UC-006 — View Price History

Field	Value
ID	UC-006
Name	View Price History
Actors	End User
Layer	UI → Application → Domain

Goal

Show how average prices for a selected FuelProduct in a municipality changed across imported SurveyWeeks.

Preconditions

• showPriceHistory preference is true (default).
• At least 2 imported SurveyWeeks for same municipality + fuel (otherwise show single-point message).

Main flow

1. User opens history from UC-005 fuel detail.
2. System queries immutable AveragePrice history (BR-003) ordered by SurveyWeek.startDate.
3. UI renders trend list or simple chart (avg price vs week).
4. User can tap a week to view full UC-005 snapshot for that week.

Alternative flows

A1 — Only one week available

• WHEN single SurveyWeek in DB
• THEN show message: "History available after more weekly syncs"

A2 — Gap in weeks

• WHEN missing intermediate weeks (user didn't sync)
• THEN show only available weeks, no interpolation (honest data)

Business rules

• BR-003, BR-006

Domain events

• None (read-only)

Postconditions

• User understands price trend from stored ANP history only.

i18n keys

• history_title
• history_insufficient_data
• history_week_label