<?php

namespace NoccyLabs\JsonEdit\Editor;

use NoccyLabs\JsonEdit\Terminal\Terminal;

class MessageBox
{
    
    const U_CORNER_TOPLEFT = "\u{250c}";
    const U_CORNER_TOPRIGHT = "\u{2510}";
    const U_CORNER_BOTTOMLEFT = "\u{2514}";
    const U_CORNER_BOTTOMRIGHT = "\u{2518}";

    const U_CORNER_ROUNDED_TOPLEFT = "\u{256d}";
    const U_CORNER_ROUNDED_TOPRIGHT = "\u{256e}";
    const U_CORNER_ROUNDED_BOTTOMLEFT = "\u{2570}";
    const U_CORNER_ROUNDED_BOTTOMRIGHT = "\u{256f}";

    const U_EDGE_HORIZONTAL = "\u{2500}";

    const U_EDGE_VERTICAL = "\u{2502}";
    const U_EDGE_VERTICAL_SCROLL = "\u{2591}";
    const U_EDGE_VERTICAL_THUMB = "\u{2593}";
    const U_EDGE_VERTICAL_LEFT = "\u{2524}";
    const U_EDGE_VERTICAL_RIGHT = "\u{251c}";

    private int $scroll = 0;

    public function __construct(private Terminal $terminal, private string $text, private string $title = 'Message')
    {
    }

    public function display(int $left, int $top, int $width, int $height = 0): void
    {
        $wrapped = explode("\n", wordwrap($this->text, $width - 4, cut_long_words:true));
        
        if ($height == 0) $height = count($wrapped) + 4;
        
        $maxScroll = (count($wrapped) > $height) ? count($wrapped) - $height + 4 : 0;

        $this->redraw($left, $top, $width, $height, $wrapped, $this->title, $maxScroll);

        $showing = true;
        while ($showing) {
            while (null === ($ch = $this->terminal->readKey())) {
                usleep(10000);
            }
            if (mb_strlen($ch) == 1) {
                if ($ch == "\x03") {
                    $showing = false;
                }
            } else {
                if ($ch == "k{UP}") {
                    $this->scroll--;
                    if ($this->scroll < 0) $this->scroll = 0;
                    $this->redraw($left, $top, $width, $height, $wrapped, $this->title, $maxScroll);
                } elseif ($ch == "k{DOWN}") {
                    $this->scroll++;
                    if ($this->scroll > $maxScroll) $this->scroll = $maxScroll; 
                    $this->redraw($left, $top, $width, $height, $wrapped, $this->title, $maxScroll);
                }
            }
        }


        return;
    }

    private function redraw(int $left, int $top, int $width, int $height, array $wrapped, string $title, int $maxScroll) {
        $visibleItems = $height - 4;

        // calculate scrollbar thumb positions
        $scrollTop = ($this->scroll / ($maxScroll + $visibleItems));
        $scrollVisible = $visibleItems / count($wrapped); // / $visibleItems;
        $scrollBottom = $scrollTop + $scrollVisible;
        $thumbTop = round($scrollTop * $visibleItems);
        $thumbBottom = round($visibleItems * $scrollBottom);

        echo "\e[40;37m";
        $this->terminal
            ->writeAt($left, $top + 0, self::U_CORNER_ROUNDED_TOPLEFT.str_repeat(self::U_EDGE_HORIZONTAL,$width - 2).self::U_CORNER_ROUNDED_TOPRIGHT)
            ->writeAt($left, $top + 1, self::U_EDGE_VERTICAL.str_repeat(" ",$width - 2).self::U_EDGE_VERTICAL)
            ->writeAt($left + 2, $top + 1, "\e[1m" . $this->title . "\e[22m")
            ->writeAt($left, $top + 2, self::U_EDGE_VERTICAL_RIGHT.str_repeat(self::U_EDGE_HORIZONTAL,$width - 2).self::U_EDGE_VERTICAL_LEFT)
            ->writeAt($left, $top + $height - 1, self::U_CORNER_BOTTOMLEFT.str_repeat(self::U_EDGE_HORIZONTAL,$width - 2).self::U_CORNER_BOTTOMRIGHT)
            ;
        for ($n = 0; $n < $visibleItems; $n++) {
            if (isset($wrapped[$n+$this->scroll])) {
                $line = $wrapped[$n+$this->scroll]??null;
                if (str_starts_with($line, "# ")) {
                    $item = " " . mb_substr($line, 2);
                    $pre = "\e[1;4m"; $post = "\e[22;24m";
                } elseif (str_starts_with($line, "## ")) {
                    $item = " " . mb_substr($line, 3);
                    $pre = "\e[1m"; $post = "\e[22m";
                } elseif (str_starts_with($line, "### ")) {
                    $item = " " . mb_substr($line, 4);
                    $pre = "\e[1;3m"; $post = "\e[23m";
                } else {
                    $item = " " . $line;
                    $pre = null; $post = null;
                }
                $item = $item . str_repeat(" ", $width - 2 - mb_strlen($item)) . "\e[40;37m";
            } else {
                $item = str_repeat(" ", $width - 2)."\e[40;37m";
            }
            $item = $pre . $item . $post;
            if ($n >= $thumbTop && $n <= $thumbBottom) {
                $scrollbar = "\e[97;1m".self::U_EDGE_VERTICAL_THUMB."\e[40;37;22m";
            } else {
                $scrollbar = "\e[37;2m".self::U_EDGE_VERTICAL_SCROLL."\e[40;37;22m";
            }
            $this->terminal
                ->writeAt($left, $top + 3 + $n, self::U_EDGE_VERTICAL.$item.$scrollbar);
        }

        echo "\e[0m";
    }

}