package platform

import (
	"context"
	"encoding/json"
	"errors"
	"os/exec"
	"strings"
)

type CapacityCheckResult struct {
	Status            string   `json:"status"`
	ActiveConnections int64    `json:"active_connections"`
	KafkaLag          float64  `json:"kafka_lag"`
	Findings          []string `json:"findings"`
}

type capacityCheckReport struct {
	Status string `json:"status"`
	Totals struct {
		ActiveConnections int64   `json:"active_connections"`
		KafkaLag          float64 `json:"kafka_lag"`
	} `json:"totals"`
	Findings []string `json:"findings"`
}

type CapacityCheckCommand struct {
	bin string
}

func NewCapacityCheckCommand(bin string) *CapacityCheckCommand {
	return &CapacityCheckCommand{bin: strings.TrimSpace(bin)}
}

func (c *CapacityCheckCommand) CheckCapacity(ctx context.Context) (CapacityCheckResult, error) {
	if c.bin == "" {
		return CapacityCheckResult{}, errors.New("capacity-check bin is empty")
	}
	output, err := exec.CommandContext(ctx, c.bin).CombinedOutput()
	var report capacityCheckReport
	if jsonErr := json.Unmarshal(output, &report); jsonErr != nil {
		if err != nil {
			return CapacityCheckResult{}, errors.New(err.Error() + ": " + strings.TrimSpace(string(output)))
		}
		return CapacityCheckResult{}, jsonErr
	}
	return CapacityCheckResult{
		Status:            report.Status,
		ActiveConnections: report.Totals.ActiveConnections,
		KafkaLag:          report.Totals.KafkaLag,
		Findings:          report.Findings,
	}, nil
}