package config

import (
	"github.com/creasty/defaults"
	"github.com/icinga/icinga-go-library/database"
	"github.com/icinga/icinga-go-library/logging"
	"github.com/icinga/icinga-go-library/redis"
	"github.com/icinga/icingadb/pkg/icingadb/history"
	"github.com/pkg/errors"
	"time"
)

// DefaultConfigPath specifies the default location of Icinga DB's config.yml for package installations.
const DefaultConfigPath = "/etc/icingadb/config.yml"

// Config defines Icinga DB config.
type Config struct {
	Database  database.Config `yaml:"database" envPrefix:"DATABASE_"`
	Redis     redis.Config    `yaml:"redis" envPrefix:"REDIS_"`
	Logging   logging.Config  `yaml:"logging" envPrefix:"LOGGING_"`
	Retention RetentionConfig `yaml:"retention" envPrefix:"RETENTION_"`
}

func (c *Config) SetDefaults() {
	// Since SetDefaults() is called after the default values of the struct's fields have been evaluated,
	// setting the default port only works here because
	// the embedded Redis config struct itself does not provide a default value.
	if defaults.CanUpdate(c.Redis.Port) {
		c.Redis.Port = 6380
	}
}

// Validate checks constraints in the supplied configuration and returns an error if they are violated.
func (c *Config) Validate() error {
	if err := c.Database.Validate(); err != nil {
		return err
	}
	if err := c.Redis.Validate(); err != nil {
		return err
	}
	if err := c.Logging.Validate(); err != nil {
		return err
	}
	if err := c.Retention.Validate(); err != nil {
		return err
	}

	return nil
}

// Flags defines CLI flags.
//
// Flags implements the [github.com/icinga/icinga-go-library/config.Flags] interface.
type Flags struct {
	// Version decides whether to just print the version and exit.
	Version bool `long:"version" description:"print version and exit"`

	// Config is the path to the config file. If not provided, it defaults to DefaultConfigPath.
	Config string `short:"c" long:"config" description:"path to config file (default: /etc/icingadb/config.yml)"`
	// default must be kept in sync with DefaultConfigPath.

	// DatabaseAutoImport results in an initial schema check and update; mostly for containerized setups.
	DatabaseAutoImport bool `long:"database-auto-import" description:"import database schema on startup if database is empty"`

	// DatabaseSchemaDir is the root directory for schema files to be used when DatabaseAutoImport is requested.
	//
	// The directory structure must mimic the git repo's schema dir, containing ./mysql/schema.sql and ./pgsql/schema.sql.
	DatabaseSchemaDir string `long:"database-schema-dir" description:"directory for --database-auto-import, expects ./{my,pg}sql/schema.sql files" default:"./schema/"`
}

// GetConfigPath retrieves the path to the configuration file.
// It returns the path specified via the command line, or DefaultConfigPath if none is provided.
//
// GetConfigPath implements parts of the [github.com/icinga/icinga-go-library/config.Flags] interface.
func (f Flags) GetConfigPath() string {
	if f.Config == "" {
		return DefaultConfigPath
	}

	return f.Config
}

// IsExplicitConfigPath indicates whether the configuration file path was explicitly set.
//
// IsExplicitConfigPath implements parts of the [github.com/icinga/icinga-go-library/config.Flags] interface.
func (f Flags) IsExplicitConfigPath() bool {
	return f.Config != ""
}

// RetentionConfig defines configuration for history retention.
type RetentionConfig struct {
	HistoryDays uint16                   `yaml:"history-days" env:"HISTORY_DAYS"`
	SlaDays     uint16                   `yaml:"sla-days" env:"SLA_DAYS"`
	Interval    time.Duration            `yaml:"interval" env:"INTERVAL" default:"1h"`
	Count       uint64                   `yaml:"count" env:"COUNT" default:"5000"`
	Options     history.RetentionOptions `yaml:"options" env:"OPTIONS"`
}

// Validate checks constraints in the supplied retention configuration and
// returns an error if they are violated.
func (r *RetentionConfig) Validate() error {
	if r.Interval <= 0 {
		return errors.New("retention interval must be positive")
	}

	if r.Count == 0 {
		return errors.New("count must be greater than zero")
	}

	return r.Options.Validate()
}
