package xmpp

import (
	"fmt"

	"dev.narayana.im/narayana/telegabber/telegram"
	"dev.narayana.im/narayana/telegabber/xmpp/gateway"

	"gosrc.io/xmpp/stanza"
)

// buildOmemoTransportFormFields builds the initial (no form submitted yet)
// field list for the transport-level "/omemo" ad-hoc command: a single
// list-single field for the account-wide mode, pre-selected to the current
// value. Plugs into handleSetQueryCommand's shared per-command
// field-then-form-then-answer construction, the same way "config"'s own
// field-building does.
func buildOmemoTransportFormFields(session *telegram.Client) []*stanza.Field {
	mode, _ := session.Session.Get("omemo")

	return []*stanza.Field{
		{
			Var:   "mode",
			Label: "OMEMO mode",
			Type:  stanza.FieldTypeListSingle,
			Options: []stanza.Option{
				{Label: "Automatic (default)", ValuesList: []string{"auto"}},
				{Label: "Always on", ValuesList: []string{"on"}},
				{Label: "Always off", ValuesList: []string{"off"}},
			},
			ValuesList: []string{mode},
		},
	}
}

// buildOmemoChatFormFields builds the initial field list for the
// chat-scoped "/omemo" ad-hoc command: a read-only effective-status field,
// a list-single override control, and two list-single "block"/"accept"
// fields - each an empty-by-default choice (no selection = no action)
// among the CURRENT opposite-state devices (block's options are the
// currently-trusted devices, accept's are the currently-blocked ones).
// This mirrors handleSetQueryCommand's existing mute/kick/ban/unmute/unban
// field-building exactly (a list-single of opposite-state members with a
// blank leading option), rather than a separate reported/item table plus
// list-multi fields - one form field per action, same as those commands.
func buildOmemoChatFormFields(session *telegram.Client, chatID int64) []*stanza.Field {
	status, err := session.GetOmemoChatStatus(chatID)
	if err != nil {
		return []*stanza.Field{
			{Type: stanza.FieldTypeFixed, Label: "Error", ValuesList: []string{err.Error()}},
		}
	}

	overrideValue := ""
	if status.OverrideSet {
		overrideValue = omemoOnOff(status.Override)
	}

	fields := []*stanza.Field{
		{
			Var:        "effective",
			Label:      "Effective right now",
			Type:       stanza.FieldTypeFixed,
			ValuesList: []string{fmt.Sprintf("%s (account-wide mode: %s)", omemoOnOff(status.Effective), status.Mode)},
		},
		{
			Var:   "override",
			Label: "Override for this chat",
			Type:  stanza.FieldTypeListSingle,
			Options: []stanza.Option{
				{Label: "Follow account-wide mode", ValuesList: []string{""}},
				{Label: "Always on", ValuesList: []string{"on"}},
				{Label: "Always off", ValuesList: []string{"off"}},
			},
			ValuesList: []string{overrideValue},
		},
	}

	// allow an empty selection ("no action"), same as mute/unmute's own
	// blank leading option
	blockOptions := []stanza.Option{{ValuesList: []string{""}}}
	acceptOptions := []stanza.Option{{ValuesList: []string{""}}}
	for _, d := range status.Devices {
		option := stanza.Option{Label: d.ID, ValuesList: []string{d.ID}}
		if d.Trusted {
			blockOptions = append(blockOptions, option)
		} else {
			acceptOptions = append(acceptOptions, option)
		}
	}

	return append(fields,
		&stanza.Field{Var: "block", Label: "Block device", Type: stanza.FieldTypeListSingle, Options: blockOptions},
		&stanza.Field{Var: "accept", Label: "Accept (unblock) device", Type: stanza.FieldTypeListSingle, Options: acceptOptions},
	)
}

