A lighthearted, increasingly wicked journey through PHP fundamentals and algorithms.
Follow Morlin, an over-eager apprentice wizard, as he unlocks spells (concepts), crafts runes (data structures), and eventually duels real enemies (algorithms & state machines).

What this collection is
A curated series of katas with a shared story, escalating difficulty, and a clear learning arc. Each chapter is self-contained but references past “unlocks” so the whole thing feels like a campaign, not random drills.

Who it’s for

• PHP learners who want more than just trivial exercises.
• Experienced devs who enjoy clean specs, tricky edge cases, and a bit of narrative chaos.
• Anyone who’s ever been burned by PHP’s “truthy” surprises and wants stricter thinking.

How it works

Start at Chapter 1 and go in order. Each kata introduces a rule set and a concept you’ll “unlock” for later use.
Read the story (short, fun), then the strict rules. The tests are unforgiving by design.
Sample tests guide; hidden tests hammer edge cases.
Expect occasional gotchas that punish lazy casting and loose comparisons.

Difficulty ladder (multiple katas per tier)

• 8 kyu — Apprentice Orientation: safe casting, string/array basics, input hygiene
• 7 kyu — Runecrafting 101: associative arrays, sorting, normalization
• 6–5 kyu — Arcane Systems: OOP immutability, custom matching, graphs/BFS, generators
• 4–3 kyu — Endgame: DP/memoization, search/backtracking, lightweight AI & combat loops

Unlocks (meta-progression)
You’ll earn “Spell Slots” (array thinking), “Runecrafting” (maps & merges), “Mana Economy” (DP/greedy), “Turn Engine” (queues & priorities), “Status Effects” (state machines), and more. Later katas lean on earlier unlocks conceptually.

Chapters included so far

• Chapter 1: The Empty Cauldron (8 kyu)
  Count only real ingredients under strict rules. Punishes sloppy truthiness.
  Signature: countIngredients(array $vals): int

• Chapter 2: Pocket Pebbles (8 kyu)
  Safely coerce scalars to integers. No numeric cosplay allowed.
  Signature: toIntSafe($v): int

• Chapter 3: Loadout Check (8 kyu)
  Normalize a fixed-size spell loadout: strict slot parsing, validate/Title-Case/dedup spells, pad with "Cantrip", and reject banned spells.
  Signature: normalizeLoadout($slots, array $spells): array

• Chapter 4: The Mirror Whisper (8 kyu)
  Palindrome ward: keep ASCII letters only, case-insensitive, non-empty after cleaning.
  Signature: isMirrorWhisper(string $phrase): bool

The 8 kyu tier is complete: input hygiene, safe casting, normalization, and a clean logic puzzle. No sloppy casting. No loose comparisons. No mercy.

• Chapter 5: Rune Backpack (7 kyu) — NEW
  Merge multiple rune bags into one inventory. Validate names, collapse spaces, case-insensitive merge, accept integer or integer-valued float quantities, prune totals ≤ 0, output Title-Cased keys, and sort by quantity DESC, then name ASC (case-insensitive).
  Signature: mergeRunes(array $bags): array

Coming up next (teasers)

• Rune Backpack (7 kyu): merge inventories, sort by quantity/name.
• Spell Cleaner (7 kyu): regex hygiene for incantations.
• Flickering Portals (5 kyu): shortest paths via BFS.
• Potion of a Thousand Steps (5 kyu): generators & state.
• Mana Economy (4 kyu): DP to hit a target at minimal cost.
• Time-Split Duel (3 kyu): backtracking for optimal sequences.

Style & testing
Tight specs, zero ambiguity; “close enough” fails.

Edge-case heavy (whitespace, signs, zeroes, nulls, booleans, deceptive strings).

PHPUnit tests: readable samples + randomized hidden oracles.

Ground rules
Prefer explicit checks over clever shortcuts.

Treat input like hostile magic: sanitize, validate, then act.

If you solve it on the first try without reading the rules carefully… you probably didn’t. Try again.