package proxmox

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net/url"
	"regexp"
	"sort"
	"strings"
)

type Snapshot struct {
	Name        string `json:"name"`
	Description string `json:"description"`
	Time        int64  `json:"snaptime"`
	Parent      string `json:"parent"`
	Memory      int    `json:"vmstate"`
	State       string `json:"snapstate"`
}

func vmPath(node string, vmid int) string {
	return fmt.Sprintf("/nodes/%s/qemu/%d", url.PathEscape(node), vmid)
}
func (c *Client) Snapshots(ctx context.Context, node string, vmid int) ([]Snapshot, error) {
	var items []Snapshot
	err := c.request(ctx, "GET", vmPath(node, vmid)+"/snapshot", nil, &items)
	out := []Snapshot{}
	for _, s := range items {
		if s.Name != "current" {
			out = append(out, s)
		}
	}
	sort.Slice(out, func(i, j int) bool {
		if out[i].Time == out[j].Time {
			return out[i].Name < out[j].Name
		}
		return out[i].Time > out[j].Time
	})
	return out, err
}
func (c *Client) SnapshotConfig(ctx context.Context, node string, vmid int, name string) (map[string]any, error) {
	var out map[string]any
	err := c.request(ctx, "GET", vmPath(node, vmid)+"/snapshot/"+url.PathEscape(name)+"/config", nil, &out)
	return out, err
}
func (c *Client) CanSnapshot(ctx context.Context, node string, vmid int) (bool, error) {
	var out struct {
		HasFeature json.RawMessage `json:"hasFeature"`
	}
	err := c.request(ctx, "GET", vmPath(node, vmid)+"/feature?feature=snapshot", nil, &out)
	return string(out.HasFeature) == "1" || string(out.HasFeature) == "true", err
}
func (c *Client) SnapshotAction(ctx context.Context, node string, vmid int, action, name, description string) (string, error) {
	path := vmPath(node, vmid) + "/snapshot"
	method := "POST"
	form := url.Values{}
	switch action {
	case "create":
		form.Set("snapname", name)
		form.Set("description", description)
		form.Set("vmstate", "0")
	case "delete":
		path += "/" + url.PathEscape(name)
		method = "DELETE"
	case "rollback":
		path += "/" + url.PathEscape(name) + "/rollback"
		form.Set("start", "0")
	default:
		return "", errors.New("unsupported snapshot action")
	}
	var upid string
	err := c.request(ctx, method, path, form, &upid)
	if err == nil && upid == "" {
		err = errors.New("PVE did not return a snapshot task ID")
	}
	return upid, err
}

// Limit automatic rollback to ordinary virtual disks. No memory, external device
// state, custom host scripts or omitted/shared disks can be restored safely here.
var snapshotDiskPattern = regexp.MustCompile(`^((scsi|sata|virtio|ide)[0-9]+|efidisk0|tpmstate0)$`)

func SnapshotDisks(config map[string]any) (map[string]string, error) {
	out := map[string]string{}
	for key, value := range config {
		if strings.HasPrefix(key, "hostpci") || strings.HasPrefix(key, "usb") || strings.HasPrefix(key, "unused") || key == "args" || key == "hookscript" {
			return nil, errors.New("包含直通设备、未使用磁盘或宿主自定义配置，请在 PVE 人工管理快照")
		}
		if !snapshotDiskPattern.MatchString(key) {
			continue
		}
		disk := fmt.Sprint(value)
		if strings.Contains(disk, "media=cdrom") || strings.Contains(disk, "cloudinit") {
			continue
		}
		volume := strings.Split(disk, ",")[0]
		storage, _, ok := strings.Cut(volume, ":")
		if !ok || storage == "" || strings.ContainsAny(storage, "/\\") {
			return nil, errors.New("包含物理磁盘或无法识别的卷，请在 PVE 人工管理快照")
		}
		for _, option := range strings.Split(disk, ",")[1:] {
			if option == "snapshot=0" || option == "shared=1" {
				return nil, errors.New("存在不参与快照或共享的磁盘，不能保证完整还原")
			}
		}
		out[key] = disk
	}
	if len(out) == 0 {
		return nil, errors.New("没有可管理快照的虚拟磁盘")
	}
	return out, nil
}