// Copyright 2014 The Gogs Authors. All rights reserved.
// Copyright 2019 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package models

import (
	"fmt"

	"code.gitea.io/gitea/modules/log"
)

// AccessMode specifies the users access mode
type AccessMode int

const (
	// AccessModeNone no access
	AccessModeNone AccessMode = iota // 0
	// AccessModeRead read access
	AccessModeRead // 1
	// AccessModeWrite write access
	AccessModeWrite // 2
	// AccessModeAdmin admin access
	AccessModeAdmin // 3
	// AccessModeOwner owner access
	AccessModeOwner // 4
)

func (mode AccessMode) String() string {
	switch mode {
	case AccessModeRead:
		return "read"
	case AccessModeWrite:
		return "write"
	case AccessModeAdmin:
		return "admin"
	case AccessModeOwner:
		return "owner"
	default:
		return "none"
	}
}

// ColorFormat provides a ColorFormatted version of this AccessMode
func (mode AccessMode) ColorFormat(s fmt.State) {
	log.ColorFprintf(s, "%d:%s",
		log.NewColoredIDValue(mode),
		mode)
}

// ParseAccessMode returns corresponding access mode to given permission string.
func ParseAccessMode(permission string) AccessMode {
	switch permission {
	case "write":
		return AccessModeWrite
	case "admin":
		return AccessModeAdmin
	default:
		return AccessModeRead
	}
}

// Access represents the highest access level of a user to the repository. The only access type
// that is not in this table is the real owner of a repository. In case of an organization
// repository, the members of the owners team are in this table.
type Access struct {
	ID     int64 `xorm:"pk autoincr"`
	UserID int64 `xorm:"UNIQUE(s)"`
	RepoID int64 `xorm:"UNIQUE(s)"`
	Mode   AccessMode
}

func accessLevel(e Engine, user *User, repo *Repository) (AccessMode, error) {
	mode := AccessModeNone
	var userID int64
	restricted := false

	if user != nil {
		userID = user.ID
		restricted = user.IsRestricted
	}

	if !restricted && !repo.IsPrivate {
		mode = AccessModeRead
	}

	if userID == 0 {
		return mode, nil
	}

	if userID == repo.OwnerID {
		return AccessModeOwner, nil
	}

	a := &Access{UserID: userID, RepoID: repo.ID}
	if has, err := e.Get(a); !has || err != nil {
		return mode, err
	}
	return a.Mode, nil
}

type repoAccess struct {
	Access     `xorm:"extends"`
	Repository `xorm:"extends"`
}

func (repoAccess) TableName() string {
	return "access"
}

// GetRepositoryAccesses finds all repositories with their access mode where a user has access but does not own.
func (user *User) GetRepositoryAccesses() (map[*Repository]AccessMode, error) {
	rows, err := x.
		Join("INNER", "repository", "repository.id = access.repo_id").
		Where("access.user_id = ?", user.ID).
		And("repository.owner_id <> ?", user.ID).
		Rows(new(repoAccess))
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var repos = make(map[*Repository]AccessMode, 10)
	var ownerCache = make(map[int64]*User, 10)
	for rows.Next() {
		var repo repoAccess
		err = rows.Scan(&repo)
		if err != nil {
			return nil, err
		}

		var ok bool
		if repo.Owner, ok = ownerCache[repo.OwnerID]; !ok {
			if err = repo.GetOwner(); err != nil {
				return nil, err
			}
			ownerCache[repo.OwnerID] = repo.Owner
		}

		repos[&repo.Repository] = repo.Access.Mode
	}
	return repos, nil
}

// GetAccessibleRepositories finds repositories which the user has access but does not own.
// If limit is smaller than 1 means returns all found results.
func (user *User) GetAccessibleRepositories(limit int) (repos []*Repository, _ error) {
	sess := x.
		Where("owner_id !=? ", user.ID).
		Desc("updated_unix")
	if limit > 0 {
		sess.Limit(limit)
		repos = make([]*Repository, 0, limit)
	} else {
		repos = make([]*Repository, 0, 10)
	}
	return repos, sess.
		Join("INNER", "access", "access.user_id = ? AND access.repo_id = repository.id", user.ID).
		Find(&repos)
}

func maxAccessMode(modes ...AccessMode) AccessMode {
	max := AccessModeNone
	for _, mode := range modes {
		if mode > max {
			max = mode
		}
	}
	return max
}

type userAccess struct {
	User *User
	Mode AccessMode
}

// updateUserAccess updates an access map so that user has at least mode
func updateUserAccess(accessMap map[int64]*userAccess, user *User, mode AccessMode) {
	ua, ok := accessMap[user.ID]
	if !ok {
		ua = &userAccess{User: user, Mode: mode}
		accessMap[user.ID] = ua
	} else {
		ua.Mode = maxAccessMode(ua.Mode, mode)
	}
}

// FIXME: do cross-comparison so reduce deletions and additions to the minimum?
func (repo *Repository) refreshAccesses(e Engine, accessMap map[int64]*userAccess) (err error) {
	minMode := AccessModeRead
	if !repo.IsPrivate {
		minMode = AccessModeWrite
	}

