package repositories

import (
	"time"

	"gorm.io/gorm"

	"github.com/treytartt/casera-api/internal/models"
	"github.com/treytartt/casera-api/internal/task"
	"github.com/treytartt/casera-api/internal/task/categorization"
)

// TaskRepository handles database operations for tasks
type TaskRepository struct {
	db *gorm.DB
}

// NewTaskRepository creates a new task repository
func NewTaskRepository(db *gorm.DB) *TaskRepository {
	return &TaskRepository{db: db}
}

// === Task CRUD ===

// FindByID finds a task by ID with preloaded relations
func (r *TaskRepository) FindByID(id uint) (*models.Task, error) {
	var task models.Task
	err := r.db.Preload("Residence").
		Preload("CreatedBy").
		Preload("AssignedTo").
		Preload("Category").
		Preload("Priority").
		Preload("Frequency").
		Preload("Completions").
		Preload("Completions.Images").
		Preload("Completions.CompletedBy").
		First(&task, id).Error
	if err != nil {
		return nil, err
	}
	return &task, nil
}

// FindByResidence finds all tasks for a residence
func (r *TaskRepository) FindByResidence(residenceID uint) ([]models.Task, error) {
	var tasks []models.Task
	err := r.db.Preload("CreatedBy").
		Preload("AssignedTo").
		Preload("Category").
		Preload("Priority").
		Preload("Frequency").
		Preload("Completions").
		Preload("Completions.Images").
		Preload("Completions.CompletedBy").
		Where("residence_id = ?", residenceID).
		Order("due_date ASC NULLS LAST, created_at DESC").
		Find(&tasks).Error
	return tasks, err
}

// FindByUser finds all tasks accessible to a user (across all their residences)
func (r *TaskRepository) FindByUser(userID uint, residenceIDs []uint) ([]models.Task, error) {
	var tasks []models.Task
	err := r.db.Preload("Residence").
		Preload("CreatedBy").
		Preload("AssignedTo").
		Preload("Category").
		Preload("Priority").
		Preload("Frequency").
		Preload("Completions").
		Preload("Completions.Images").
		Preload("Completions.CompletedBy").
		Where("residence_id IN ?", residenceIDs).
		Order("due_date ASC NULLS LAST, created_at DESC").
		Find(&tasks).Error
	return tasks, err
}

// Create creates a new task
func (r *TaskRepository) Create(task *models.Task) error {
	return r.db.Create(task).Error
}

// Update updates a task
// Uses Omit to exclude associations that shouldn't be updated via Save
func (r *TaskRepository) Update(task *models.Task) error {
	return r.db.Omit("Residence", "CreatedBy", "AssignedTo", "Category", "Priority", "Frequency", "ParentTask", "Completions").Save(task).Error
}

// Delete hard-deletes a task
func (r *TaskRepository) Delete(id uint) error {
	return r.db.Delete(&models.Task{}, id).Error
}

// === Task State Operations ===

// MarkInProgress marks a task as in progress
func (r *TaskRepository) MarkInProgress(id uint) error {
	return r.db.Model(&models.Task{}).
		Where("id = ?", id).
		Update("in_progress", true).Error
}

// Cancel cancels a task
func (r *TaskRepository) Cancel(id uint) error {
	return r.db.Model(&models.Task{}).
		Where("id = ?", id).
		Update("is_cancelled", true).Error
}

// Uncancel uncancels a task
func (r *TaskRepository) Uncancel(id uint) error {
	return r.db.Model(&models.Task{}).
		Where("id = ?", id).
		Update("is_cancelled", false).Error
}

// Archive archives a task
func (r *TaskRepository) Archive(id uint) error {
	return r.db.Model(&models.Task{}).
		Where("id = ?", id).
		Update("is_archived", true).Error
}

// Unarchive unarchives a task
func (r *TaskRepository) Unarchive(id uint) error {
	return r.db.Model(&models.Task{}).
		Where("id = ?", id).
		Update("is_archived", false).Error
}

// === Kanban Board ===

// GetKanbanData retrieves tasks organized for kanban display
// Uses the task.categorization package as the single source of truth for categorization logic.
func (r *TaskRepository) GetKanbanData(residenceID uint, daysThreshold int) (*models.KanbanBoard, error) {
	var tasks []models.Task
	err := r.db.Preload("CreatedBy").
		Preload("AssignedTo").
		Preload("Category").
		Preload("Priority").
		Preload("Frequency").
		Preload("Completions").
		Preload("Completions.Images").
		Preload("Completions.CompletedBy").
		Where("residence_id = ? AND is_archived = ?", residenceID, false).
		Scopes(task.ScopeKanbanOrder).
		Find(&tasks).Error
	if err != nil {
		return nil, err
	}

