RpgRoller/TASKS.md

Rolemaster Support Plan

Goal

Extend the app with a new rolemaster ruleset that supports generic standard Rolemaster expressions plus the special open-ended percentile case:

1. Standard expressions: NdS + x, with an implicit dice count of 1 when no digit appears before d
2. Open-ended percentile: d100! + x with Rolemaster low-end and high-end behavior

The initial scope is only roll definition, validation, execution, logging, and UI support for generic standard Rolemaster rolls and open-ended percentile rolls. This does not include Rolemaster attack tables, critical tables, resistance rolls, maneuver tables, or character sheet math beyond the explicit roll modifier entered for a skill.

Scope Assumptions

• A Rolemaster campaign chooses the new rolemaster ruleset at campaign creation time.
• Rolemaster skills are ruleset-specific and should not reuse D6-only options such as WildDice and AllowFumble.
• Open-ended percentile behavior is defined as:
  • Roll the first d100.
  • If the first roll is 96 or higher, roll another high-ended d100 recursively and add it.
  • If the first roll is less than or equal to the skill's configured fumble range, roll another high-ended d100 recursively and subtract it.
  • Recursive follow-up rolls are high-ended only.
• Standard Rolemaster rolls do not open-end and do not use a fumble range.
• The modifier x should be an integer.
• Negative modifiers are supported for Rolemaster only.
• D6 and D&D 5e keep their current non-negative modifier rules unless separately re-scoped in a future change.
• Existing D6 and D&D 5e behavior must remain unchanged.
• The migration must be validated against a copied temp-file instance of RpgRoller/App_Data/rpgroller.development.db, which currently contains a D6 campaign.

Clarifications

• The Rolemaster modifier should allow negative values only for Rolemaster.
• The standard fumble range for open-ended percentile skills is 0-5, but can be configured individually for each skill.
• The fumble range has to be guaranteed to be less than 96.
• Roll breakdown text format for low-ended subtraction: 12 (03) -97 -44 +15 = -114
• Skill groups need to support Rolemaster defaults for all of these fields, to stay consistent with current prototype behavior
• Rolemaster uses expression parsing with canonical syntax:
  • standard roll with implicit count: d10
  • standard roll with explicit count: 15d10
  • standard percentile: d100+4
  • open-ended percentile: d100!+85
  • negative modifiers are valid only for Rolemaster, for example d100-15
  • open-ended syntax is only valid for d100!

Architecture Guardrails

• Keep minimal API endpoint handlers thin and continue to place gameplay validation and roll execution in services.
• Keep Blazor components focused on form state, rendering, and API orchestration; do not duplicate Rolemaster rules in component code.
• Keep request/response DTOs separate from domain/persistence models.
• Preserve the current lazy log-detail loading flow so Rolemaster detail stays out of hot list payloads.
• Prefer additive changes to contracts and storage over replacing current D6 / D&D shapes outright.

Backward Compatibility

• Existing D6 and D&D 5e API request and response fields must remain valid throughout the Rolemaster rollout.
• Existing persisted skills, skill groups, and roll log rows must continue to load without migration-time data loss.
• Startup migration against the existing development SQLite database shape must succeed without data loss or post-migration behavior regressions for legacy D6 data.
• Any richer die metadata must deserialize safely for old rows that only contain the current RollDieResult shape.
• Payload budgets for roster, log page, roll mutation responses, and lazy-loaded roll detail must remain explicitly guarded by tests.

Design Direction

1. Add a new ruleset

Introduce RulesetKind.Rolemaster and expose it through DiceRules and campaign ruleset APIs.

Tasks:

• Add Rolemaster to RulesetKind.
• Update DiceRules.TryParseRulesetId.
• Update DiceRules.ToRulesetId.
• Add rolemaster to DiceRules.SupportedRulesets.
• Update tests that enumerate supported rulesets and campaign creation behavior.

Affected areas:

• RpgRoller/Domain/GameModels.cs
• RpgRoller/Services/DiceRules.cs
• RpgRoller/Contracts/ApiContracts.cs
• related service and API tests

2. Refactor skill definition from "expression + D6 options" to "ruleset-aware roll definition"

The current model is D6-shaped:

• DiceRollDefinition
• WildDice
• AllowFumble

That shape is not a clean fit for Rolemaster. The Rolemaster extension should still preserve expression parsing, but it needs a ruleset-aware internal definition so the app can validate, execute, and display Rolemaster rolls safely.

Recommended model additions:

• Keep existing fields working for D6 and D&D 5e.
• Preserve DiceRollDefinition as the authoritative user-facing input for D6, D&D 5e, and Rolemaster.
• Add only the extra Rolemaster fields that cannot be encoded cleanly in the expression itself, specifically the fumble range.
• Centralize parsing and validation into a single ruleset-aware validator that returns a canonical internal representation.

