feat: add customisable spellcheck (#6)

* feat(landing): update landing page to include new option
* chore: version bump + changelog
* docs: add VALID_LANGUAGES
* docs: add SPELL CHECK section in REFERENCE
* feat(spellcheck): implement customizable spell check setup and language selection
* test(spellcheck): add tests for spell check functionality and language setup

Author: DeepanshKhurana

CHANGELOG.md

@@ -5,6 +5,18 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.5.0] - 2026-04-27
+
+### Added
+
+- Spell check now supports 80+ languages powered by hunspell, including Hungarian, Arabic, Polish, French, and many more. Language is set per profile during setup and can be changed any time in manage profiles.
+- Spell check language selection is part of the setup wizard and the new profile flow.
+- Existing users are prompted to set a language on first launch after upgrading, with the option to configure each profile individually.
+- `--languages` flag lists all supported language codes with names.
+- Spellcheck settings persist per profile.
+- Spell check on/off toggle added to edit and new profile modals (`ctrl+k`).
+- SPELL CHECK section added to `--reference`.
+
 ## [1.4.5] - 2026-04-27
 
 ### Added

landing/documentation.html

@@ -46,8 +46,8 @@ <h2 class="docs-heading"># Options</h2>
                             <span class="docs-desc">Run setup wizard again</span>
                         </div>
                         <div class="docs-row">
-                            <span class="docs-option">--reference</span>
-                            <span class="docs-desc">Show reference</span>
+                            <span class="docs-option">--reference / --languages </span>
+                            <span class="docs-desc">Show reference or list valid languages</span>
                         </div>
                         <div class="docs-row">
                             <span class="docs-option">--license</span>

prosaic/REFERENCE

@@ -83,6 +83,19 @@ Each profile has its own archive, git remote, and theme.
 Manage from dashboard (m key) or edit settings.json.
 
 
+SPELL CHECK
+-----------
+
+Spell check is powered by hunspell and supports 80+ languages.
+Each profile has its own language setting.
+
+  F7                          Toggle spell check on/off
+  prosaic --languages         List all supported language codes
+
+Language is set per profile during setup or via manage profiles (m).
+Misspelled words are underlined in the editor.
+
+
 PANE DEFAULTS
 -------------
 

prosaic/VALID_LANGUAGES

@@ -0,0 +1,78 @@
+af_ZA	Afrikaans
+an_ES	Aragonese
+ar	Arabic
+be_BY	Belarusian
+bg_BG	Bulgarian
+br_FR	Breton
+ca_ES	Catalan
+cs_CZ	Czech
+da_DK	Danish
+de_AT	German (Austria)
+de_CH	German (Switzerland)
+de_DE	German (Germany)
+el_GR	Greek
+en_AU	English (Australian)
+en_CA	English (Canada)
+en_GB	English (Great Britain)
+en_US	English (US)
+en_ZA	English (South African)
+es	Spanish (all variants)
+es_AR	Spanish (Argentina)
+es_BO	Spanish (Bolivia)
+es_CL	Spanish (Chile)
+es_CO	Spanish (Colombia)
+es_CR	Spanish (Costa Rica)
+es_CU	Spanish (Cuba)
+es_DO	Spanish (Dominican Republic)
+es_EC	Spanish (Ecuador)
+es_ES	Spanish (Spain)
+es_GQ	Spanish (Equatorial Guinea)
+es_GT	Spanish (Guatemala)
+es_HN	Spanish (Honduras)
+es_MX	Spanish (Mexico)
+es_NI	Spanish (Nicaragua)
+es_PA	Spanish (Panama)
+es_PE	Spanish (Peru)
+es_PH	Spanish (Philippines)
+es_PR	Spanish (Puerto Rico)
+es_PY	Spanish (Paraguay)
+es_SV	Spanish (El Salvador)
+es_US	Spanish (US)
+es_UY	Spanish (Uruguay)
+es_VE	Spanish (Venezuela)
+et_EE	Estonian
+fr_FR	French
+gd_GB	Scottish Gaelic
+gu_IN	Gujarati
+gug_PY	Guarani
+he_IL	Hebrew
+hi_IN	Hindi
+hr_HR	Croatian
+hu_HU	Hungarian
+id_ID	Indonesian
+is	Icelandic
+it_IT	Italian
+ku_TR	Kurdish (Turkey)
+lt_LT	Lithuanian
+lv_LV	Latvian
+md	Mapudungun
+nb_NO	Norwegian (Bokmal)
+nl_NL	Dutch (Netherlands)
+nn_NO	Norwegian (Nynorsk)
+oc_FR	Occitan
+pl_PL	Polish
+pt_BR	Portuguese (Brazilian)
+pt_PT	Portuguese
+ro_RO	Romanian
+si_LK	Sinhala
+sk_SK	Slovak
+sl_SI	Slovenian
+sr	Serbian (Cyrillic)
+sr-Latn	Serbian (Latin)
+sv_SE	Swedish
+sw_TZ	Swahili
+ta	Tamil
+th_TH	Thai
+tr_TR	Turkish
+uk_UA	Ukrainian
+vi_VN	Vietnamese

