// Copyright 2023 Harness, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package pullreq

import (
	"context"
	"fmt"

	"github.com/harness/gitness/gitrpc"
	gitrpcenum "github.com/harness/gitness/gitrpc/enum"
	"github.com/harness/gitness/lock"
	apiauth "github.com/harness/gitness/pkg/api/auth"
	"github.com/harness/gitness/pkg/api/usererror"
	"github.com/harness/gitness/pkg/auth"
	"github.com/harness/gitness/pkg/auth/authz"
	pullreqevents "github.com/harness/gitness/pkg/events/pullreq"
	"github.com/harness/gitness/pkg/services/codecomments"
	"github.com/harness/gitness/pkg/services/pullreq"
	"github.com/harness/gitness/pkg/sse"
	"github.com/harness/gitness/pkg/store"
	"github.com/harness/gitness/pkg/url"
	"github.com/harness/gitness/types"
	"github.com/harness/gitness/types/enum"

	"github.com/jmoiron/sqlx"
)

type Controller struct {
	db                  *sqlx.DB
	urlProvider         *url.Provider
	authorizer          authz.Authorizer
	pullreqStore        store.PullReqStore
	activityStore       store.PullReqActivityStore
	codeCommentView     store.CodeCommentView
	reviewStore         store.PullReqReviewStore
	reviewerStore       store.PullReqReviewerStore
	repoStore           store.RepoStore
	principalStore      store.PrincipalStore
	fileViewStore       store.PullReqFileViewStore
	gitRPCClient        gitrpc.Interface
	eventReporter       *pullreqevents.Reporter
	mtxManager          lock.MutexManager
	codeCommentMigrator *codecomments.Migrator
	pullreqService      *pullreq.Service
	sseStreamer         sse.Streamer
}

func NewController(
	db *sqlx.DB,
	urlProvider *url.Provider,
	authorizer authz.Authorizer,
	pullreqStore store.PullReqStore,
	pullreqActivityStore store.PullReqActivityStore,
	codeCommentView store.CodeCommentView,
	pullreqReviewStore store.PullReqReviewStore,
	pullreqReviewerStore store.PullReqReviewerStore,
	repoStore store.RepoStore,
	principalStore store.PrincipalStore,
	fileViewStore store.PullReqFileViewStore,
	gitRPCClient gitrpc.Interface,
	eventReporter *pullreqevents.Reporter,
	mtxManager lock.MutexManager,
	codeCommentMigrator *codecomments.Migrator,
	pullreqService *pullreq.Service,
	sseStreamer sse.Streamer,
) *Controller {
	return &Controller{
		db:                  db,
		urlProvider:         urlProvider,
		authorizer:          authorizer,
		pullreqStore:        pullreqStore,
		activityStore:       pullreqActivityStore,
		codeCommentView:     codeCommentView,
		reviewStore:         pullreqReviewStore,
		reviewerStore:       pullreqReviewerStore,
		repoStore:           repoStore,
		principalStore:      principalStore,
		fileViewStore:       fileViewStore,
		gitRPCClient:        gitRPCClient,
		codeCommentMigrator: codeCommentMigrator,
		eventReporter:       eventReporter,
		mtxManager:          mtxManager,
		pullreqService:      pullreqService,
		sseStreamer:         sseStreamer,
	}
}

func (c *Controller) verifyBranchExistence(ctx context.Context,
	repo *types.Repository, branch string,
) (string, error) {
	if branch == "" {
		return "", usererror.BadRequest("branch name can't be empty")
	}

	ref, err := c.gitRPCClient.GetRef(ctx,
		gitrpc.GetRefParams{
			ReadParams: gitrpc.ReadParams{RepoUID: repo.GitUID},
			Name:       branch,
			Type:       gitrpcenum.RefTypeBranch,
		})
	if gitrpc.ErrorStatus(err) == gitrpc.StatusNotFound {
		return "", usererror.BadRequest(
			fmt.Sprintf("branch %s does not exist in the repository %s", branch, repo.UID))
	}
	if err != nil {
		return "", fmt.Errorf(
			"failed to check existence of the branch %s in the repository %s: %w",
			branch, repo.UID, err)
	}

