Replace tiers with achievements

src/levels/mod.rs

@@ -15,37 +15,47 @@ pub mod l02_kv;
 
 use serde::{Deserialize, Serialize};
 
-/// Game-wide difficulty. Chosen once on the TierSelect screen; persisted
+/// Awarded per level based on the grade score. Replaces the old
-/// in `Progress.tier`. Maps to a fixed passing threshold per level.
+/// game-wide difficulty tier. Thresholds:
+/// - Gold   ≥ 95 %
+/// - Silver ≥ 80 %
+/// - Bronze ≥ 70 %
+/// - Below 70 % → no nugget (retry).
 #[derive(Copy, Clone, Debug, Serialize, Deserialize, PartialEq, Eq)]
-pub enum Difficulty {
+pub enum Nugget {
-    Easy,
+    Bronze,
-    Medium,
+    Silver,
-    Hard,
+    Gold,
 }
 
-impl Difficulty {
+impl Nugget {
-    pub fn threshold(self) -> f64 {
+    /// Map a grade ratio (0.0..=1.0) to a nugget. `None` means the
-        match self {
+    /// player didn't clear the level — retry without advancing.
-            Self::Easy => 0.70,
+    pub fn from_score(score: f64) -> Option<Self> {
-            Self::Medium => 0.80,
+        if score >= 0.95 {
-            Self::Hard => 0.95,
+            Some(Nugget::Gold)
+        } else if score >= 0.80 {
+            Some(Nugget::Silver)
+        } else if score >= 0.70 {
+            Some(Nugget::Bronze)
+        } else {
+            None
         }
     }
 
-    pub fn label(self) -> &'static str {
+    pub fn emoji(self) -> &'static str {
         match self {
-            Self::Easy => "Easy (70%)",
+            Self::Bronze => "🥉",
-            Self::Medium => "Medium (80%)",
+            Self::Silver => "🥈",
-            Self::Hard => "Hard (95%)",
+            Self::Gold => "🥇",
         }
     }
 
     pub fn name(self) -> &'static str {
         match self {
-            Self::Easy => "Easy",
+            Self::Bronze => "Bronze",
-            Self::Medium => "Medium",
+            Self::Silver => "Silver",
-            Self::Hard => "Hard",
+            Self::Gold => "Gold",
         }
     }
 }

src/lib.rs

@@ -69,15 +69,14 @@ mod smoke {
         // (4) Progress round-trips through the same YAML pipeline that disk
         // save/load will use.
         let p = progress::Progress {
-            tier: Some(levels::Difficulty::Medium),
+            nuggets: vec![(1, levels::Nugget::Silver), (2, levels::Nugget::Gold)],
-            completed: vec![1, 2],
             current_level: 3,
             current_seed: 0xCAFE,
             attempts: 1,
         };
         let s = serde_yaml::to_string(&p).unwrap();
         let loaded: progress::Progress = serde_yaml::from_str(&s).unwrap();
-        assert_eq!(loaded.tier, p.tier);
+        assert_eq!(loaded.nuggets, p.nuggets);
         assert_eq!(loaded.current_level, p.current_level);
         assert_eq!(loaded.current_seed, p.current_seed);
     }

src/progress.rs

@@ -4,13 +4,16 @@ use anyhow::Result;
 use serde::{Deserialize, Serialize};
 use std::path::PathBuf;
 
-use crate::levels::Difficulty;
+use crate::levels::Nugget;
 
 #[derive(Default, Serialize, Deserialize)]
+#[serde(default)]
 pub struct Progress {
-    pub tier: Option<Difficulty>,
+    /// Nuggets awarded per level: `(level_id, nugget)` in order of
-    pub completed: Vec<u8>,
+    /// completion. A level appears at most once (re-runs after reset
-    pub current_level: u8,
+    /// rebuild the list from scratch).
+    pub nuggets: Vec<(u8, Nugget)>,
+    pub current_level: u8, // 1-indexed; 0 means a new game
     pub current_seed: u64,
     pub attempts: u32,
 }

src/tui.rs

@@ -13,7 +13,7 @@ use std::io::{stdout, Stdout};
 use std::time::{Duration, Instant};
 
 use crate::config;
-use crate::levels::{self, Difficulty, Level};
+use crate::levels::{self, Level, Nugget};
 use crate::progress::{self, Progress};
 use crate::similarity;
 