prosaic/__main__.py

@@ -8,19 +8,25 @@
 from textual.screen import ModalScreen
 
 from prosaic.config import (
+    LANGUAGE_NAMES,
+    VALID_LANGUAGE_CODES,
     ensure_workspace,
     get_active_profile,
     get_app_version,
     get_notes_path,
     get_profile_config,
     get_workspace_dir,
-    list_profiles,
     load_config,
+    needs_language_setup,
+    profiles_needing_language_setup,
     save_config,
+    save_profile_config,
     set_active_profile,
     set_last_file,
+    set_spell_check_enabled,
     was_just_migrated,
 )
+
 from prosaic.core.metrics import MetricsTracker
 from prosaic.screens import DashboardScreen, EditorScreen
 from prosaic.themes import PROSAIC_DARK_CSS, PROSAIC_LIGHT_CSS
@@ -47,6 +53,66 @@ def _get_license_text() -> str:
     return _wrap_output(content)
 
 
+def _run_spell_setup(profile_name: str) -> None:
+    """Run the one-time spell check setup for existing users upgrading to 1.5.0."""
+    current_version = get_app_version()
+    click.echo()
+    click.secho(f"welcome to prosaic {current_version}!", fg="yellow", bold=True)
+    click.echo(
+        "this version brings a more powerful spell check with support for"
+        " 80+ languages powered by hunspell."
+    )
+    click.echo()
+
+    enable = click.confirm("enable spell check?", default=True)
+    set_spell_check_enabled(enable, profile_name)
+
+    if not enable:
+        return
+
+    click.echo()
+    for code in sorted(VALID_LANGUAGE_CODES):
+        name = LANGUAGE_NAMES.get(code, "")
+        click.echo(f"  {code:<10}  {name}")
+    click.echo()
+    click.echo("you can also view this later with:  prosaic --languages")
+    click.echo()
+    lang = click.prompt(
+        f"language for '{profile_name}'",
+        default="en_US",
+        show_default=True,
+    ).strip()
+    if lang not in VALID_LANGUAGE_CODES:
+        click.secho(f"unknown language code '{lang}' — defaulting to en_US", fg="yellow")
+        lang = "en_US"
+    else:
+        click.secho(f"  {LANGUAGE_NAMES.get(lang, lang)}", fg="green")
+
+    data = get_profile_config(profile_name)
+    data["spell_language"] = lang
+    save_profile_config(data, profile_name)
+
+    others = [p for p in profiles_needing_language_setup() if p != profile_name]
+    if others:
+        click.echo()
+        if click.confirm(f"configure other profiles now? ({', '.join(others)})", default=False):
+            for other in others:
+                click.echo()
+                other_lang = click.prompt(
+                    f"language for '{other}'",
+                    default="en_US",
+                    show_default=True,
+                ).strip()
+                if other_lang not in VALID_LANGUAGE_CODES:
+                    click.secho(f"  unknown code '{other_lang}' — defaulting to en_US", fg="yellow")
+                    other_lang = "en_US"
+                else:
+                    click.secho(f"  {LANGUAGE_NAMES.get(other_lang, other_lang)}", fg="green")
+                other_data = get_profile_config(other)
+                other_data["spell_language"] = other_lang
+                save_profile_config(other_data, other)
+
+
 class ProsaicApp(App):
     """Main Prosaic application."""
 
