package storage

import (
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/dokku/dokku/plugins/common"
)

// CommandCreateInput captures the flags accepted by storage:create.
type CommandCreateInput struct {
	Name           string
	Path           string
	Scheduler      string
	Size           string
	AccessMode     string
	StorageClass   string
	Namespace      string
	Chown          string
	ReclaimPolicy  string
	Annotations    map[string]string
	Labels         map[string]string
}

// CommandCreate registers a new storage entry.
func CommandCreate(input CommandCreateInput) error {
	if err := ValidateEntryName(input.Name, false); err != nil {
		return err
	}

	scheduler := input.Scheduler
	if scheduler == "" {
		scheduler = SchedulerDockerLocal
	}

	hostPath := input.Path
	if scheduler == SchedulerDockerLocal && hostPath == "" {
		hostPath = filepath.Join(GetStorageDirectory(), input.Name)
	}

	entry := &Entry{
		Name:          input.Name,
		Scheduler:     scheduler,
		HostPath:      hostPath,
		Size:          input.Size,
		AccessMode:    input.AccessMode,
		StorageClass:  input.StorageClass,
		Namespace:     input.Namespace,
		Chown:         input.Chown,
		ReclaimPolicy: input.ReclaimPolicy,
		Annotations:   input.Annotations,
		Labels:        input.Labels,
		SchemaVersion: SchemaVersion,
	}

	if err := entry.Validate(); err != nil {
		return err
	}

	if EntryExists(entry.Name) {
		existing, err := LoadEntry(entry.Name)
		if err != nil {
			return err
		}
		if existing.Scheduler != entry.Scheduler {
			return fmt.Errorf("storage entry %q already exists with scheduler %q; refusing to redefine", entry.Name, existing.Scheduler)
		}
		common.LogInfo1Quiet(fmt.Sprintf("Storage entry %s already exists, leaving in place", entry.Name))
	}

	if scheduler == SchedulerDockerLocal {
		if err := ensureDockerLocalPath(entry); err != nil {
			return err
		}
	}

	if err := SaveEntry(entry); err != nil {
		return err
	}

	if scheduler == SchedulerK3s {
		if err := callSchedulerCreateTrigger(entry); err != nil {
			// Roll back the on-disk entry so the disk and the cluster stay in sync.
			_ = DeleteEntry(entry.Name)
			return fmt.Errorf("scheduler refused storage entry %q: %w", entry.Name, err)
		}
	}

	common.LogInfo1(fmt.Sprintf("Storage entry %s created", entry.Name))
	return nil
}

// CommandDestroy removes a registered storage entry. Refuses to remove
// an entry that any app still has attached.
func CommandDestroy(name string) error {
	if name == "" {
		return errors.New("storage entry name is required")
	}
	if !EntryExists(name) {
		return fmt.Errorf("storage entry %q does not exist", name)
	}

	using, err := AppsUsingEntry(name)
	if err != nil {
		return err
	}
	if len(using) > 0 {
		return fmt.Errorf("storage entry %q is still mounted by app(s): %s", name, strings.Join(using, ", "))
	}

	entry, err := LoadEntry(name)
	if err != nil {
		return err
	}

	if entry.Scheduler == SchedulerK3s {
		if err := callSchedulerDestroyTrigger(entry); err != nil {
			return fmt.Errorf("scheduler refused to remove storage entry %q: %w", name, err)
		}
	}

	if err := DeleteEntry(name); err != nil {
		return err
	}
	common.LogInfo1(fmt.Sprintf("Storage entry %s destroyed", name))
	return nil
}

// CommandInfo prints a single entry's details, optionally as JSON.
func CommandInfo(name string, format string) error {
	if name == "" {
		return errors.New("storage entry name is required")
	}
	if !EntryExists(name) {
		return fmt.Errorf("storage entry %q does not exist", name)
	}

	entry, err := LoadEntry(name)
	if err != nil {
		return err
	}

	if format == "json" {
		data, err := json.MarshalIndent(entry, "", "  ")
		if err != nil {
			return err
		}
		fmt.Println(string(data))
		return nil
	}

