package main

import (
	"bytes"
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"git.softuniq.eu/UniqAI/GoClaw/gateway/internal/db"
)

// ─── Mock DB agent config ─────────────────────────────────────────────────────

func mockAgentConfig() *db.AgentConfig {
	return &db.AgentConfig{
		ID:              42,
		Name:            "Test Agent",
		Model:           "qwen2.5:7b",
		SystemPrompt:    "You are a test agent.",
		AllowedTools:    []string{"http_request", "file_list"},
		Temperature:     0.7,
		MaxTokens:       2048,
		IsSystem:        false,
		IsOrchestrator:  false,
		IsActive:        true,
		ContainerImage:  "goclaw-agent-worker:latest",
		ContainerStatus: "running",
		ServiceName:     "goclaw-agent-42",
		ServicePort:     8001,
	}
}

// ─── Unit: AgentWorker struct ─────────────────────────────────────────────────

func TestAgentWorkerInit(t *testing.T) {
	w := &AgentWorker{
		agentID:   42,
		cfg:       mockAgentConfig(),
		taskQueue: make(chan *Task, taskQueueDepth),
		tasks:     make(map[string]*Task),
	}
	if w.agentID != 42 {
		t.Errorf("expected agentID=42, got %d", w.agentID)
	}
	if w.cfg.Name != "Test Agent" {
		t.Errorf("expected name 'Test Agent', got %q", w.cfg.Name)
	}
}

// ─── Unit: Task enqueue ───────────────────────────────────────────────────────

func TestEnqueueTask(t *testing.T) {
	w := &AgentWorker{
		agentID:   42,
		cfg:       mockAgentConfig(),
		taskQueue: make(chan *Task, taskQueueDepth),
		tasks:     make(map[string]*Task),
	}

	task := w.EnqueueTask(TaskRequest{
		Input:       "hello world",
		TimeoutSecs: 30,
	})

	if task.ID == "" {
		t.Error("task ID should not be empty")
	}
	if task.Status != TaskPending {
		t.Errorf("expected status=pending, got %q", task.Status)
	}
	if task.Input != "hello world" {
		t.Errorf("expected input='hello world', got %q", task.Input)
	}
	if len(w.taskQueue) != 1 {
		t.Errorf("expected 1 task in queue, got %d", len(w.taskQueue))
	}

	// Task should be in store
	w.tasksMu.RLock()
	stored, ok := w.tasks[task.ID]
	w.tasksMu.RUnlock()
	if !ok {
		t.Error("task not found in store")
	}
	if stored.ID != task.ID {
		t.Errorf("stored task ID mismatch: %q != %q", stored.ID, task.ID)
	}
}

func TestEnqueueTask_QueueFull(t *testing.T) {
	// Queue depth = 1 for this test
	w := &AgentWorker{
		agentID:   42,
		cfg:       mockAgentConfig(),
		taskQueue: make(chan *Task, 1),
		tasks:     make(map[string]*Task),
	}

	// Fill the queue
	w.EnqueueTask(TaskRequest{Input: "task 1"})
	// Overflow
	task2 := w.EnqueueTask(TaskRequest{Input: "task 2"})

	w.tasksMu.RLock()
	status := task2.Status
	w.tasksMu.RUnlock()

	if status != TaskFailed {
		t.Errorf("expected task2 status=failed when queue full, got %q", status)
	}
}

func TestEnqueueTask_DefaultTimeout(t *testing.T) {
	w := &AgentWorker{
		agentID:   42,
		cfg:       mockAgentConfig(),
		taskQueue: make(chan *Task, taskQueueDepth),
		tasks:     make(map[string]*Task),
	}

	task := w.EnqueueTask(TaskRequest{Input: "no timeout set"})
	if task.TimeoutSecs != defaultTimeout {
		t.Errorf("expected default timeout=%d, got %d", defaultTimeout, task.TimeoutSecs)
	}
}

// ─── HTTP Handlers ────────────────────────────────────────────────────────────

func makeTestWorker() *AgentWorker {
	return &AgentWorker{
		agentID:   42,
		cfg:       mockAgentConfig(),
		taskQueue: make(chan *Task, taskQueueDepth),
		tasks:     make(map[string]*Task),
	}
}

func TestHandleHealth(t *testing.T) {
	w := makeTestWorker()
	rr := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/health", nil)
	w.handleHealth(rr, req)

	if rr.Code != http.StatusOK {
		t.Errorf("expected 200, got %d", rr.Code)
	}

	var body map[string]any
	if err := json.NewDecoder(rr.Body).Decode(&body); err != nil {
		t.Fatalf("invalid JSON response: %v", err)
	}
	if body["status"] != "ok" {
		t.Errorf("expected status=ok, got %v", body["status"])
	}
	if int(body["agentId"].(float64)) != 42 {
		t.Errorf("expected agentId=42, got %v", body["agentId"])
	}
}