// submitOmemoTransportForm applies a submitted transport-level "/omemo"
// form.
func submitOmemoTransportForm(session *telegram.Client, form *stanza.Form) *stanza.Command {
	var mode string
	for _, field := range form.Fields {
		if field != nil && field.Var == "mode" && len(field.ValuesList) > 0 {
			mode = field.ValuesList[0]
		}
	}

	var note stanza.Note
	if value, err := session.Session.Set("omemo", mode); err != nil {
		note = stanza.Note{Text: err.Error(), Type: stanza.CommandNoteTypeErr}
	} else {
		gateway.DirtySessions = true
		note = stanza.Note{Text: fmt.Sprintf("omemo mode set to %s", value), Type: stanza.CommandNoteTypeInfo}
	}

	return &stanza.Command{
		SessionId:       "omemo",
		Node:            "omemo",
		Status:          stanza.CommandStatusCompleted,
		CommandElements: []stanza.CommandElement{&note},
	}
}

// submitOmemoChatForm applies a submitted chat-scoped "/omemo" form: the
// override change (if submitted), then at most one block and one accept
// (each field is a single empty-or-one-device selection, not a multi-pick
// - see buildOmemoChatFormFields) - all in one round trip, since XEP-0050
// single-stage commands only get one.
func submitOmemoChatForm(session *telegram.Client, chatID int64, form *stanza.Form) *stanza.Command {
	var overrideValue string
	var overrideSubmitted bool
	var blockID, acceptID string
	for _, field := range form.Fields {
		if field == nil {
			continue
		}
		switch field.Var {
		case "override":
			overrideSubmitted = true
			if len(field.ValuesList) > 0 {
				overrideValue = field.ValuesList[0]
			}
		case "block":
			if len(field.ValuesList) > 0 {
				blockID = field.ValuesList[0]
			}
		case "accept":
			if len(field.ValuesList) > 0 {
				acceptID = field.ValuesList[0]
			}
		}
	}

	var notes []stanza.CommandElement
	if overrideSubmitted {
		switch overrideValue {
		case "":
			if err := session.SetOmemoChatOverride(chatID, nil); err != nil {
				notes = append(notes, &stanza.Note{Text: err.Error(), Type: stanza.CommandNoteTypeErr})
			} else {
				notes = append(notes, &stanza.Note{Text: "OMEMO override cleared for this chat", Type: stanza.CommandNoteTypeInfo})
			}
		case "on", "off":
			on := overrideValue == "on"
			if err := session.SetOmemoChatOverride(chatID, &on); err != nil {
				notes = append(notes, &stanza.Note{Text: err.Error(), Type: stanza.CommandNoteTypeErr})
			} else {
				notes = append(notes, &stanza.Note{Text: fmt.Sprintf("OMEMO forced %s for this chat", overrideValue), Type: stanza.CommandNoteTypeInfo})
			}
		}
	}

	if blockID != "" {
		if err := session.SetOmemoDeviceBlocked(chatID, blockID, true); err != nil {
			notes = append(notes, &stanza.Note{Text: fmt.Sprintf("Failed to block device %s: %v", blockID, err), Type: stanza.CommandNoteTypeErr})
		} else {
			notes = append(notes, &stanza.Note{Text: fmt.Sprintf("Device %s blocked", blockID), Type: stanza.CommandNoteTypeInfo})
		}
	}
	if acceptID != "" {
		if err := session.SetOmemoDeviceBlocked(chatID, acceptID, false); err != nil {
			notes = append(notes, &stanza.Note{Text: fmt.Sprintf("Failed to accept device %s: %v", acceptID, err), Type: stanza.CommandNoteTypeErr})
		} else {
			notes = append(notes, &stanza.Note{Text: fmt.Sprintf("Device %s accepted", acceptID), Type: stanza.CommandNoteTypeInfo})
		}
	}
	if len(notes) == 0 {
		notes = append(notes, &stanza.Note{Text: "No changes", Type: stanza.CommandNoteTypeInfo})
	}

	return &stanza.Command{
		SessionId:       "omemo",
		Node:            "omemo",
		Status:          stanza.CommandStatusCompleted,
		CommandElements: notes,
	}
}

func omemoOnOff(b bool) string {
	if b {
		return "on"
	}
	return "off"
}