package models

import (
	"time"

	"github.com/shopspring/decimal"
)

// TaskCategory represents the task_taskcategory table
type TaskCategory struct {
	BaseModel
	Name        string `gorm:"column:name;size:50;not null" json:"name"`
	Description string `gorm:"column:description;type:text" json:"description"`
	Icon        string `gorm:"column:icon;size:50" json:"icon"`
	Color       string `gorm:"column:color;size:7" json:"color"` // Hex color
	DisplayOrder int   `gorm:"column:display_order;default:0" json:"display_order"`
}

// TableName returns the table name for GORM
func (TaskCategory) TableName() string {
	return "task_taskcategory"
}

// TaskPriority represents the task_taskpriority table
type TaskPriority struct {
	BaseModel
	Name        string `gorm:"column:name;size:20;not null" json:"name"`
	Level       int    `gorm:"column:level;not null" json:"level"` // 1=low, 2=medium, 3=high, 4=urgent
	Color       string `gorm:"column:color;size:7" json:"color"`
	DisplayOrder int   `gorm:"column:display_order;default:0" json:"display_order"`
}

// TableName returns the table name for GORM
func (TaskPriority) TableName() string {
	return "task_taskpriority"
}

// TaskFrequency represents the task_taskfrequency table
type TaskFrequency struct {
	BaseModel
	Name        string `gorm:"column:name;size:20;not null" json:"name"`
	Days        *int   `gorm:"column:days" json:"days"` // Number of days between occurrences (nil = one-time)
	DisplayOrder int   `gorm:"column:display_order;default:0" json:"display_order"`
}

// TableName returns the table name for GORM
func (TaskFrequency) TableName() string {
	return "task_taskfrequency"
}

// Task represents the task_task table
type Task struct {
	BaseModel
	ResidenceID   uint             `gorm:"column:residence_id;index;not null" json:"residence_id"`
	Residence     Residence        `gorm:"foreignKey:ResidenceID" json:"residence,omitempty"`
	CreatedByID   uint             `gorm:"column:created_by_id;index;not null" json:"created_by_id"`
	CreatedBy     User             `gorm:"foreignKey:CreatedByID" json:"created_by,omitempty"`
	AssignedToID  *uint            `gorm:"column:assigned_to_id;index" json:"assigned_to_id"`
	AssignedTo    *User            `gorm:"foreignKey:AssignedToID" json:"assigned_to,omitempty"`

	Title         string           `gorm:"column:title;size:200;not null" json:"title"`
	Description   string           `gorm:"column:description;type:text" json:"description"`

	CategoryID    *uint            `gorm:"column:category_id;index" json:"category_id"`
	Category      *TaskCategory    `gorm:"foreignKey:CategoryID" json:"category,omitempty"`
	PriorityID    *uint            `gorm:"column:priority_id;index" json:"priority_id"`
	Priority      *TaskPriority    `gorm:"foreignKey:PriorityID" json:"priority,omitempty"`
	FrequencyID   *uint            `gorm:"column:frequency_id;index" json:"frequency_id"`
	Frequency     *TaskFrequency   `gorm:"foreignKey:FrequencyID" json:"frequency,omitempty"`
	CustomIntervalDays *int        `gorm:"column:custom_interval_days" json:"custom_interval_days"` // For "Custom" frequency, user-specified days

	// In Progress flag - replaces status lookup
	InProgress    bool             `gorm:"column:in_progress;default:false;index" json:"in_progress"`

	DueDate       *time.Time       `gorm:"column:due_date;type:date;index" json:"due_date"`
	NextDueDate   *time.Time       `gorm:"column:next_due_date;type:date;index" json:"next_due_date"` // For recurring tasks, updated after each completion
	EstimatedCost *decimal.Decimal `gorm:"column:estimated_cost;type:decimal(10,2)" json:"estimated_cost"`
	ActualCost    *decimal.Decimal `gorm:"column:actual_cost;type:decimal(10,2)" json:"actual_cost"`

	// Contractor association
	ContractorID  *uint            `gorm:"column:contractor_id;index" json:"contractor_id"`
	// Contractor    *Contractor      `gorm:"foreignKey:ContractorID" json:"contractor,omitempty"`

	// State flags
	IsCancelled   bool             `gorm:"column:is_cancelled;default:false;index" json:"is_cancelled"`
	IsArchived    bool             `gorm:"column:is_archived;default:false;index" json:"is_archived"`

