// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.
// All rights reserved. This file is part of cc-backend.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package metricdata

import (
	"context"
	"encoding/json"
	"fmt"
	"time"

	"github.com/ClusterCockpit/cc-backend/internal/config"
	cclog "github.com/ClusterCockpit/cc-lib/ccLogger"
	"github.com/ClusterCockpit/cc-lib/schema"
)

type MetricDataRepository interface {
	// Initialize this MetricDataRepository. One instance of
	// this interface will only ever be responsible for one cluster.
	Init(rawConfig json.RawMessage) error

	// Return the JobData for the given job, only with the requested metrics.
	LoadData(job *schema.Job, metrics []string, scopes []schema.MetricScope, ctx context.Context, resolution int) (schema.JobData, error)

	// Return a map of metrics to a map of nodes to the metric statistics of the job. node scope only.
	LoadStats(job *schema.Job, metrics []string, ctx context.Context) (map[string]map[string]schema.MetricStatistics, error)

	// Return a map of metrics to a map of scopes to the scoped metric statistics of the job.
	LoadScopedStats(job *schema.Job, metrics []string, scopes []schema.MetricScope, ctx context.Context) (schema.ScopedJobStats, error)

	// Return a map of hosts to a map of metrics at the requested scopes (currently only node) for that node.
	LoadNodeData(cluster string, metrics, nodes []string, scopes []schema.MetricScope, from, to time.Time, ctx context.Context) (map[string]map[string][]*schema.JobMetric, error)

	// Return a map of hosts to a map of metrics to a map of scopes for multiple nodes.
	LoadNodeListData(cluster, subCluster string, nodes, metrics []string, scopes []schema.MetricScope, resolution int, from, to time.Time, ctx context.Context) (map[string]schema.JobData, error)
}

var upstreamMetricDataRepo MetricDataRepository

// func Init() error {
// 	for _, cluster := range config.Clusters {
// 		if cluster.MetricDataRepository != nil {
// 			var kind struct {
// 				Kind string `json:"kind"`
// 			}
// 			if err := json.Unmarshal(cluster.MetricDataRepository, &kind); err != nil {
// 				cclog.Warn("Error while unmarshaling raw json MetricDataRepository")
// 				return err
// 			}
//
// 			var mdr MetricDataRepository
// 			switch kind.Kind {
// 			case "cc-metric-store":
// 				mdr = &CCMetricStore{}
// 			case "prometheus":
// 				mdr = &PrometheusDataRepository{}
// 			case "test":
// 				mdr = &TestMetricDataRepository{}
// 			default:
// 				return fmt.Errorf("METRICDATA/METRICDATA > Unknown MetricDataRepository %v for cluster %v", kind.Kind, cluster.Name)
// 			}
//
// 			if err := mdr.Init(cluster.MetricDataRepository); err != nil {
// 				cclog.Errorf("Error initializing MetricDataRepository %v for cluster %v", kind.Kind, cluster.Name)
// 				return err
// 			}
// 			metricDataRepos[cluster.Name] = mdr
// 		}
// 	}
// 	return nil
// }

// func GetMetricDataRepo(cluster string) (MetricDataRepository, error) {
// 	var err error
// 	repo, ok := metricDataRepos[cluster]
//
// 	if !ok {
// 		err = fmt.Errorf("METRICDATA/METRICDATA > no metric data repository configured for '%s'", cluster)
// 	}
//
// 	return repo, err
// }

// InitUpstreamRepos initializes global upstream metric data repository for the pull worker
func InitUpstreamRepos() error {
	if config.Keys.UpstreamMetricRepository == nil {
		return nil
	}

	var kind struct {
		Kind string `json:"kind"`
	}
	if err := json.Unmarshal(*config.Keys.UpstreamMetricRepository, &kind); err != nil {
		cclog.Warn("Error while unmarshaling raw json UpstreamMetricRepository")
		return err
	}

	var mdr MetricDataRepository
	switch kind.Kind {
	case "cc-metric-store":
		mdr = &CCMetricStore{}
	case "prometheus":
		mdr = &PrometheusDataRepository{}
	case "test":
		mdr = &TestMetricDataRepository{}
	default:
		return fmt.Errorf("METRICDATA/METRICDATA > Unknown UpstreamMetricRepository %v", kind.Kind)
	}

	if err := mdr.Init(*config.Keys.UpstreamMetricRepository); err != nil {
		cclog.Errorf("Error initializing UpstreamMetricRepository %v", kind.Kind)
		return err
	}
	upstreamMetricDataRepo = mdr
	cclog.Infof("Initialized global upstream metric repository '%s'", kind.Kind)
	return nil
}

// GetUpstreamMetricDataRepo returns the global upstream metric data repository
func GetUpstreamMetricDataRepo() (MetricDataRepository, error) {
	if upstreamMetricDataRepo == nil {
		return nil, fmt.Errorf("METRICDATA/METRICDATA > no upstream metric data repository configured")
	}
	return upstreamMetricDataRepo, nil
}