PSAISuite

0.2.2

Public/Invoke-ChatCompletion.ps1

<#
.SYNOPSIS
Invokes a completion request to a specified AI model provider.
 
.DESCRIPTION
The Invoke-ChatCompletion function sends a prompt to a specified AI model provider and returns the completion response.
The model provider and model name must be specified in the 'provider:model' format. The function dynamically constructs
the provider-specific function name and invokes it to get the response.
 
.PARAMETER Messages
The messages to be sent to the AI model for completion. This parameter is mandatory and can accept either:
- A string, which will be wrapped in a user message automatically
- A hashtable array containing properly formatted chat messages
 
.PARAMETER Model
The model to be used for the completion request, specified in 'provider:model' format. Defaults to "openai:gpt-4o-mini".
 
.PARAMETER TextOnly
A switch parameter that, if specified, returns only the response text. If not specified, a custom object containing
the response text, model information, and timestamp is returned.
 
.PARAMETER IncludeElapsedTime
A switch parameter that, if specified, measures and includes the elapsed time of the API request in the output.
 
.EXAMPLE
$Message = New-ChatMessage -Prompt "Hello, world!"
Invoke-ChatCompletion -Messages $Message -Model "openai:gpt-4o-mini"
 
Sends the prompt "Hello, world!" to the OpenAI GPT-4o-mini model and returns the completion response.
 
.EXAMPLE
Invoke-ChatCompletion -Messages "Hello, world!" -Model "openai:gpt-4o-mini" -TextOnly
 
Sends the string "Hello, world!" as a user message to the OpenAI GPT-4o-mini model and returns only the completion response text.
 
.EXAMPLE
$Message = New-ChatMessage -Prompt "Hello, world!"
Invoke-ChatCompletion -Messages $Message -Model "openai:gpt-4o-mini" -IncludeElapsedTime
 
Sends the prompt and returns the completion response with the elapsed time information.
 
.NOTES
The function dynamically constructs the provider-specific function name based on the provider specified in the Model
parameter. If the provider function does not exist, an error is thrown.
 
#>
function Invoke-ChatCompletion {
    [CmdletBinding()]
    param(
        [Parameter(Mandatory)]
        [object]$Messages,
        [string]$Model = "openai:gpt-4o-mini",
        [switch]$TextOnly,
        [switch]$IncludeElapsedTime
    )
    
    # Convert string input to a proper message format if needed
    if ($Messages -is [string]) {
        $Messages = @(
            @{
                'role'    = 'user'
                'content' = $Messages
            }
        )
    }
    
    # Parse provider and model from the Model parameter
    if ($Model -match "^([^:]+):(.+)$") {
        $provider = $Matches[1].ToLower()
        $modelName = $Matches[2]
    }
    else {
        throw "Model must be specified in 'provider:model' format."
    }
    
    # Dynamically construct provider function name
    $providerFunction = "Invoke-${provider}Provider"
    
    # Check if the provider function exists
    if (-not (Get-Command $providerFunction -ErrorAction SilentlyContinue)) {
        throw "Unsupported provider: $provider. No function named $providerFunction found."
    }
    
    # Start measuring execution time if requested
    if ($IncludeElapsedTime) {
        $stopwatch = [System.Diagnostics.Stopwatch]::StartNew()
    }
    
    # Invoke the provider-specific implementation
    $functionParams = @{
        ModelName = $modelName
        Messages  = $Messages
    }

    if ($SystemRole) {
        $functionParams.SystemRole = $SystemRole
    }

    $responseText = & $providerFunction @functionParams
    
    # Stop measuring execution time if requested
    if ($IncludeElapsedTime) {
        $stopwatch.Stop()
        $elapsedTime = $stopwatch.Elapsed
    }
    
    # Return the result based on the TextOnly switch
    if ($TextOnly) {
        # Format the text output to include the elapsed time if requested
        if ($IncludeElapsedTime) {
            return "$responseText`n`nElapsed Time: $($elapsedTime.ToString('hh\:mm\:ss\.fff'))"
        }
        else {
            return $responseText
        }
    }
    else {
        # Create the base response object
        $responseObject = [PSCustomObject]@{
            Messages  = ($Messages | ConvertTo-Json -Compress)
            Response  = $responseText
            Model     = $Model
            Provider  = $provider
            ModelName = $modelName
            Timestamp = Get-Date
        }
        
        # Add elapsed time if requested
        if ($IncludeElapsedTime) {
            $responseObject | Add-Member -MemberType NoteProperty -Name 'ElapsedTime' -Value $elapsedTime
        }

        if ($SystemRole) {
            $responseObject | Add-Member -MemberType NoteProperty -Name 'SystemRole' -Value $SystemRole
        }
        
        return $responseObject
    }
}