	// Optimistic locking version
	Version       int              `gorm:"column:version;not null;default:1" json:"-"`

	// Parent task for recurring tasks
	ParentTaskID  *uint            `gorm:"column:parent_task_id;index" json:"parent_task_id"`
	ParentTask    *Task            `gorm:"foreignKey:ParentTaskID" json:"parent_task,omitempty"`

	// Completions
	Completions   []TaskCompletion `gorm:"foreignKey:TaskID" json:"completions,omitempty"`

	// CompletionCount is a computed field populated via subquery for optimized queries.
	// When populated (>= 0 and Completions slice is empty), predicates should use this
	// instead of len(Completions) to avoid N+1 queries.
	CompletionCount int `gorm:"-:all" json:"-"`
}

// TableName returns the table name for GORM
func (Task) TableName() string {
	return "task_task"
}

// IsOverdue returns true if the task is past its due date and not completed.
//
// IMPORTANT: This method delegates to the predicates package which is the
// single source of truth for task logic. It uses EffectiveDate (NextDueDate ?? DueDate)
// rather than just DueDate, ensuring consistency with kanban categorization.
//
// Uses day-based comparison: a task due TODAY is NOT overdue, it only becomes
// overdue the NEXT day.
//
// Deprecated: Prefer using task.IsOverdue(t, time.Now().UTC()) directly for explicit time control.
func (t *Task) IsOverdue() bool {
	return t.IsOverdueAt(time.Now().UTC())
}

// IsOverdueAt returns true if the task would be overdue at the given time.
// Uses day-based comparison: a task due on the same day as `now` is NOT overdue.
func (t *Task) IsOverdueAt(now time.Time) bool {
	// Logic must match predicates.IsOverdue exactly:
	// - Check active (not cancelled, not archived)
	// - Check not completed (NextDueDate != nil || no completions)
	// - Check effective date < start of today
	if t.IsCancelled || t.IsArchived {
		return false
	}
	// Completed check: NextDueDate == nil AND has completions
	// Supports both preloaded Completions and computed CompletionCount
	hasCompletions := len(t.Completions) > 0 || t.CompletionCount > 0
	if t.NextDueDate == nil && hasCompletions {
		return false
	}
	// Effective date: NextDueDate ?? DueDate
	effectiveDate := t.NextDueDate
	if effectiveDate == nil {
		effectiveDate = t.DueDate
	}
	if effectiveDate == nil {
		return false
	}
	// Day-based comparison: compare against start of today
	startOfDay := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
	return effectiveDate.Before(startOfDay)
}

// IsDueSoon returns true if the task is due within the specified days.
//
// IMPORTANT: This method uses EffectiveDate (NextDueDate ?? DueDate)
// rather than just DueDate, ensuring consistency with kanban categorization.
//
// Deprecated: Prefer using task.IsDueSoon(t, time.Now().UTC(), days) directly for explicit time control.
func (t *Task) IsDueSoon(days int) bool {
	// Delegate to predicates package logic - single source of truth
	// Logic must match predicates.IsDueSoon exactly
	if t.IsCancelled || t.IsArchived {
		return false
	}
	// Completed check: NextDueDate == nil AND has completions
	// Supports both preloaded Completions and computed CompletionCount
	hasCompletions := len(t.Completions) > 0 || t.CompletionCount > 0
	if t.NextDueDate == nil && hasCompletions {
		return false
	}
	// Effective date: NextDueDate ?? DueDate
	effectiveDate := t.NextDueDate
	if effectiveDate == nil {
		effectiveDate = t.DueDate
	}
	if effectiveDate == nil {
		return false
	}
	now := time.Now().UTC()
	threshold := now.AddDate(0, 0, days)
	// Due soon = not overdue AND before threshold
	return !effectiveDate.Before(now) && effectiveDate.Before(threshold)
}

// GetKanbanColumn returns the kanban column name for this task using the
// Chain of Responsibility pattern from the categorization package.
// Uses UTC time for categorization.
//
// For timezone-aware categorization, use GetKanbanColumnWithTimezone.
func (t *Task) GetKanbanColumn(daysThreshold int) string {
	// Import would cause circular dependency, so we inline the logic
	// This delegates to the categorization package via internal/task re-export
	return t.GetKanbanColumnWithTimezone(daysThreshold, time.Now().UTC())
}

