package inventory

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

	"github.com/jackc/pgx/v5"
)

// MachineAccount is what a machine said it is made of (novox/hq issue 160), from the profile it last
// reported: the architecture and kernel family the profile always carried, and the facts a node-engine that
// knows how says beside them. Read by `node`, so what a machine says of itself is visible in one place —
// collected and shown in the same breath, not collected and read by nothing (issue 160's pattern).
type MachineAccount struct {
	Architecture string `json:"architecture"`
	Kernel       string `json:"kernel"`
	// Machine is nil when the node-engine that reported is older than the one that says it.
	Machine *MadeOf `json:"machine"`
}

// MadeOf is the node-engine's account of what it is made of, as it put it on the wire. A fact it could
// not determine is absent here and named in Unknown with why — never a zero.
type MadeOf struct {
	ObservedAt    time.Time           `json:"observed_at"`
	KernelRelease string              `json:"kernel_release"`
	Distribution  string              `json:"distribution"`
	Version       string              `json:"version"`
	Processor     string              `json:"processor"`
	Cores         int                 `json:"cores"`
	Threads       int                 `json:"threads"`
	MemoryBytes   int64               `json:"memory_bytes"`
	Virtual       string              `json:"virtual"`
	BootedAt      *time.Time          `json:"booted_at"`
	Timezone      string              `json:"timezone"`
	Filesystems   []MountedFilesystem `json:"filesystems"`
	Unknown       map[string]string   `json:"unknown"`
}

// MountedFilesystem is one local filesystem a machine has mounted.
type MountedFilesystem struct {
	Mount     string `json:"mount"`
	Device    string `json:"device"`
	Type      string `json:"type"`
	SizeBytes int64  `json:"size_bytes"`
	FreeBytes int64  `json:"free_bytes"`
}

// MachineOf is what a node last said it is made of. had is false for a node that has never reported a
// profile at all, which is a different answer from one whose node-engine does not say the facts yet.
func (i *Inventory) MachineOf(ctx context.Context, nodeName string) (account MachineAccount, had bool, err error) {
	var raw []byte
	err = i.store.Pool().QueryRow(ctx, `select profile from node where name = $1`, nodeName).Scan(&raw)
	if errors.Is(err, pgx.ErrNoRows) {
		return MachineAccount{}, false, fmt.Errorf("%w: %s", ErrNoSuchNode, nodeName)
	}
	if err != nil {
		return MachineAccount{}, false, err
	}
	return machineFrom(raw)
}

func machineFrom(raw []byte) (MachineAccount, bool, error) {
	if len(raw) == 0 {
		return MachineAccount{}, false, nil
	}
	var account MachineAccount
	if err := json.Unmarshal(raw, &account); err != nil {
		return MachineAccount{}, false, err
	}
	return account, true, nil
}