ := taskStore.GetByID(context.Background(), taskID)
		if task != nil && task.WorkDir != "" {
			if _, err := os.Stat(task.WorkDir); os.IsNotExist(err) {
				t.Fatalf("work dir %s not created", task.WorkDir)
			}
			if !filepath.IsAbs(task.WorkDir) {
				t.Errorf("expected absolute work dir, got %s", task.WorkDir)
			}
			return
		}
		time.Sleep(50 * time.Millisecond)
	}

	task, _ := taskStore.GetByID(context.Background(), taskID)
	if task == nil {
		t.Fatalf("task %d not found after deadline", taskID)
	}
	t.Fatalf("work dir never set; status=%s workdir=%s", task.Status, task.WorkDir)
}