@@ -21,7 +21,6 @@ use crate::similarity;
 
 enum Screen {
     Welcome,
-    TierSelect { cursor: u8 },
     /// Active play: left column = HistoryLog, right column = Editor.
     Game,
     ResetConfirm,
@@ -35,34 +34,31 @@ enum Focus {
 }
 
 enum LogEntry {
-    /// Game rules + the full controls listing. Appended once on
+    /// Game rules + the full controls listing. Seeded at startup.
-    /// Welcome → TierSelect so the player can scroll back to it.
     Intro,
-    /// The full tier table with a marker on the chosen one.
-    TierChoice {
-        chosen: u8, // 0=Easy, 1=Medium, 2=Hard
-    },
     LevelPrompt {
         level_id: u8,
         level_name: String,
-        tier_name: &'static str,
         flavor: String,
         description: String,
     },
     ResultPass {
         level_name: String,
         score: f64,
-        threshold: f64,
+        nugget: Nugget,
     },
     ResultFail {
         level_name: String,
         score: f64,
-        threshold: f64,
     },
     InvalidYaml {
         error: String,
     },
-    Completed,
+    Completed {
+        gold: u32,
+        silver: u32,
+        bronze: u32,
+    },
 }
 
 /// Append-only chronological log of game events. Rendered bottom-anchored
@@ -259,54 +255,57 @@ fn leave() -> Result<()> {
     Ok(())
 }
 
-fn tier_index(t: Difficulty) -> u8 {
-    match t {
-        Difficulty::Easy => 0,
-        Difficulty::Medium => 1,
-        Difficulty::Hard => 2,
-    }
-}
-
 fn initial_state(prog: &Progress, registry: &[Box<dyn Level>]) -> (Screen, HistoryLog) {
     let mut log = HistoryLog::new();
-    // The Intro entry is always the bottom of the log on startup so that
+    // The Intro entry is always at the bottom of the log on startup so
-    // Welcome and TierSelect can render it inline (the player can scroll
+    // Welcome can show it inline; the player can scroll back to it any
-    // back to it any time).
+    // time during play.
     log.push(LogEntry::Intro);
 
-    match (prog.tier, prog.current_level) {
+    match prog.current_level {
-        (None, 0) => (Screen::Welcome, log),
+        0 => (Screen::Welcome, log),
-        (None, _) => (Screen::TierSelect { cursor: 0 }, log),
+        n if (n as usize) > registry.len() => {
-        (Some(tier), 0) => (Screen::TierSelect { cursor: tier_index(tier) }, log),
+            let (gold, silver, bronze) = count_nuggets(&prog.nuggets);
-        (Some(_), n) if (n as usize) > registry.len() => {
+            log.push(LogEntry::Completed {
-            log.push(LogEntry::Completed);
+                gold,
+                silver,
+                bronze,
+            });
             (Screen::Completed, log)
         }
-        (Some(tier), _) => {
+        _ => {
-            log.push(LogEntry::TierChoice { chosen: tier_index(tier) });
+            log.push(level_prompt_entry(prog, registry));
-            log.push(level_prompt_entry(prog, registry, tier));
             (Screen::Game, log)
         }
     }
 }
 
-fn level_prompt_entry(
+fn level_prompt_entry(prog: &Progress, registry: &[Box<dyn Level>]) -> LogEntry {
-    prog: &Progress,
-    registry: &[Box<dyn Level>],
-    tier: Difficulty,
-) -> LogEntry {
     let idx = (prog.current_level - 1) as usize;
     let level = &registry[idx];
     let g = level.generate(prog.current_seed);
     LogEntry::LevelPrompt {
         level_id: level.id(),
         level_name: level.name().to_string(),
-        tier_name: tier.name(),
         flavor: g.flavor,
         description: g.description,
     }
 }
 
+fn count_nuggets(nuggets: &[(u8, Nugget)]) -> (u32, u32, u32) {
+    let mut gold = 0;
+    let mut silver = 0;
+    let mut bronze = 0;
+    for (_, n) in nuggets {
+        match n {
+            Nugget::Gold => gold += 1,
+            Nugget::Silver => silver += 1,
+            Nugget::Bronze => bronze += 1,
+        }
+    }
+    (gold, silver, bronze)
+}
+
 fn default_focus(screen: &Screen) -> Focus {
     match screen {
         Screen::Game => Focus::Editor,
@@ -326,7 +325,8 @@ fn main_loop(
     let mut focus = default_focus(&screen);
     let mut editor = Editor::new();
 
-    // If resume put a LevelPrompt at the bottom, typewriter it from scratch.
+    // Resume case: if the bottom of the log is a LevelPrompt, animate it
+    // from scratch so resumed sessions feel the same as fresh ones.
     let mut typewriter = if cfg.typewriter_enabled {
         start_typewriter(&log, &cfg)
     } else {
@@ -409,7 +409,7 @@ fn step(
 ) -> Result<bool> {
     let ctrl = key.modifiers.contains(KeyModifiers::CONTROL);
 
