package storage

import (
	"strings"
	"time"

	"gardomatic.kleiax.de/internal/platform/validate"
)

// TaskRecurrence identifies the calendar interval of a manual task.
type TaskRecurrence string

// Supported task recurrence values. An empty value disables recurrence.
const (
	TaskRecurrenceNone    TaskRecurrence = ""
	TaskRecurrenceDaily   TaskRecurrence = "daily"
	TaskRecurrenceWeekly  TaskRecurrence = "weekly"
	TaskRecurrenceMonthly TaskRecurrence = "monthly"
	TaskRecurrenceYearly  TaskRecurrence = "yearly"
)

// TaskModelInterface persists garden work items and generated task instances.
type TaskModelInterface interface {
	Insert(task Task) (Task, error)
	Get(gardenID, id int) (Task, error)
	GetAllForGarden(gardenID int) ([]Task, error)
	Update(gardenID int, task Task) (Task, error)
	Delete(gardenID, id int) error
}

// ValidateTask applies persistence-independent rules for manual garden tasks.
func ValidateTask(v *validate.Validator, task Task) {
	v.Check(strings.TrimSpace(task.Title) != "", "title", "must be provided")
	v.Check(len(task.Title) <= 500, "title", "must not be more than 500 bytes long")
	v.Check(len(task.Description) <= 10_000, "description", "must not be more than 10000 bytes long")
	v.Check(task.Priority >= -100 && task.Priority <= 100, "priority", "must be between -100 and 100")
	if task.PlantID != nil {
		v.Check(*task.PlantID > 0, "plant_id", "must be a positive integer")
	}
	if task.LocationID != nil {
		v.Check(*task.LocationID > 0, "location_id", "must be a positive integer")
	}
	if task.DueAtStart != nil && task.DueAtEnd != nil {
		v.Check(!task.DueAtStart.After(*task.DueAtEnd), "due_at_end", "must not be before due_at_start")
	}
	v.Check(task.Recurrence == TaskRecurrenceNone || task.Recurrence == TaskRecurrenceDaily || task.Recurrence == TaskRecurrenceWeekly || task.Recurrence == TaskRecurrenceMonthly || task.Recurrence == TaskRecurrenceYearly, "recurrence", "is invalid")
	if task.Recurrence != TaskRecurrenceNone {
		v.Check(task.DueAtStart != nil || task.DueAtEnd != nil, "recurrence", "requires a due date")
		v.Check(task.RecurrenceInterval > 0, "recurrence_interval", "must be greater than zero")
	}
	validateOptionalEnum(v, "plant_status_on_completion", task.PlantStatusOnCompletion, "alive", "dead", "removed", "infested", "harvested")
	if task.PlantStatusOnCompletion != nil {
		v.Check(task.PlantID != nil, "plant_status_on_completion", "requires a plant")
	}
	if task.CompletedAt != nil {
		v.Check(task.CompletedBy != nil && *task.CompletedBy > 0, "completed_by", "must be set for a completed task")
	}
	if task.CompletedBy != nil {
		v.Check(task.CompletedAt != nil, "completed_at", "must be set when completed_by is set")
	}
}

// Task represents a manual or template-generated garden work item.
type Task struct {
	ID                      int            `json:"id"`
	GardenID                int            `json:"garden_id"`
	PlantID                 *int           `json:"plant_id,omitempty"`
	LocationID              *int           `json:"location_id,omitempty"`
	TemplateID              *int           `json:"template_id,omitempty"`
	Title                   string         `json:"title"`
	Description             string         `json:"description"`
	DueAtStart              *time.Time     `json:"due_at_start,omitempty"`
	DueAtEnd                *time.Time     `json:"due_at_end,omitempty"`
	GeneratedFor            *time.Time     `json:"generated_for,omitempty"`
	Recurrence              TaskRecurrence `json:"recurrence,omitempty"`
	RecurrenceInterval      int            `json:"recurrence_interval"`
	RepeatFromID            *int           `json:"repeat_from_id,omitempty"`
	CompletedAt             *time.Time     `json:"completed_at,omitempty"`
	CompletedBy             *int           `json:"completed_by,omitempty"`
	Priority                int            `json:"priority"`
	Active                  bool           `json:"active"`
	CreatedBy               int            `json:"created_by"`
	CreatedAt               time.Time      `json:"created_at"`
	UpdatedAt               time.Time      `json:"updated_at"`
	Version                 int            `json:"version"`
	Tags                    []string       `json:"tags,omitempty"`
	PlantStatusOnCompletion *string        `json:"plant_status_on_completion,omitempty"`
}