	// Use the categorization package as the single source of truth
	categorized := categorization.CategorizeTasksIntoColumns(tasks, daysThreshold)

	columns := []models.KanbanColumn{
		{
			Name:        string(categorization.ColumnOverdue),
			DisplayName: "Overdue",
			ButtonTypes: []string{"edit", "complete", "cancel", "mark_in_progress"},
			Icons:       map[string]string{"ios": "exclamationmark.triangle", "android": "Warning"},
			Color:       "#FF3B30",
			Tasks:       categorized[categorization.ColumnOverdue],
			Count:       len(categorized[categorization.ColumnOverdue]),
		},
		{
			Name:        string(categorization.ColumnInProgress),
			DisplayName: "In Progress",
			ButtonTypes: []string{"edit", "complete", "cancel"},
			Icons:       map[string]string{"ios": "hammer", "android": "Build"},
			Color:       "#5856D6",
			Tasks:       categorized[categorization.ColumnInProgress],
			Count:       len(categorized[categorization.ColumnInProgress]),
		},
		{
			Name:        string(categorization.ColumnDueSoon),
			DisplayName: "Due Soon",
			ButtonTypes: []string{"edit", "complete", "cancel", "mark_in_progress"},
			Icons:       map[string]string{"ios": "clock", "android": "Schedule"},
			Color:       "#FF9500",
			Tasks:       categorized[categorization.ColumnDueSoon],
			Count:       len(categorized[categorization.ColumnDueSoon]),
		},
		{
			Name:        string(categorization.ColumnUpcoming),
			DisplayName: "Upcoming",
			ButtonTypes: []string{"edit", "complete", "cancel", "mark_in_progress"},
			Icons:       map[string]string{"ios": "calendar", "android": "Event"},
			Color:       "#007AFF",
			Tasks:       categorized[categorization.ColumnUpcoming],
			Count:       len(categorized[categorization.ColumnUpcoming]),
		},
		{
			Name:        string(categorization.ColumnCompleted),
			DisplayName: "Completed",
			ButtonTypes: []string{},
			Icons:       map[string]string{"ios": "checkmark.circle", "android": "CheckCircle"},
			Color:       "#34C759",
			Tasks:       categorized[categorization.ColumnCompleted],
			Count:       len(categorized[categorization.ColumnCompleted]),
		},
		{
			Name:        string(categorization.ColumnCancelled),
			DisplayName: "Cancelled",
			ButtonTypes: []string{"uncancel", "delete"},
			Icons:       map[string]string{"ios": "xmark.circle", "android": "Cancel"},
			Color:       "#8E8E93",
			Tasks:       categorized[categorization.ColumnCancelled],
			Count:       len(categorized[categorization.ColumnCancelled]),
		},
	}

	return &models.KanbanBoard{
		Columns:       columns,
		DaysThreshold: daysThreshold,
		ResidenceID:   string(rune(residenceID)),
	}, nil
}

// GetKanbanDataForMultipleResidences retrieves tasks from multiple residences organized for kanban display
// Uses the task.categorization package as the single source of truth for categorization logic.
func (r *TaskRepository) GetKanbanDataForMultipleResidences(residenceIDs []uint, daysThreshold int) (*models.KanbanBoard, error) {
	var tasks []models.Task
	err := r.db.Preload("CreatedBy").
		Preload("AssignedTo").
		Preload("Category").
		Preload("Priority").
		Preload("Frequency").
		Preload("Completions").
		Preload("Completions.Images").
		Preload("Completions.CompletedBy").
		Preload("Residence").
		Where("residence_id IN ? AND is_archived = ?", residenceIDs, false).
		Scopes(task.ScopeKanbanOrder).
		Find(&tasks).Error
	if err != nil {
		return nil, err
	}

	// Use the categorization package as the single source of truth
	categorized := categorization.CategorizeTasksIntoColumns(tasks, daysThreshold)

