package repository

import (
	"context"
	"encoding/json"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"gorm.io/gorm"

	"github.com/gochat/gochat/internal/model"
)

// createTestCopilotMessage is a helper that builds a CopilotMessage with typical fields.
func createTestCopilotMessage(accountID, threadID uint, messageType model.CopilotMessageType, content string) *model.CopilotMessage {
	message, _ := json.Marshal(map[string]interface{}{
		"content": content,
	})
	return &model.CopilotMessage{
		AccountID:       accountID,
		CopilotThreadID: threadID,
		MessageType:     messageType,
		Message:         message,
	}
}

// createTestCopilotThread is a helper that creates a CopilotThread in the DB.
func createTestCopilotThread(t *testing.T, db *gorm.DB, accountID, userID uint, title string) *model.CopilotThread {
	t.Helper()
	thread := &model.CopilotThread{
		AccountID: accountID,
		UserID:    userID,
		Title:     title,
	}
	require.NoError(t, db.Create(thread).Error)
	return thread
}

// --- 1. Create ---
func TestCopilotMessageRepo_Create(t *testing.T) {
	db := setupTestDB(t, &model.CopilotThread{}, &model.CopilotMessage{})
	repo := NewCopilotMessageRepo(db)

	thread := createTestCopilotThread(t, db, 1, 1, "Test Thread")
	msg := createTestCopilotMessage(1, thread.ID, model.CopilotMessageTypeUser, "Hello copilot")

	err := repo.Create(context.Background(), msg)
	require.NoError(t, err)
	assert.NotZero(t, msg.ID, "ID should be set after Create")
	assert.Equal(t, uint(1), msg.AccountID)
	assert.Equal(t, thread.ID, msg.CopilotThreadID)
	assert.Equal(t, model.CopilotMessageTypeUser, msg.MessageType)
}

// --- 2. GetByID ---
func TestCopilotMessageRepo_GetByID(t *testing.T) {
	db := setupTestDB(t, &model.CopilotThread{}, &model.CopilotMessage{})
	repo := NewCopilotMessageRepo(db)

	thread := createTestCopilotThread(t, db, 1, 1, "Test Thread")
	msg := createTestCopilotMessage(1, thread.ID, model.CopilotMessageTypeAssistant, "Hi there")
	require.NoError(t, db.Create(msg).Error)

	found, err := repo.GetByID(context.Background(), msg.ID)
	require.NoError(t, err)
	assert.Equal(t, msg.ID, found.ID)
	assert.Equal(t, msg.CopilotThreadID, found.CopilotThreadID)
	assert.Equal(t, model.CopilotMessageTypeAssistant, found.MessageType)
}

func TestCopilotMessageRepo_GetByID_NotFound(t *testing.T) {
	db := setupTestDB(t, &model.CopilotThread{}, &model.CopilotMessage{})
	repo := NewCopilotMessageRepo(db)

	found, err := repo.GetByID(context.Background(), 9999)
	assert.Error(t, err)
	assert.Nil(t, found)
}

// --- 3. FindByThreadID ---
func TestCopilotMessageRepo_FindByThreadID(t *testing.T) {
	db := setupTestDB(t, &model.CopilotThread{}, &model.CopilotMessage{})
	repo := NewCopilotMessageRepo(db)

	thread := createTestCopilotThread(t, db, 1, 1, "Test Thread")

	// Create multiple messages in the thread
	msg1 := createTestCopilotMessage(1, thread.ID, model.CopilotMessageTypeUser, "First message")
	msg2 := createTestCopilotMessage(1, thread.ID, model.CopilotMessageTypeAssistant, "Second message")
	msg3 := createTestCopilotMessage(1, thread.ID, model.CopilotMessageTypeAssistantThinking, "Thinking...")
	require.NoError(t, db.Create(msg1).Error)
	require.NoError(t, db.Create(msg2).Error)
	require.NoError(t, db.Create(msg3).Error)

	msgs, count, err := repo.FindByThreadID(context.Background(), thread.ID, 0, 10)
	require.NoError(t, err)
	assert.Equal(t, int64(3), count)
	assert.Len(t, msgs, 3)
	// Messages should be ordered by created_at ASC
	assert.Equal(t, msg1.ID, msgs[0].ID)
	assert.Equal(t, msg2.ID, msgs[1].ID)
	assert.Equal(t, msg3.ID, msgs[2].ID)
}

func TestCopilotMessageRepo_FindByThreadID_Pagination(t *testing.T) {
	db := setupTestDB(t, &model.CopilotThread{}, &model.CopilotMessage{})
	repo := NewCopilotMessageRepo(db)

	thread := createTestCopilotThread(t, db, 1, 1, "Paginated Thread")