Tasks:

• Define a ruleset-aware skill definition model in domain/contracts.
• Keep DiceRollDefinition as persisted state and define canonical formatting rules for Rolemaster expressions.
• Add mapping helpers so UI and API get a stable, ruleset-aware DTO.
• Ensure skill groups can store the same Rolemaster defaults as skills.

Affected areas:

• RpgRoller/Domain/GameModels.cs
• RpgRoller/Contracts/ApiContracts.cs
• RpgRoller/Services/GameService.cs
• RpgRoller/Components/Pages/Home.Models.cs

3. Add Rolemaster-specific validation

Current validation is split between generic expression parsing and D6 option validation. Rolemaster needs its own validation layer.

Validation rules to add:

• standard Rolemaster expressions
  • supports generic NdS syntax with any supported side count
  • assumes a dice count of 1 when the count is omitted before d
  • integer modifier required
  • no fumble range
• RolemasterOpenEndedPercentile
  • fixed base roll 1d100
  • integer modifier required
  • fumble range required and validated
  • fumble range must be below 96
• reject D6-only options for Rolemaster skills
• reject Rolemaster-only fields for D6 / D&D 5e skills
• reject negative modifiers for D6 / D&D 5e expressions
• accept negative modifiers for Rolemaster expressions only

Tasks:

• Replace or extend ValidateSkillDefinition.
• Extend DiceRules.ParseExpression with a Rolemaster-focused parser/validator path.
• Add canonical Rolemaster expression parsing rules:
  • d10, 2d10+48, and 15d10-15 for generic standard rolls
  • d100+4 and d100-20 for standard percentile
  • d100!+85 and d100!-15 for open-ended percentile
  • reject open-ended syntax for non-percentile or multi-die expressions such as 2d10!+1
• Keep Rolemaster fumble range validation separate from the expression because it is configured independently.
• Add canonical display formatting for Rolemaster skills, for example:
  • Rolemaster: d10
  • Rolemaster: 15d10+15
  • Open-ended percentile: OE 1d100+48, fumble <= 5
• Add explicit regression tests that D6 / D&D still reject negative modifiers after Rolemaster support lands.

Affected areas:

• RpgRoller/Services/DiceRules.cs
• RpgRoller/Services/GameService.cs
• RpgRoller.Tests/Services/DiceRulesTests.cs
• RpgRoller.Tests/Services/ServiceSkillGroupAndOwnershipTests.cs
• RpgRoller.Tests/Services/ServiceSkillRollTests.cs

4. Implement Rolemaster roll execution

Add a new Rolemaster execution path alongside the existing D6 and standard roll logic.

Recommended internal shape:

• ComputeRoll dispatches by ruleset and roll kind.
• Add dedicated methods:
  • ComputeRolemasterStandardRoll
  • ComputeRolemasterOpenEndedRoll
  • helper RollRolemasterHighOpenEndedChain

Open-ended algorithm:

• Roll first d100.
• Start total with first roll.
• If first roll >= 96:
  • roll one or more high-ended follow-up d100s
  • add all follow-up rolls
• Else if first roll <= fumble range:
  • roll one or more high-ended follow-up d100s
  • subtract the follow-up total
• Apply modifier after base/follow-up math.
• Produce a full breakdown string.
• Persist enough die detail to reconstruct the event in log detail and UI.

Tasks:

• Extend ComputeRoll dispatch.
• Add Rolemaster-specific roll methods.
• Parse Rolemaster expressions into an internal roll definition before execution rather than branching on raw strings in multiple places.
• Decide whether the current RollDieResult DTO is sufficient.
  • likely not sufficient, because it only has Crit, Fumble, Wild, Removed, Added
• Recommended DTO extension:
  • Sequence or Order
  • Phase / Kind such as initial, open-ended-high, open-ended-low-subtract
  • SignedContribution or equivalent metadata for subtraction
• Update log summary generation so Rolemaster rolls remain understandable in compact log entries without bloating list payloads.
• Keep lazy detail expansion as the place where the full Rolemaster breakdown and rich die metadata are loaded.

Affected areas:

• RpgRoller/Services/GameService.cs
• RpgRoller/Contracts/ApiContracts.cs
• RpgRoller/Contracts/RpgRollerJsonSerializerContext.cs
• RpgRoller/Components/Pages/HomeControls/RollDiceStrip.razor.cs

5. Update persistence and migrations

Rolemaster support needs persisted structured fields for skills and skill groups, and possibly richer serialized roll-die details.

