// Copyright 2020 Dolthub, 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 actions

import (
	"context"
	"fmt"
	"sort"

	"github.com/dolthub/dolt/go/libraries/doltcore/doltdb"
	"github.com/dolthub/dolt/go/libraries/doltcore/env"
	"github.com/dolthub/dolt/go/libraries/doltcore/ref"
	"github.com/dolthub/dolt/go/store/datas"
)

type TagProps struct {
	TaggerName  string
	TaggerEmail string
	Description string
}

func CreateTag(ctx context.Context, dEnv *env.DoltEnv, tagName, startPoint string, props TagProps) error {
	return CreateTagOnDB(ctx, dEnv.DoltDB, tagName, startPoint, props, dEnv.RepoStateReader().CWBHeadRef())
}

func CreateTagOnDB(ctx context.Context, ddb *doltdb.DoltDB, tagName, startPoint string, props TagProps, headRef ref.DoltRef) error {
	tagRef := ref.NewTagRef(tagName)

	hasRef, err := ddb.HasRef(ctx, tagRef)

	if err != nil {
		return err
	}

	if hasRef {
		return ErrAlreadyExists
	}

	if !ref.IsValidTagName(tagName) {
		return doltdb.ErrInvTagName
	}

	cs, err := doltdb.NewCommitSpec(startPoint)

	if err != nil {
		return err
	}

	cm, err := ddb.Resolve(ctx, cs, headRef)

	if err != nil {
		return err
	}

	meta := datas.NewTagMeta(props.TaggerName, props.TaggerEmail, props.Description)

	return ddb.NewTagAtCommit(ctx, tagRef, cm, meta)
}

func DeleteTags(ctx context.Context, dEnv *env.DoltEnv, tagNames ...string) error {
	return DeleteTagsOnDB(ctx, dEnv.DoltDB, tagNames...)
}

func DeleteTagsOnDB(ctx context.Context, ddb *doltdb.DoltDB, tagNames ...string) error {
	for _, tn := range tagNames {
		dref := ref.NewTagRef(tn)

		hasRef, err := ddb.HasRef(ctx, dref)

		if err != nil {
			return err
		}
		if !hasRef {
			return doltdb.ErrTagNotFound
		}

		err = ddb.DeleteTag(ctx, dref)

		if err != nil {
			return err
		}
	}
	return nil
}

// IterResolvedTags iterates over tags in dEnv.DoltDB from newest to oldest, resolving the tag to a commit and calling cb().
func IterResolvedTags(ctx context.Context, ddb *doltdb.DoltDB, cb func(tag *doltdb.Tag) (stop bool, err error)) error {
	tagRefs, err := ddb.GetTags(ctx)

	if err != nil {
		return err
	}

	var resolved []*doltdb.Tag
	for _, r := range tagRefs {
		tr, ok := r.(ref.TagRef)
		if !ok {
			return fmt.Errorf("DoltDB.GetTags() returned non-tag DoltRef")
		}

		tag, err := ddb.ResolveTag(ctx, tr)
		if err != nil {
			return err
		}

		resolved = append(resolved, tag)
	}

	// iterate newest to oldest
	sort.Slice(resolved, func(i, j int) bool {
		return resolved[i].Meta.Timestamp > resolved[j].Meta.Timestamp
	})

	for _, tag := range resolved {
		stop, err := cb(tag)

		if err != nil {
			return err
		}
		if stop {
			break
		}
	}

	return nil
}
