// Copyright 2021 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package packages

import (
	"context"
	"strconv"
	"strings"

	"code.gitea.io/gitea/models/db"
	"code.gitea.io/gitea/modules/optional"
	"code.gitea.io/gitea/modules/timeutil"
	"code.gitea.io/gitea/modules/util"

	"xorm.io/builder"
	"xorm.io/xorm"
)

// ErrDuplicatePackageVersion indicates a duplicated package version error
var ErrDuplicatePackageVersion = util.NewAlreadyExistErrorf("package version already exists")

func init() {
	db.RegisterModel(new(PackageVersion))
}

// PackageVersion represents a package version
type PackageVersion struct {
	ID            int64              `xorm:"pk autoincr"`
	PackageID     int64              `xorm:"UNIQUE(s) INDEX NOT NULL"`
	CreatorID     int64              `xorm:"NOT NULL DEFAULT 0"`
	Version       string             `xorm:"NOT NULL"`
	LowerVersion  string             `xorm:"UNIQUE(s) INDEX NOT NULL"`
	CreatedUnix   timeutil.TimeStamp `xorm:"created INDEX NOT NULL"`
	IsInternal    bool               `xorm:"INDEX NOT NULL DEFAULT false"`
	MetadataJSON  string             `xorm:"metadata_json LONGTEXT"`
	DownloadCount int64              `xorm:"NOT NULL DEFAULT 0"`
}

// IsPrerelease checks if the version is a prerelease version according to semantic versioning
func (pv *PackageVersion) IsPrerelease() bool {
	if pv == nil || pv.Version == "" {
		return false
	}
	return strings.Contains(pv.Version, "-")
}

// GetOrInsertVersion inserts a version. If the same version exist already ErrDuplicatePackageVersion is returned
func GetOrInsertVersion(ctx context.Context, pv *PackageVersion) (*PackageVersion, error) {
	e := db.GetEngine(ctx)

	existing := &PackageVersion{}

	has, err := e.Where(builder.Eq{
		"package_id":    pv.PackageID,
		"lower_version": pv.LowerVersion,
	}).Get(existing)
	if err != nil {
		return nil, err
	}
	if has {
		return existing, ErrDuplicatePackageVersion
	}
	if _, err = e.Insert(pv); err != nil {
		return nil, err
	}
	return pv, nil
}

// UpdateVersion updates a version
func UpdateVersion(ctx context.Context, pv *PackageVersion) error {
	_, err := db.GetEngine(ctx).ID(pv.ID).Update(pv)
	return err
}

// IncrementDownloadCounter increments the download counter of a version
func IncrementDownloadCounter(ctx context.Context, versionID int64) error {
	_, err := db.GetEngine(ctx).Exec("UPDATE `package_version` SET `download_count` = `download_count` + 1 WHERE `id` = ?", versionID)
	return err
}

// GetVersionByID gets a version by id
func GetVersionByID(ctx context.Context, versionID int64) (*PackageVersion, error) {
	pv := &PackageVersion{}

	has, err := db.GetEngine(ctx).ID(versionID).Get(pv)
	if err != nil {
		return nil, err
	}
	if !has {
		return nil, ErrPackageNotExist
	}
	return pv, nil
}

// GetVersionByNameAndVersion gets a version by name and version number
func GetVersionByNameAndVersion(ctx context.Context, ownerID int64, packageType Type, name, version string) (*PackageVersion, error) {
	return getVersionByNameAndVersion(ctx, ownerID, packageType, name, version, false)
}

// GetInternalVersionByNameAndVersion gets a version by name and version number
func GetInternalVersionByNameAndVersion(ctx context.Context, ownerID int64, packageType Type, name, version string) (*PackageVersion, error) {
	return getVersionByNameAndVersion(ctx, ownerID, packageType, name, version, true)
}

func getVersionByNameAndVersion(ctx context.Context, ownerID int64, packageType Type, name, version string, isInternal bool) (*PackageVersion, error) {
	pvs, _, err := SearchVersions(ctx, &PackageSearchOptions{
		OwnerID: ownerID,
		Type:    packageType,
		Name: SearchValue{
			ExactMatch: true,
			Value:      name,
		},
		Version: SearchValue{
			ExactMatch: true,
			Value:      version,
		},
		IsInternal: optional.Some(isInternal),
		Paginator:  db.NewAbsoluteListOptions(0, 1),
	})
	if err != nil {
		return nil, err
	}
	if len(pvs) == 0 {
		return nil, ErrPackageNotExist
	}
	return pvs[0], nil
}