-    // Global: Ctrl-Q quits.
+    // Global: Ctrl-Q quits from anywhere.
     if ctrl && key.code == KeyCode::Char('q') {
         return Ok(true);
     }
@@ -417,7 +417,7 @@ fn step(
     // Global: Ctrl-X grades while in Game.
     if ctrl && key.code == KeyCode::Char('x') && matches!(screen, Screen::Game) {
         grade(editor.text(), prog, registry, log)?;
-        if matches!(log.entries.last(), Some(LogEntry::Completed)) {
+        if matches!(log.entries.last(), Some(LogEntry::Completed { .. })) {
             *screen = Screen::Completed;
             *focus = default_focus(screen);
         }
@@ -468,10 +468,17 @@ fn step(
         return Ok(false);
     }
 
-    // Other screens (Welcome, TierSelect, ResetConfirm, Completed).
+    // Other screens (Welcome, ResetConfirm, Completed).
     match (&*screen, key.code) {
         (Screen::Welcome, KeyCode::Enter) => {
-            *screen = Screen::TierSelect { cursor: 0 };
+            if prog.current_level == 0 {
+                prog.current_level = 1;
+                prog.current_seed = rand::random();
+            }
+            progress::save(prog)?;
+            editor.clear();
+            log.push(level_prompt_entry(prog, registry));
+            *screen = Screen::Game;
             *focus = default_focus(screen);
         }
         (Screen::Welcome, KeyCode::Char('q')) => return Ok(true),
@@ -480,37 +487,6 @@ fn step(
         (Screen::Welcome, KeyCode::PageUp) => log.scroll_up(10),
         (Screen::Welcome, KeyCode::PageDown) => log.scroll_down(10),
 
-        (Screen::TierSelect { cursor }, KeyCode::Up) => {
-            let c = cursor.saturating_sub(1);
-            *screen = Screen::TierSelect { cursor: c };
-        }
-        (Screen::TierSelect { cursor }, KeyCode::Down) => {
-            let c = (*cursor + 1).min(2);
-            *screen = Screen::TierSelect { cursor: c };
-        }
-        (Screen::TierSelect { cursor }, KeyCode::Enter) => {
-            let chosen = *cursor;
-            let tier = match chosen {
-                0 => Difficulty::Easy,
-                1 => Difficulty::Medium,
-                _ => Difficulty::Hard,
-            };
-            prog.tier = Some(tier);
-            if prog.current_level == 0 {
-                prog.current_level = 1;
-                prog.current_seed = rand::random();
-            }
-            progress::save(prog)?;
-            editor.clear();
-            log.push(LogEntry::TierChoice { chosen });
-            log.push(level_prompt_entry(prog, registry, tier));
-            *screen = Screen::Game;
-            *focus = default_focus(screen);
-        }
-        (Screen::TierSelect { .. }, KeyCode::Char('q')) => return Ok(true),
-        (Screen::TierSelect { .. }, KeyCode::PageUp) => log.scroll_up(10),
-        (Screen::TierSelect { .. }, KeyCode::PageDown) => log.scroll_down(10),
-
         (Screen::ResetConfirm, KeyCode::Char('y')) => {
             let _ = std::fs::remove_file(progress::save_path());
             *prog = Progress::default();
@@ -529,11 +505,11 @@ fn step(
         (Screen::Completed, KeyCode::Down) => log.scroll_down(1),
         (Screen::Completed, KeyCode::PageUp) => log.scroll_up(10),
         (Screen::Completed, KeyCode::PageDown) => log.scroll_down(10),
+        (Screen::Completed, KeyCode::Char('q')) => return Ok(true),
         (Screen::Completed, KeyCode::Char('r')) => {
             *screen = Screen::ResetConfirm;
             *focus = default_focus(screen);
         }
-        (Screen::Completed, KeyCode::Char('q')) => return Ok(true),
 
         _ => {}
     }
@@ -559,38 +535,39 @@ fn grade(
     let level = &registry[idx];
     let g = level.generate(prog.current_seed);
     let score = similarity::semantic_or_textual(&g.target_yaml, &candidate);
-    let tier = prog.tier.expect("tier set before grading");
-    let threshold = tier.threshold();
-    let passed = score >= threshold;
     let level_name = level.name().to_string();
     let level_id = level.id();
 
