// Copyright 2017 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package repo

import (
	"context"
	"fmt"

	"gitea.dev/models/db"
	"gitea.dev/models/perm"
	"gitea.dev/models/unit"
	"gitea.dev/modules/json"
	"gitea.dev/modules/setting"
	"gitea.dev/modules/timeutil"
	"gitea.dev/modules/util"

	"xorm.io/xorm"
	"xorm.io/xorm/convert"
)

// ErrUnitTypeNotExist represents a "UnitTypeNotExist" kind of error.
type ErrUnitTypeNotExist struct {
	UT unit.Type
}

// IsErrUnitTypeNotExist checks if an error is a ErrUnitNotExist.
func IsErrUnitTypeNotExist(err error) bool {
	_, ok := err.(ErrUnitTypeNotExist)
	return ok
}

func (err ErrUnitTypeNotExist) Error() string {
	return "Unit type does not exist: " + err.UT.LogString()
}

func (err ErrUnitTypeNotExist) Unwrap() error {
	return util.ErrNotExist
}

// RepoUnit describes all units of a repository
type RepoUnit struct { //revive:disable-line:exported
	ID                  int64
	RepoID              int64              `xorm:"INDEX(s)"`
	Type                unit.Type          `xorm:"INDEX(s)"`
	Config              convert.Conversion `xorm:"TEXT"`
	CreatedUnix         timeutil.TimeStamp `xorm:"INDEX CREATED"`
	AnonymousAccessMode perm.AccessMode    `xorm:"NOT NULL DEFAULT 0"`
	EveryoneAccessMode  perm.AccessMode    `xorm:"NOT NULL DEFAULT 0"`
}

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

// UnitConfig describes common unit config
type UnitConfig struct{}

// FromDB fills up a UnitConfig from serialized format.
func (cfg *UnitConfig) FromDB(bs []byte) error {
	return json.UnmarshalHandleDoubleEncode(bs, &cfg)
}

// ToDB exports a UnitConfig to a serialized format.
func (cfg *UnitConfig) ToDB() ([]byte, error) {
	return json.Marshal(cfg)
}

// ExternalWikiConfig describes external wiki config
type ExternalWikiConfig struct {
	ExternalWikiURL string
}

// FromDB fills up a ExternalWikiConfig from serialized format.
func (cfg *ExternalWikiConfig) FromDB(bs []byte) error {
	return json.UnmarshalHandleDoubleEncode(bs, &cfg)
}

// ToDB exports a ExternalWikiConfig to a serialized format.
func (cfg *ExternalWikiConfig) ToDB() ([]byte, error) {
	return json.Marshal(cfg)
}

// ExternalTrackerConfig describes external tracker config
type ExternalTrackerConfig struct {
	ExternalTrackerURL           string
	ExternalTrackerFormat        string
	ExternalTrackerStyle         string
	ExternalTrackerRegexpPattern string
}

// FromDB fills up a ExternalTrackerConfig from serialized format.
func (cfg *ExternalTrackerConfig) FromDB(bs []byte) error {
	return json.UnmarshalHandleDoubleEncode(bs, &cfg)
}

// ToDB exports a ExternalTrackerConfig to a serialized format.
func (cfg *ExternalTrackerConfig) ToDB() ([]byte, error) {
	return json.Marshal(cfg)
}

// IssuesConfig describes issues config
type IssuesConfig struct {
	EnableTimetracker                bool
	AllowOnlyContributorsToTrackTime bool
	EnableDependencies               bool
}

// FromDB fills up a IssuesConfig from serialized format.
func (cfg *IssuesConfig) FromDB(bs []byte) error {
	return json.UnmarshalHandleDoubleEncode(bs, &cfg)
}

// ToDB exports a IssuesConfig to a serialized format.
func (cfg *IssuesConfig) ToDB() ([]byte, error) {
	return json.Marshal(cfg)
}

// PullRequestsConfig describes pull requests config
type PullRequestsConfig struct {
	IgnoreWhitespaceConflicts     bool
	AllowMerge                    bool
	AllowRebase                   bool
	AllowRebaseMerge              bool
	AllowSquash                   bool
	AllowFastForwardOnly          bool
	AllowManualMerge              bool
	AutodetectManualMerge         bool
	AllowMergeUpdate              bool
	AllowRebaseUpdate             bool
	DefaultUpdateStyle            UpdateStyle
	DefaultDeleteBranchAfterMerge bool
	DefaultMergeStyle             MergeStyle
	DefaultSquashMergeMessage     SquashMergeMessage
	DefaultAllowMaintainerEdit    bool
	DefaultTargetBranch           string
}

