/*
 * Copyright (c) 2002-2020, the original author or authors.
 *
 * This software is distributable under the BSD license. See the terms of the
 * BSD license in the documentation provided with this software.
 *
 * https://opensource.org/licenses/BSD-3-Clause
 */
package jdk.internal.org.jline.utils;

import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.stream.Collectors;

import jdk.internal.org.jline.terminal.Terminal;
import jdk.internal.org.jline.utils.InfoCmp.Capability;

Handle display and visual cursor.
Author:
Guillaume Nodet/**
 * Handle display and visual cursor.
 *
 * @author <a href="mailto:gnodet@gmail.com">Guillaume Nodet</a>
 */
public class Display {

    
OpenJDK:
When true, when the cursor is moved to column 0, carriage_return capability is not used,
but rather the cursor is moved left the appropriate number of positions.
This is useful when there's something already printed on the first line (which is not
specified as a prompt), for example when the user is providing an input.
/**OpenJDK:
     * When true, when the cursor is moved to column 0, carriage_return capability is not used,
     * but rather the cursor is moved left the appropriate number of positions.
     * This is useful when there's something already printed on the first line (which is not
     * specified as a prompt), for example when the user is providing an input.
     */
    public static boolean DISABLE_CR = false;

    protected final Terminal terminal;
    protected final boolean fullScreen;
    protected List<AttributedString> oldLines = Collections.emptyList();
    protected int cursorPos;
    private int columns;
    private int columns1; // columns+1
    protected int rows;
    protected boolean reset;
    protected boolean delayLineWrap;

    protected final Map<Capability, Integer> cost = new HashMap<>();
    protected final boolean canScroll;
    protected final boolean wrapAtEol;
    protected final boolean delayedWrapAtEol;
    protected final boolean cursorDownIsNewLine;

    public Display(Terminal terminal, boolean fullscreen) {
        this.terminal = terminal;
        this.fullScreen = fullscreen;

        this.canScroll = can(Capability.insert_line, Capability.parm_insert_line)
                            && can(Capability.delete_line, Capability.parm_delete_line);
        this.wrapAtEol = terminal.getBooleanCapability(Capability.auto_right_margin);
        this.delayedWrapAtEol = this.wrapAtEol
            && terminal.getBooleanCapability(Capability.eat_newline_glitch);
        this.cursorDownIsNewLine = "\n".equals(Curses.tputs(terminal.getStringCapability(Capability.cursor_down)));
    }

    
If cursor is at right margin, don't wrap immediately.
See org.jline.reader.LineReader.Option#DELAY_LINE_WRAP.
Returns:
true if line wrap is delayed, false otherwise/**
     * If cursor is at right margin, don't wrap immediately.
     * See <code>org.jline.reader.LineReader.Option#DELAY_LINE_WRAP</code>.
     * @return <code>true</code> if line wrap is delayed, <code>false</code> otherwise
     */
    public boolean delayLineWrap() {
        return delayLineWrap;
    }
    public void setDelayLineWrap(boolean v) { delayLineWrap = v; }

    public void resize(int rows, int columns) {
        if (this.rows != rows || this.columns != columns) {
            this.rows = rows;
            this.columns = columns;
            this.columns1 = columns + 1;
            oldLines = AttributedString.join(AttributedString.EMPTY, oldLines).columnSplitLength(columns, true, delayLineWrap());
        }
    }

    public void reset() {
        oldLines = Collections.emptyList();
    }

    
Clears the whole screen.
Use this method only when using full-screen / application mode.
/**
     * Clears the whole screen.
     * Use this method only when using full-screen / application mode.
     */
    public void clear() {
        if (fullScreen) {
            reset = true;
        }
    }

    public void updateAnsi(List<String> newLines, int targetCursorPos) {
        update(newLines.stream().map(AttributedString::fromAnsi).collect(Collectors.toList()), targetCursorPos);
    }

    
Update the display according to the new lines and flushes the output.
Params:
newLines – the lines to display
targetCursorPos – desired cursor position - see Size.cursorPos./**
     * Update the display according to the new lines and flushes the output.
     * @param newLines the lines to display
     * @param targetCursorPos desired cursor position - see Size.cursorPos.
     */
    public void update(List<AttributedString> newLines, int targetCursorPos) {
        update(newLines, targetCursorPos, true);
    }

