package tui

import (
	"time"

	"github.com/charmbracelet/bubbles/spinner"
	tea "github.com/charmbracelet/bubbletea"

	"proxyctl/internal/app"
)

type operationError struct {
	status app.OperationStatus
	detail string
	intent app.Intent
}

// operationCoordinator owns the complete interactive operation lifecycle. The
// root Model delegates stream consumption, progress, confirmation, current
// error, spinner, and deferred-exit state here instead of mirroring them.
type operationCoordinator struct {
	active             bool
	intent             app.Intent
	updates            <-chan app.OperationUpdate
	cancel             func()
	progress           map[string]app.TargetProgressPhase
	status             app.OperationStatus
	currentError       *operationError
	errorExpanded      bool
	errorOffset        int
	confirmation       *app.Confirmation
	confirmationDialog confirmationDialog
	confirmationIntent *app.Intent
	quitRequested      bool
	spinner            spinner.Model
}

type operationProgress struct {
	update  app.OperationUpdate
	updates <-chan app.OperationUpdate
	closed  bool
}

var applyingSpinner = spinner.Spinner{
	Frames: []string{"|", "/", "-", "\\"},
	FPS:    90 * time.Millisecond,
}

func newOperationCoordinator() operationCoordinator {
	return operationCoordinator{
		progress: make(map[string]app.TargetProgressPhase),
		spinner:  spinner.New(spinner.WithSpinner(applyingSpinner)),
	}
}

func waitForOperation(updates <-chan app.OperationUpdate) tea.Cmd {
	return func() tea.Msg {
		update, ok := <-updates
		if !ok {
			return operationProgress{updates: updates, closed: true}
		}
		return operationProgress{update: update, updates: updates}
	}
}

func (o operationCoordinator) wait() tea.Cmd {
	if !o.active || o.updates == nil {
		return nil
	}
	return waitForOperation(o.updates)
}

func (o operationCoordinator) commands() tea.Cmd {
	if !o.active {
		return nil
	}
	return tea.Batch(o.wait(), o.spinner.Tick)
}

func (o *operationCoordinator) start(application app.InteractiveModule, intent app.Intent) (app.Snapshot, tea.Cmd, bool) {
	if o.quitRequested || o.active || o.confirmation != nil {
		o.status = app.OperationStatus{Kind: app.StatusBlocked, Summary: "Wait for the current operation to finish before starting another modification"}
		return application.Snapshot(), nil, false
	}
	stream := application.StartOperation(intent)
	o.active = true
	o.intent = intent
	o.updates = stream.Updates
	o.cancel = stream.Cancel
	o.progress = make(map[string]app.TargetProgressPhase)
	o.spinner = spinner.New(spinner.WithSpinner(applyingSpinner))
	if intent.TargetID != "" {
		o.progress[intent.TargetID] = app.TargetProgressRunning
	}
	o.status = app.OperationStatus{Kind: app.StatusProgress, Summary: operationStartingSummary(intent.Kind)}
	return stream.Snapshot, o.commands(), true
}

func operationStartingSummary(kind app.IntentKind) string {
	switch kind {
	case app.RefreshTargets:
		return "Checking Target availability and state…"
	case app.ActivateProfile:
		return "Changing Active Profile…"
	case app.CreateProfile, app.UpdateProfile, app.DeleteProfile:
		return "Saving Proxy Profile changes…"
	default:
		return "Starting Target mutation…"
	}
}

func (o *operationCoordinator) tick(message spinner.TickMsg) tea.Cmd {
	if !o.active {
		return nil
	}
	updated, nextTick := o.spinner.Update(message)
	o.spinner = updated
	return nextTick
}

func (o *operationCoordinator) apply(update app.OperationUpdate) (firstFailedTargetID string) {
	decoded := update.Decode()
	for _, item := range decoded.Progress {
		o.progress[item.TargetID] = item.Phase
	}
	if decoded.Status.Summary != "" {
		o.status = decoded.Status
	}
	switch decoded.Kind {
	case app.OperationSucceeded:
		o.resolveError(o.intent)
	case app.OperationFailed:
		o.recordError(&operationError{status: decoded.Status, detail: errorDetail(decoded.Err), intent: o.intent})
		firstFailedTargetID = decoded.FirstFailedTargetID
	case app.OperationConfirmation:
		intent := o.intent
		o.confirmation = decoded.Confirmation
		o.confirmationDialog = newConfirmationDialog(*decoded.Confirmation)
		o.confirmationIntent = &intent
	}
	if decoded.IsTerminal() {
		o.finish()
	}
	return firstFailedTargetID
}