func TestHandleInfo(t *testing.T) {
	w := makeTestWorker()
	rr := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/info", nil)
	w.handleInfo(rr, req)

	if rr.Code != http.StatusOK {
		t.Errorf("expected 200, got %d", rr.Code)
	}
	var body map[string]any
	json.NewDecoder(rr.Body).Decode(&body)
	if body["name"] != "Test Agent" {
		t.Errorf("expected name='Test Agent', got %v", body["name"])
	}
}

func TestHandleTask_Valid(t *testing.T) {
	w := makeTestWorker()
	body := `{"input":"do something useful","timeout_secs":60}`
	req := httptest.NewRequest(http.MethodPost, "/task", bytes.NewBufferString(body))
	req.Header.Set("Content-Type", "application/json")
	rr := httptest.NewRecorder()
	w.handleTask(rr, req)

	if rr.Code != http.StatusAccepted {
		t.Errorf("expected 202, got %d", rr.Code)
	}
	var resp map[string]any
	json.NewDecoder(rr.Body).Decode(&resp)
	if resp["task_id"] == "" || resp["task_id"] == nil {
		t.Error("task_id should be in response")
	}
	if resp["status"] != string(TaskPending) {
		t.Errorf("expected status=pending, got %v", resp["status"])
	}
}

func TestHandleTask_EmptyInput(t *testing.T) {
	w := makeTestWorker()
	req := httptest.NewRequest(http.MethodPost, "/task", bytes.NewBufferString(`{"input":""}`))
	req.Header.Set("Content-Type", "application/json")
	rr := httptest.NewRecorder()
	w.handleTask(rr, req)

	if rr.Code != http.StatusBadRequest {
		t.Errorf("expected 400, got %d", rr.Code)
	}
}

func TestHandleTask_InvalidJSON(t *testing.T) {
	w := makeTestWorker()
	req := httptest.NewRequest(http.MethodPost, "/task", bytes.NewBufferString(`not-json`))
	rr := httptest.NewRecorder()
	w.handleTask(rr, req)

	if rr.Code != http.StatusBadRequest {
		t.Errorf("expected 400, got %d", rr.Code)
	}
}

func TestHandleGetTask_NotFound(t *testing.T) {
	// We can't easily use chi.URLParam in unit tests without a full router.
	// Test the store logic directly instead.
	w := makeTestWorker()
	w.tasksMu.RLock()
	_, ok := w.tasks["nonexistent-id"]
	w.tasksMu.RUnlock()
	if ok {
		t.Error("nonexistent task should not be found")
	}
}

func TestHandleListTasks_Empty(t *testing.T) {
	w := makeTestWorker()
	rr := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/tasks", nil)
	w.handleListTasks(rr, req)

	if rr.Code != http.StatusOK {
		t.Errorf("expected 200, got %d", rr.Code)
	}
	var resp map[string]any
	json.NewDecoder(rr.Body).Decode(&resp)
	if resp["total"].(float64) != 0 {
		t.Errorf("expected total=0, got %v", resp["total"])
	}
}

func TestHandleListTasks_WithTasks(t *testing.T) {
	w := makeTestWorker()
	w.EnqueueTask(TaskRequest{Input: "task A"})
	w.EnqueueTask(TaskRequest{Input: "task B"})

	rr := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/tasks", nil)
	w.handleListTasks(rr, req)

	var resp map[string]any
	json.NewDecoder(rr.Body).Decode(&resp)
	if int(resp["total"].(float64)) != 2 {
		t.Errorf("expected total=2, got %v", resp["total"])
	}
}

func TestHandleMemory_NoDB(t *testing.T) {
	w := makeTestWorker() // no database set
	rr := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/memory", nil)
	w.handleMemory(rr, req)

	if rr.Code != http.StatusOK {
		t.Errorf("expected 200, got %d", rr.Code)
	}
	var resp map[string]any
	json.NewDecoder(rr.Body).Decode(&resp)
	if int(resp["total"].(float64)) != 0 {
		t.Errorf("expected total=0 without DB, got %v", resp["total"])
	}
}

// ─── Unit: getAgentTools ──────────────────────────────────────────────────────

func TestGetAgentTools_WithAllowedTools(t *testing.T) {
	w := makeTestWorker()
	agentTools := w.getAgentTools()

