// Copyright 2022 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT

package secret

import (
	"context"
	"fmt"
	"strings"

	actions_model "forgejo.org/models/actions"
	"forgejo.org/models/db"
	actions_module "forgejo.org/modules/actions"
	"forgejo.org/modules/keying"
	"forgejo.org/modules/log"
	"forgejo.org/modules/timeutil"
	"forgejo.org/modules/util"

	"xorm.io/builder"
)

// Secret represents a secret
//
// It can be:
//  1. org/user level secret, OwnerID is org/user ID and RepoID is 0
//  2. repo level secret, OwnerID is 0 and RepoID is repo ID
//
// Please note that it's not acceptable to have both OwnerID and RepoID to be non-zero,
// or it will be complicated to find secrets belonging to a specific owner.
// For example, conditions like `OwnerID = 1` will also return secret {OwnerID: 1, RepoID: 1},
// but it's a repo level secret, not an org/user level secret.
// To avoid this, make it clear with {OwnerID: 0, RepoID: 1} for repo level secrets.
//
// Please note that it's not acceptable to have both OwnerID and RepoID to zero, global secrets are not supported.
// It's for security reasons, admin may be not aware of that the secrets could be stolen by any user when setting them as global.
type Secret struct {
	ID          int64
	OwnerID     int64              `xorm:"INDEX UNIQUE(owner_repo_name) NOT NULL"`
	RepoID      int64              `xorm:"INDEX UNIQUE(owner_repo_name) NOT NULL DEFAULT 0"`
	Name        string             `xorm:"UNIQUE(owner_repo_name) NOT NULL"`
	Data        []byte             `xorm:"BLOB"` // encrypted data
	CreatedUnix timeutil.TimeStamp `xorm:"created NOT NULL"`
}

// ErrSecretNotFound represents a "secret not found" error.
type ErrSecretNotFound struct {
	Name string
}

func (err ErrSecretNotFound) Error() string {
	return fmt.Sprintf("secret was not found [name: %s]", err.Name)
}

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

// InsertEncryptedSecret Creates, encrypts, and validates a new secret with yet unencrypted data and insert into database
func InsertEncryptedSecret(ctx context.Context, ownerID, repoID int64, name, data string) (*Secret, error) {
	if ownerID != 0 && repoID != 0 {
		// It's trying to create a secret that belongs to a repository, but OwnerID has been set accidentally.
		// Remove OwnerID to avoid confusion; it's not worth returning an error here.
		ownerID = 0
	}
	if ownerID == 0 && repoID == 0 {
		return nil, fmt.Errorf("%w: ownerID and repoID cannot be both zero, global secrets are not supported", util.ErrInvalidArgument)
	}

	secret := &Secret{
		OwnerID: ownerID,
		RepoID:  repoID,
		Name:    strings.ToUpper(name),
	}

	return secret, db.WithTx(ctx, func(ctx context.Context) error {
		if err := db.Insert(ctx, secret); err != nil {
			return err
		}

		secret.SetSecret(data)
		_, err := db.GetEngine(ctx).ID(secret.ID).Cols("data").Update(secret)
		return err
	})
}

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

type FindSecretsOptions struct {
	db.ListOptions
	RepoID   int64
	OwnerID  int64 // it will be ignored if RepoID is set
	SecretID int64
	Name     string
}

func (opts FindSecretsOptions) ToConds() builder.Cond {
	cond := builder.NewCond()

	cond = cond.And(builder.Eq{"repo_id": opts.RepoID})
	if opts.RepoID != 0 { // if RepoID is set
		// ignore OwnerID and treat it as 0
		cond = cond.And(builder.Eq{"owner_id": 0})
	} else {
		cond = cond.And(builder.Eq{"owner_id": opts.OwnerID})
	}

	if opts.SecretID != 0 {
		cond = cond.And(builder.Eq{"id": opts.SecretID})
	}
	if opts.Name != "" {
		cond = cond.And(builder.Eq{"name": strings.ToUpper(opts.Name)})
	}

	return cond
}

func (s *Secret) SetSecret(data string) {
	key := keying.DeriveKey(keying.ContextActionSecret)
	s.Data = key.Encrypt([]byte(data), keying.ColumnAndID("data", s.ID))
}

func GetSecretsOfTask(ctx context.Context, task *actions_model.ActionTask) (map[string]string, error) {
	secrets := map[string]string{}

	secrets["GITHUB_TOKEN"] = task.Token
	secrets["GITEA_TOKEN"] = task.Token
	secrets["FORGEJO_TOKEN"] = task.Token

	if task.Job.Run.IsForkPullRequest && task.Job.Run.TriggerEvent != actions_module.GithubEventPullRequestTarget {
		// ignore secrets for fork pull request, except GITHUB_TOKEN, GITEA_TOKEN and FORGEJO_TOKEN which are automatically generated.
		// for the tasks triggered by pull_request_target event, they could access the secrets because they will run in the context of the base branch
		// see the documentation: https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target
		return secrets, nil
	}

	ownerSecrets, err := db.Find[Secret](ctx, FindSecretsOptions{OwnerID: task.Job.Run.Repo.OwnerID})
	if err != nil {
		log.Error("find secrets of owner %v: %v", task.Job.Run.Repo.OwnerID, err)
		return nil, err
	}
	repoSecrets, err := db.Find[Secret](ctx, FindSecretsOptions{RepoID: task.Job.Run.RepoID})
	if err != nil {
		log.Error("find secrets of repo %v: %v", task.Job.Run.RepoID, err)
		return nil, err
	}

	key := keying.DeriveKey(keying.ContextActionSecret)
	for _, secret := range append(ownerSecrets, repoSecrets...) {
		v, err := key.Decrypt(secret.Data, keying.ColumnAndID("data", secret.ID))
		if err != nil {
			log.Error("unable to decrypt secret[id=%d,name=%q]: %v", secret.ID, secret.Name, err)
			return nil, err
		}
		secrets[secret.Name] = string(v)
	}

	return secrets, nil
}