R/mod_welcome.R

In bayprior: Bayesian Prior Elicitation and Diagnostics for Clinical Trials

#' @noRd
mod_welcome_ui <- function(id) {
  ns <- NS(id)
  fluidRow(
    shinydashboard::box(
      width = 8, status = "primary", solidHeader = TRUE,
      title = tagList(icon("house"), " Welcome to bayprior"),
      tags$p(class = "lead",
        "A structured toolkit for Bayesian prior elicitation, conflict
         diagnostics, and sensitivity analysis \u2014 informed by the FDA's
         2026 draft guidance and EMA's 2026 concept paper on Bayesian
         methods in clinical development."
      ),
      tags$hr(),
      tags$h5("Analytical Workflow"),

      # -- SVG Workflow Diagram --------------------------------------------
      tags$div(
        style = "overflow-x: auto; padding: 6px 0 16px;",
        HTML('
<svg viewBox="0 0 860 130" xmlns="http://www.w3.org/2000/svg"
     style="width:100%; max-width:860px; font-family:Arial,sans-serif;">
  <defs>
    <marker id="arr" markerWidth="8" markerHeight="8" refX="7" refY="3"
            orient="auto">
      <path d="M0,0 L0,6 L8,3 z" fill="#adb5bd"/>
    </marker>
  </defs>

  <!-- Step boxes -->
  <!-- 1 Elicitation -->
  <rect x="2"   y="30" width="112" height="64" rx="8" fill="#185FA5"/>
  <text x="58"  y="55" text-anchor="middle" fill="white" font-size="11"
        font-weight="bold">1. Elicitation</text>
  <text x="58"  y="70" text-anchor="middle" fill="#b0c8e0" font-size="9">
    Beta . Normal . Gamma</text>
  <text x="58"  y="82" text-anchor="middle" fill="#b0c8e0" font-size="9">
    LogNormal . Exp . Weibull</text>

  <!-- 2 Pooling -->
  <rect x="134" y="30" width="112" height="64" rx="8" fill="#1D9E75"/>
  <text x="190" y="55" text-anchor="middle" fill="white" font-size="11"
        font-weight="bold">2. Pooling</text>
  <text x="190" y="70" text-anchor="middle" fill="#cef5e8" font-size="9">
    Linear . Logarithmic</text>
  <text x="190" y="82" text-anchor="middle" fill="#cef5e8" font-size="9">
    Bhattacharyya checks</text>

  <!-- 3 Conflict -->
  <rect x="266" y="30" width="112" height="64" rx="8" fill="#D85A30"/>
  <text x="322" y="55" text-anchor="middle" fill="white" font-size="11"
        font-weight="bold">3. Conflict</text>
  <text x="322" y="70" text-anchor="middle" fill="#fdd5c6" font-size="9">
    Box p . Surprise . KL</text>
  <text x="322" y="82" text-anchor="middle" fill="#fdd5c6" font-size="9">
    Overlap . Mahalanobis</text>

  <!-- 4 Sensitivity -->
  <rect x="398" y="30" width="112" height="64" rx="8" fill="#6C63FF"/>
  <text x="454" y="55" text-anchor="middle" fill="white" font-size="11"
        font-weight="bold">4. Sensitivity</text>
  <text x="454" y="70" text-anchor="middle" fill="#d8d6ff" font-size="9">
    Grid . Tornado</text>
  <text x="454" y="82" text-anchor="middle" fill="#d8d6ff" font-size="9">
    Heatmap . CrI width</text>

  <!-- 5 Robust -->
  <rect x="530" y="30" width="112" height="64" rx="8" fill="#0F3460"/>
  <text x="586" y="55" text-anchor="middle" fill="white" font-size="11"
        font-weight="bold">5. Robust</text>
  <text x="586" y="70" text-anchor="middle" fill="#b0c8e0" font-size="9">
    Sceptical . Mixture</text>
  <text x="586" y="82" text-anchor="middle" fill="#b0c8e0" font-size="9">
    Power prior</text>