func DefaultPullRequestsConfig() *PullRequestsConfig {
	cfg := &PullRequestsConfig{
		AllowMerge:                 true,
		AllowRebase:                true,
		AllowRebaseMerge:           true,
		AllowSquash:                true,
		AllowFastForwardOnly:       true,
		AllowMergeUpdate:           true,
		AllowRebaseUpdate:          true,
		DefaultUpdateStyle:         UpdateStyleMerge,
		DefaultAllowMaintainerEdit: true,
	}
	cfg.DefaultDeleteBranchAfterMerge = setting.Repository.PullRequest.DefaultDeleteBranchAfterMerge
	cfg.DefaultMergeStyle = MergeStyle(setting.Repository.PullRequest.DefaultMergeStyle)
	cfg.DefaultMergeStyle = util.IfZero(cfg.DefaultMergeStyle, MergeStyleMerge)
	cfg.DefaultSquashMergeMessage = SquashMergeMessage(setting.Repository.PullRequest.DefaultSquashMergeMessage)
	return cfg
}

// FromDB fills up a PullRequestsConfig from serialized format.
func (cfg *PullRequestsConfig) FromDB(bs []byte) error {
	// set default values for existing PullRequestConfig in DB
	*cfg = *DefaultPullRequestsConfig()
	_ = json.UnmarshalHandleDoubleEncode(bs, &cfg) // don't let corrupted database value cause unnecessary 500 error
	cfg.DefaultUpdateStyle = util.IfZero(cfg.DefaultUpdateStyle, UpdateStyleMerge)
	return nil
}

// ToDB exports a PullRequestsConfig to a serialized format.
func (cfg *PullRequestsConfig) ToDB() ([]byte, error) {
	return json.Marshal(cfg)
}

// IsMergeStyleAllowed returns if merge style is allowed
func (cfg *PullRequestsConfig) IsMergeStyleAllowed(mergeStyle MergeStyle) bool {
	return mergeStyle == MergeStyleMerge && cfg.AllowMerge ||
		mergeStyle == MergeStyleRebase && cfg.AllowRebase ||
		mergeStyle == MergeStyleRebaseMerge && cfg.AllowRebaseMerge ||
		mergeStyle == MergeStyleSquash && cfg.AllowSquash ||
		mergeStyle == MergeStyleFastForwardOnly && cfg.AllowFastForwardOnly ||
		mergeStyle == MergeStyleManuallyMerged && cfg.AllowManualMerge
}

// IsUpdateStyleAllowed returns if a pull request branch update style is allowed
func (cfg *PullRequestsConfig) IsUpdateStyleAllowed(updateStyle UpdateStyle) bool {
	switch updateStyle {
	case UpdateStyleMerge:
		return cfg.AllowMergeUpdate
	case UpdateStyleRebase:
		return cfg.AllowRebaseUpdate
	default:
		return false
	}
}

// ValidateUpdateSettings checks that the AllowMerge/RebaseUpdate flags and DefaultUpdateStyle are mutually consistent.
func (cfg *PullRequestsConfig) ValidateUpdateSettings() error {
	if cfg.DefaultUpdateStyle != UpdateStyleMerge && cfg.DefaultUpdateStyle != UpdateStyleRebase {
		return util.NewInvalidArgumentErrorf("default update style must be merge or rebase")
	}
	if !cfg.AllowMergeUpdate && !cfg.AllowRebaseUpdate {
		return util.NewInvalidArgumentErrorf("at least one pull request branch update style must be enabled")
	}
	if !cfg.IsUpdateStyleAllowed(cfg.DefaultUpdateStyle) {
		return util.NewInvalidArgumentErrorf("default update style must be enabled")
	}
	return nil
}

func DefaultPullRequestsUnit(repoID int64) RepoUnit {
	return RepoUnit{RepoID: repoID, Type: unit.TypePullRequests, Config: DefaultPullRequestsConfig()}
}

// ProjectsMode represents the projects enabled for a repository
type ProjectsMode string

const (
	// ProjectsModeRepo allows only repo-level projects
	ProjectsModeRepo ProjectsMode = "repo"
	// ProjectsModeOwner allows only owner-level projects
	ProjectsModeOwner ProjectsMode = "owner"
	// ProjectsModeAll allows both kinds of projects
	ProjectsModeAll ProjectsMode = "all"
	// ProjectsModeNone doesn't allow projects
	ProjectsModeNone ProjectsMode = "none"
)

// ProjectsConfig describes projects config
type ProjectsConfig struct {
	ProjectsMode ProjectsMode
}

// FromDB fills up a ProjectsConfig from serialized format.
func (cfg *ProjectsConfig) FromDB(bs []byte) error {
	// TODO: remove GetProjectsMode, only use ProjectsMode
	cfg.ProjectsMode = ProjectsModeAll
	return json.UnmarshalHandleDoubleEncode(bs, &cfg)
}