-    if passed {
+    match Nugget::from_score(score) {
-        prog.completed.push(level_id);
+        Some(nugget) => {
-        prog.current_level += 1;
+            prog.nuggets.push((level_id, nugget));
-        prog.current_seed = rand::random();
+            prog.current_level += 1;
-        progress::save(prog)?;
+            prog.current_seed = rand::random();
-        log.push(LogEntry::ResultPass {
+            progress::save(prog)?;
-            level_name,
+            log.push(LogEntry::ResultPass {
-            score,
+                level_name,
-            threshold,
+                score,
-        });
+                nugget,
+            });
 
-        // Append the next LevelPrompt, or Completed if we ran out.
+            // Append the next LevelPrompt, or Completed if we ran out.
-        let next_idx = (prog.current_level - 1) as usize;
+            let next_idx = (prog.current_level - 1) as usize;
-        if next_idx >= registry.len() {
+            if next_idx >= registry.len() {
-            log.push(LogEntry::Completed);
+                let (gold, silver, bronze) = count_nuggets(&prog.nuggets);
-        } else {
+                log.push(LogEntry::Completed {
-            log.push(level_prompt_entry(prog, registry, tier));
+                    gold,
+                    silver,
+                    bronze,
+                });
+            } else {
+                log.push(level_prompt_entry(prog, registry));
+            }
+        }
+        None => {
+            prog.attempts += 1;
+            progress::save(prog)?;
+            log.push(LogEntry::ResultFail { level_name, score });
         }
-    } else {
-        prog.attempts += 1;
-        progress::save(prog)?;
-        log.push(LogEntry::ResultFail {
-            level_name,
-            score,
-            threshold,
-        });
     }
 
     Ok(())
@@ -621,16 +598,7 @@ fn render(
     let (left, right) = (chunks[0], chunks[1]);
 
     match screen {
-        Screen::Welcome => {
+        Screen::Welcome => render_log(frame, left, log, None, typewriter),
-            render_log(frame, left, log, Some(&welcome_prompt_lines()), typewriter)
-        }
-        Screen::TierSelect { cursor } => render_log(
-            frame,
-            left,
-            log,
-            Some(&tier_picker_lines(*cursor)),
-            typewriter,
-        ),
         Screen::Game | Screen::Completed => render_log(frame, left, log, None, typewriter),
         Screen::ResetConfirm => render_reset_confirm(frame, left),
     }
@@ -655,9 +623,6 @@ fn status_text(screen: &Screen, focus: Focus) -> String {
         (Screen::Welcome, _) => {
             " [Enter] begin · [↑/↓] scroll · [PgUp/PgDn] page · [q] quit".into()
         }
-        (Screen::TierSelect { .. }, _) => {
-            " [↑/↓] choose · [Enter] confirm · [PgUp/PgDn] scroll · [q] quit".into()
-        }
         (Screen::Game, Focus::Editor) => {
             " [Ctrl-X] grade · [Tab] focus log · [Esc] focus log · [Ctrl-Q] quit".into()
         }
@@ -677,28 +642,6 @@ fn screen_widget<'a>(title: String, body: String) -> Paragraph<'a> {
         .wrap(Wrap { trim: false })
 }
 
