package report

import (
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"
)

// Recovery pull error types for UI display.
var (
	ErrHubUnreachable = errors.New("hub unreachable")
	ErrAuthFailed     = errors.New("authentication failed")
	ErrNotFound       = errors.New("customer not found")
	ErrHubError       = errors.New("hub error")
)

// RecoveryResponse is the combined config + infra backup from the Hub recovery endpoint.
type RecoveryResponse struct {
	CustomerID     string       `json:"customer_id"`
	ConfigYAML     string       `json:"config_yaml"`
	InfraBackup    *InfraBackup `json:"infra_backup"`
	HasInfraBackup bool         `json:"has_infra_backup"`
}

// PullRecovery fetches combined recovery data from the Hub (config + infra backup).
// Auth: X-Retrieval-Password header.
func PullRecovery(hubURL, customerID, retrievalPassword string) (*RecoveryResponse, error) {
	url := strings.TrimRight(hubURL, "/") + "/api/v1/recovery/" + customerID

	client := &http.Client{Timeout: 30 * time.Second}

	req, err := http.NewRequest(http.MethodGet, url, nil)
	if err != nil {
		return nil, fmt.Errorf("%w: %v", ErrHubError, err)
	}
	req.Header.Set("X-Retrieval-Password", retrievalPassword)

	resp, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("%w: %v", ErrHubUnreachable, err)
	}
	defer resp.Body.Close()

	switch resp.StatusCode {
	case http.StatusOK:
		// success, continue below
	case http.StatusUnauthorized:
		return nil, ErrAuthFailed
	case http.StatusNotFound:
		return nil, ErrNotFound
	default:
		return nil, fmt.Errorf("%w: HTTP %d", ErrHubError, resp.StatusCode)
	}

	body, err := io.ReadAll(io.LimitReader(resp.Body, 10<<20)) // 10MB limit
	if err != nil {
		return nil, fmt.Errorf("%w: reading response: %v", ErrHubError, err)
	}

	var rr RecoveryResponse
	if err := json.Unmarshal(body, &rr); err != nil {
		return nil, fmt.Errorf("%w: parsing response: %v", ErrHubError, err)
	}

	return &rr, nil
}

// PullConfig fetches a generated controller.yaml from the Hub config endpoint.
// Auth: X-Retrieval-Password header.
func PullConfig(hubURL, customerID, retrievalPassword string) (string, error) {
	url := strings.TrimRight(hubURL, "/") + "/api/v1/config/" + customerID

	client := &http.Client{Timeout: 30 * time.Second}

	req, err := http.NewRequest(http.MethodGet, url, nil)
	if err != nil {
		return "", fmt.Errorf("%w: %v", ErrHubError, err)
	}
	req.Header.Set("X-Retrieval-Password", retrievalPassword)

	resp, err := client.Do(req)
	if err != nil {
		return "", fmt.Errorf("%w: %v", ErrHubUnreachable, err)
	}
	defer resp.Body.Close()

	switch resp.StatusCode {
	case http.StatusOK:
		// success
	case http.StatusUnauthorized:
		return "", ErrAuthFailed
	case http.StatusNotFound:
		return "", ErrNotFound
	default:
		return "", fmt.Errorf("%w: HTTP %d", ErrHubError, resp.StatusCode)
	}

	body, err := io.ReadAll(io.LimitReader(resp.Body, 1<<20)) // 1MB limit
	if err != nil {
		return "", fmt.Errorf("%w: reading response: %v", ErrHubError, err)
	}

	return string(body), nil
}

// PullInfraBackup fetches the infrastructure backup from the Hub.
// Returns nil, nil if no backup exists for this customer.
func PullInfraBackup(hubURL, apiKey, customerID string) (*InfraBackup, error) {
	url := strings.TrimRight(hubURL, "/") + "/api/v1/infra-backup/" + customerID

	client := &http.Client{Timeout: 30 * time.Second}

	req, err := http.NewRequest(http.MethodGet, url, nil)
	if err != nil {
		return nil, err
	}
	if apiKey != "" {
		req.Header.Set("Authorization", "Bearer "+apiKey)
	}

	resp, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("hub request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode == http.StatusNotFound {
		return nil, nil // no backup for this customer
	}
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("hub returned HTTP %d", resp.StatusCode)
	}

	body, err := io.ReadAll(io.LimitReader(resp.Body, 5<<20)) // 5MB limit
	if err != nil {
		return nil, fmt.Errorf("reading response: %w", err)
	}

	var ib InfraBackup
	if err := json.Unmarshal(body, &ib); err != nil {
		return nil, fmt.Errorf("parsing infra backup: %w", err)
	}

	return &ib, nil
}