// GetKanbanColumnWithTimezone returns the kanban column name using a specific
// time (in the user's timezone). The time is used to determine "today" for
// overdue/due-soon calculations.
//
// Example: For a user in Tokyo, pass time.Now().In(tokyoLocation) to get
// accurate categorization relative to their local date.
func (t *Task) GetKanbanColumnWithTimezone(daysThreshold int, now time.Time) string {
	// Note: We can't import categorization directly due to circular dependency.
	// Instead, this method implements the categorization logic inline.
	// The logic MUST match categorization.Chain exactly.

	if daysThreshold <= 0 {
		daysThreshold = 30
	}

	// Start of day normalization
	startOfDay := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
	threshold := startOfDay.AddDate(0, 0, daysThreshold)

	// Priority 1: Cancelled
	if t.IsCancelled {
		return "cancelled_tasks"
	}

	// Priority 2: Archived (goes to cancelled column - both are "inactive" states)
	if t.IsArchived {
		return "cancelled_tasks"
	}

	// Priority 3: Completed (NextDueDate nil with completions)
	hasCompletions := len(t.Completions) > 0 || t.CompletionCount > 0
	if t.NextDueDate == nil && hasCompletions {
		return "completed_tasks"
	}

	// Priority 4: In Progress
	if t.InProgress {
		return "in_progress_tasks"
	}

	// Get effective date: NextDueDate ?? DueDate
	var effectiveDate *time.Time
	if t.NextDueDate != nil {
		effectiveDate = t.NextDueDate
	} else {
		effectiveDate = t.DueDate
	}

	if effectiveDate != nil {
		// Normalize effective date to same timezone for calendar date comparison
		// Task dates are stored as UTC but represent calendar dates (YYYY-MM-DD)
		normalizedEffective := time.Date(
			effectiveDate.Year(), effectiveDate.Month(), effectiveDate.Day(),
			0, 0, 0, 0, now.Location(),
		)

		// Priority 5: Overdue (effective date before today)
		if normalizedEffective.Before(startOfDay) {
			return "overdue_tasks"
		}

		// Priority 6: Due Soon (effective date before threshold)
		if normalizedEffective.Before(threshold) {
			return "due_soon_tasks"
		}
	}

	// Priority 7: Upcoming (default)
	return "upcoming_tasks"
}

// TaskCompletion represents the task_taskcompletion table
type TaskCompletion struct {
	BaseModel
	TaskID        uint             `gorm:"column:task_id;index;not null" json:"task_id"`
	Task          Task             `gorm:"foreignKey:TaskID" json:"-"`
	CompletedByID uint             `gorm:"column:completed_by_id;index;not null" json:"completed_by_id"`
	CompletedBy   User             `gorm:"foreignKey:CompletedByID" json:"completed_by,omitempty"`
	CompletedAt   time.Time        `gorm:"column:completed_at;not null" json:"completed_at"`
	Notes         string           `gorm:"column:notes;type:text" json:"notes"`
	ActualCost    *decimal.Decimal `gorm:"column:actual_cost;type:decimal(10,2)" json:"actual_cost"`
	Rating        *int             `gorm:"column:rating" json:"rating"` // 1-5 star rating

	// Multiple images support
	Images        []TaskCompletionImage `gorm:"foreignKey:CompletionID" json:"images,omitempty"`
}

// TableName returns the table name for GORM
func (TaskCompletion) TableName() string {
	return "task_taskcompletion"
}

// TaskCompletionImage represents the task_taskcompletionimage table
type TaskCompletionImage struct {
	BaseModel
	CompletionID uint   `gorm:"column:completion_id;index;not null" json:"completion_id"`
	ImageURL     string `gorm:"column:image_url;size:500;not null" json:"image_url"`
	Caption      string `gorm:"column:caption;size:255" json:"caption"`
}

// TableName returns the table name for GORM
func (TaskCompletionImage) TableName() string {
	return "task_taskcompletionimage"
}

// KanbanColumn represents a column in the kanban board
type KanbanColumn struct {
	Name        string            `json:"name"`
	DisplayName string            `json:"display_name"`
	ButtonTypes []string          `json:"button_types"`
	Icons       map[string]string `json:"icons"`
	Color       string            `json:"color"`
	Tasks       []Task            `json:"tasks"`
	Count       int               `json:"count"`
}

// KanbanBoard represents the full kanban board response
type KanbanBoard struct {
	Columns       []KanbanColumn `json:"columns"`
	DaysThreshold int            `json:"days_threshold"`
	ResidenceID   string         `json:"residence_id"`
}