// 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

import (
	"strconv"
	"unicode"

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

type TableCell struct {
	start, end int // trimmed, half-open Unicode cell bounds; empty cells retained
}

// Match Python's delimiter preference and two-or-more-space aligned columns.
// Bounds come directly from screen positions, never byte offsets or searches
// for cell text (which can repeat within a row).
func table_cells(line []rune) []TableCell {
	end := len(line)
	for end > 0 && (line[end-1] == ' ' || line[end-1] == 0) {
		end--
	}
	if end == 0 {
		return nil
	}
	separator := table_separator(line[:end])
	var cells []TableCell
	appendCell := func(start, end int) {
		for start < end && unicode.IsSpace(line[start]) {
			start++
		}
		for end > start && unicode.IsSpace(line[end-1]) {
			end--
		}
		cells = append(cells, TableCell{start: start, end: end})
	}
	start := 0
	for index := 0; index < end; index++ {
		if separator != 0 {
			if line[index] == separator {
				appendCell(start, index)
				start = index + 1
			}
			continue
		}
		if line[index] != ' ' {
			continue
		}
		gap := index
		for index+1 < end && line[index+1] == ' ' {
			index++
		}
		if index-gap >= 1 {
			// Leading indentation is not an empty aligned column.
			if gap > start {
				appendCell(start, gap)
			}
			start = index + 1
		}
	}
	appendCell(start, end)
	return cells
}

func (r *Review) Set_table_mode(enabled bool) {
	if r.tableMode == enabled {
		return
	}
	r.tableMode = enabled
	r.tableHeaders = nil
	r.tableLayout = tableLayout{}
	r.tableManual, r.tableAutoDisabled = false, false
	if enabled && r.ready {
		r.sync_table_column()
	}
}

func (r *Review) sync_table_column() {
	cells := r.current_table_cells()
	r.tableColumn = 0
	for index, cell := range cells {
		if r.x < cell.start {
			break
		}
		r.tableColumn = index
	}
}

func (r *Review) column_header() string {
	if r.tableColumn < len(r.tableHeaders) && r.tableHeaders[r.tableColumn] != "" {
		return r.tableHeaders[r.tableColumn]
	}
	// Python's generic column label is not a gettext message ID.
	return "Column " + strconv.Itoa(r.tableColumn+1)
}

func (r *Review) table_cell_text(cells []TableCell) string {
	cell := cells[r.tableColumn]
	text := string(r.screen.Line(r.y)[cell.start:cell.end])
	if text == "" {
		text = i18n.T("blank")
	}
	return text + " " + r.column_header()
}

func (r *Review) set_table_headers() presentation.Message {
	layout := r.layout_at(r.y)
	cells := layout.cells(r.screen.Line(r.y))
	if len(cells) == 0 {
		return presentation.Message{Text: i18n.T("could not set header row")}
	}
	r.tableHeaders = nil
	r.tableLayout, r.tableManual = layout, true
	for _, cell := range cells {
		r.tableHeaders = append(r.tableHeaders, string(r.screen.Line(r.y)[cell.start:cell.end]))
	}
	return presentation.Message{Text: i18n.T("header row set"), Cue: presentation.PlaceStartMark}
}

func (r *Review) table_command(id command.ID) (string, bool) {
	switch id {
	case command.CurrentWord, command.PreviousWord, command.NextWord, command.LineStart, command.LineEnd,
		command.CurrentChar, command.PreviousChar, command.NextChar, command.FirstText, command.LastText:
	default:
		return "", false
	}
	cells := r.current_table_cells()
	if len(cells) == 0 {
		return i18n.T("no table data"), true
	}
	if id == command.LineStart {
		r.tableColumn = 0
	} else if id == command.LineEnd {
		r.tableColumn = len(cells) - 1
	}
	if r.tableColumn >= len(cells) {
		return i18n.T("no table data"), true
	}
	switch id {
	case command.CurrentWord:
		return r.table_cell_text(cells), true
	case command.PreviousWord, command.NextWord, command.LineStart, command.LineEnd:
		boundary := ""
		switch id {
		case command.PreviousWord:
			if r.tableColumn == 0 {
				boundary = i18n.T("start of line")
				r.result.After.Cue = presentation.LineStart
			} else {
				r.tableColumn--
			}
		case command.NextWord:
			if r.tableColumn == len(cells)-1 {
				boundary = i18n.T("end of line")
				r.result.After.Cue = presentation.LineEnd
			} else {
				r.tableColumn++
			}
		case command.LineStart:
			r.tableColumn = 0
		case command.LineEnd:
			r.tableColumn = len(cells) - 1
		}
		r.x = min(cells[r.tableColumn].start, r.screen.Cols-1)
		text := r.table_cell_text(cells)
		if boundary != "" {
			r.result.After.Text = boundary
		} else if id == command.LineStart {
			r.result.After.Text = i18n.T("first cell")
		} else if id == command.LineEnd {
			r.result.After.Text = i18n.T("last cell")
		}
		return text, true
	}
	cell := cells[r.tableColumn]
	first, last := min(cell.start, r.screen.Cols-1), max(cell.start, cell.end-1)
	last = min(last, r.screen.Cols-1)
	if r.x < first || r.x > last {
		r.x = first
	}
	character := func() string {
		if cell.start == cell.end {
			r.result.Cue = presentation.Blank
			return i18n.T("blank")
		}
		return r.currentCharacter()
	}
	switch id {
	case command.PreviousChar:
		if r.x == first {
			r.result.After.Text, r.result.After.Cue = i18n.T("start of cell"), presentation.LineStart
			return character(), true
		}
		r.x--
	case command.NextChar:
		if r.x == last {
			r.result.After.Text, r.result.After.Cue = i18n.T("end of cell"), presentation.LineEnd
			return character(), true
		}
		r.x++
	case command.FirstText:
		r.x = first
		return character() + " " + i18n.Format("first character in cell {0}", r.column_header()), true
	case command.LastText:
		r.x = last
		return character() + " " + i18n.Format("last character in cell {0}", r.column_header()), true
	}
	return character(), true
}