// 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"
	"time"

	"github.com/harness/gitness/app/auth"
	"github.com/harness/gitness/types"
	"github.com/harness/gitness/types/enum"

	"github.com/rs/zerolog/log"
)

type CommentUpdateInput struct {
	Text string `json:"text"`
}

func (in *CommentUpdateInput) Validate() error {
	// TODO: Check Text length
	return nil
}

func (in *CommentUpdateInput) hasChanges(act *types.PullReqActivity) bool {
	return in.Text != act.Text
}

// CommentUpdate updates a pull request comment.
func (c *Controller) CommentUpdate(
	ctx context.Context,
	session *auth.Session,
	repoRef string,
	prNum int64,
	commentID int64,
	in *CommentUpdateInput,
) (*types.PullReqActivity, error) {
	repo, err := c.getRepoCheckAccess(ctx, session, repoRef, enum.PermissionRepoView)
	if err != nil {
		return nil, fmt.Errorf("failed to acquire access to repo: %w", err)
	}

	pr, err := c.pullreqStore.FindByNumber(ctx, repo.ID, prNum)
	if err != nil {
		return nil, fmt.Errorf("failed to find pull request by number: %w", err)
	}

	if errValidate := in.Validate(); errValidate != nil {
		return nil, errValidate
	}

	act, err := c.getCommentCheckEditAccess(ctx, session, pr, commentID)
	if err != nil {
		return nil, fmt.Errorf("failed to get comment: %w", err)
	}

	if !in.hasChanges(act) {
		return act, nil
	}

	// fetch parent activity
	var parentAct *types.PullReqActivity
	if act.IsReply() {
		parentAct, err = c.activityStore.Find(ctx, *act.ParentID)
		if err != nil {
			return nil, fmt.Errorf("failed to find parent pull request activity: %w", err)
		}
	}

	// generate all metadata updates
	var metadataUpdates []types.PullReqActivityMetadataUpdate

	metadataUpdates, principalInfos, err := c.appendMetadataUpdateForMentions(
		ctx, metadataUpdates, in.Text,
	)
	if err != nil {
		return nil, fmt.Errorf("failed to update metadata for mentions: %w", err)
	}

	// suggestion metadata in case of code comments or code comment replies (don't restrict to either side for now).
	if act.IsValidCodeComment() || (act.IsReply() && parentAct.IsValidCodeComment()) {
		metadataUpdates = appendMetadataUpdateForSuggestions(metadataUpdates, in.Text)
	}

	act, err = c.activityStore.UpdateOptLock(ctx, act, func(act *types.PullReqActivity) error {
		now := time.Now().UnixMilli()
		act.Edited = now
		act.Text = in.Text
		act.UpdateMetadata(metadataUpdates...)
		return nil
	})
	if err != nil {
		return nil, fmt.Errorf("failed to update comment: %w", err)
	}

	// Populate activity mentions (used only for response purposes).
	act.Mentions = principalInfos

	if err = c.sseStreamer.Publish(ctx, repo.ParentID, enum.SSETypePullRequestUpdated, pr); err != nil {
		log.Ctx(ctx).Warn().Err(err).Msg("failed to publish PR changed event")
	}

	return act, nil
}