    
Update the display according to the new lines.
Params:
newLines – the lines to display
targetCursorPos – desired cursor position - see Size.cursorPos.
flush – whether the output should be flushed or not/**
     * Update the display according to the new lines.
     * @param newLines the lines to display
     * @param targetCursorPos desired cursor position - see Size.cursorPos.
     * @param flush whether the output should be flushed or not
     */
    public void update(List<AttributedString> newLines, int targetCursorPos, boolean flush) {
        if (reset) {
            terminal.puts(Capability.clear_screen);
            oldLines.clear();
            cursorPos = 0;
            reset = false;
        }

        // If dumb display, get rid of ansi sequences now
        Integer cols = terminal.getNumericCapability(Capability.max_colors);
        if (cols == null || cols < 8) {
            newLines = newLines.stream().map(s -> new AttributedString(s.toString()))
                    .collect(Collectors.toList());
        }

        // Detect scrolling
        if ((fullScreen || newLines.size() >= rows) && newLines.size() == oldLines.size() && canScroll) {
            int nbHeaders = 0;
            int nbFooters = 0;
            // Find common headers and footers
            int l = newLines.size();
            while (nbHeaders < l
                   && Objects.equals(newLines.get(nbHeaders), oldLines.get(nbHeaders))) {
                nbHeaders++;
            }
            while (nbFooters < l - nbHeaders - 1
                    && Objects.equals(newLines.get(newLines.size() - nbFooters - 1), oldLines.get(oldLines.size() - nbFooters - 1))) {
                nbFooters++;
            }
            List<AttributedString> o1 = newLines.subList(nbHeaders, newLines.size() - nbFooters);
            List<AttributedString> o2 = oldLines.subList(nbHeaders, oldLines.size() - nbFooters);
            int[] common = longestCommon(o1, o2);
            if (common != null) {
                int s1 = common[0];
                int s2 = common[1];
                int sl = common[2];
                if (sl > 1 && s1 < s2) {
                    moveVisualCursorTo((nbHeaders + s1) * columns1);
                    int nb = s2 - s1;
                    deleteLines(nb);
                    for (int i = 0; i < nb; i++) {
                        oldLines.remove(nbHeaders + s1);
                    }
                    if (nbFooters > 0) {
                        moveVisualCursorTo((nbHeaders + s1 + sl) * columns1);
                        insertLines(nb);
                        for (int i = 0; i < nb; i++) {
                            oldLines.add(nbHeaders + s1 + sl, new AttributedString(""));
                        }
                    }
                } else if (sl > 1 && s1 > s2) {
                    int nb = s1 - s2;
                    if (nbFooters > 0) {
                        moveVisualCursorTo((nbHeaders + s2 + sl) * columns1);
                        deleteLines(nb);
                        for (int i = 0; i < nb; i++) {
                            oldLines.remove(nbHeaders + s2 + sl);
                        }
                    }
                    moveVisualCursorTo((nbHeaders + s2) * columns1);
                    insertLines(nb);
                    for (int i = 0; i < nb; i++) {
                        oldLines.add(nbHeaders + s2, new AttributedString(""));
                    }
                }
            }
        }