// GetVersionsByPackageType gets all versions of a specific type
func GetVersionsByPackageType(ctx context.Context, ownerID int64, packageType Type) ([]*PackageVersion, error) {
	pvs, _, err := SearchVersions(ctx, &PackageSearchOptions{
		OwnerID:    ownerID,
		Type:       packageType,
		IsInternal: optional.Some(false),
	})
	return pvs, err
}

// GetVersionsByPackageName gets all versions of a specific package
func GetVersionsByPackageName(ctx context.Context, ownerID int64, packageType Type, name string) ([]*PackageVersion, error) {
	pvs, _, err := SearchVersions(ctx, &PackageSearchOptions{
		OwnerID: ownerID,
		Type:    packageType,
		Name: SearchValue{
			ExactMatch: true,
			Value:      name,
		},
		IsInternal: optional.Some(false),
	})
	return pvs, err
}

// DeleteVersionByID deletes a version by id
func DeleteVersionByID(ctx context.Context, versionID int64) error {
	_, err := db.GetEngine(ctx).ID(versionID).Delete(&PackageVersion{})
	return err
}

// HasVersionFileReferences checks if there are associated files
func HasVersionFileReferences(ctx context.Context, versionID int64) (bool, error) {
	return db.GetEngine(ctx).Get(&PackageFile{
		VersionID: versionID,
	})
}

// SearchValue describes a value to search
// If ExactMatch is true, the field must match the value otherwise a LIKE search is performed.
type SearchValue struct {
	Value      string
	ExactMatch bool
}

type VersionSort = string

const (
	SortNameAsc     VersionSort = "name_asc"
	SortNameDesc    VersionSort = "name_desc"
	SortVersionAsc  VersionSort = "version_asc"
	SortVersionDesc VersionSort = "version_desc"
	SortCreatedAsc  VersionSort = "created_asc"
	SortCreatedDesc VersionSort = "created_desc"
)

// PackageSearchOptions are options for SearchXXX methods
// All fields optional and are not used if they have their default value (nil, "", 0)
type PackageSearchOptions struct {
	OwnerID         int64
	RepoID          int64
	Type            Type
	PackageID       int64
	Name            SearchValue       // only results with the specific name are found
	Version         SearchValue       // only results with the specific version are found
	Properties      map[string]string // only results are found which contain all listed version properties with the specific value
	IsInternal      optional.Option[bool]
	HasFileWithName string                // only results are found which are associated with a file with the specific name
	HasFiles        optional.Option[bool] // only results are found which have associated files
	Sort            VersionSort
	Paginator       db.Paginator
}

func (opts *PackageSearchOptions) ToConds() builder.Cond {
	cond := builder.NewCond()
	if opts.IsInternal.Has() {
		cond = builder.Eq{
			"package_version.is_internal": opts.IsInternal.Value(),
		}
	}

	if opts.OwnerID != 0 {
		cond = cond.And(builder.Eq{"package.owner_id": opts.OwnerID})
	}
	if opts.RepoID != 0 {
		cond = cond.And(builder.Eq{"package.repo_id": opts.RepoID})
	}
	if opts.Type != "" && opts.Type != "all" {
		cond = cond.And(builder.Eq{"package.type": opts.Type})
	}
	if opts.PackageID != 0 {
		cond = cond.And(builder.Eq{"package.id": opts.PackageID})
	}
	if opts.Name.Value != "" {
		if opts.Name.ExactMatch {
			cond = cond.And(builder.Eq{"package.lower_name": strings.ToLower(opts.Name.Value)})
		} else {
			cond = cond.And(builder.Like{"package.lower_name", strings.ToLower(opts.Name.Value)})
		}
	}
	if opts.Version.Value != "" {
		if opts.Version.ExactMatch {
			cond = cond.And(builder.Eq{"package_version.lower_version": strings.ToLower(opts.Version.Value)})
		} else {
			cond = cond.And(builder.Like{"package_version.lower_version", strings.ToLower(opts.Version.Value)})
		}
	}

