package chat

import (
	"context"

	"github.com/google/uuid"
	"go.uber.org/zap"
	"gorm.io/gorm"
)

type PermissionService struct {
	db     *gorm.DB
	logger *zap.Logger
}

func NewPermissionService(db *gorm.DB, logger *zap.Logger) *PermissionService {
	if logger == nil {
		logger = zap.NewNop()
	}
	return &PermissionService{
		db:     db,
		logger: logger,
	}
}

type roomMemberCheck struct {
	Role    string `gorm:"column:role"`
	IsMuted bool   `gorm:"column:is_muted"`
}

func (p *PermissionService) getMembership(ctx context.Context, userID, roomID uuid.UUID) (*roomMemberCheck, bool) {
	var member roomMemberCheck
	err := p.db.WithContext(ctx).
		Table("room_members").
		Select("role, is_muted").
		Where("user_id = ? AND room_id = ?", userID, roomID).
		First(&member).Error
	if err != nil {
		return nil, false
	}
	return &member, true
}

func (p *PermissionService) CanRead(ctx context.Context, userID, roomID uuid.UUID) bool {
	// GL3-01: Live stream chat — allow read when roomID is a live_streams.id (public)
	var count int64
	if err := p.db.WithContext(ctx).
		Table("live_streams").
		Where("id = ?", roomID).
		Count(&count).Error; err == nil && count > 0 {
		return true
	}
	_, isMember := p.getMembership(ctx, userID, roomID)
	return isMember
}

func (p *PermissionService) CanSend(ctx context.Context, userID, roomID uuid.UUID) bool {
	// GL3-01: Live stream chat — allow send when roomID is a live_streams.id (public)
	var count int64
	if err := p.db.WithContext(ctx).
		Table("live_streams").
		Where("id = ?", roomID).
		Count(&count).Error; err == nil && count > 0 {
		return true
	}
	member, isMember := p.getMembership(ctx, userID, roomID)
	if !isMember {
		return false
	}
	return !member.IsMuted
}

func (p *PermissionService) CanJoin(ctx context.Context, userID, roomID uuid.UUID) bool {
	// GL3-01: Live stream chat — allow join when roomID is a live_streams.id (public)
	var count int64
	if err := p.db.WithContext(ctx).
		Table("live_streams").
		Where("id = ?", roomID).
		Count(&count).Error; err == nil && count > 0 {
		return true
	}
	_, isMember := p.getMembership(ctx, userID, roomID)
	return isMember
}

// IsLiveRoom returns true if roomID is a live_streams.id (F474).
func (p *PermissionService) IsLiveRoom(ctx context.Context, roomID uuid.UUID) bool {
	var count int64
	if err := p.db.WithContext(ctx).
		Table("live_streams").
		Where("id = ?", roomID).
		Count(&count).Error; err != nil {
		return false
	}
	return count > 0
}

func (p *PermissionService) CanModerate(ctx context.Context, userID, roomID uuid.UUID) bool {
	member, isMember := p.getMembership(ctx, userID, roomID)
	if !isMember {
		return false
	}
	return member.Role == "admin" || member.Role == "moderator" || member.Role == "owner"
}