Add Custom Formula Item Templates with AI generation and wizard integration

Introduces per-company reusable NCalc2 pricing formula templates for complex
fabricated items (roof curbs, enclosures, welded frames). Templates support
two output modes — FixedRate (formula yields a dollar amount) and SurfaceAreaSqFt
(formula yields sq ft fed into the standard coating engine). Includes:

- CustomItemTemplate entity, migration (AddCustomItemTemplates), IUnitOfWork repo
- IsCustomFormulaItem / CustomItemTemplateId / FormulaFieldValuesJson flags on
  QuoteItem, JobItem, CreateQuoteItemDto; mapped in all 3 JobItemAssemblyService
  overloads and all existingItemsData JSON projections + pageMeta blocks
- ICustomFormulaAiService / CustomFormulaAiService: Claude-powered formula
  generator (natural language + optional diagram image) and NCalc2 evaluator
- CompanySettings CRUD endpoints: GetCustomItemTemplates, Create/Update/Delete,
  UploadTemplateDiagram, TemplateDiagram (blob serve), EvaluateFormula, GenerateFormulaFromAi
- Company Settings "Custom Formulas" tab + cfModal + company-settings-custom-formulas.js
- item-wizard.js: formula item type card, renderFormulaFields, wzFormulaRecalc
  (live evaluate via POST), collectStep2 formula branch, buildCardHtml / emitHiddenFields
- Formula badge in Quotes/Details and Jobs/Details; AI badge gap fixed in Jobs/Details
- Help article (CustomFormulaTemplates.cshtml), Help Index card, HelpController action,
  HelpKnowledgeBase entry; 225/225 unit tests passing

