# goal:
# use pandoc -M to change the key: diagram:engine:mermaid:outputFormat to svg or pdf if output is html or pdf.
# use the script at stuff/pandoc-diagram.ps1 to set the env vars and pass the filter to pandoc.
param(
    [Parameter(Mandatory = $true, HelpMessage = "The output type to generate. Must be either 'html' or 'pdf'.")]
    [string]$type,
    [Parameter(Mandatory = $true, HelpMessage = "The input Markdown file to process.")]
    [string]$InputFile = (Join-Path $PSScriptRoot "system-design-implementation.md"),
    [string]$OutputFile = (Join-Path $PSScriptRoot "system-design-implementation.$type"),
    [Parameter(ValueFromRemainingArguments = $true, HelpMessage = "Additional arguments to pass to pandoc.
    
    Notable use: 
    - passing --resource-path to specify the directory where images and other resources are located,
    - passing --pdf-engine=xelatex to specify the PDF engine for PDF output.")]
    [string[]]$RemainingArgs
)
function New-PandocDiagramMetadata([string] $outputFormat) {
    return @{
        "diagram" = @{
            "engine" = @{
                "mermaid" = @{
                    "outputFormat" = "$outputFormat"
                }
            }
        }
    }
} 
# 
if ($type -eq "html") {
    $outputFormat = "svg"
}
elseif ($type -eq "pdf") {
    $outputFormat = "pdf"
}
else {
    Write-Error "Unsupported type: $type. Supported types are: html, pdf."
    exit 1
}

$metadata = New-PandocDiagramMetadata $outputFormat | ConvertTo-Json -Depth 10
$pandoc_diagram = Join-Path $PSScriptRoot "../../stuff/pandoc-diagram.ps1"
if (-not (Test-Path $pandoc_diagram)) {
    Write-Error "pandoc diagram wrapper not found at $pandoc_diagram. Make sure it exists, then rerun this command."
    exit 1
}

function Test-RenderNeedsAgentResults([string[]] $arguments) {
    for ($index = 0; $index -lt $arguments.Count; $index++) {
        $candidate = $null
        if ($arguments[$index] -in @("-i", "--input")) {
            if ($index + 1 -lt $arguments.Count) {
                $candidate = $arguments[$index + 1]
                $index++
            }
        }
        elseif ($arguments[$index].EndsWith(".md")) {
            $candidate = $arguments[$index]
        }
        if (
            $candidate -and
            (Test-Path -LiteralPath $candidate) -and
            (Select-String -LiteralPath $candidate -SimpleMatch "include-agent-challenge-results" -Quiet)
        ) {
            return $true
        }
    }
    return $false
}
. $pandoc_diagram

$pandoc_crossref = Get-Command pandoc-crossref -ErrorAction SilentlyContinue
if (-not $pandoc_crossref) {
    Write-Error "pandoc-crossref is required for Figure cross-references. Install it, then rerun this command."
    exit 1
}

$diagram_filter = Join-Path $PSScriptRoot "../../stuff/diagram.lua"
if (-not (Test-Path $diagram_filter)) {
    Write-Error "diagram.lua filter not found at $diagram_filter. Make sure it exists, then rerun this command."
    exit 1
}

$figure_format_filter = Join-Path $PSScriptRoot "figure-format.lua"
if (-not (Test-Path $figure_format_filter)) {
    Write-Error "figure-format.lua filter not found at $figure_format_filter. Make sure it exists, then rerun this command."
    exit 1
}

$include_markdown_filter = Join-Path $PSScriptRoot "include-markdown.lua"
if (-not (Test-Path $include_markdown_filter)) {
    Write-Error "include-markdown.lua filter not found at $include_markdown_filter. Make sure it exists, then rerun this command."
    exit 1
}

$agent_results = Join-Path $PSScriptRoot "agent-challenge-results.md"
if ((Test-RenderNeedsAgentResults $RemainingArgs) -and -not (Test-Path $agent_results)) {
    Write-Error "agent-challenge-results.md is missing. Run generate_agent_challenge_evaluation.py first."
    exit 1
}

$title_pages_header = Join-Path $PSScriptRoot "title-pages.tex"
if (-not (Test-Path $title_pages_header)) {
    Write-Error "title-pages.tex is missing. Make sure the thesis front matter header exists."
    exit 1
}
$title_pages_args = @()
if ($type -eq "pdf") {
    $title_pages_args = @("--include-in-header", $title_pages_header)
}

$tex_preamble_header = Join-Path $PSScriptRoot "header-includes.tex"
if (-not (Test-Path $tex_preamble_header)) {
    Write-Error "header-includes.tex is missing. Make sure the thesis preamble header exists."
    exit 1
}
$html_preamble_header = Join-Path $PSScriptRoot "header-includes.html"
if (-not (Test-Path $html_preamble_header)) {
    Write-Error "header-includes.html is missing. Make sure the thesis preamble header exists."
    exit 1
}

$preamble_args = @()
if ($type -eq "pdf") {
    $preamble_args += @("--include-in-header", $tex_preamble_header)
}
elseif ($type -eq "html") {
    $preamble_args += @("--include-in-header", $html_preamble_header)
}

$info_md = Join-Path $PSScriptRoot "info.md"
if (-not (Test-Path $info_md)) {
    Write-Error "info.md is missing. Make sure the thesis info.md file exists."
    exit 1
}

$input_files = @($info_md, $InputFile)

$metatempfile = New-TemporaryFile
$pandocExitCode = 0

$pandoc_args = $(
    @(
        "--lua-filter", $include_markdown_filter,
        "--lua-filter", $diagram_filter,
        "--lua-filter", $figure_format_filter,
        "--filter=pandoc-crossref",
        "--pdf-engine=xelatex"
    ) + 
    $title_pages_args + 
    $preamble_args + 
    @(
        "--metadata", "thesisFigureFormat=$outputFormat",
        "--metadata", "thesisAgentResults=$agent_results",
        "--metadata-file", $metatempfile,
        "--embed-resources", "--standalone", "--citeproc"
    ) +
    $input_files + 
    @("--output", $OutputFile) + 
    $RemainingArgs
).Where({ [string]::IsNullOrWhiteSpace($_) -eq $false })

try {
    Set-Content -Path $metatempfile -Value $metadata
    Write-Host "Running pandoc for file $($InputFile | Split-Path -Leaf) to generate $($OutputFile | Split-Path -Leaf)..."
    pandoc @pandoc_args
    $pandocExitCode = $LASTEXITCODE
}
finally {
    Remove-Item $metatempfile
}

if ($pandocExitCode -ne 0) {
    throw "pandoc failed with exit code $pandocExitCode"
}