	// Create 5 messages
	for i := 0; i < 5; i++ {
		msg := createTestCopilotMessage(1, thread.ID, model.CopilotMessageTypeUser, "Message "+string(rune('A'+i)))
		require.NoError(t, db.Create(msg).Error)
	}

	// Fetch first page (offset=0, limit=2)
	msgs, count, err := repo.FindByThreadID(context.Background(), thread.ID, 0, 2)
	require.NoError(t, err)
	assert.Equal(t, int64(5), count)
	assert.Len(t, msgs, 2)

	// Fetch second page (offset=2, limit=2)
	msgs2, count2, err := repo.FindByThreadID(context.Background(), thread.ID, 2, 2)
	require.NoError(t, err)
	assert.Equal(t, int64(5), count2)
	assert.Len(t, msgs2, 2)
	assert.NotEqual(t, msgs[0].ID, msgs2[0].ID, "different pages should return different messages")
}

// --- 4. ListByThread (alias for FindByThreadID) ---
func TestCopilotMessageRepo_ListByThread(t *testing.T) {
	db := setupTestDB(t, &model.CopilotThread{}, &model.CopilotMessage{})
	repo := NewCopilotMessageRepo(db)

	thread := createTestCopilotThread(t, db, 1, 1, "ListByThread Thread")

	msg1 := createTestCopilotMessage(1, thread.ID, model.CopilotMessageTypeUser, "User msg")
	msg2 := createTestCopilotMessage(1, thread.ID, model.CopilotMessageTypeAssistant, "Assistant reply")
	require.NoError(t, db.Create(msg1).Error)
	require.NoError(t, db.Create(msg2).Error)

	msgs, count, err := repo.ListByThread(context.Background(), thread.ID, 0, 10)
	require.NoError(t, err)
	assert.Equal(t, int64(2), count)
	assert.Len(t, msgs, 2)

	// Verify ListByThread returns the same results as FindByThreadID
	msgsFind, countFind, errFind := repo.FindByThreadID(context.Background(), thread.ID, 0, 10)
	require.NoError(t, errFind)
	assert.Equal(t, count, countFind)
	assert.Equal(t, msgs[0].ID, msgsFind[0].ID)
	assert.Equal(t, msgs[1].ID, msgsFind[1].ID)
}

// --- 5. DeleteByThread ---
func TestCopilotMessageRepo_DeleteByThread(t *testing.T) {
	db := setupTestDB(t, &model.CopilotThread{}, &model.CopilotMessage{})
	repo := NewCopilotMessageRepo(db)

	thread := createTestCopilotThread(t, db, 1, 1, "Delete Thread")

	msg1 := createTestCopilotMessage(1, thread.ID, model.CopilotMessageTypeUser, "To be deleted")
	msg2 := createTestCopilotMessage(1, thread.ID, model.CopilotMessageTypeAssistant, "Also deleted")
	require.NoError(t, db.Create(msg1).Error)
	require.NoError(t, db.Create(msg2).Error)

	// Verify messages exist before deletion
	msgs, count, err := repo.FindByThreadID(context.Background(), thread.ID, 0, 10)
	require.NoError(t, err)
	assert.Equal(t, int64(2), count)
	assert.Len(t, msgs, 2)

	// Delete all messages in the thread
	err = repo.DeleteByThread(context.Background(), thread.ID)
	require.NoError(t, err)

	// Verify messages are gone
	msgsAfter, countAfter, errAfter := repo.FindByThreadID(context.Background(), thread.ID, 0, 10)
	require.NoError(t, errAfter)
	assert.Equal(t, int64(0), countAfter)
	assert.Len(t, msgsAfter, 0)
}