// ToDB exports a ProjectsConfig to a serialized format.
func (cfg *ProjectsConfig) ToDB() ([]byte, error) {
	return json.Marshal(cfg)
}

func (cfg *ProjectsConfig) GetProjectsMode() ProjectsMode {
	if cfg.ProjectsMode != "" {
		return cfg.ProjectsMode
	}

	return ProjectsModeAll
}

func (cfg *ProjectsConfig) IsProjectsAllowed(m ProjectsMode) bool {
	projectsMode := cfg.GetProjectsMode()

	if m == ProjectsModeNone {
		return true
	}

	return projectsMode == m || projectsMode == ProjectsModeAll
}

// BeforeSet is invoked from XORM before setting the value of a field of this object.
func (r *RepoUnit) BeforeSet(colName string, val xorm.Cell) {
	switch colName {
	case "type":
		var err error
		r.Type, _, err = db.CellToInt(val, unit.TypeInvalid)
		if err != nil {
			setting.PanicInDevOrTesting("Unable to convert repo unit (id=%d) type: %v", r.ID, err)
		}
		switch r.Type {
		case unit.TypeExternalWiki:
			r.Config = new(ExternalWikiConfig)
		case unit.TypeExternalTracker:
			r.Config = new(ExternalTrackerConfig)
		case unit.TypePullRequests:
			r.Config = new(PullRequestsConfig)
		case unit.TypeIssues:
			r.Config = new(IssuesConfig)
		case unit.TypeActions:
			r.Config = new(ActionsConfig)
		case unit.TypeProjects:
			r.Config = new(ProjectsConfig)
		case unit.TypeCode, unit.TypeReleases, unit.TypeWiki, unit.TypePackages:
			fallthrough
		default:
			r.Config = new(UnitConfig)
		}
	case "config":
		if *val == nil {
			// XROM doesn't call FromDB if the value is nil, but we need to set default values for the config fields
			_ = r.Config.FromDB(nil)
		}
	}
}

// Unit returns Unit
func (r *RepoUnit) Unit() unit.Unit {
	return unit.Units[r.Type]
}

// unitConfig returns the unit's config, which BeforeSet has created from the unit type
func unitConfig[T interface {
	*E
	convert.Conversion
}, E any](r *RepoUnit) T {
	config, ok := r.Config.(T)
	if !ok {
		panic(fmt.Errorf("repo unit %d of type %s has config type %T instead of %T", r.ID, r.Type.LogString(), r.Config, config))
	}
	return config
}

// CodeConfig returns config for unit.TypeCode
func (r *RepoUnit) CodeConfig() *UnitConfig {
	return unitConfig[*UnitConfig](r)
}

// PullRequestsConfig returns config for unit.TypePullRequests
func (r *RepoUnit) PullRequestsConfig() *PullRequestsConfig {
	return unitConfig[*PullRequestsConfig](r)
}

// ReleasesConfig returns config for unit.TypeReleases
func (r *RepoUnit) ReleasesConfig() *UnitConfig {
	return unitConfig[*UnitConfig](r)
}

// ExternalWikiConfig returns config for unit.TypeExternalWiki
func (r *RepoUnit) ExternalWikiConfig() *ExternalWikiConfig {
	return unitConfig[*ExternalWikiConfig](r)
}

// IssuesConfig returns config for unit.TypeIssues
func (r *RepoUnit) IssuesConfig() *IssuesConfig {
	return unitConfig[*IssuesConfig](r)
}

// ExternalTrackerConfig returns config for unit.TypeExternalTracker
func (r *RepoUnit) ExternalTrackerConfig() *ExternalTrackerConfig {
	return unitConfig[*ExternalTrackerConfig](r)
}

// ActionsConfig returns config for unit.ActionsConfig
func (r *RepoUnit) ActionsConfig() *ActionsConfig {
	return unitConfig[*ActionsConfig](r)
}

// ProjectsConfig returns config for unit.ProjectsConfig
func (r *RepoUnit) ProjectsConfig() *ProjectsConfig {
	return unitConfig[*ProjectsConfig](r)
}

func getUnitsByRepoID(ctx context.Context, repoID int64) (units []*RepoUnit, err error) {
	var tmpUnits []*RepoUnit
	if err := db.GetEngine(ctx).Where("repo_id = ?", repoID).Find(&tmpUnits); err != nil {
		return nil, err
	}

	for _, u := range tmpUnits {
		if !u.Type.UnitGlobalDisabled() {
			units = append(units, u)
		}
	}

	return units, nil
}

// UpdateRepoUnitConfig updates the config of the provided repo unit
func UpdateRepoUnitConfig(ctx context.Context, unit *RepoUnit) error {
	_, err := db.GetEngine(ctx).ID(unit.ID).Cols("config").Update(unit)
	return err
}

func UpdateRepoUnitPublicAccess(ctx context.Context, unit *RepoUnit) error {
	_, err := db.GetEngine(ctx).Where("repo_id=? AND `type`=?", unit.RepoID, unit.Type).
		Cols("anonymous_access_mode", "everyone_access_mode").Update(unit)
	return err
}