	common.LogInfo1Quiet(fmt.Sprintf("Storage entry %s", entry.Name))
	common.LogVerbose(fmt.Sprintf("Scheduler:        %s", entry.Scheduler))
	if entry.HostPath != "" {
		common.LogVerbose(fmt.Sprintf("Host path:        %s", entry.HostPath))
	}
	if entry.Size != "" {
		common.LogVerbose(fmt.Sprintf("Size:             %s", entry.Size))
	}
	if entry.AccessMode != "" {
		common.LogVerbose(fmt.Sprintf("Access mode:      %s", entry.AccessMode))
	}
	if entry.StorageClass != "" {
		common.LogVerbose(fmt.Sprintf("Storage class:    %s", entry.StorageClass))
	}
	if entry.Namespace != "" {
		common.LogVerbose(fmt.Sprintf("Namespace:        %s", entry.Namespace))
	}
	if entry.Chown != "" {
		common.LogVerbose(fmt.Sprintf("Chown:            %s", entry.Chown))
	}
	if entry.ReclaimPolicy != "" {
		common.LogVerbose(fmt.Sprintf("Reclaim policy:   %s", entry.ReclaimPolicy))
	}
	return nil
}

// CommandSetInput captures the flags accepted by storage:set.
type CommandSetInput struct {
	Name          string
	Size          string
	AccessMode    string
	StorageClass  string
	Namespace     string
	Chown         string
	ReclaimPolicy string
	Annotations   map[string]string
	Labels        map[string]string
}

// CommandSet edits an existing entry's mutable fields and re-fires the
// scheduler-side helm release. Refuses changes Kubernetes can't apply
// in place (access-mode swap, storage-class swap, size shrink).
func CommandSet(input CommandSetInput) error {
	if !EntryExists(input.Name) {
		return fmt.Errorf("storage entry %q does not exist", input.Name)
	}
	entry, err := LoadEntry(input.Name)
	if err != nil {
		return err
	}

	if input.AccessMode != "" && input.AccessMode != entry.AccessMode {
		return fmt.Errorf("storage:set cannot change access-mode in place; recreate the entry")
	}
	if input.StorageClass != "" && input.StorageClass != entry.StorageClass {
		return fmt.Errorf("storage:set cannot change storage-class-name in place; recreate the entry")
	}
	if input.Size != "" {
		entry.Size = input.Size
	}
	if input.Namespace != "" {
		entry.Namespace = input.Namespace
	}
	if input.Chown != "" {
		entry.Chown = input.Chown
	}
	if input.ReclaimPolicy != "" {
		entry.ReclaimPolicy = input.ReclaimPolicy
	}
	if input.Annotations != nil {
		entry.Annotations = input.Annotations
	}
	if input.Labels != nil {
		entry.Labels = input.Labels
	}

	if err := entry.Validate(); err != nil {
		return err
	}
	if err := SaveEntry(entry); err != nil {
		return err
	}
	if entry.Scheduler == SchedulerK3s {
		if err := callSchedulerCreateTrigger(entry); err != nil {
			return fmt.Errorf("scheduler refused storage:set for %q: %w", entry.Name, err)
		}
	}
	common.LogInfo1(fmt.Sprintf("Storage entry %s updated", entry.Name))
	return nil
}

// CommandExecInput captures the storage:exec subcommand inputs.
type CommandExecInput struct {
	Name   string
	Image  string
	AsUser string
	Args   []string
}

// CommandExec delegates the actual exec to the scheduler plugin that owns
// the storage entry, by firing the scheduler-storage-exec plugn trigger
// with stdin/stdout/stderr streamed through. The handler decides between
// docker run, the k8s exec SDK, etc. - storage stays scheduler-agnostic.
//
// Exit codes from the underlying tool are propagated verbatim via
// os.Exit so callers in scripts see the right status.
func CommandExec(input CommandExecInput) error {
	if !EntryExists(input.Name) {
		return fmt.Errorf("storage entry %q does not exist", input.Name)
	}
	entry, err := LoadEntry(input.Name)
	if err != nil {
		return err
	}

	image := input.Image
	if image == "" {
		image = "alpine:3"
	}

	interactive, tty := stdinModes()

	triggerArgs := []string{
		entry.Scheduler,
		entry.Name,
		image,
	}
	triggerArgs = append(triggerArgs, fmt.Sprintf("--interactive=%t", interactive))
	triggerArgs = append(triggerArgs, fmt.Sprintf("--tty=%t", tty))
	if input.AsUser != "" {
		triggerArgs = append(triggerArgs, "--as-user", input.AsUser)
	}
	if len(input.Args) > 0 {
		triggerArgs = append(triggerArgs, "--")
		triggerArgs = append(triggerArgs, input.Args...)
	}

	results, err := common.CallPlugnTrigger(common.PlugnTriggerInput{
		Trigger:     "scheduler-storage-exec",
		Args:        triggerArgs,
		StreamStdio: true,
	})
	// common.CallExecCommand wraps a non-zero exit code as an error, but
	// for storage:exec the underlying tool's exit code IS the signal we
	// want to surface - it's how `dokku storage:exec demo -- exit 42`
	// reaches the user as exit 42. Check ExitCode first so that branch
	// runs before err collapses to LogFailWithError → exit 1.
	if results.ExitCode != 0 {
		os.Exit(results.ExitCode)
	}
	if err != nil {
		return err
	}
	return nil
}

