# Implementation Plan: Proper Timezone Handling & Recurring Events

## Phase 1: Foundation - Timezone Mapping & Resolver [checkpoint: b8bf269]
- [x] Task: Setup Timezone Map (WINDOWS_TO_IANA)
    - [x] Write failing tests for `resolveIanaName`
    - [x] Implement `WINDOWS_TO_IANA` mapping and `resolveIanaName` in `timezones.ts`
- [x] Task: Implement UTC Offset Resolver using Intl
    - [x] Write failing tests for `getUtcOffsetMs`
    - [x] Implement `getUtcOffsetMs` in `timezones.ts`
- [x] Task: Conductor - User Manual Verification 'Phase 1: Foundation' (Protocol in workflow.md)

## Phase 2: Core Logic - Extraction & Shifting [checkpoint: 10a6db5]
- [x] Task: Fix Wall-Clock Extraction logic
    - [x] Write failing tests for `resolveEventStart` (mocking `Intl` if necessary)
    - [x] Implement `resolveEventStart` in `icalendar.ts` to handle local time ground truth
- [x] Task: Conductor - User Manual Verification 'Phase 2: Core Logic' (Protocol in workflow.md)

## Phase 3: Features - Recurring Events & Filtering
- [ ] Task: Integrate `rrule` library
    - [ ] Add `rrule` to `deno.json` imports
    - [ ] Verify import works in a simple script
- [ ] Task: Implement Recurring Event Expansion
    - [ ] Write failing tests for `expandRecurrences`
    - [ ] Implement `expandRecurrences` in `icalendar.ts`
- [ ] Task: Implement EXDATE support
    - [ ] Write failing tests for EXDATE exclusion
    - [ ] Update `expandRecurrences` to handle `EXDATE`
- [ ] Task: Implement Status Filtering
    - [ ] Write failing tests for filtering "CANCELLED" events
    - [ ] Update sync logic to filter based on iCalendar status
- [ ] Task: Conductor - User Manual Verification 'Phase 3: Features' (Protocol in workflow.md)

## Phase 4: Cleanup & Configuration
- [ ] Task: Remove obsolete configuration
    - [ ] Write failing tests verifying `tzShift` is ignored/deprecated
    - [ ] Remove `tzShift` and `hourShift` from `getSources` and `fetchAndParseCalendar`
- [ ] Task: Add `syncWindowDays` configuration
    - [ ] Write failing tests for configurable expansion window
    - [ ] Implement `syncWindowDays` in config and sync logic
- [ ] Task: Conductor - User Manual Verification 'Phase 4: Cleanup & Configuration' (Protocol in workflow.md)