Tasks:

• Update Skill and SkillGroup EF models.
• Update RpgRollerDbContext configuration.
• Add EF Core migration for new Rolemaster fields.
• Preserve existing data for D6 / D&D 5e campaigns.
• Decide migration defaults for legacy rows.
• Update SqliteSchemaUpgrader coverage expectations if schema assumptions change.
• Verify serialized roll log payloads remain readable for old entries after DTO extension.
• Ensure additive schema changes allow mixed old/new data during migration and startup upgrade.
• Validate the real startup migration path against a copied temp-file instance of RpgRoller/App_Data/rpgroller.development.db.
• Verify that the migrated copy still loads the existing D6 campaign data and that legacy D6 skills remain rollable after startup migration.

Data migration recommendations:

• Legacy D6 / D&D 5e skills should retain current behavior with deterministic defaults.
• New Rolemaster fields should be nullable or have safe defaults during migration.
• Avoid destructive migration patterns; favor additive schema evolution.
• Never run destructive migration verification against the source development DB file; always copy it first and test the copy.

Affected areas:

• RpgRoller/Data/RpgRollerDbContext.cs
• RpgRoller/Migrations/*
• RpgRoller/Hosting/SqliteSchemaUpgrader.cs
• RpgRoller.Tests/HostingCoverageTests.cs

6. Expose Rolemaster in APIs and frontend models

The UI currently assumes only IsD6 versus "not D6". That binary split will not scale to Rolemaster.

Tasks:

• Replace IsD6 branching with a ruleset-aware UI model.
• Extend skill and skill-group request/response contracts with Rolemaster fields.
• Ensure campaign creation UI includes Rolemaster in the ruleset picker.
• Update workspace models and display helpers so Rolemaster skill summaries render correctly.

Recommended frontend model changes:

• Introduce ruleset-aware form state rather than raw D6 toggles.
• Keep "Expression" as the primary input, and provide Rolemaster-specific help text, examples, and validation when the selected campaign ruleset is rolemaster.
• Show fumble range input only when the current Rolemaster expression is an open-ended percentile roll.
• Use progressive disclosure so only the fields relevant to the current Rolemaster expression are shown.
• Add inline validation on blur and submit, visible required indicators, and aria-live / alert semantics for validation errors.
• Preserve the existing app visual language instead of introducing a separate Rolemaster-specific theme.

Affected areas:

• RpgRoller/Contracts/ApiContracts.cs
• RpgRoller/Components/Pages/Home.Models.cs
• RpgRoller/Components/Pages/HomeControls/SkillFormModal.razor
• RpgRoller/Components/Pages/HomeControls/SkillFormModal.razor.cs
• RpgRoller/Components/Pages/HomeControls/CharacterPanel.razor
• RpgRoller/Components/Pages/HomeControls/CharacterPanel.razor.cs
• RpgRoller/Components/Pages/Workspace.razor.cs

7. Update roll visualization and log readability

Rolemaster open-ended rolls will be hard to interpret if they reuse the current D6-oriented chip styling without extra context.

Tasks:

• Extend RollDiceStrip to distinguish:
  • initial percentile roll
  • added high-open-ended rolls
  • subtracted low-end follow-up rolls
• Add tooltip or title text that explains each die's role in the chain.
• Update compact log summaries so they surface open-ended behavior.
• Ensure private/public visibility behavior remains unchanged.
• Keep roll list rows dense and readable; reserve multi-line breakdown detail for expanded rows or detail fetches.

Recommended display goals:

• A normal percentile roll should read as simple and uncluttered.
• A high-open-ended roll should clearly show chained additions.
• A low-ended roll should clearly show subtraction, not just a list of numbers.

Affected areas:

• RpgRoller/Components/Pages/HomeControls/RollDiceStrip.razor
• RpgRoller/Components/Pages/HomeControls/RollDiceStrip.razor.cs
• RpgRoller/Components/Pages/Workspace.razor.cs
• RpgRoller/Services/GameService.cs

8. Expand tests to preserve behavior and coverage

This repo expects very high coverage and already has strong service/API regression tests. Rolemaster support should land with exhaustive tests, not just happy paths.