// stdinModes inspects os.Stdin to decide whether docker / the k8s exec
// SDK should request an interactive session and a TTY.
func stdinModes() (interactive bool, tty bool) {
	fi, err := os.Stdin.Stat()
	if err != nil || fi == nil {
		return false, false
	}
	mode := fi.Mode()
	tty = mode&os.ModeCharDevice != 0
	hasStdinData := mode&os.ModeNamedPipe != 0
	interactive = tty || hasStdinData
	return interactive, tty
}

// CommandMigrate re-runs the legacy `-v` → entry/attachment migration
// for a single app or every app on the install. Useful when an operator
// has restored an app from a backup that predates the install-time
// migration, or when they've added `-v` lines via docker-options:add
// after the per-app flag was set.
func CommandMigrate(appName string, all bool) error {
	if all && appName != "" {
		return errors.New("storage:migrate accepts either an app name or --all, not both")
	}
	if !all && appName == "" {
		return errors.New("storage:migrate requires an app name (or --all)")
	}
	if all {
		apps, err := common.DokkuApps()
		if err != nil {
			if errors.Is(err, common.NoAppsExist) {
				return nil
			}
			return err
		}
		for _, app := range apps {
			if err := MigrateApp(app); err != nil {
				return err
			}
		}
		common.LogInfo1(fmt.Sprintf("Re-migrated %d app(s)", len(apps)))
		return nil
	}
	if err := common.VerifyAppName(appName); err != nil {
		return err
	}
	if err := MigrateApp(appName); err != nil {
		return err
	}
	common.LogInfo1(fmt.Sprintf("Re-migrated %s", appName))
	return nil
}

// CommandWait blocks until a k3s storage entry's PVC is bound.
func CommandWait(name string) error {
	if !EntryExists(name) {
		return fmt.Errorf("storage entry %q does not exist", name)
	}
	entry, err := LoadEntry(name)
	if err != nil {
		return err
	}
	if entry.Scheduler != SchedulerK3s {
		// Docker-local entries are immediately "ready" once the directory exists.
		if entry.HostPath != "" {
			info, statErr := os.Stat(entry.HostPath)
			if statErr != nil || !info.IsDir() {
				return fmt.Errorf("storage entry %q host path %s is not present", name, entry.HostPath)
			}
		}
		return nil
	}

	data, err := json.Marshal(entry)
	if err != nil {
		return err
	}
	results, err := common.CallPlugnTrigger(common.PlugnTriggerInput{
		Trigger: "storage-status",
		Args:    []string{entry.Name},
		Stdin:   strings.NewReader(string(data)),
	})
	if err != nil {
		return err
	}
	status := strings.TrimSpace(results.StdoutContents())
	if status != "Bound" {
		return fmt.Errorf("storage entry %q is %s, not Bound", name, status)
	}
	common.LogInfo1(fmt.Sprintf("Storage entry %s is bound", name))
	return nil
}

// CommandReportGlobal prints a global storage report listing every entry
// and the apps that mount it. Output is text by default; pass
// format="json" for machine-readable output.
func CommandReportGlobal(format string) error {
	entries, err := ListEntries()
	if err != nil {
		return err
	}
	type entryWithUse struct {
		Entry      *Entry   `json:"entry"`
		MountedBy  []string `json:"mounted_by"`
	}
	rows := []entryWithUse{}
	for _, entry := range entries {
		using, err := AppsUsingEntry(entry.Name)
		if err != nil {
			return err
		}
		rows = append(rows, entryWithUse{Entry: entry, MountedBy: using})
	}
	if format == "json" {
		data, err := json.MarshalIndent(rows, "", "  ")
		if err != nil {
			return err
		}
		fmt.Println(string(data))
		return nil
	}
	if len(rows) == 0 {
		common.LogInfo1Quiet("No storage entries registered")
		return nil
	}
	common.LogInfo1Quiet("Storage report (global):")
	for _, row := range rows {
		mountedBy := "—"
		if len(row.MountedBy) > 0 {
			mountedBy = strings.Join(row.MountedBy, ", ")
		}
		common.LogVerbose(fmt.Sprintf("%s\t%s\tmounted by: %s", row.Entry.Name, row.Entry.Scheduler, mountedBy))
	}
	return nil
}

