package domain

import (
	"strings"
	"time"
)

// LessonPublishStatus controls learner visibility for an LMS lesson row (like PracticePublishStatus).
type LessonPublishStatus string

const (
	LessonPublishDraft     LessonPublishStatus = "DRAFT"
	LessonPublishPublished LessonPublishStatus = "PUBLISHED"
)

// LessonPublishStatusFromDB normalizes persisted values.
func LessonPublishStatusFromDB(raw string) LessonPublishStatus {
	switch strings.TrimSpace(strings.ToUpper(raw)) {
	case string(LessonPublishPublished):
		return LessonPublishPublished
	default:
		return LessonPublishDraft
	}
}

// LessonPublishStatusFromCreateInput resolves create body: omit → draft; explicit value validated separately.
func LessonPublishStatusFromCreateInput(raw *string) LessonPublishStatus {
	if raw == nil || strings.TrimSpace(*raw) == "" {
		return LessonPublishDraft
	}
	return LessonPublishStatusFromDB(*raw)
}

// Lesson belongs to a Module.
type Lesson struct {
	ID             int64               `json:"id"`
	ModuleID       int64               `json:"module_id"`
	Title          string              `json:"title"`
	VideoURL       *string             `json:"video_url,omitempty"`
	Thumbnail      *string             `json:"thumbnail,omitempty"`
	Description    *string             `json:"description,omitempty"`
	SortOrder      int                 `json:"sort_order"`
	PublishStatus  LessonPublishStatus `json:"publish_status"`
	HasPractice    bool                `json:"has_practice"`
	CreatedAt      time.Time           `json:"created_at"`
	UpdatedAt      *time.Time          `json:"updated_at,omitempty"`
	Access         *LMSEntityAccess    `json:"access,omitempty"`
}

// VisibleToLearners is true when the lesson appears in subscriber/catalog LMS APIs.
func (l Lesson) VisibleToLearners() bool {
	return l.PublishStatus == LessonPublishPublished
}

type CreateLessonInput struct {
	Title       string  `json:"title" validate:"required"`
	VideoURL    *string `json:"video_url,omitempty"`
	Thumbnail   *string `json:"thumbnail,omitempty"`
	Description *string `json:"description,omitempty"`
	// SortOrder within the module when set; omit to append after current max within module_id.
	SortOrder *int `json:"sort_order,omitempty" validate:"omitempty,min=0"`
	// Omit or empty defaults to DRAFT; set PUBLISHED to make visible to learners immediately.
	PublishStatus *string `json:"publish_status,omitempty" validate:"omitempty,oneof=DRAFT draft PUBLISHED published"`
}

type UpdateLessonInput struct {
	Title           *string `json:"title,omitempty"`
	VideoURL        *string `json:"video_url,omitempty"`
	Thumbnail       *string `json:"thumbnail,omitempty"`
	Description     *string `json:"description,omitempty"`
	SortOrder       *int    `json:"sort_order,omitempty"`
	PublishStatus   *string `json:"publish_status,omitempty" validate:"omitempty,oneof=DRAFT draft PUBLISHED published"`
}