  <!-- 6 Report -->
  <rect x="662" y="30" width="112" height="64" rx="8" fill="#1A7A4A"/>
  <text x="718" y="55" text-anchor="middle" fill="white" font-size="11"
        font-weight="bold">6. Report</text>
  <text x="718" y="70" text-anchor="middle" fill="#cef5e8" font-size="9">
    HTML . PDF . Word</text>
  <text x="718" y="82" text-anchor="middle" fill="#cef5e8" font-size="9">
    FDA (2026) informed</text>

  <!-- Arrows -->
  <line x1="115" y1="62" x2="132" y2="62" stroke="#adb5bd" stroke-width="2"
        marker-end="url(#arr)"/>
  <line x1="247" y1="62" x2="264" y2="62" stroke="#adb5bd" stroke-width="2"
        marker-end="url(#arr)"/>
  <line x1="379" y1="62" x2="396" y2="62" stroke="#adb5bd" stroke-width="2"
        marker-end="url(#arr)"/>
  <line x1="511" y1="62" x2="528" y2="62" stroke="#adb5bd" stroke-width="2"
        marker-end="url(#arr)"/>
  <line x1="643" y1="62" x2="660" y2="62" stroke="#adb5bd" stroke-width="2"
        marker-end="url(#arr)"/>

  <!-- Step numbers (top) -->
  <text x="58"  y="22" text-anchor="middle" fill="#185FA5"
        font-size="9" font-weight="bold">STEP 1</text>
  <text x="190" y="22" text-anchor="middle" fill="#1D9E75"
        font-size="9" font-weight="bold">STEP 2</text>
  <text x="322" y="22" text-anchor="middle" fill="#D85A30"
        font-size="9" font-weight="bold">STEP 3</text>
  <text x="454" y="22" text-anchor="middle" fill="#6C63FF"
        font-size="9" font-weight="bold">STEP 4</text>
  <text x="586" y="22" text-anchor="middle" fill="#0F3460"
        font-size="9" font-weight="bold">STEP 5</text>
  <text x="718" y="22" text-anchor="middle" fill="#1A7A4A"
        font-size="9" font-weight="bold">STEP 6</text>

  <!-- Footnote -->
  <text x="430" y="120" text-anchor="middle" fill="#adb5bd" font-size="9">
    Steps 2, 3, 4, and 5 are optional - proceed directly to Report when only
    elicitation is required.
  </text>
</svg>
        ')
      ),

      tags$hr(),
      tags$h6("Key references"),
      tags$ul(
        tags$li("O'Hagan et al. (2006). Uncertain Judgements. Wiley."),
        tags$li("Box (1980). JRSS-A 143, 383-430."),
        tags$li("Schmidli et al. (2014). Biometrics 70, 1023-1032."),
        tags$li("Ibrahim & Chen (2000). Statistical Science 15, 46-60."),
        tags$li("FDA (2026). Use of Bayesian Methodology in Clinical Trials
                 of Drug and Biological Products.")
      )
    ),
    column(4,
      shinydashboard::infoBox(
        "Distributions", "6",
        subtitle = "Beta . Normal . Gamma . LogNormal . Exp . Weibull",
        icon = icon("shapes"), color = "blue", fill = TRUE, width = 12),
      shinydashboard::infoBox(
        "Elicitation methods", "3",
        subtitle = "Quantile . Moment . Roulette",
        icon = icon("sliders"), color = "green", fill = TRUE, width = 12),
      shinydashboard::infoBox(
        "Data types", "4",
        subtitle = "Binary . Continuous . Poisson . Survival",
        icon = icon("vial"), color = "orange", fill = TRUE, width = 12),
      shinydashboard::infoBox(
        "Report formats", "3",
        subtitle = "HTML . PDF . Word (.docx)",
        icon = icon("file"), color = "red", fill = TRUE, width = 12)
    )
  )
}

#' @noRd
mod_welcome_server <- function(id) {
  moduleServer(id, function(input, output, session) {})
}