// Copyright (c) 2026 Storm Dragon
// SPDX-License-Identifier: GPL-3.0-or-later

package reader

import (
	"git.stormux.org/storm/fenrir/internal/presentation"
	"git.stormux.org/storm/fenrir/internal/screen"
	"slices"
)

// Cursor feedback requires unchanged composer text. Comparing masked snapshots
// allows simultaneous tool/status redraws outside the input field to stay quiet.
func input_cursor_feedback(previous, next screen.Snapshot) []presentation.Message {
	if !slices.Equal(previous.Cells, next.Cells) {
		return nil
	}
	return changes(previous, next, true)
}

// SessionState preserves shortcut-only state as well as configuration. Screen,
// input timestamps and detached review positions are deliberately not restored.
type SessionState struct {
	automatic                                                     bool
	mode, attributeConfigured, attributeMode, attributeResumeMode string
	regions                                                       *terminalRegions
}

func clone_regions(source *terminalRegions) *terminalRegions {
	if source == nil {
		return nil
	}
	result := *source
	clone := func(region *screen.Region) *screen.Region {
		if region == nil {
			return nil
		}
		value := *region
		return &value
	}
	result.window = clone(source.window)
	for index, region := range source.live {
		result.live[index] = clone(region)
	}
	return &result
}

func (r *Reader) Capture_session() SessionState {
	return r.Capture_terminal_session(r.screen.Terminal)
}

func (r *Reader) Capture_terminal_session(terminal int) SessionState {
	return SessionState{r.automatic, r.trackingMode, r.attributeConfigured, r.attributeMode, r.attributeResumeMode, clone_regions(r.regions[terminal])}
}

func (r *Reader) Restore_session(state SessionState, terminal int) {
	r.automatic = state.automatic
	r.Configure_tracking(state.mode)
	r.attributeConfigured, r.attributeMode, r.attributeResumeMode = state.attributeConfigured, state.attributeMode, state.attributeResumeMode
	if r.regions == nil {
		r.regions = make(map[int]*terminalRegions)
	}
	r.regions[terminal] = clone_regions(state.regions)
	r.regionRevision++
	r.attributeKnown, r.indentKnown = false, false
	r.Reset_progress()
}

func (r *Reader) Clear_session_regions(terminal int) {
	delete(r.regions, terminal)
	r.regionRevision++
}

func input_snapshot(snapshot screen.Snapshot, region screen.Region) screen.Snapshot {
	snapshot.Cells = slices.Clone(snapshot.Cells)
	for row := range snapshot.Rows {
		for col := range snapshot.Cols {
			if !region.Contains(col, row, snapshot.Cols) {
				snapshot.Cells[row*snapshot.Cols+col] = ' '
			}
		}
	}
	return snapshot
}