package storage

import (
	"strings"
	"time"

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

// TaskTriggerType identifies how a species task template calculates its due window.
type TaskTriggerType string

// TaskDurationUnit is the calendar unit used for offsets and durations.
type TaskDurationUnit string

// TaskTemplateOrigin identifies whether a template was entered manually or derived from species data.
type TaskTemplateOrigin string

// Supported task duration units.
const (
	TaskDurationDay   TaskDurationUnit = "day"
	TaskDurationWeek  TaskDurationUnit = "week"
	TaskDurationMonth TaskDurationUnit = "month"
)

// Supported task trigger types.
const (
	// TaskTriggerMonthOfYear repeats within a calendar-year date window.
	TaskTriggerMonthOfYear TaskTriggerType = "month_of_year"
	// TaskTriggerRelativeToPlanting is offset from the planting date.
	TaskTriggerRelativeToPlanting TaskTriggerType = "relative_to_planting"
	// TaskTriggerRelativeToLastTask is offset from the last completion.
	TaskTriggerRelativeToLastTask        TaskTriggerType = "relative_to_last_task"
	TaskTriggerRelativeToSowing          TaskTriggerType = "relative_to_sowing"
	TaskTriggerRelativeToHarvest         TaskTriggerType = "relative_to_harvest"
	TaskTriggerRelativeToSpeciesPlanting TaskTriggerType = "relative_to_species_planting"
)

// Supported template origins.
const (
	TaskTemplateOriginManual         TaskTemplateOrigin = "manual"
	TaskTemplateOriginSeasonSowing   TaskTemplateOrigin = "season_sowing"
	TaskTemplateOriginSeasonPlanting TaskTemplateOrigin = "season_planting"
	TaskTemplateOriginSeasonHarvest  TaskTemplateOrigin = "season_harvest"
)

// SpeciesTaskTemplateModelInterface persists recurring rules for species tasks.
type SpeciesTaskTemplateModelInterface interface {
	Insert(template SpeciesTaskTemplate) (SpeciesTaskTemplate, error)
	Get(gardenID, id int) (SpeciesTaskTemplate, error)
	GetAllForSpecies(gardenID, speciesID int) ([]SpeciesTaskTemplate, error)
	Update(gardenID int, template SpeciesTaskTemplate) (SpeciesTaskTemplate, error)
	Delete(gardenID, id int) error
}

// ValidateSpeciesTaskTemplate applies scheduling and recurrence rules to a
// species task template.
func ValidateSpeciesTaskTemplate(v *validate.Validator, template SpeciesTaskTemplate) {
	v.Check(strings.TrimSpace(template.Title) != "", "title", "must be provided")
	v.Check(len(template.Title) <= 500, "title", "must not be more than 500 bytes long")
	v.Check(len(template.Description) <= 10_000, "description", "must not be more than 10000 bytes long")
	v.Check(template.Priority >= -100 && template.Priority <= 100, "priority", "must be between -100 and 100")
	v.Check(template.TriggerType == TaskTriggerMonthOfYear || template.TriggerType == TaskTriggerRelativeToPlanting || template.TriggerType == TaskTriggerRelativeToLastTask || template.TriggerType == TaskTriggerRelativeToSowing || template.TriggerType == TaskTriggerRelativeToHarvest || template.TriggerType == TaskTriggerRelativeToSpeciesPlanting, "trigger_type", "is invalid")
	v.Check(template.Origin == TaskTemplateOriginManual || template.Origin == TaskTemplateOriginSeasonSowing || template.Origin == TaskTemplateOriginSeasonPlanting || template.Origin == TaskTemplateOriginSeasonHarvest, "origin", "is invalid")
	if template.TriggerType == TaskTriggerMonthOfYear {
		v.Check(template.MonthFrom != nil && *template.MonthFrom >= 1 && *template.MonthFrom <= 12, "month_from", "must be between 1 and 12")
		validateTemplateDay(v, "day_from", template.DayFrom)
		v.Check(template.DayFrom != nil, "day_from", "must be provided")
	} else {
		v.Check(template.TriggerOffset >= 0, "trigger_offset", "must not be negative")
	}
	v.Check(template.Duration >= 0, "duration", "must not be negative")
	v.Check(validTaskDurationUnit(template.DurationUnit), "duration_unit", "is invalid")
	v.Check(validTaskDurationUnit(template.TriggerOffsetUnit), "trigger_offset_unit", "is invalid")
	v.Check(template.Recurrence == TaskRecurrenceNone || template.Recurrence == TaskRecurrenceDaily || template.Recurrence == TaskRecurrenceWeekly || template.Recurrence == TaskRecurrenceMonthly || template.Recurrence == TaskRecurrenceYearly, "recurrence", "is invalid")
	if template.Recurrence != TaskRecurrenceNone {
		v.Check(template.RecurrenceInterval > 0, "recurrence_interval", "must be greater than zero")
	}
}

func validTaskDurationUnit(unit TaskDurationUnit) bool {
	return unit == TaskDurationDay || unit == TaskDurationWeek || unit == TaskDurationMonth
}

func validateTemplateDay(v *validate.Validator, field string, value *int) {
	if value != nil {
		v.Check(*value >= 1 && *value <= 31, field, "must be between 1 and 31")
	}
}

// SpeciesTaskTemplate defines a recurring task rule for a species.
type SpeciesTaskTemplate struct {
	ID                 int                `json:"id"`
	SpeciesID          int                `json:"species_id"`
	Origin             TaskTemplateOrigin `json:"origin"`
	Title              string             `json:"title"`
	Description        string             `json:"description"`
	TriggerType        TaskTriggerType    `json:"trigger_type"`
	MonthFrom          *int               `json:"month_from,omitempty"`
	DayFrom            *int               `json:"day_from,omitempty"`
	MonthTo            *int               `json:"month_to,omitempty"`
	DayTo              *int               `json:"day_to,omitempty"`
	OffsetDaysFrom     *int               `json:"offset_days_from,omitempty"`
	OffsetDaysTo       *int               `json:"offset_days_to,omitempty"`
	IntervalDays       *int               `json:"interval_days,omitempty"`
	TriggerOffset      int                `json:"trigger_offset"`
	TriggerOffsetUnit  TaskDurationUnit   `json:"trigger_offset_unit"`
	Duration           int                `json:"duration"`
	DurationUnit       TaskDurationUnit   `json:"duration_unit"`
	Recurrence         TaskRecurrence     `json:"recurrence,omitempty"`
	RecurrenceInterval int                `json:"recurrence_interval"`
	Priority           int                `json:"priority"`
	Active             bool               `json:"active"`
	CreatedAt          time.Time          `json:"created_at"`
	UpdatedAt          time.Time          `json:"updated_at"`
	Version            int                `json:"version"`
}