	// Worker has allowedTools = ["http_request", "file_list"]
	if len(agentTools) == 0 {
		t.Error("expected some tools, got none")
	}
	names := make(map[string]bool)
	for _, t := range agentTools {
		names[t.Function.Name] = true
	}
	if !names["http_request"] {
		t.Error("expected http_request in allowed tools")
	}
	if !names["file_list"] {
		t.Error("expected file_list in allowed tools")
	}
	// shell_exec should NOT be allowed
	if names["shell_exec"] {
		t.Error("shell_exec should NOT be in allowed tools for this agent")
	}
}

func TestGetAgentTools_EmptyAllowedTools_UsesDefaults(t *testing.T) {
	cfg := mockAgentConfig()
	cfg.AllowedTools = []string{} // empty
	w := &AgentWorker{agentID: 1, cfg: cfg, taskQueue: make(chan *Task, 1), tasks: map[string]*Task{}}
	tools := w.getAgentTools()
	if len(tools) == 0 {
		t.Error("expected default tools when allowedTools is empty")
	}
}

// ─── Unit: recent task ring ───────────────────────────────────────────────────

func TestRecentRing_MaxCapacity(t *testing.T) {
	w := makeTestWorker()
	// Enqueue more than maxRecentTasks
	for i := 0; i < maxRecentTasks+10; i++ {
		// Don't block — drain queue
		w.EnqueueTask(TaskRequest{Input: "task"})
		select {
		case <-w.taskQueue:
		default:
		}
	}

	w.recentMu.Lock()
	count := len(w.recentKeys)
	w.recentMu.Unlock()

	if count > maxRecentTasks {
		t.Errorf("recent ring should not exceed %d, got %d", maxRecentTasks, count)
	}
}

// ─── Unit: Task lifecycle ─────────────────────────────────────────────────────

func TestTaskLifecycle_Timestamps(t *testing.T) {
	w := makeTestWorker()
	before := time.Now()
	task := w.EnqueueTask(TaskRequest{Input: "lifecycle test"})
	after := time.Now()

	if task.CreatedAt.Before(before) || task.CreatedAt.After(after) {
		t.Errorf("CreatedAt=%v should be between %v and %v", task.CreatedAt, before, after)
	}
	if task.StartedAt != nil {
		t.Error("StartedAt should be nil for pending task")
	}
	if task.DoneAt != nil {
		t.Error("DoneAt should be nil for pending task")
	}
}

// ─── Unit: HTTP Chat handler (no LLM) ────────────────────────────────────────

func TestHandleChat_InvalidJSON(t *testing.T) {
	w := makeTestWorker()
	req := httptest.NewRequest(http.MethodPost, "/chat", bytes.NewBufferString(`not-json`))
	rr := httptest.NewRecorder()
	w.handleChat(rr, req)
	if rr.Code != http.StatusBadRequest {
		t.Errorf("expected 400, got %d", rr.Code)
	}
}

func TestHandleChat_EmptyMessages(t *testing.T) {
	w := makeTestWorker()
	req := httptest.NewRequest(http.MethodPost, "/chat",
		bytes.NewBufferString(`{"messages":[]}`))
	req.Header.Set("Content-Type", "application/json")
	rr := httptest.NewRecorder()
	w.handleChat(rr, req)
	if rr.Code != http.StatusBadRequest {
		t.Errorf("expected 400 for empty messages, got %d", rr.Code)
	}
}

// ─── Integration: worker goroutine processes task ─────────────────────────────

func TestWorkerProcessesTask_WithMockLLM(t *testing.T) {
	// Create a mock LLM server that returns a simple response
	mockLLM := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		json.NewEncoder(w).Encode(map[string]any{
			"choices": []map[string]any{
				{
					"message":       map[string]string{"role": "assistant", "content": "Mock answer"},
					"finish_reason": "stop",
				},
			},
			"model": "mock-model",
		})
	}))
	defer mockLLM.Close()

	// We can't easily create a full AgentWorker with llm client without more refactoring,
	// so we test the task state machine directly
	w := makeTestWorker()

	task := w.EnqueueTask(TaskRequest{Input: "test task", TimeoutSecs: 5})
	if task.Status != TaskPending {
		t.Errorf("expected pending, got %s", task.Status)
	}

	// Simulate task processing (without LLM)
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()

	now := time.Now()
	w.tasksMu.Lock()
	task.Status = TaskRunning
	task.StartedAt = &now
	w.tasksMu.Unlock()

	// Simulate done
	doneAt := time.Now()
	w.tasksMu.Lock()
	task.Status = TaskDone
	task.Result = "completed"
	task.DoneAt = &doneAt
	w.tasksMu.Unlock()

	_ = ctx

	w.tasksMu.RLock()
	finalStatus := task.Status
	w.tasksMu.RUnlock()

	if finalStatus != TaskDone {
		t.Errorf("expected task done, got %s", finalStatus)
	}
}