package education

import (
	"time"

	"github.com/google/uuid"
	"github.com/lib/pq"
	"gorm.io/gorm"
)

// CourseStatus represents the publication status of a course
type CourseStatus string

const (
	CourseStatusDraft     CourseStatus = "draft"
	CourseStatusPublished CourseStatus = "published"
	CourseStatusArchived  CourseStatus = "archived"
)

// CourseLevel represents the difficulty level
type CourseLevel string

const (
	CourseLevelBeginner     CourseLevel = "beginner"
	CourseLevelIntermediate CourseLevel = "intermediate"
	CourseLevelAdvanced     CourseLevel = "advanced"
)

// PricingModel represents the pricing strategy
type PricingModel string

const (
	PricingFixed      PricingModel = "fixed"
	PricingPayWhatYou PricingModel = "pay_what_you_want"
	PricingFree       PricingModel = "free"
)

// EnrollmentStatus represents the enrollment state
type EnrollmentStatus string

const (
	EnrollmentActive   EnrollmentStatus = "active"
	EnrollmentExpired  EnrollmentStatus = "expired"
	EnrollmentRefunded EnrollmentStatus = "refunded"
)

// TranscodingStatus represents video processing state
type TranscodingStatus string

const (
	TranscodingPending    TranscodingStatus = "pending"
	TranscodingProcessing TranscodingStatus = "processing"
	TranscodingComplete   TranscodingStatus = "complete"
	TranscodingFailed     TranscodingStatus = "failed"
)

// CertificateStatus represents certificate validity
type CertificateStatus string

const (
	CertificateActive  CertificateStatus = "active"
	CertificateRevoked CertificateStatus = "revoked"
)

// ReviewStatus represents review moderation status
type ReviewStatus string

const (
	ReviewApproved ReviewStatus = "approved"
	ReviewPending  ReviewStatus = "pending"
	ReviewRejected ReviewStatus = "rejected"
)

// Course represents an educational course created by a user
type Course struct {
	ID                   uuid.UUID      `gorm:"type:uuid;primaryKey" json:"id"`
	CreatorID            uuid.UUID      `gorm:"type:uuid;not null" json:"creator_id"`
	Title                string         `gorm:"size:255;not null" json:"title"`
	Slug                 string         `gorm:"size:255;not null;uniqueIndex" json:"slug"`
	Description          string         `gorm:"type:text;not null;default:''" json:"description"`
	Category             string         `gorm:"size:100" json:"category,omitempty"`
	Tags                 pq.StringArray `gorm:"type:varchar(50)[];default:'{}'" json:"tags"`
	CoverImageURL        string         `gorm:"type:text" json:"cover_image_url,omitempty"`
	PriceCents           int            `gorm:"not null;default:0" json:"price_cents"`
	Currency             string         `gorm:"size:3;not null;default:'USD'" json:"currency"`
	PricingModel         PricingModel   `gorm:"size:50;not null;default:'fixed'" json:"pricing_model"`
	MinimumPriceCents    int            `gorm:"default:0" json:"minimum_price_cents"`
	Status               CourseStatus   `gorm:"size:50;not null;default:'draft'" json:"status"`
	Level                CourseLevel    `gorm:"size:50;default:'beginner'" json:"level"`
	Language             string         `gorm:"size:5;default:'en'" json:"language"`
	TotalDurationSeconds int            `gorm:"not null;default:0" json:"total_duration_seconds"`
	LessonCount          int            `gorm:"not null;default:0" json:"lesson_count"`
	EnrollmentCount      int            `gorm:"not null;default:0" json:"enrollment_count"`
	ReviewCount          int            `gorm:"not null;default:0" json:"review_count"`
	AverageRating        float64        `gorm:"type:numeric(3,2);default:0" json:"average_rating"`
	PublishedAt          *time.Time     `json:"published_at,omitempty"`
	CreatedAt            time.Time      `gorm:"autoCreateTime" json:"created_at"`
	UpdatedAt            time.Time      `gorm:"autoUpdateTime" json:"updated_at"`
	DeletedAt            gorm.DeletedAt `gorm:"index" json:"deleted_at,omitempty"`
}

func (Course) TableName() string {
	return "courses"
}

func (c *Course) BeforeCreate(tx *gorm.DB) error {
	if c.ID == uuid.Nil {
		c.ID = uuid.New()
	}
	return nil
}

// Lesson represents a single lesson within a course
type Lesson struct {
	ID                   uuid.UUID         `gorm:"type:uuid;primaryKey" json:"id"`
	CourseID             uuid.UUID         `gorm:"type:uuid;not null" json:"course_id"`
	OrderIndex           int               `gorm:"not null" json:"order_index"`
	Title                string            `gorm:"size:255;not null" json:"title"`
	Description          string            `gorm:"type:text" json:"description,omitempty"`
	VideoFilePath        string            `gorm:"size:512" json:"video_file_path,omitempty"`
	DurationSeconds      int               `gorm:"not null;default:0" json:"duration_seconds"`
	IsPreviewFree        bool              `gorm:"not null;default:false" json:"is_preview_free"`
	TranscodingStatus    TranscodingStatus `gorm:"size:50;not null;default:'pending'" json:"transcoding_status"`
	HLSMasterPlaylistURL string            `gorm:"type:text" json:"hls_master_playlist_url,omitempty"`
	ThumbnailURL         string            `gorm:"type:text" json:"thumbnail_url,omitempty"`
	CreatedAt            time.Time         `gorm:"autoCreateTime" json:"created_at"`
	UpdatedAt            time.Time         `gorm:"autoUpdateTime" json:"updated_at"`
}

func (Lesson) TableName() string {
	return "lessons"
}

func (l *Lesson) BeforeCreate(tx *gorm.DB) error {
	if l.ID == uuid.Nil {
		l.ID = uuid.New()
	}
	return nil
}

