package maptracker

import (
	"encoding/json"
	"errors"
	"time"

	"github.com/ipfs/ipfs-cluster/config"
)

const configKey = "maptracker"

// Default values for this Config.
const (
	DefaultPinningTimeout   = 60 * time.Minute
	DefaultUnpinningTimeout = 5 * time.Minute
	DefaultMaxPinQueueSize  = 4096
)

// Config allows to initialize a Monitor and customize some parameters.
type Config struct {
	config.Saver

	// PinningTimeout specifies how long to wait before a pinning state becomes a pin error
	PinningTimeout time.Duration
	// UnpinningTimeout specifies how long to wait before an unpinning state becomes a pin error
	UnpinningTimeout time.Duration
	// MaxPinQueueSize specifies how many pin or unpin requests we can hold in the queue
	// If higher, they will automatically marked with an error.
	MaxPinQueueSize int
}

type jsonConfig struct {
	PinningTimeout   string `json:"pinning_timeout"`
	UnpinningTimeout string `json:"unpinning_timeout"`
	MaxPinQueueSize  int    `json:"max_pin_queue_size"`
}

// ConfigKey provides a human-friendly identifier for this type of Config.
func (cfg *Config) ConfigKey() string {
	return configKey
}

// Default sets the fields of this Config to sensible values.
func (cfg *Config) Default() error {
	cfg.PinningTimeout = DefaultPinningTimeout
	cfg.UnpinningTimeout = DefaultUnpinningTimeout
	cfg.MaxPinQueueSize = DefaultMaxPinQueueSize
	return nil
}

// Validate checks that the fields of this Config have working values,
// at least in appearance.
func (cfg *Config) Validate() error {
	if cfg.PinningTimeout <= 0 {
		return errors.New("maptracker.pinning_timeout too low")
	}
	if cfg.UnpinningTimeout <= 0 {
		return errors.New("maptracker.unpinning_timeout too low")
	}
	if cfg.MaxPinQueueSize <= 0 {
		return errors.New("maptracker.max_pin_queue_size too low")
	}
	return nil
}

// LoadJSON sets the fields of this Config to the values defined by the JSON
// representation of it, as generated by ToJSON.
func (cfg *Config) LoadJSON(raw []byte) error {
	jcfg := &jsonConfig{}
	err := json.Unmarshal(raw, jcfg)
	if err != nil {
		logger.Error("Error unmarshaling basic monitor config")
		return err
	}

	cfg.Default()

	parseDuration := func(txt string) time.Duration {
		d, _ := time.ParseDuration(txt)
		if txt != "" && d == 0 {
			logger.Warningf("%s is not a valid duration. Default will be used", txt)
		}
		return d
	}

	pinningTimeo := parseDuration(jcfg.PinningTimeout)
	unpinningTimeo := parseDuration(jcfg.UnpinningTimeout)
	config.SetIfNotDefault(pinningTimeo, &cfg.PinningTimeout)
	config.SetIfNotDefault(unpinningTimeo, &cfg.UnpinningTimeout)
	config.SetIfNotDefault(jcfg.MaxPinQueueSize, &cfg.MaxPinQueueSize)

	return cfg.Validate()
}

// ToJSON generates a human-friendly JSON representation of this Config.
func (cfg *Config) ToJSON() ([]byte, error) {
	jcfg := &jsonConfig{}

	jcfg.PinningTimeout = cfg.PinningTimeout.String()
	jcfg.UnpinningTimeout = cfg.UnpinningTimeout.String()
	jcfg.MaxPinQueueSize = cfg.MaxPinQueueSize

	return config.DefaultJSONMarshal(jcfg)
}