tsvm/assets/disk0/tvdos/include/playgui.mjs

// Common GUI for media player
// Created by CuriousTorvald on 2025-09-30.

// Subtitle display functions
function clearSubtitleArea() {
    // Clear the subtitle area at the bottom of the screen
    // Text mode is 80x32, so clear the bottom few lines
    let oldFgColour = con.get_color_fore()
    let oldBgColour = con.get_color_back()

    con.color_pair(255, 255)  // transparent to clear

    // Clear bottom 4 lines for subtitles
    for (let row = 28; row <= 31; row++) {
        con.move(row, 1)
        for (let col = 1; col <= 80; col++) {
            print(" ")
        }
    }

    con.color_pair(oldFgColour, oldBgColour)
}

function getVisualLength(line) {
    // Calculate the visual length of a line excluding formatting tags
    let visualLength = 0
    let i = 0

    while (i < line.length) {
        if (i < line.length - 2 && line[i] === '<') {
            // Check for formatting tags and skip them
            if (line.substring(i, i + 3).toLowerCase() === '<b>' ||
                line.substring(i, i + 3).toLowerCase() === '<i>') {
                i += 3  // Skip tag
            } else if (i < line.length - 3 &&
                      (line.substring(i, i + 4).toLowerCase() === '</b>' ||
                       line.substring(i, i + 4).toLowerCase() === '</i>')) {
                i += 4  // Skip closing tag
            } else {
                // Not a formatting tag, count the character
                visualLength++
                i++
            }
        } else {
            // Regular character, count it
            visualLength++
            i++
        }
    }

    return visualLength
}

function displayFormattedLine(line) {
    // Parse line and handle <b> and <i> tags with colour changes
    // Default subtitle colour: yellow (231), formatted text: white (254)

    let i = 0
    let inBoldOrItalic = false

    // insert initial padding block
    con.color_pair(0, 255)
    con.prnch(0xDE)
    con.color_pair(231, 0)

    while (i < line.length) {
        if (i < line.length - 2 && line[i] === '<') {
            // Check for opening tags
            if (line.substring(i, i + 3).toLowerCase() === '<b>' ||
                line.substring(i, i + 3).toLowerCase() === '<i>') {
                con.color_pair(254, 0)  // Switch to white for formatted text
                inBoldOrItalic = true
                i += 3
            } else if (i < line.length - 3 &&
                      (line.substring(i, i + 4).toLowerCase() === '</b>' ||
                       line.substring(i, i + 4).toLowerCase() === '</i>')) {
                con.color_pair(231, 0)  // Switch back to yellow for normal text
                inBoldOrItalic = false
                i += 4
            } else {
                // Not a formatting tag, print the character
                print(line[i])
                i++
            }
        } else {
            // Regular character, print it
            print(line[i])
            i++
        }
    }

    // insert final padding block
    con.color_pair(0, 255)
    con.prnch(0xDD)
    con.color_pair(231, 0)
}

function displaySubtitle(text, position = 0) {
    if (!text || text.length === 0) {
        clearSubtitleArea()
        return
    }

    // Set subtitle colours: yellow (231) on black (0)
    let oldFgColour = con.get_color_fore()
    let oldBgColour = con.get_color_back()
    con.color_pair(231, 0)

    // Split text into lines
    let lines = text.split('\n')

    // Calculate position based on subtitle position setting
    let startRow, startCol
    // Calculate visual length without formatting tags for positioning
    let longestLineLength = lines.map(s => getVisualLength(s)).sort().last()

    switch (position) {
        case 2: // center left
        case 6: // center right
        case 8: // dead center
            startRow = 16 - Math.floor(lines.length / 2)
            break
        case 3: // top left
        case 4: // top center
        case 5: // top right
            startRow = 2
            break
        case 0: // bottom center
        case 1: // bottom left
        case 7: // bottom right
        default:
            startRow = 31 - lines.length
            startRow = 31 - lines.length
            startRow = 31 - lines.length  // Default to bottom center
    }

    // Display each line
    for (let i = 0; i < lines.length; i++) {
        let line = lines[i].trim()
        if (line.length === 0) continue

        let row = startRow + i
        if (row < 1) row = 1
        if (row > 32) row = 32

        // Calculate column based on alignment
        switch (position) {
            case 1: // bottom left
            case 2: // center left
            case 3: // top left
                startCol = 1
                break
            case 5: // top right
            case 6: // center right
            case 7: // bottom right
                startCol = Math.max(1, 78 - getVisualLength(line) - 2)
                break
            case 0: // bottom center
            case 4: // top center
            case 8: // dead center
            default:
                startCol = Math.max(1, Math.floor((80 - longestLineLength - 2) / 2) + 1)
                break
        }

        con.move(row, startCol)

        // Parse and display line with formatting tag support
        displayFormattedLine(line)
    }

    con.color_pair(oldFgColour, oldBgColour)
}

exports = {
    clearSubtitleArea,
    displaySubtitle
}