// Fenrir console screen reader.
// Copyright (c) 2026 Storm Dragon
// SPDX-License-Identifier: GPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation, either version 3 of the License, or (at your option)
// any later version.
//
// This program is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
// more details.
//
// You should have received a copy of the GNU General Public License along with
// this program. If not, see <https://www.gnu.org/licenses/gpl-3.0.html>.

// Package review owns the review cursor and actions on a visible screen.
// All state is used by the reader's event loop; actions never perform device or speech I/O.
package review

import (
	"git.stormux.org/storm/fenrir/internal/command"
	"git.stormux.org/storm/fenrir/internal/i18n"
	"git.stormux.org/storm/fenrir/internal/presentation"
	"git.stormux.org/storm/fenrir/internal/screen"
)

// Review has a cursor independent of the application. Its zero value is ready for Update.
type Review struct {
	result                        presentation.CommandResult
	attributeFormat               string
	screen                        screen.Snapshot
	suppressLineBreak             bool
	suppressScreenBoundary        bool
	keepOnScreenChange            bool
	ready                         bool
	reviewing                     bool
	x, y                          int
	markCount, startMark, endMark int
	tableMode                     bool
	tableColumn                   int
	tableHeaders                  []string
	tableLayout                   tableLayout
	tableManual                   bool
	tableAutoDisabled             bool
}

func (r *Review) Configure(lineBreak, endOfScreen, leaveOnScreenChange bool) {
	r.suppressLineBreak = !lineBreak
	r.suppressScreenBoundary = !endOfScreen
	r.keepOnScreenChange = !leaveOnScreenChange
}

// handlers is the explicit list of review actions. Add an action file and an
// entry here; input bindings live separately in package input.
var handlers = map[command.ID]func(*Review) string{
	command.AttributeCursor:    (*Review).attribute_cursor,
	command.CursorLine:         (*Review).cursor_line,
	command.CursorColumn:       (*Review).cursor_column,
	command.LineToCursor:       (*Review).line_to_cursor,
	command.LineFromCursor:     (*Review).line_from_cursor,
	command.ScreenFirstChar:    (*Review).screen_first_character,
	command.ScreenLastChar:     (*Review).screen_last_character,
	command.ScreenBeforeCursor: (*Review).screen_before_cursor,
	command.ScreenAfterCursor:  (*Review).screen_after_cursor,
	command.ReviewUp:           (*Review).review_up,
	command.ReviewDown:         (*Review).review_down,

	command.SpellWord:    (*Review).spell_word,
	command.PhoneticWord: (*Review).phonetic_word,
	command.SpellLine:    (*Review).spell_line,
	command.PhoneticLine: (*Review).phonetic_line,
	command.PhoneticChar: (*Review).phonetic_character,
	command.PreviousLine: (*Review).previousLine,
	command.CurrentLine:  (*Review).currentLine,
	command.NextLine:     (*Review).nextLine,
	command.Top:          (*Review).top,
	command.Bottom:       (*Review).bottom,
	command.PreviousChar: (*Review).previousCharacter,
	command.CurrentChar:  (*Review).currentCharacter,
	command.NextChar:     (*Review).nextCharacter,
	command.LineStart:    (*Review).lineStart,
	command.LineEnd:      (*Review).lineEnd,
	command.FirstText:    (*Review).firstText,
	command.LastText:     (*Review).lastText,
	command.PreviousWord: (*Review).previousWord,
	command.CurrentWord:  (*Review).currentWord,
	command.NextWord:     (*Review).nextWord,
	command.Position:     (*Review).position,
	command.ReadScreen:   (*Review).readScreen,
	command.FollowCursor: (*Review).followCursor,
}

// Update refreshes the screen, applying the configured review-exit policy.
// It reports whether the screen session changed, for automatic reading.
func (r *Review) Update(next screen.Snapshot) bool {
	previous := r.screen
	switched := !r.ready || previous.Terminal != next.Terminal || previous.Generation != next.Generation || previous.Active != next.Active || previous.Rows != next.Rows || previous.Cols != next.Cols
	r.screen = next
	r.ready = next.Active
	if switched {
		r.Clear_marks()
		r.tableHeaders = nil
		r.tableLayout = tableLayout{}
		r.tableManual, r.tableAutoDisabled = false, false
		r.tableColumn = 0
	}
	if !next.Active {
		r.reviewing = false
		return switched
	}
	if switched && !r.keepOnScreenChange || !r.reviewing {
		r.x, r.y = next.X, next.Y
		if switched {
			r.reviewing = false
		}
	}
	r.x, r.y = max(0, min(r.x, next.Cols-1)), max(0, min(r.y, next.Rows-1))
	if r.tableMode && (switched || !r.reviewing) {
		r.sync_table_column()
	}
	return switched
}

// Active reports whether review is detached from the application cursor.
func (r *Review) Active() bool { return r.reviewing }

// Execute checks screen availability before invoking an action. Action methods
// share this guard; the caller owns presentation and interruption.
func (r *Review) Execute(id command.ID) presentation.CommandResult {
	r.result = presentation.CommandResult{}
	r.result.Text = r.execute(id)
	return r.result
}

func (r *Review) execute(id command.ID) string {
	if !r.ready {
		r.result.Cue = presentation.Error
		return i18n.T("no text console")
	}
	action, ok := handlers[id]
	if !ok {
		r.result.Cue = presentation.Error
		return i18n.T("unbound")
	}
	switch id {
	case command.AttributeCursor, command.CursorLine, command.CursorColumn, command.LineToCursor, command.LineFromCursor, command.FollowCursor:
		// Reports use the active cursor without entering detached review.
	default:
		if !r.reviewing {
			r.start_table_review()
		}
		r.reviewing = true
	}
	if r.tableMode {
		if text, handled := r.table_command(id); handled {
			return text
		}
	}
	return action(r)
}