	return ref.SHA, nil
}

func (c *Controller) getRepoCheckAccess(ctx context.Context,
	session *auth.Session, repoRef string, reqPermission enum.Permission,
) (*types.Repository, error) {
	if repoRef == "" {
		return nil, usererror.BadRequest("A valid repository reference must be provided.")
	}

	repo, err := c.repoStore.FindByRef(ctx, repoRef)
	if err != nil {
		return nil, fmt.Errorf("failed to find repository: %w", err)
	}

	if repo.Importing {
		return nil, usererror.BadRequest("Repository import is in progress.")
	}

	if err = apiauth.CheckRepo(ctx, c.authorizer, session, repo, reqPermission, false); err != nil {
		return nil, fmt.Errorf("access check failed: %w", err)
	}

	return repo, nil
}

func (c *Controller) getCommentCheckModifyAccess(ctx context.Context,
	pr *types.PullReq, commentID int64,
) (*types.PullReqActivity, error) {
	if commentID <= 0 {
		return nil, usererror.BadRequest("A valid comment ID must be provided.")
	}

	comment, err := c.activityStore.Find(ctx, commentID)
	if err != nil {
		return nil, fmt.Errorf("failed to find comment by ID: %w", err)
	}

	if comment == nil {
		return nil, usererror.ErrNotFound
	}

	if comment.Deleted != nil || comment.RepoID != pr.TargetRepoID || comment.PullReqID != pr.ID {
		return nil, usererror.ErrNotFound
	}

	if comment.Kind == enum.PullReqActivityKindSystem {
		return nil, usererror.BadRequest("Can't update a comment created by the system.")
	}

	if comment.Type != enum.PullReqActivityTypeComment && comment.Type != enum.PullReqActivityTypeCodeComment {
		return nil, usererror.BadRequest("Only comments and code comments can be edited.")
	}

	return comment, nil
}

func (c *Controller) getCommentCheckEditAccess(ctx context.Context,
	session *auth.Session, pr *types.PullReq, commentID int64,
) (*types.PullReqActivity, error) {
	comment, err := c.getCommentCheckModifyAccess(ctx, pr, commentID)
	if err != nil {
		return nil, err
	}

	if comment.CreatedBy != session.Principal.ID {
		return nil, usererror.BadRequest("Only own comments may be updated.")
	}

	return comment, nil
}

func (c *Controller) getCommentCheckChangeStatusAccess(ctx context.Context,
	pr *types.PullReq, commentID int64,
) (*types.PullReqActivity, error) {
	comment, err := c.getCommentCheckModifyAccess(ctx, pr, commentID)
	if err != nil {
		return nil, err
	}

	if comment.SubOrder != 0 {
		return nil, usererror.BadRequest("Can't change status of replies.")
	}

	return comment, nil
}

func (c *Controller) checkIfAlreadyExists(ctx context.Context,
	targetRepoID, sourceRepoID int64, targetBranch, sourceBranch string,
) error {
	existing, err := c.pullreqStore.List(ctx, &types.PullReqFilter{
		SourceRepoID: sourceRepoID,
		SourceBranch: sourceBranch,
		TargetRepoID: targetRepoID,
		TargetBranch: targetBranch,
		States:       []enum.PullReqState{enum.PullReqStateOpen},
		Size:         1,
		Sort:         enum.PullReqSortNumber,
		Order:        enum.OrderAsc,
	})
	if err != nil {
		return fmt.Errorf("failed to get existing pull requests: %w", err)
	}
	if len(existing) > 0 {
		return usererror.ConflictWithPayload(
			"a pull request for this target and source branch already exists",
			map[string]any{
				"type":   "pr already exists",
				"number": existing[0].Number,
				"title":  existing[0].Title,
			},
		)
	}

	return nil
}

func eventBase(pr *types.PullReq, principal *types.Principal) pullreqevents.Base {
	return pullreqevents.Base{
		PullReqID:    pr.ID,
		SourceRepoID: pr.SourceRepoID,
		TargetRepoID: pr.TargetRepoID,
		Number:       pr.Number,
		PrincipalID:  principal.ID,
	}
}