func errorDetail(err error) string {
	if err == nil {
		return ""
	}
	return err.Error()
}

func (o *operationCoordinator) recordError(candidate *operationError) {
	if o.currentError != nil && !relatedResolution(o.currentError.intent, candidate.intent) {
		return
	}
	o.currentError = candidate
	o.errorExpanded = false
	o.errorOffset = 0
}

func (o *operationCoordinator) resolveError(success app.Intent) {
	if o.currentError == nil || !relatedResolution(o.currentError.intent, success) {
		return
	}
	o.currentError = nil
	o.errorExpanded = false
	o.errorOffset = 0
}

func relatedResolution(failed, success app.Intent) bool {
	switch {
	case failed.Kind == app.RefreshTargets:
		return success.Kind == app.RefreshTargets
	case failed.Kind == app.ActivateProfile:
		return success.Kind == app.ActivateProfile && failed.Name == success.Name
	case isProfileMutation(failed.Kind):
		return isProfileMutation(success.Kind) && failed.Name == success.Name
	case isTargetMutation(failed.Kind):
		return isTargetMutation(success.Kind) && failed.TargetID != "" && failed.TargetID == success.TargetID
	default:
		return false
	}
}

func isTargetMutation(kind app.IntentKind) bool {
	switch kind {
	case app.EnableTarget, app.DisableTarget, app.ApplyProfileToTarget, app.ReapplyActiveProfile, app.RestoreOriginal:
		return true
	default:
		return false
	}
}

func (o *operationCoordinator) finish() {
	// start seeds speculative Running progress before the stream publishes its
	// first update. A terminal update may contain no replacement progress (most
	// notably a confirmation request), so never let that transient phase outlive
	// the operation that created it.
	for targetID, phase := range o.progress {
		if phase == app.TargetProgressRunning {
			delete(o.progress, targetID)
		}
	}
	o.active = false
	o.intent = app.Intent{}
	o.updates = nil
	o.cancel = nil
}

func (o *operationCoordinator) unexpectedClose() {
	o.status = app.OperationStatus{Kind: app.StatusError, Summary: "Operation ended without a final result"}
	o.recordError(&operationError{
		status: o.status,
		detail: "The Application operation stream closed before publishing a terminal result.",
		intent: o.intent,
	})
	o.finish()
}

func (o *operationCoordinator) acknowledgeError() {
	o.currentError = nil
	o.errorExpanded = false
	o.errorOffset = 0
	if o.status.Kind == app.StatusError {
		o.status = app.OperationStatus{}
	}
}

func (o *operationCoordinator) cancelConfirmation() {
	o.confirmation = nil
	o.confirmationDialog = confirmationDialog{}
	o.confirmationIntent = nil
	o.status = app.OperationStatus{}
}

func (o *operationCoordinator) confirmedIntent() (app.Intent, bool) {
	if o.confirmationIntent == nil {
		return app.Intent{}, false
	}
	intent := *o.confirmationIntent
	intent.Confirm = true
	intent.ConfirmationToken = o.confirmation.Token
	o.confirmation = nil
	o.confirmationDialog = confirmationDialog{}
	o.confirmationIntent = nil
	return intent, true
}

func (o operationCoordinator) busy() bool {
	return o.quitRequested || o.active || o.confirmation != nil
}

func (o operationCoordinator) deferredQuit() tea.Cmd {
	if o.quitRequested && !o.active {
		return tea.Quit
	}
	return nil
}

func (o *operationCoordinator) requestQuit() tea.Cmd {
	o.quitRequested = true
	if o.active {
		if o.cancel != nil {
			o.cancel()
		}
		return nil
	}
	return tea.Quit
}