        int lineIndex = 0;
        int currentPos = 0;
        int numLines = Math.max(oldLines.size(), newLines.size());
        boolean wrapNeeded = false;
        while (lineIndex < numLines) {
            AttributedString oldLine =
                lineIndex < oldLines.size() ? oldLines.get(lineIndex)
                : AttributedString.NEWLINE;
            AttributedString newLine =
                 lineIndex < newLines.size() ? newLines.get(lineIndex)
                : AttributedString.NEWLINE;
            currentPos = lineIndex * columns1;
            int curCol = currentPos;
            int oldLength = oldLine.length();
            int newLength = newLine.length();
            boolean oldNL = oldLength > 0 && oldLine.charAt(oldLength-1)=='\n';
            boolean newNL = newLength > 0 && newLine.charAt(newLength-1)=='\n';
            if (oldNL) {
                oldLength--;
                oldLine = oldLine.substring(0, oldLength);
            }
            if (newNL) {
                newLength--;
                newLine = newLine.substring(0, newLength);
            }
            if (wrapNeeded
                && lineIndex == (cursorPos + 1) / columns1
                && lineIndex < newLines.size()) {
                // move from right margin to next line's left margin
                cursorPos++;
                if (newLength == 0 || newLine.isHidden(0)) {
                    // go to next line column zero
                    rawPrint(new AttributedString(" \b"));
                } else {
                    AttributedString firstChar = newLine.substring(0, 1);
                    // go to next line column one
                    rawPrint(firstChar);
                    cursorPos += firstChar.columnLength(); // normally 1
                    newLine = newLine.substring(1, newLength);
                    newLength--;
                    if (oldLength > 0) {
                        oldLine = oldLine.substring(1, oldLength);
                        oldLength--;
                    }
                    currentPos = cursorPos;
                }
            }
            List<DiffHelper.Diff> diffs = DiffHelper.diff(oldLine, newLine);
            boolean ident = true;
            boolean cleared = false;
            for (int i = 0; i < diffs.size(); i++) {
                DiffHelper.Diff diff = diffs.get(i);
                int width = diff.text.columnLength();
                switch (diff.operation) {
                    case EQUAL:
                        if (!ident) {
                            cursorPos = moveVisualCursorTo(currentPos);
                            rawPrint(diff.text);
                            cursorPos += width;
                            currentPos = cursorPos;
                        } else {
                            currentPos += width;
                        }
                        break;
                    case INSERT:
                        if (i <= diffs.size() - 2
                                && diffs.get(i + 1).operation == DiffHelper.Operation.EQUAL) {
                            cursorPos = moveVisualCursorTo(currentPos);
                            if (insertChars(width)) {
                                rawPrint(diff.text);
                                cursorPos += width;
                                currentPos = cursorPos;
                                break;
                            }
                        } else if (i <= diffs.size() - 2
                                && diffs.get(i + 1).operation == DiffHelper.Operation.DELETE
                                && width == diffs.get(i + 1).text.columnLength()) {
                            moveVisualCursorTo(currentPos);
                            rawPrint(diff.text);
                            cursorPos += width;
                            currentPos = cursorPos;
                            i++; // skip delete
                            break;
                        }
                        moveVisualCursorTo(currentPos);
                        rawPrint(diff.text);
                        cursorPos += width;
                        currentPos = cursorPos;
                        ident = false;
                        break;
                    case DELETE:
                        if (cleared) {
                            continue;
                        }
                        if (currentPos - curCol >= columns) {
                            continue;
                        }
                        if (i <= diffs.size() - 2
                                && diffs.get(i + 1).operation == DiffHelper.Operation.EQUAL) {
                            if (currentPos + diffs.get(i + 1).text.columnLength() < columns) {
                                moveVisualCursorTo(currentPos);
                                if (deleteChars(width)) {
                                    break;
                                }
                            }
                        }
                        int oldLen = oldLine.columnLength();
                        int newLen = newLine.columnLength();
                        int nb = Math.max(oldLen, newLen) - (currentPos - curCol);
                        moveVisualCursorTo(currentPos);
                        if (!terminal.puts(Capability.clr_eol)) {
                            rawPrint(' ', nb);
                            cursorPos += nb;
                        }
                        cleared = true;
                        ident = false;
                        break;
                }
            }
            lineIndex++;
            boolean newWrap = ! newNL && lineIndex < newLines.size();
            if (targetCursorPos + 1 == lineIndex * columns1
                && (newWrap || ! delayLineWrap))
                targetCursorPos++;
            boolean atRight = (cursorPos - curCol) % columns1 == columns;
            wrapNeeded = false;
            if (this.delayedWrapAtEol) {
                boolean oldWrap = ! oldNL && lineIndex < oldLines.size();
                if (newWrap != oldWrap && ! (oldWrap && cleared)) {
                    moveVisualCursorTo(lineIndex*columns1-1, newLines);
                    if (newWrap)
                        wrapNeeded = true;
                    else
                        terminal.puts(Capability.clr_eol);
                }
            } else if (atRight) {
                if (this.wrapAtEol) {
                    terminal.writer().write(" \b");
                    cursorPos++;
                } else {
                    terminal.puts(Capability.carriage_return); // CR / not newline.
                    cursorPos = curCol;
                }
                currentPos = cursorPos;
            }
        }
        if (cursorPos != targetCursorPos) {
            moveVisualCursorTo(targetCursorPos < 0 ? currentPos : targetCursorPos, newLines);
        }
        oldLines = newLines;

        if (flush) {
            terminal.flush();
        }
    }

    protected boolean deleteLines(int nb) {
        return perform(Capability.delete_line, Capability.parm_delete_line, nb);
    }

    protected boolean insertLines(int nb) {
        return perform(Capability.insert_line, Capability.parm_insert_line, nb);
    }

    protected boolean insertChars(int nb) {
        return perform(Capability.insert_character, Capability.parm_ich, nb);
    }

    protected boolean deleteChars(int nb) {
        return perform(Capability.delete_character, Capability.parm_dch, nb);
    }

    protected boolean can(Capability single, Capability multi) {
        return terminal.getStringCapability(single) != null
                || terminal.getStringCapability(multi) != null;
    }

