// 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 git

import (
	"context"
	"fmt"
	"os"

	"github.com/harness/gitness/git/types"

	"github.com/drone/go-generate/builder"
	"github.com/drone/go-generate/chroot"
	"github.com/rs/zerolog/log"
)

type GeneratePipelineParams struct {
	ReadParams
}

type GeneratePipelinesOutput struct {
	PipelineYAML []byte
}

func (s *Service) GeneratePipeline(ctx context.Context,
	params *GeneratePipelineParams,
) (GeneratePipelinesOutput, error) {
	if err := params.Validate(); err != nil {
		return GeneratePipelinesOutput{}, err
	}
	repoPath := getFullPathForRepo(s.reposRoot, params.RepoUID)

	tempDir, err := os.MkdirTemp(s.tmpDir, "*-"+params.RepoUID)
	if err != nil {
		return GeneratePipelinesOutput{}, fmt.Errorf("error creating temp dir for repo %s: %w", params.RepoUID, err)
	}
	defer func(path string) {
		// when repo is successfully created remove temp dir
		errRm := os.RemoveAll(path)
		if errRm != nil {
			log.Err(errRm).Msg("failed to cleanup temporary dir.")
		}
	}(tempDir)

	// Clone repository to temp dir
	if err = s.adapter.Clone(ctx, repoPath, tempDir, types.CloneRepoOptions{Depth: 1}); err != nil {
		return GeneratePipelinesOutput{}, fmt.Errorf("failed to clone repo: %w", err)
	}

	// create a chroot virtual filesystem that we
	// pass to the builder for isolation purposes.
	chroot, err := chroot.New(tempDir)
	if err != nil {
		return GeneratePipelinesOutput{}, fmt.Errorf("failed to set the temp directory as active directory: %w", err)
	}

	// builds the pipeline configuration based on
	// the contents of the virtual filesystem.
	builder := builder.New()
	out, err := builder.Build(chroot)
	if err != nil {
		return GeneratePipelinesOutput{}, fmt.Errorf("failed to build pipeline: %w", err)
	}

	return GeneratePipelinesOutput{
		PipelineYAML: out,
	}, nil
}