	if len(opts.Properties) != 0 {
		var propsCond builder.Cond = builder.Eq{
			"package_property.ref_type": PropertyTypeVersion,
		}
		propsCond = propsCond.And(builder.Expr("package_property.ref_id = package_version.id"))

		propsCondBlock := builder.NewCond()
		for name, value := range opts.Properties {
			propsCondBlock = propsCondBlock.Or(builder.Eq{
				"package_property.name":  name,
				"package_property.value": value,
			})
		}
		propsCond = propsCond.And(propsCondBlock)

		cond = cond.And(builder.Eq{
			strconv.Itoa(len(opts.Properties)): builder.Select("COUNT(*)").Where(propsCond).From("package_property"),
		})
	}

	if opts.HasFileWithName != "" {
		fileCond := builder.Expr("package_file.version_id = package_version.id").And(builder.Eq{"package_file.lower_name": strings.ToLower(opts.HasFileWithName)})

		cond = cond.And(builder.Exists(builder.Select("package_file.id").From("package_file").Where(fileCond)))
	}

	if opts.HasFiles.Has() {
		filesCond := builder.Exists(builder.Select("package_file.id").From("package_file").Where(builder.Expr("package_file.version_id = package_version.id")))

		if !opts.HasFiles.Value() {
			filesCond = builder.Not{filesCond}
		}

		cond = cond.And(filesCond)
	}

	return cond
}

func (opts *PackageSearchOptions) configureOrderBy(e db.Engine) {
	switch opts.Sort {
	case SortNameAsc:
		e.Asc("package.name")
	case SortNameDesc:
		e.Desc("package.name")
	case SortVersionDesc:
		e.Desc("package_version.version")
	case SortVersionAsc:
		e.Asc("package_version.version")
	case SortCreatedAsc:
		e.Asc("package_version.created_unix")
	default:
		e.Desc("package_version.created_unix")
	}
	e.Desc("package_version.id") // Sort by id for stable order with duplicates in the other field
}

func searchVersionsBySession(sess *xorm.Session, opts *PackageSearchOptions) ([]*PackageVersion, int64, error) {
	opts.configureOrderBy(sess)
	pvs := make([]*PackageVersion, 0, 10)
	if opts.Paginator != nil {
		sess = db.SetSessionPagination(sess, opts.Paginator)
		count, err := sess.FindAndCount(&pvs)
		return pvs, count, err
	}
	err := sess.Find(&pvs)
	return pvs, int64(len(pvs)), err
}

// SearchVersions gets all versions of packages matching the search options
func SearchVersions(ctx context.Context, opts *PackageSearchOptions) ([]*PackageVersion, int64, error) {
	sess := db.GetEngine(ctx).
		Select("package_version.*").
		Table("package_version").
		Join("INNER", "package", "package.id = package_version.package_id").
		Where(opts.ToConds())
	return searchVersionsBySession(sess, opts)
}

// SearchLatestVersions gets the latest version of every package matching the search options
func SearchLatestVersions(ctx context.Context, opts *PackageSearchOptions) ([]*PackageVersion, int64, error) {
	in := builder.
		Select("MAX(package_version.id)").
		From("package_version").
		InnerJoin("package", "package.id = package_version.package_id").
		Where(opts.ToConds()).
		GroupBy("package_version.package_id")

	sess := db.GetEngine(ctx).
		Select("package_version.*").
		Table("package_version").
		Join("INNER", "package", "package.id = package_version.package_id").
		Where(builder.In("package_version.id", in))

	return searchVersionsBySession(sess, opts)
}

// ExistVersion checks if a version matching the search options exist
func ExistVersion(ctx context.Context, opts *PackageSearchOptions) (bool, error) {
	return db.GetEngine(ctx).
		Where(opts.ToConds()).
		Table("package_version").
		Join("INNER", "package", "package.id = package_version.package_id").
		Exist(new(PackageVersion))
}

// CountVersions counts all versions of packages matching the search options
func CountVersions(ctx context.Context, opts *PackageSearchOptions) (int64, error) {
	return db.GetEngine(ctx).
		Where(opts.ToConds()).
		Table("package_version").
		Join("INNER", "package", "package.id = package_version.package_id").
		Count(new(PackageVersion))
}