// CourseEnrollment represents a user's enrollment (purchase) in a course
type CourseEnrollment struct {
	ID                 uuid.UUID        `gorm:"type:uuid;primaryKey" json:"id"`
	UserID             uuid.UUID        `gorm:"type:uuid;not null" json:"user_id"`
	CourseID           uuid.UUID        `gorm:"type:uuid;not null" json:"course_id"`
	PurchasedPriceCents int             `gorm:"not null;default:0" json:"purchased_price_cents"`
	Currency           string           `gorm:"size:3;not null;default:'USD'" json:"currency"`
	Status             EnrollmentStatus `gorm:"size:50;not null;default:'active'" json:"status"`
	AccessExpiresAt    *time.Time       `json:"access_expires_at,omitempty"`
	PurchasedAt        time.Time        `gorm:"not null" json:"purchased_at"`
	RefundedAt         *time.Time       `json:"refunded_at,omitempty"`
	CreatedAt          time.Time        `gorm:"autoCreateTime" json:"created_at"`
	UpdatedAt          time.Time        `gorm:"autoUpdateTime" json:"updated_at"`
}

func (CourseEnrollment) TableName() string {
	return "course_enrollments"
}

func (e *CourseEnrollment) BeforeCreate(tx *gorm.DB) error {
	if e.ID == uuid.Nil {
		e.ID = uuid.New()
	}
	return nil
}

// LessonProgress tracks a user's progress on a specific lesson
type LessonProgress struct {
	ID                      uuid.UUID  `gorm:"type:uuid;primaryKey" json:"id"`
	UserID                  uuid.UUID  `gorm:"type:uuid;not null" json:"user_id"`
	LessonID                uuid.UUID  `gorm:"type:uuid;not null" json:"lesson_id"`
	EnrollmentID            uuid.UUID  `gorm:"type:uuid;not null" json:"enrollment_id"`
	WatchedPercentage       int        `gorm:"default:0" json:"watched_percentage"`
	WatchedDurationSeconds  int        `gorm:"default:0" json:"watched_duration_seconds"`
	PlaybackPositionSeconds int        `gorm:"default:0" json:"playback_position_seconds"`
	IsCompleted             bool       `gorm:"not null;default:false" json:"is_completed"`
	CompletedAt             *time.Time `json:"completed_at,omitempty"`
	CreatedAt               time.Time  `gorm:"autoCreateTime" json:"created_at"`
	UpdatedAt               time.Time  `gorm:"autoUpdateTime" json:"updated_at"`
}

func (LessonProgress) TableName() string {
	return "lesson_progress"
}

func (p *LessonProgress) BeforeCreate(tx *gorm.DB) error {
	if p.ID == uuid.Nil {
		p.ID = uuid.New()
	}
	return nil
}

// Certificate represents a course completion certificate
type Certificate struct {
	ID              uuid.UUID         `gorm:"type:uuid;primaryKey" json:"id"`
	UserID          uuid.UUID         `gorm:"type:uuid;not null" json:"user_id"`
	CourseID        uuid.UUID         `gorm:"type:uuid;not null" json:"course_id"`
	EnrollmentID    uuid.UUID         `gorm:"type:uuid;not null" json:"enrollment_id"`
	CertificateCode string           `gorm:"size:255;not null;uniqueIndex" json:"certificate_code"`
	IssueDate       time.Time         `gorm:"not null" json:"issue_date"`
	Status          CertificateStatus `gorm:"size:50;not null;default:'active'" json:"status"`
	CreatedAt       time.Time         `gorm:"autoCreateTime" json:"created_at"`
}

func (Certificate) TableName() string {
	return "certificates"
}

func (cert *Certificate) BeforeCreate(tx *gorm.DB) error {
	if cert.ID == uuid.Nil {
		cert.ID = uuid.New()
	}
	return nil
}

// CourseReview represents a user's review of a course
type CourseReview struct {
	ID           uuid.UUID      `gorm:"type:uuid;primaryKey" json:"id"`
	CourseID     uuid.UUID      `gorm:"type:uuid;not null" json:"course_id"`
	UserID       uuid.UUID      `gorm:"type:uuid;not null" json:"user_id"`
	EnrollmentID uuid.UUID      `gorm:"type:uuid;not null" json:"enrollment_id"`
	Rating       int            `gorm:"not null" json:"rating"`
	Title        string         `gorm:"size:255" json:"title,omitempty"`
	Content      string         `gorm:"type:text;not null" json:"content"`
	Status       ReviewStatus   `gorm:"size:50;not null;default:'approved'" json:"status"`
	HelpfulCount int            `gorm:"not null;default:0" json:"helpful_count"`
	CreatedAt    time.Time      `gorm:"autoCreateTime" json:"created_at"`
	UpdatedAt    time.Time      `gorm:"autoUpdateTime" json:"updated_at"`
	DeletedAt    gorm.DeletedAt `gorm:"index" json:"deleted_at,omitempty"`
}

func (CourseReview) TableName() string {
	return "course_reviews"
}

func (r *CourseReview) BeforeCreate(tx *gorm.DB) error {
	if r.ID == uuid.Nil {
		r.ID = uuid.New()
	}
	return nil
}