	columns := []models.KanbanColumn{
		{
			Name:        string(categorization.ColumnOverdue),
			DisplayName: "Overdue",
			ButtonTypes: []string{"edit", "complete", "cancel", "mark_in_progress"},
			Icons:       map[string]string{"ios": "exclamationmark.triangle", "android": "Warning"},
			Color:       "#FF3B30",
			Tasks:       categorized[categorization.ColumnOverdue],
			Count:       len(categorized[categorization.ColumnOverdue]),
		},
		{
			Name:        string(categorization.ColumnInProgress),
			DisplayName: "In Progress",
			ButtonTypes: []string{"edit", "complete", "cancel"},
			Icons:       map[string]string{"ios": "hammer", "android": "Build"},
			Color:       "#5856D6",
			Tasks:       categorized[categorization.ColumnInProgress],
			Count:       len(categorized[categorization.ColumnInProgress]),
		},
		{
			Name:        string(categorization.ColumnDueSoon),
			DisplayName: "Due Soon",
			ButtonTypes: []string{"edit", "complete", "cancel", "mark_in_progress"},
			Icons:       map[string]string{"ios": "clock", "android": "Schedule"},
			Color:       "#FF9500",
			Tasks:       categorized[categorization.ColumnDueSoon],
			Count:       len(categorized[categorization.ColumnDueSoon]),
		},
		{
			Name:        string(categorization.ColumnUpcoming),
			DisplayName: "Upcoming",
			ButtonTypes: []string{"edit", "complete", "cancel", "mark_in_progress"},
			Icons:       map[string]string{"ios": "calendar", "android": "Event"},
			Color:       "#007AFF",
			Tasks:       categorized[categorization.ColumnUpcoming],
			Count:       len(categorized[categorization.ColumnUpcoming]),
		},
		{
			Name:        string(categorization.ColumnCompleted),
			DisplayName: "Completed",
			ButtonTypes: []string{},
			Icons:       map[string]string{"ios": "checkmark.circle", "android": "CheckCircle"},
			Color:       "#34C759",
			Tasks:       categorized[categorization.ColumnCompleted],
			Count:       len(categorized[categorization.ColumnCompleted]),
		},
		{
			Name:        string(categorization.ColumnCancelled),
			DisplayName: "Cancelled",
			ButtonTypes: []string{"uncancel", "delete"},
			Icons:       map[string]string{"ios": "xmark.circle", "android": "Cancel"},
			Color:       "#8E8E93",
			Tasks:       categorized[categorization.ColumnCancelled],
			Count:       len(categorized[categorization.ColumnCancelled]),
		},
	}

	return &models.KanbanBoard{
		Columns:       columns,
		DaysThreshold: daysThreshold,
		ResidenceID:   "all",
	}, nil
}

// === Lookup Operations ===

// GetAllCategories returns all task categories
func (r *TaskRepository) GetAllCategories() ([]models.TaskCategory, error) {
	var categories []models.TaskCategory
	err := r.db.Order("display_order, name").Find(&categories).Error
	return categories, err
}

// GetAllPriorities returns all task priorities
func (r *TaskRepository) GetAllPriorities() ([]models.TaskPriority, error) {
	var priorities []models.TaskPriority
	err := r.db.Order("level").Find(&priorities).Error
	return priorities, err
}

// GetAllFrequencies returns all task frequencies
func (r *TaskRepository) GetAllFrequencies() ([]models.TaskFrequency, error) {
	var frequencies []models.TaskFrequency
	err := r.db.Order("display_order").Find(&frequencies).Error
	return frequencies, err
}

// CountByResidence counts tasks in a residence
func (r *TaskRepository) CountByResidence(residenceID uint) (int64, error) {
	var count int64
	err := r.db.Model(&models.Task{}).
		Where("residence_id = ? AND is_cancelled = ? AND is_archived = ?", residenceID, false, false).
		Count(&count).Error
	return count, err
}

// === Task Completion Operations ===

// CreateCompletion creates a new task completion
func (r *TaskRepository) CreateCompletion(completion *models.TaskCompletion) error {
	return r.db.Create(completion).Error
}

// FindCompletionByID finds a completion by ID
func (r *TaskRepository) FindCompletionByID(id uint) (*models.TaskCompletion, error) {
	var completion models.TaskCompletion
	err := r.db.Preload("Task").
		Preload("CompletedBy").
		Preload("Images").
		First(&completion, id).Error
	if err != nil {
		return nil, err
	}
	return &completion, nil
}

// FindCompletionsByTask finds all completions for a task
func (r *TaskRepository) FindCompletionsByTask(taskID uint) ([]models.TaskCompletion, error) {
	var completions []models.TaskCompletion
	err := r.db.Preload("CompletedBy").
		Preload("Images").
		Where("task_id = ?", taskID).
		Order("completed_at DESC").
		Find(&completions).Error
	return completions, err
}

// FindCompletionsByUser finds all completions by a user
func (r *TaskRepository) FindCompletionsByUser(userID uint, residenceIDs []uint) ([]models.TaskCompletion, error) {
	var completions []models.TaskCompletion
	err := r.db.Preload("Task").
		Preload("CompletedBy").
		Preload("Images").
		Joins("JOIN task_task ON task_task.id = task_taskcompletion.task_id").
		Where("task_task.residence_id IN ?", residenceIDs).
		Order("completed_at DESC").
		Find(&completions).Error
	return completions, err
}