// CommandListEntries lists registered entries (distinct from the legacy
// per-app storage:list which lists colon-form mounts).
func CommandListEntries(scheduler string, format string) error {
	entries, err := ListEntries()
	if err != nil {
		return err
	}

	filtered := []*Entry{}
	for _, entry := range entries {
		if scheduler != "" && entry.Scheduler != scheduler {
			continue
		}
		filtered = append(filtered, entry)
	}

	if format == "json" {
		data, err := json.MarshalIndent(filtered, "", "  ")
		if err != nil {
			return err
		}
		fmt.Println(string(data))
		return nil
	}

	if len(filtered) == 0 {
		common.LogInfo1Quiet("No storage entries registered")
		return nil
	}
	common.LogInfo1Quiet("Storage entries:")
	for _, entry := range filtered {
		common.LogVerbose(fmt.Sprintf("%s\t%s\t%s", entry.Name, entry.Scheduler, entry.HostPath))
	}
	return nil
}

// ensureDockerLocalPath creates the host directory referenced by a
// docker-local entry if it doesn't already exist. Idempotent: a
// pre-existing directory is left in place.
func ensureDockerLocalPath(entry *Entry) error {
	info, err := os.Stat(entry.HostPath)
	if err != nil && !os.IsNotExist(err) {
		return fmt.Errorf("unable to stat %s: %w", entry.HostPath, err)
	}
	if err == nil && !info.IsDir() {
		return fmt.Errorf("storage entry path %s exists but is not a directory", entry.HostPath)
	}
	if err != nil {
		if mkdirErr := os.MkdirAll(entry.HostPath, 0755); mkdirErr != nil {
			return fmt.Errorf("unable to create %s: %w", entry.HostPath, mkdirErr)
		}
		common.LogVerbose(fmt.Sprintf("Created %s", entry.HostPath))
	}

	if entry.Chown != "" && entry.Chown != "false" {
		chownID, err := ResolveChownID(entry.Chown)
		if err != nil {
			return err
		}
		if chownID != "false" {
			pluginPath := common.MustGetEnv("PLUGIN_AVAILABLE_PATH")
			chownScript := filepath.Join(pluginPath, "storage", "bin", "chown-storage-dir")
			result, err := common.CallExecCommand(common.ExecCommandInput{
				Command: "sudo",
				Args:    []string{chownScript, entry.HostPath, chownID},
			})
			if err != nil {
				return fmt.Errorf("unable to chown %s: %w", entry.HostPath, err)
			}
			if result.ExitCode != 0 {
				return fmt.Errorf("unable to chown %s: %s", entry.HostPath, result.StderrContents())
			}
		}
	}
	return nil
}

// callSchedulerCreateTrigger asks the scheduler plugin (k3s) to provision
// the underlying PVC/PV. The scheduler is responsible for any
// cluster-level validation (storage class existence, etc.).
func callSchedulerCreateTrigger(entry *Entry) error {
	data, err := json.Marshal(entry)
	if err != nil {
		return err
	}
	results, err := common.CallPlugnTrigger(common.PlugnTriggerInput{
		Trigger:     "storage-create",
		Args:        []string{entry.Name},
		StreamStdio: true,
		Stdin:       strings.NewReader(string(data)),
	})
	if err != nil {
		return err
	}
	if results.ExitCode != 0 {
		return fmt.Errorf("storage-create trigger exited with %d: %s", results.ExitCode, results.StderrContents())
	}
	return nil
}

// callSchedulerDestroyTrigger asks the scheduler plugin to release the
// underlying PVC/PV.
func callSchedulerDestroyTrigger(entry *Entry) error {
	data, err := json.Marshal(entry)
	if err != nil {
		return err
	}
	results, err := common.CallPlugnTrigger(common.PlugnTriggerInput{
		Trigger:     "storage-destroy",
		Args:        []string{entry.Name},
		StreamStdio: true,
		Stdin:       strings.NewReader(string(data)),
	})
	if err != nil {
		return err
	}
	if results.ExitCode != 0 {
		return fmt.Errorf("storage-destroy trigger exited with %d: %s", results.ExitCode, results.StderrContents())
	}
	return nil
}