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-05-23 15:09:22 -04:00
parent e443457139
commit 1eba50cf0f
40 changed files with 12846 additions and 33 deletions
@@ -0,0 +1,197 @@
using System.Text;
using System.Text.Json;
using NCalc2;
using Anthropic.SDK;
using Anthropic.SDK.Messaging;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using PowderCoating.Application.DTOs.Company;
using PowderCoating.Application.Interfaces;
namespace PowderCoating.Infrastructure.Services;
/// <summary>
/// Generates NCalc pricing formula templates from natural-language descriptions using
/// Claude Sonnet. Accepts an optional diagram image so the model can see the physical
/// shape being estimated. The model returns a structured JSON object containing the
/// field list, NCalc expression, output mode, and verification inputs; the service
/// parses and returns it as a <see cref="GenerateFormulaFromAiResponse"/>.
/// </summary>
public class CustomFormulaAiService : ICustomFormulaAiService
{
private readonly IConfiguration _config;
private readonly ILogger<CustomFormulaAiService> _logger;
private const string SystemPrompt = @"You are an expert pricing formula engineer for a powder coating business.
Your job is to generate NCalc expressions that calculate either a fixed price or a surface area
from user-supplied field values. NCalc supports standard math operators (+, -, *, /, %, Pow()),
comparison operators, and the Abs(), Round(), Max(), Min() built-in functions.
The user will describe a custom fabricated item (e.g., 'Roof curb', 'Electrical enclosure',
'Tubular frame') and you must produce a pricing formula template.
Respond ONLY with a valid JSON object matching this exact schema — no markdown, no explanation:
{
""name"": ""string — short template name (e.g. 'Roof Curb', 'Electrical Enclosure')"",
""outputMode"": ""FixedRate"" | ""SurfaceAreaSqFt"",
""fields"": [
{
""name"": ""snake_case_variable_name"",
""label"": ""Human-readable label"",
""unit"": ""in / ft / mm / cm / qty / lbs — or empty string"",
""defaultValue"": number
}
],
""formula"": ""NCalc expression using field name variables and optionally 'rate'"",
""defaultRate"": number or null,
""rateLabel"": ""string label for the rate field, e.g. '$/sq ft' — null if no rate"",
""reasoning"": ""1-2 sentences explaining how the formula was derived"",
""verificationInputs"": { ""variable_name"": number },
""verificationResult"": number
}
Rules:
- Use FixedRate when the formula directly calculates a dollar amount (e.g. surface area × rate per sqft)
- Use SurfaceAreaSqFt when the formula calculates square footage and the standard pricing engine handles the rest
- Always include a 'rate' variable when outputMode is FixedRate and the price scales with dimensions
- Field names must be valid NCalc identifiers (letters, digits, underscores; no spaces or hyphens)
- verificationInputs and verificationResult must use the exact field names and formula you generated
- Surface area formulas for box shapes: 2*(L*W + L*H + W*H) where L/W/H are in the same unit; convert to sqft if needed
- For inch inputs convert to sqft: divide by 144 (sqin→sqft) or use /12 per side before multiplying
";
public CustomFormulaAiService(IConfiguration config, ILogger<CustomFormulaAiService> logger)
{
_config = config;
_logger = logger;
}
/// <inheritdoc />
public async Task<GenerateFormulaFromAiResponse> GenerateFormulaAsync(
GenerateFormulaFromAiRequest request,
byte[]? imageBytes = null,
string? imageContentType = null)
{
var apiKey = _config["AI:Anthropic:ApiKey"];
if (string.IsNullOrWhiteSpace(apiKey) || apiKey.StartsWith("your-"))
{
return new GenerateFormulaFromAiResponse
{
Success = false,
Error = "Anthropic API key is not configured. Add AI:Anthropic:ApiKey to appsettings.json."
};
}
try
{
var client = new AnthropicClient(apiKey);
var userContent = new List<ContentBase>();
if (imageBytes is { Length: > 0 } && !string.IsNullOrWhiteSpace(imageContentType))
{
userContent.Add(new ImageContent
{
Source = new ImageSource
{
MediaType = imageContentType,
Data = Convert.ToBase64String(imageBytes)
}
});
}
userContent.Add(new TextContent { Text = request.Description });
var messages = new List<Message>
{
new() { Role = RoleType.User, Content = userContent }
};
var response = await client.Messages.GetClaudeMessageAsync(new MessageParameters
{
Model = "claude-sonnet-4-6",
MaxTokens = 1024,
SystemMessage = SystemPrompt,
Messages = messages
});
var rawJson = response.Message.ToString().Trim();
// Strip markdown code fences if the model adds them
if (rawJson.StartsWith("```"))
{
var start = rawJson.IndexOf('\n') + 1;
var end = rawJson.LastIndexOf("```");
if (end > start) rawJson = rawJson[start..end].Trim();
}
using var doc = JsonDocument.Parse(rawJson);
var root = doc.RootElement;
var fieldsJson = root.TryGetProperty("fields", out var fieldsEl)
? fieldsEl.GetRawText()
: "[]";
decimal? defaultRate = null;
if (root.TryGetProperty("defaultRate", out var rateEl) && rateEl.ValueKind == JsonValueKind.Number)
defaultRate = rateEl.GetDecimal();
decimal? verificationResult = null;
if (root.TryGetProperty("verificationResult", out var vrEl) && vrEl.ValueKind == JsonValueKind.Number)
verificationResult = vrEl.GetDecimal();
string? verificationInputs = null;
if (root.TryGetProperty("verificationInputs", out var viEl))
verificationInputs = viEl.GetRawText();
return new GenerateFormulaFromAiResponse
{
Success = true,
Name = root.TryGetProperty("name", out var nameEl) ? nameEl.GetString() : null,
OutputMode = root.TryGetProperty("outputMode", out var omEl) ? omEl.GetString() : "FixedRate",
FieldsJson = fieldsJson,
Formula = root.TryGetProperty("formula", out var fEl) ? fEl.GetString() : null,
DefaultRate = defaultRate,
RateLabel = root.TryGetProperty("rateLabel", out var rlEl) ? rlEl.GetString() : null,
Reasoning = root.TryGetProperty("reasoning", out var reEl) ? reEl.GetString() : null,
VerificationResult = verificationResult,
VerificationInputs = verificationInputs
};
}
catch (Exception ex)
{
_logger.LogError(ex, "CustomFormulaAiService.GenerateFormulaAsync failed");
return new GenerateFormulaFromAiResponse { Success = false, Error = ex.Message };
}
}
/// <inheritdoc />
public EvaluateFormulaResponse EvaluateFormula(EvaluateFormulaRequest request)
{
if (string.IsNullOrWhiteSpace(request?.Formula))
return new EvaluateFormulaResponse { Success = false, Error = "Formula is required." };
try
{
var variables = JsonSerializer.Deserialize<Dictionary<string, JsonElement>>(
request.VariablesJson ?? "{}") ?? new();
var expr = new Expression(request.Formula);
foreach (var kv in variables)
{
expr.Parameters[kv.Key] = kv.Value.ValueKind == JsonValueKind.Number
? (object)kv.Value.GetDecimal()
: (object)(kv.Value.GetString() ?? "");
}
var result = expr.Evaluate();
var decResult = Convert.ToDecimal(result);
return new EvaluateFormulaResponse { Success = true, Result = Math.Round(decResult, 4) };
}
catch (Exception ex)
{
return new EvaluateFormulaResponse { Success = false, Error = ex.Message };
}
}
}