	// build a map of the actual entries we want to create
	entryMap := make(map[int64]AccessMode, len(accessMap))
	for userID, ua := range accessMap {
		if ua.Mode < minMode && !ua.User.IsRestricted {
			continue
		}
		entryMap[userID] = ua.Mode
	}

	newAccesses := make([]Access, 0, len(entryMap))
	for userID, mode := range entryMap {
		newAccesses = append(newAccesses, Access{
			UserID: userID,
			RepoID: repo.ID,
			Mode:   mode,
		})
	}

	// Delete old accesses and insert new ones for repository.
	if _, err = e.Delete(&Access{RepoID: repo.ID}); err != nil {
		return fmt.Errorf("delete old accesses: %v", err)
	} else if _, err = e.Insert(newAccesses); err != nil {
		return fmt.Errorf("insert new accesses: %v", err)
	}
	return nil
}

// refreshCollaboratorAccesses retrieves repository collaborations with their access modes.
func (repo *Repository) refreshCollaboratorAccesses(e Engine, accessMap map[int64]*userAccess) error {
	collaborators, err := repo.getCollaborators(e)
	if err != nil {
		return fmt.Errorf("getCollaborations: %v", err)
	}
	for _, c := range collaborators {
		updateUserAccess(accessMap, c.User, c.Collaboration.Mode)
	}
	return nil
}

// recalculateTeamAccesses recalculates new accesses for teams of an organization
// except the team whose ID is given. It is used to assign a team ID when
// remove repository from that team.
func (repo *Repository) recalculateTeamAccesses(e Engine, ignTeamID int64) (err error) {
	accessMap := make(map[int64]*userAccess, 20)

	if err = repo.getOwner(e); err != nil {
		return err
	} else if !repo.Owner.IsOrganization() {
		return fmt.Errorf("owner is not an organization: %d", repo.OwnerID)
	}

	if err = repo.refreshCollaboratorAccesses(e, accessMap); err != nil {
		return fmt.Errorf("refreshCollaboratorAccesses: %v", err)
	}

	if err = repo.Owner.getTeams(e); err != nil {
		return err
	}

	for _, t := range repo.Owner.Teams {
		if t.ID == ignTeamID {
			continue
		}

		// Owner team gets owner access, and skip for teams that do not
		// have relations with repository.
		if t.IsOwnerTeam() {
			t.Authorize = AccessModeOwner
		} else if !t.hasRepository(e, repo.ID) {
			continue
		}

		if err = t.getMembers(e); err != nil {
			return fmt.Errorf("getMembers '%d': %v", t.ID, err)
		}
		for _, m := range t.Members {
			updateUserAccess(accessMap, m, t.Authorize)
		}
	}

	return repo.refreshAccesses(e, accessMap)
}

// recalculateUserAccess recalculates new access for a single user
// Usable if we know access only affected one user
func (repo *Repository) recalculateUserAccess(e Engine, uid int64) (err error) {
	minMode := AccessModeRead
	if !repo.IsPrivate {
		minMode = AccessModeWrite
	}

	accessMode := AccessModeNone
	collaborator, err := repo.getCollaboration(e, uid)
	if err != nil {
		return err
	} else if collaborator != nil {
		accessMode = collaborator.Mode
	}

	if err = repo.getOwner(e); err != nil {
		return err
	} else if repo.Owner.IsOrganization() {
		var teams []Team
		if err := e.Join("INNER", "team_repo", "team_repo.team_id = team.id").
			Join("INNER", "team_user", "team_user.team_id = team.id").
			Where("team.org_id = ?", repo.OwnerID).
			And("team_repo.repo_id=?", repo.ID).
			And("team_user.uid=?", uid).
			Find(&teams); err != nil {
			return err
		}

		for _, t := range teams {
			if t.IsOwnerTeam() {
				t.Authorize = AccessModeOwner
			}

			accessMode = maxAccessMode(accessMode, t.Authorize)
		}
	}

	// Delete old user accesses and insert new one for repository.
	if _, err = e.Delete(&Access{RepoID: repo.ID, UserID: uid}); err != nil {
		return fmt.Errorf("delete old user accesses: %v", err)
	} else if accessMode >= minMode {
		if _, err = e.Insert(&Access{RepoID: repo.ID, UserID: uid, Mode: accessMode}); err != nil {
			return fmt.Errorf("insert new user accesses: %v", err)
		}
	}
	return nil
}

func (repo *Repository) recalculateAccesses(e Engine) error {
	if repo.Owner.IsOrganization() {
		return repo.recalculateTeamAccesses(e, 0)
	}

	accessMap := make(map[int64]*userAccess, 20)
	if err := repo.refreshCollaboratorAccesses(e, accessMap); err != nil {
		return fmt.Errorf("refreshCollaboratorAccesses: %v", err)
	}
	return repo.refreshAccesses(e, accessMap)
}

// RecalculateAccesses recalculates all accesses for repository.
func (repo *Repository) RecalculateAccesses() error {
	return repo.recalculateAccesses(x)
}