-fn welcome_prompt_lines() -> Vec<String> {
-    vec![
-        "🏰 You stand at the entrance, brave explorer. Press [Enter] to enter the dungeon.".to_string(),
-    ]
-}
-
-fn tier_picker_lines(cursor: u8) -> Vec<String> {
-    let rows = [
-        ("🥉", "Easy",   "70 %", "forgive small slips"),
-        ("🥈", "Medium", "80 %", "most details must match"),
-        ("🥇", "Hard",   "95 %", "only near-perfect passes"),
-    ];
-    let mut v = vec!["🎚  Choose your tier:".to_string()];
-    for (i, (emoji, name, pct, hint)) in rows.iter().enumerate() {
-        let marker = if i == cursor as usize { "›" } else { " " };
-        v.push(format!("  {marker} {emoji} {name:<7} ({pct})   {hint}"));
-    }
-    v.push(String::new());
-    v.push("   ↑/↓ choose · [Enter] confirm · [PgUp/PgDn] scroll · [q] quit".to_string());
-    v
-}
-
 fn render_reset_confirm(frame: &mut Frame, area: Rect) {
     let body = "\n💀  Wipe progress and start over?\n\n[y] yes, wipe · any other key cancels"
         .to_string();
@@ -726,8 +669,8 @@ fn render_log(
         };
         all_lines.extend(entry_view);
     }
-    // Append the transient prompt (Welcome / TierSelect) as the bottom block.
+    // Append the transient prompt (rare — none currently) as the bottom
-    // It's part of the bottom-anchored view but not part of the log itself.
+    // block. Kept for future use.
     if let Some(prompt) = trailing_prompt {
         if !all_lines.is_empty() {
             all_lines.push(String::new());
@@ -770,11 +713,16 @@ fn truncate_entry_to_chars(entry: &LogEntry, max_chars: usize) -> Vec<String> {
 fn entry_lines(entry: &LogEntry) -> Vec<String> {
     match entry {
         LogEntry::Intro => vec![
+            "🏰 You stand at the entrance, brave explorer.".to_string(),
+            String::new(),
             "🌀 YAMLabyrinth — learn YAML by writing your way through.".to_string(),
             String::new(),
             "  Each chamber reveals a target. Match it with YAML in the editor".to_string(),
             "  on the right, then press Ctrl-X to grade your attempt.".to_string(),
             String::new(),
+            "  Score ≥ 95 % → 🥇 Gold · ≥ 80 % → 🥈 Silver · ≥ 70 % → 🥉 Bronze.".to_string(),
+            "  Below 70 % means retry — refine your YAML and press Ctrl-X again.".to_string(),
+            String::new(),
             "  ⌨  Controls".to_string(),
             "    [Tab]            swap focus between log and editor".to_string(),
             "    [Ctrl-X]         grade your YAML".to_string(),
@@ -783,28 +731,14 @@ fn entry_lines(entry: &LogEntry) -> Vec<String> {
             "    [r]              reset progress".to_string(),
             "    [q] / [Ctrl-Q]   quit".to_string(),
         ],
-        LogEntry::TierChoice { chosen } => {
-            let rows = [
-                ("🥉", "Easy",   "70 %", "forgive small slips"),
-                ("🥈", "Medium", "80 %", "most details must match"),
-                ("🥇", "Hard",   "95 %", "only near-perfect passes"),
-            ];
-            let mut v = vec!["🎚  Difficulty".to_string(), String::new()];
-            for (i, (emoji, name, pct, hint)) in rows.iter().enumerate() {
-                let mark = if i == *chosen as usize { "  ← chosen" } else { "" };
-                v.push(format!("   {emoji} {name:<7} ({pct})   {hint}{mark}"));
-            }
-            v
-        }
         LogEntry::LevelPrompt {
             level_id,
             level_name,
-            tier_name,
             flavor,
             description,
         } => {
             let mut v = vec![
-                format!("🗺  Level {} — {} ({})", level_id, level_name, tier_name),
+                format!("🗺  Level {} — {}", level_id, level_name),
                 flavor.clone(),
                 String::new(),
             ];
@@ -816,23 +750,19 @@ fn entry_lines(entry: &LogEntry) -> Vec<String> {
         LogEntry::ResultPass {
             level_name,
             score,
-            threshold,
+            nugget,
         } => vec![format!(
-            "  🗝  {} cleared at {:.0} %   (threshold {:.0} %)  ✨",
+            "  {} {} cleared with a {} nugget at {:.0} %  ✨",
+            nugget.emoji(),
             level_name,
+            nugget.name(),
             score * 100.0,
-            threshold * 100.0
         )],
-        LogEntry::ResultFail {
+        LogEntry::ResultFail { level_name, score } => vec![
-            level_name,
-            score,
-            threshold,
-        } => vec![
             format!(
-                "  🕸  {} not yet — {:.0} %   (threshold {:.0} %)",
+                "  🕸  {} not yet — {:.0} %   (need 70 % for a 🥉 Bronze)",
                 level_name,
                 score * 100.0,
-                threshold * 100.0
             ),
             "     Refine your YAML and press Ctrl-X to retry.".to_string(),
         ],
@@ -841,8 +771,13 @@ fn entry_lines(entry: &LogEntry) -> Vec<String> {
             format!("     {error}"),
             "     Fix it in the editor and press Ctrl-X to retry.".to_string(),
         ],
-        LogEntry::Completed => vec![
+        LogEntry::Completed {
+            gold,
+            silver,
+            bronze,
+        } => vec![
             "  🏆 Labyrinth complete!".to_string(),
+            format!("     🥇 ×{}  🥈 ×{}  🥉 ×{}", gold, silver, bronze),
             "     [r] reset and replay · [q] quit".to_string(),
         ],
     }
@@ -877,7 +812,7 @@ fn render_editor(frame: &mut Frame, area: Rect, editor: &Editor, focused: bool)
 }
 
 fn render_editor_inactive(frame: &mut Frame, area: Rect) {
-    let body = "\n  🪶 The quill rests. Pick a tier first…".to_string();
+    let body = "\n  🪶 The quill rests. Press [Enter] on the welcome screen to begin.".to_string();
     frame.render_widget(
         screen_widget(" 📝 Editor (inactive) ".to_string(), body),
         area,