package centrifugo

import (
	"context"
	"encoding/json"
	"errors"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/bonfire"
)

// HealthCommandName is the name of the Centrifugo health check command.
const HealthCommandName = "websockets:health"

// healthFailed is returned by the health command after it has printed why
// the check failed: bonfire.Reported makes the binary exit 1 without
// repeating the message.
func healthFailed() error {
	return bonfire.Reported(errors.New(HealthCommandName + ": check failed"))
}

// healthJSON is websockets:health --json. The API key is never included.
type healthJSON struct {
	Healthy   bool   `json:"healthy"`
	APIURL    string `json:"api_url"`
	Enabled   bool   `json:"enabled"`
	APIKeySet bool   `json:"api_key_set"`
	Error     string `json:"error,omitempty"`
}

// Commands returns the Centrifugo console commands for an application
// binary: the HealthCommandName check. An application appends them to the
// commands its plugin returns from Commands.
func Commands(app *backpack.App) []bonfire.Command {
	return []bonfire.Command{healthCommand(app)}
}

// healthCommand ports the WinterCMS CentrifugoHealthCheck command. The
// WinterCMS command only read the local configuration; this one also calls
// the Centrifugo info API, so a wrong URL or key fails the check. The API
// key is never printed.
func healthCommand(app *backpack.App) bonfire.Command {
	return bonfire.Command{
		Name:        HealthCommandName,
		Description: "Check Centrifugo connection health",
		Long: `Reads the Centrifugo settings (realtime.centrifugo.*) and calls the Centrifugo
info API with them, so a wrong URL or API key fails the check. The API key is
never printed. It exits 1 when Centrifugo is not configured or does not
answer. --json prints {healthy, api_url, enabled, api_key_set, error} for
monitoring scripts.`,
		Flags: []bonfire.Flag{{Name: "json", Description: "Print the result as JSON", Bare: true}},
		Examples: []bonfire.Example{
			{Command: HealthCommandName, Description: "Check the connection"},
			{Command: HealthCommandName + " --json", Description: "Machine-readable result for a monitoring check"},
		},
		Run: func(ctx context.Context, in bonfire.Input, out bonfire.Output) error {
			var cfg Config
			if app != nil {
				cfg = LoadConfig(app.Config)
			} else {
				cfg = LoadConfig(nil)
			}
			client := NewClient(cfg, nil)
			asJSON := false
			if in != nil {
				v, _ := in.Flag("json")
				asJSON = v == "true"
			}
			if asJSON {
				info := client.DebugInfo()
				res := healthJSON{APIURL: info.APIURL, Enabled: info.Enabled, APIKeySet: info.APIKeySet}
				if !client.Enabled() {
					res.Error = "Centrifugo not configured (API key missing)"
				} else if _, err := client.Info(ctx); err != nil {
					res.Error = err.Error()
				} else {
					res.Healthy = true
				}
				b, err := json.MarshalIndent(res, "", "  ")
				if err != nil {
					return err
				}
				out.Println(string(b))
				if !res.Healthy {
					return healthFailed()
				}
				return nil
			}
			if !client.Enabled() {
				out.Error("Centrifugo not configured (API key missing)")
				out.Println("Set SUMMER_REALTIME__CENTRIFUGO__API_KEY in the environment")
				return healthFailed()
			}
			out.Info("Checking Centrifugo connection...")
			out.Println("API URL: " + cfg.APIURL)
			if _, err := client.Info(ctx); err != nil {
				out.Error("Connection check failed: " + err.Error())
				return healthFailed()
			}
			info := client.DebugInfo()
			out.Success("Configuration OK")
			out.Table([]string{"Setting", "Value"}, [][]string{
				{"API URL", info.APIURL},
				{"Enabled", yesNo(info.Enabled)},
				{"API Key Set", yesNo(info.APIKeySet)},
			})
			return nil
		},
	}
}

func yesNo(b bool) string {
	if b {
		return "Yes"
	}
	return "No"
}