// DeleteCompletion deletes a task completion
func (r *TaskRepository) DeleteCompletion(id uint) error {
	// Delete images first
	r.db.Where("completion_id = ?", id).Delete(&models.TaskCompletionImage{})
	return r.db.Delete(&models.TaskCompletion{}, id).Error
}

// CreateCompletionImage creates a new completion image
func (r *TaskRepository) CreateCompletionImage(image *models.TaskCompletionImage) error {
	return r.db.Create(image).Error
}

// DeleteCompletionImage deletes a completion image
func (r *TaskRepository) DeleteCompletionImage(id uint) error {
	return r.db.Delete(&models.TaskCompletionImage{}, id).Error
}

// FindCompletionImageByID finds a completion image by ID
func (r *TaskRepository) FindCompletionImageByID(id uint) (*models.TaskCompletionImage, error) {
	var image models.TaskCompletionImage
	err := r.db.First(&image, id).Error
	if err != nil {
		return nil, err
	}
	return &image, nil
}

// TaskStatistics represents aggregated task statistics
type TaskStatistics struct {
	TotalTasks        int
	TotalPending      int
	TotalOverdue      int
	TasksDueNextWeek  int
	TasksDueNextMonth int
}

// GetTaskStatistics returns aggregated task statistics for multiple residences.
// Uses the task.scopes package for consistent filtering logic.
func (r *TaskRepository) GetTaskStatistics(residenceIDs []uint) (*TaskStatistics, error) {
	if len(residenceIDs) == 0 {
		return &TaskStatistics{}, nil
	}

	now := time.Now().UTC()

	var totalTasks, totalOverdue, totalPending, tasksDueNextWeek, tasksDueNextMonth int64

	// Count total active tasks (not cancelled, not archived)
	// Uses: task.ScopeActive, task.ScopeForResidences
	err := r.db.Model(&models.Task{}).
		Scopes(task.ScopeForResidences(residenceIDs), task.ScopeActive).
		Count(&totalTasks).Error
	if err != nil {
		return nil, err
	}

	// Count overdue tasks using consistent scope
	// Uses: task.ScopeOverdue (which includes ScopeActive and ScopeNotCompleted)
	err = r.db.Model(&models.Task{}).
		Scopes(task.ScopeForResidences(residenceIDs), task.ScopeOverdue(now)).
		Count(&totalOverdue).Error
	if err != nil {
		return nil, err
	}

	// Count pending tasks (active, not completed)
	// Uses: task.ScopeActive, task.ScopeNotCompleted
	err = r.db.Model(&models.Task{}).
		Scopes(task.ScopeForResidences(residenceIDs), task.ScopeActive, task.ScopeNotCompleted).
		Count(&totalPending).Error
	if err != nil {
		return nil, err
	}

	// Count tasks due next week using consistent scope
	// Uses: task.ScopeDueSoon with 7-day threshold
	err = r.db.Model(&models.Task{}).
		Scopes(task.ScopeForResidences(residenceIDs), task.ScopeDueSoon(now, 7)).
		Count(&tasksDueNextWeek).Error
	if err != nil {
		return nil, err
	}

	// Count tasks due next month using consistent scope
	// Uses: task.ScopeDueSoon with 30-day threshold
	err = r.db.Model(&models.Task{}).
		Scopes(task.ScopeForResidences(residenceIDs), task.ScopeDueSoon(now, 30)).
		Count(&tasksDueNextMonth).Error
	if err != nil {
		return nil, err
	}

	return &TaskStatistics{
		TotalTasks:        int(totalTasks),
		TotalPending:      int(totalPending),
		TotalOverdue:      int(totalOverdue),
		TasksDueNextWeek:  int(tasksDueNextWeek),
		TasksDueNextMonth: int(tasksDueNextMonth),
	}, nil
}

// GetOverdueCountByResidence returns a map of residence ID to overdue task count.
// Uses the task.scopes package for consistent filtering logic.
func (r *TaskRepository) GetOverdueCountByResidence(residenceIDs []uint) (map[uint]int, error) {
	if len(residenceIDs) == 0 {
		return map[uint]int{}, nil
	}

	now := time.Now().UTC()

	// Query to get overdue count grouped by residence
	type result struct {
		ResidenceID uint
		Count       int64
	}
	var results []result

	err := r.db.Model(&models.Task{}).
		Select("residence_id, COUNT(*) as count").
		Scopes(task.ScopeForResidences(residenceIDs), task.ScopeOverdue(now)).
		Group("residence_id").
		Scan(&results).Error
	if err != nil {
		return nil, err
	}

	// Convert to map
	countMap := make(map[uint]int)
	for _, r := range results {
		countMap[r.ResidenceID] = int(r.Count)
	}

	return countMap, nil
}