    protected boolean perform(Capability single, Capability multi, int nb) {
        boolean hasMulti = terminal.getStringCapability(multi) != null;
        boolean hasSingle = terminal.getStringCapability(single) != null;
        if (hasMulti && (!hasSingle || cost(single) * nb > cost(multi))) {
            terminal.puts(multi, nb);
            return true;
        } else if (hasSingle) {
            for (int i = 0; i < nb; i++) {
                terminal.puts(single);
            }
            return true;
        } else {
            return false;
        }
    }

    private int cost(Capability cap) {
        return cost.computeIfAbsent(cap, this::computeCost);
    }

    private int computeCost(Capability cap) {
        String s = Curses.tputs(terminal.getStringCapability(cap), 0);
        return s != null ? s.length() : Integer.MAX_VALUE;
    }

    private static int[] longestCommon(List<AttributedString> l1, List<AttributedString> l2) {
        int start1 = 0;
        int start2 = 0;
        int max = 0;
        for (int i = 0; i < l1.size(); i++) {
            for (int j = 0; j < l2.size(); j++) {
                int x = 0;
                while (Objects.equals(l1.get(i + x), l2.get(j + x))) {
                    x++;
                    if (((i + x) >= l1.size()) || ((j + x) >= l2.size())) break;
                }
                if (x > max) {
                    max = x;
                    start1 = i;
                    start2 = j;
                }
            }
        }
        return max != 0 ? new int[] { start1, start2, max } : null;
    }

    /*
     * Move cursor from cursorPos to argument, updating cursorPos
     * We're at the right margin if {@code (cursorPos % columns1) == columns}.
     * This method knows how to move both *from* and *to* the right margin.
     */
    protected void moveVisualCursorTo(int targetPos,
                                      List<AttributedString> newLines) {
        if (cursorPos != targetPos) {
            boolean atRight = (targetPos % columns1) == columns;
            moveVisualCursorTo(targetPos - (atRight ? 1 : 0));
            if (atRight) {
                // There is no portable way to move to the right margin
                // except by writing a character in the right-most column.
                int row = targetPos / columns1;
                AttributedString lastChar = row >= newLines.size() ? AttributedString.EMPTY
                    : newLines.get(row).columnSubSequence(columns-1, columns);
                if (lastChar.length() == 0)
                    rawPrint((int) ' ');
                else
                    rawPrint(lastChar);
                cursorPos++;
            }
        }
    }

    /*
     * Move cursor from cursorPos to argument, updating cursorPos
     * We're at the right margin if {@code (cursorPos % columns1) == columns}.
     * This method knows how to move *from* the right margin,
     * but does not know how to move *to* the right margin.
     * I.e. {@code (i1 % columns1) == column} is not allowed.
     */
    protected int moveVisualCursorTo(int i1) {
        int i0 = cursorPos;
        if (i0 == i1) return i1;
        int width = columns1;
        int l0 = i0 / width;
        int c0 = i0 % width;
        int l1 = i1 / width;
        int c1 = i1 % width;
        if (c0 == columns) { // at right margin
            terminal.puts(Capability.carriage_return);
            c0 = 0;
        }
        if (l0 > l1) {
            perform(Capability.cursor_up, Capability.parm_up_cursor, l0 - l1);
        } else if (l0 < l1) {
            // TODO: clean the following
            if (fullScreen) {
                if (!terminal.puts(Capability.parm_down_cursor, l1 - l0)) {
                    for (int i = l0; i < l1; i++) {
                        terminal.puts(Capability.cursor_down);
                    }
                    if (cursorDownIsNewLine) {
                        c0 = 0;
                    }
                }
            } else {
                terminal.puts(Capability.carriage_return);
                rawPrint('\n', l1 - l0);
                c0 = 0;
            }
        }
        if (c0 != 0 && c1 == 0 && !DISABLE_CR) {
            terminal.puts(Capability.carriage_return);
        } else if (c0 < c1) {
            perform(Capability.cursor_right, Capability.parm_right_cursor, c1 - c0);
        } else if (c0 > c1) {
            perform(Capability.cursor_left, Capability.parm_left_cursor, c0 - c1);
        }
        cursorPos = i1;
        return i1;
    }

    void rawPrint(char c, int num) {
        for (int i = 0; i < num; i++) {
            rawPrint(c);
        }
    }

    void rawPrint(int c) {
        terminal.writer().write(c);
    }

    void rawPrint(AttributedString str) {
        str.print(terminal);
    }

    public int wcwidth(String str) {
        return str != null ? AttributedString.fromAnsi(str).columnLength() : 0;
    }

}