package harvester

import (
	"fmt"
	"sync"
	"time"

	cfg "github.com/elastic/beats/filebeat/config"
	"github.com/elastic/beats/filebeat/harvester/reader"
	"github.com/elastic/beats/libbeat/common"
	"github.com/elastic/beats/libbeat/common/match"

	"github.com/dustin/go-humanize"
	"github.com/elastic/beats/libbeat/logp"
)

var (
	defaultConfig = harvesterConfig{
		BufferSize:      16 * humanize.KiByte,
		DocumentType:    "log",
		InputType:       cfg.DefaultInputType,
		Backoff:         1 * time.Second,
		BackoffFactor:   2,
		MaxBackoff:      10 * time.Second,
		CloseInactive:   5 * time.Minute,
		MaxBytes:        10 * humanize.MiByte,
		CloseRemoved:    true,
		CloseRenamed:    false,
		CloseEOF:        false,
		CloseTimeout:    0,
		ForceCloseFiles: false,
	}
)

type harvesterConfig struct {
	common.EventMetadata `config:",inline"`      // Fields and tags to add to events.
	BufferSize           int                     `config:"harvester_buffer_size"`
	DocumentType         string                  `config:"document_type"`
	Encoding             string                  `config:"encoding"`
	InputType            string                  `config:"input_type"`
	Backoff              time.Duration           `config:"backoff" validate:"min=0,nonzero"`
	BackoffFactor        int                     `config:"backoff_factor" validate:"min=1"`
	MaxBackoff           time.Duration           `config:"max_backoff" validate:"min=0,nonzero"`
	CloseInactive        time.Duration           `config:"close_inactive"`
	CloseOlder           time.Duration           `config:"close_older"`
	CloseRemoved         bool                    `config:"close_removed"`
	CloseRenamed         bool                    `config:"close_renamed"`
	CloseEOF             bool                    `config:"close_eof"`
	CloseTimeout         time.Duration           `config:"close_timeout" validate:"min=0"`
	ForceCloseFiles      bool                    `config:"force_close_files"`
	ExcludeLines         []match.Matcher         `config:"exclude_lines"`
	IncludeLines         []match.Matcher         `config:"include_lines"`
	MaxBytes             int                     `config:"max_bytes" validate:"min=0,nonzero"`
	Multiline            *reader.MultilineConfig `config:"multiline"`
	JSON                 *reader.JSONConfig      `config:"json"`
	Pipeline             string                  `config:"pipeline"`
	Module               string                  `config:"_module_name"`  // hidden option to set the module name
	Fileset              string                  `config:"_fileset_name"` // hidden option to set the fileset name
}

var onceCheck sync.Once

func (config *harvesterConfig) Validate() error {

	// DEPRECATED: remove in 6.0
	if config.ForceCloseFiles {
		config.CloseRemoved = true
		config.CloseRenamed = true
		logp.Warn("DEPRECATED: force_close_files was set to true. Use close_removed + close_rename")
	}

	// DEPRECATED: remove in 6.0
	if config.CloseOlder > 0 {
		config.CloseInactive = config.CloseOlder
		logp.Warn("DEPRECATED: close_older is deprecated. Use close_inactive")
	}

	// Check input type
	if _, ok := cfg.ValidInputType[config.InputType]; !ok {
		return fmt.Errorf("Invalid input type: %v", config.InputType)
	}

	if config.JSON != nil && len(config.JSON.MessageKey) == 0 &&
		config.Multiline != nil {
		return fmt.Errorf("When using the JSON decoder and multiline together, you need to specify a message_key value")
	}

	if config.JSON != nil && len(config.JSON.MessageKey) == 0 &&
		(len(config.IncludeLines) > 0 || len(config.ExcludeLines) > 0) {
		return fmt.Errorf("When using the JSON decoder and line filtering together, you need to specify a message_key value")
	}

	if config.DocumentType != "log" {
		onceCheck.Do(func() {
			logp.Warn("DEPRECATED: document_type is deprecated. Use fields instead.")
		})
	}
	return nil
}