Generic Forms (#4561)

* Custom Forms

* Update BTCPayServer.Data/Migrations/20230125085242_AddForms.cs

* Cleanups

* Explain public form

* Add store branding

* Add form name to POS form

* add tests

* fix migration

* Minor cleanups

* Code improvements

* Add form validation

Closes #4317.

* Adapt form validation for Bootstrap 5

* update logic for forms

* pr changes

* Minor code cleanup

* Remove unused parameters

* Refactor Form data handling to avoid O(n3) issues

* Rename Hidden to Constant

* Pre-populate FormView from the query string params

* Fix test

---------

Co-authored-by: d11n <mail@dennisreimann.de>
Co-authored-by: nicolas.dorier <nicolas.dorier@gmail.com>

BTCPayServer/Forms/FormDataService.cs

@@ -1,26 +1,48 @@
 #nullable enable
 using System;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Globalization;
 using System.Linq;
+using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using BTCPayServer.Abstractions.Form;
+using BTCPayServer.Client.Models;
 using BTCPayServer.Data;
 using BTCPayServer.Data.Data;
+using BTCPayServer.Models;
+using BTCPayServer.Services.Stores;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+using Microsoft.AspNetCore.Mvc.Rendering;
 using Microsoft.EntityFrameworkCore;
+using Newtonsoft.Json.Linq;
 
 namespace BTCPayServer.Forms;
 
 public class FormDataService
 {
+    public const string InvoiceParameterPrefix = "invoice_";
+    private readonly ApplicationDbContextFactory _applicationDbContextFactory;
+    private readonly FormComponentProviders _formProviders;
+
+    public FormDataService(
+        ApplicationDbContextFactory applicationDbContextFactory, 
+        FormComponentProviders formProviders)
+    {
+        _applicationDbContextFactory = applicationDbContextFactory;
+        _formProviders = formProviders;
+    }
 
     public static readonly Form StaticFormEmail = new()
     {
-        Fields = new List<Field>() { Field.Create("Enter your email", "buyerEmail", null, true, null, "email") }
+        Fields = new List<Field> { Field.Create("Enter your email", "buyerEmail", null, true, null, "email") }
     };
 
     public static readonly Form StaticFormAddress = new()
     {
-        Fields = new List<Field>()
+        Fields = new List<Field>
         {
             Field.Create("Enter your email", "buyerEmail", null, true, null, "email"),
             Field.Create("Name", "buyerName", null, true, null),
@@ -32,4 +54,109 @@ public class FormDataService
             Field.Create("Country", "buyerCountry", null, true, null)
         }
     };
+    
+    private static readonly Dictionary<string, (string selectText, string name, Form form)> _hardcodedOptions = new()
+    {
+        {"", ("Do not request any information", null, null)!},
+        {"Email", ("Request email address only", "Provide your email address", StaticFormEmail )},
+        {"Address", ("Request shipping address", "Provide your address", StaticFormAddress)},
+    };
+
+    public async Task<SelectList> GetSelect(string storeId ,string selectedFormId)
+    {
+        var forms = await GetForms(storeId);
+        return new SelectList(_hardcodedOptions.Select(pair => new SelectListItem(pair.Value.selectText, pair.Key, selectedFormId == pair.Key)).Concat(forms.Select(data => new SelectListItem(data.Name, data.Id, data.Id == selectedFormId))),
+            nameof(SelectListItem.Value), nameof(SelectListItem.Text));
+    }
+    
+    public async Task<List<FormData>> GetForms(string storeId)
+    {
+        ArgumentNullException.ThrowIfNull(storeId);
+        await using var context = _applicationDbContextFactory.CreateContext();
+        return await context.Forms.Where(data => data.StoreId == storeId).ToListAsync();
+    }
+
+    public async Task<FormData?> GetForm(string storeId, string? id)
+    {
+        if (id is null)
+        {
+            return null;
+        }
+        await using var context = _applicationDbContextFactory.CreateContext();
+        return await context.Forms.Where(data => data.Id == id && data.StoreId == storeId).FirstOrDefaultAsync();
+    }
+    public async Task<FormData?> GetForm(string? id)
+    {
+        if (id is null)
+        {
+            return null;
+        }
+
+        if (_hardcodedOptions.TryGetValue(id, out var hardcodedForm))
+        {
+            return new FormData
+            {
+                Config = hardcodedForm.form.ToString(),
+                Id = id,
+                Name = hardcodedForm.name,
+                Public = false
+            };
+        }
+        await using var context = _applicationDbContextFactory.CreateContext();
+        return await context.Forms.Where(data => data.Id == id).FirstOrDefaultAsync();
+    }
+
+    public async Task RemoveForm(string id, string storeId)
+    {
+        await using var context = _applicationDbContextFactory.CreateContext();
+        var item = await context.Forms.SingleOrDefaultAsync(data => data.StoreId == storeId && id == data.Id);
+        if (item is not null)
+            context.Remove(item);
+        await context.SaveChangesAsync();
+    }
+
+    public async Task AddOrUpdateForm(FormData data)
+    {
+        await using var context = _applicationDbContextFactory.CreateContext();
+
+        context.Update(data);
+        await context.SaveChangesAsync();
+    }
+
+    public bool Validate(Form form, ModelStateDictionary modelState)
+    {
+        return _formProviders.Validate(form, modelState);
+    }
+    
+    public bool IsFormSchemaValid(string schema, [MaybeNullWhen(false)] out Form form, [MaybeNullWhen(false)] out string error)
+    {
+        error = null;
+        form = null;
+        try
+        {
+            form = Form.Parse(schema);
+            if (!form.ValidateFieldNames(out var errors))
+            {
+                error = errors.First();
+            }
+        }
+        catch (Exception ex)
+        {
+            error =  $"Form config was invalid: {ex.Message}";
+        }
+        return error is null && form is not null;
+    }
+
+    public CreateInvoiceRequest GenerateInvoiceParametersFromForm(Form form)
+    {
+        var amt = form.GetFieldByFullName($"{InvoiceParameterPrefix}amount")?.Value;
+        return new CreateInvoiceRequest
+        {
+            Currency = form.GetFieldByFullName($"{InvoiceParameterPrefix}currency")?.Value,
+            Amount = string.IsNullOrEmpty(amt) ? null : decimal.Parse(amt, CultureInfo.InvariantCulture),
+            
+            Metadata = form.GetValues(),
+            
+        };
+    }
 }