Service-level tests to add:

• parse and ruleset mapping for rolemaster
• skill creation validation for each Rolemaster roll type
• rejection of invalid fumble ranges
• rejection of D6-only options on Rolemaster skills
• rejection of negative modifiers on D6 / D&D skills
• acceptance of negative modifiers on Rolemaster expressions
• generic standard Rolemaster roll math
• standard percentile roll math
• open-ended high roll with one extra roll
• open-ended high roll with recursive extra rolls
• open-ended low roll with subtraction
• open-ended low roll where the subtract chain itself recursively high-opens
• breakdown formatting and die metadata correctness

API tests to add:

• create Rolemaster campaign
• create/update skill groups with Rolemaster defaults
• create/update Rolemaster skills
• roll each Rolemaster skill type via API
• verify log page and detail endpoints for Rolemaster rolls
• verify old D6 / D&D contracts still round-trip without requiring Rolemaster-only fields
• verify that a migrated copy of RpgRoller/App_Data/rpgroller.development.db still supports legacy D6 API flows after startup migration

Frontend/regression checks:

• Rolemaster ruleset appears in campaign creation UI
• Rolemaster skill form shows correct conditional fields
• roll results render correctly for open-ended cases
• validation errors are announced and visible for invalid Rolemaster expressions / fumble ranges
• the compact log remains readable and detail expansion shows the full Rolemaster breakdown

Coverage-sensitive files likely needing tests:

• RpgRoller.Tests/Services/DiceRulesTests.cs
• RpgRoller.Tests/Services/ServiceSkillRollTests.cs
• new dedicated Rolemaster service tests
• RpgRoller.Tests/Api/CampaignApiTests.cs
• RpgRoller.Tests/HostingCoverageTests.cs
• RpgRoller.Tests/PayloadBudgetTests.cs

9. Documentation updates

The repository instructions require related docs to be updated whenever behavior changes.

Tasks:

• Update README.md to list Rolemaster as a supported ruleset.
• Document the three supported Rolemaster roll types.
• Document the open-ended percentile algorithm, including:
  • 96+ recursive addition
  • <= fumble range recursive subtraction
• Document any limits on modifier and fumble range values.
• If API contracts change materially, update openapi/RpgRoller.json.

10. Delivery plan in small iterations

Recommended implementation order:

Iteration 1: ruleset plumbing

• Add Rolemaster ruleset enum/id/display support.
• Add campaign creation support.
• Add parser/validator scaffolding for Rolemaster expressions and Rolemaster-only negative modifier support.
• Add baseline tests for ruleset mapping and validation.

Iteration 2: structured skill model

• Preserve DiceRollDefinition as the canonical persisted expression and add only the extra persisted Rolemaster fields the expression cannot represent.
• Add migration and schema tests.
• Add startup-migration validation against a copied temp-file instance of RpgRoller/App_Data/rpgroller.development.db.
• Update API contracts and service mapping.
• Keep existing D6 / D&D behavior green.

Iteration 3: roll engine

• Implement generic standard and standard percentile execution.
• Implement open-ended percentile execution with recursive high-end chaining and low-end subtraction.
• Extend die-result metadata and breakdown formatting.
• Add focused service tests for roll math and payload/detail serialization compatibility.

Iteration 4: frontend editing

• Update campaign ruleset selection UI.
• Replace D6-only form branching with ruleset-aware skill editing.
• Support Rolemaster skill groups and skills in create/edit flows.
• Add accessible inline validation and progressive disclosure to the Rolemaster editor.
• Verify with ephemeral Playwright.

Iteration 5: log/detail polish and docs

• Improve roll chip rendering and compact summaries for Rolemaster.
• Re-run payload-budget checks and confirm lazy detail loading still holds.
• Update README/OpenAPI/docs.
• Run full local CI and coverage checks.

Risks

• The current skill contract is tightly coupled to D6-era fields, so a shallow patch will create long-term complexity.
• The current RollDieResult type is too generic for clear Rolemaster open-ended auditing.
• Allowing negative Rolemaster modifiers requires carefully scoping validation changes so D6/D&D rules do not loosen unintentionally.
• Migration design needs care to avoid breaking legacy SQLite databases.
• A migration that works on an empty test database but fails on the existing D6 production-shaped database would be a release blocker.
• UI complexity will grow if ruleset-specific fields are bolted onto the current IsD6 logic instead of replacing it with a ruleset-aware form model.
• Richer Rolemaster die metadata could regress payload sizes or list readability if detail is not kept behind the existing lazy-load flow.

Recommended Acceptance Criteria

• A campaign can be created with ruleset id rolemaster.
• Rolemaster skill groups and skills can be created and edited through API and UI.
• Supported Rolemaster roll types are:
  • generic standard rolls NdS + x, with implicit dice count 1 for dS
  • open-ended percentile d100! + x with fumble range
• Open-ended percentile rolls correctly:
  • add recursively on first-roll 96+
  • subtract a recursive high-end chain on first-roll <= fumble range
• Roll logs and detail views clearly show how a Rolemaster result was produced.
• Existing D6 and D&D 5e flows remain unchanged.
• App startup successfully migrates a copied temp-file instance of RpgRoller/App_Data/rpgroller.development.db.
• The migrated copy preserves the existing D6 campaign data and passes legacy D6 read/roll regression checks after startup migration.
• Local CI, coverage checks, and frontend verification all pass.