@@ -178,6 +244,7 @@ def action_hide_help_panel(self) -> None:
 @click.option("--setup", is_flag=True, help="Run setup wizard again")
 @click.option("--profile", default=None, help="Use a named profile (see --profiles)")
 @click.option("--profiles", "show_profiles", is_flag=True, help="List available profiles")
+@click.option("--languages", "show_languages", is_flag=True, help="List valid spell check language codes")
 @click.option("--reference", is_flag=True, help="Show reference")
 @click.option("--license", "show_license", is_flag=True, help="Show MIT license")
 @click.argument("file", required=False, type=click.Path())
@@ -186,6 +253,7 @@ def main(
     setup: bool,
     profile: str | None,
     show_profiles: bool,
+    show_languages: bool,
     reference: bool,
     show_license: bool,
     file: str | None,
@@ -206,6 +274,16 @@ def main(
             click.echo("no profiles configured. run: prosaic --setup")
         return
 
+    if show_languages:
+        click.echo("valid spell check language codes:")
+        click.echo()
+        for code in sorted(VALID_LANGUAGE_CODES):
+            name = LANGUAGE_NAMES.get(code, "")
+            click.echo(f"  {code:<10}  {name}")
+        click.echo()
+        click.echo("set language in manage profiles (m) or via  prosaic --profile <name>")
+        return
+
     if reference:
         click.echo(_get_reference_text())
         return
@@ -223,16 +301,16 @@ def main(
 
     if is_legacy_upgrade and not setup:
         click.echo()
-        click.secho(f"new in prosaic {current_version}!", fg="yellow", bold=True)
+        click.secho(f"hello from prosaic {current_version}!", fg="yellow", bold=True)
         click.echo()
-        click.echo("this version introduces profiles - separate workspaces for")
-        click.echo("different writing projects (personal, work, fiction, etc.)")
+        click.echo("looks like you just upgraded. we've automatically migrated")
+        click.echo("your config to the new format and taken a backup just in case.")
         click.echo()
+        click.echo("this version introduces profiles — separate workspaces for")
+        click.echo("different writing projects (personal, work, fiction, etc.)")
         click.echo("your existing setup has been preserved as the 'default' profile.")
         click.echo()
-
-        click.echo("would you like to learn about profiles and set up more now?")
-        click.echo("you can always do it later with prosaic --setup")
+        click.echo("you can always run  prosaic --setup  to configure more.")
         click.echo()
         run_profiles_setup = click.confirm("set up profiles now?", default=False)
 
@@ -272,11 +350,15 @@ def main(
                 setup_workspace(profile_data)
 
         set_active_profile(result["active_profile"])
+        profile_name = result["active_profile"]
 
     if config.get("app_version") != current_version:
         config["app_version"] = current_version
         save_config(config)
 
+    if needs_language_setup(profile_name):
+        _run_spell_setup(profile_name)
+
     if light is None:
         profile_config = get_profile_config(get_active_profile())
         light_mode = profile_config.get("theme", "light") == "light"

prosaic/config.py

@@ -15,6 +15,34 @@
 
 _active_profile: str = "default"
 _just_migrated: bool = False
+_runtime_config: dict | None = None
+
+def _load_valid_languages() -> tuple[frozenset[str], dict[str, str]]:
+    path = Path(__file__).parent / "VALID_LANGUAGES"
+    try:
+        lines = path.read_text(encoding="utf-8").splitlines()
+        codes = {}
+        for line in lines:
+            parts = line.split("\t", 1)
+            if len(parts) == 2:
+                codes[parts[0].strip()] = parts[1].strip()
+        return frozenset(codes.keys()), codes
+    except OSError:
+        return frozenset({"en_US", "en_GB"}), {"en_US": "English (US)", "en_GB": "English (Great Britain)"}
+
+VALID_LANGUAGE_CODES, LANGUAGE_NAMES = _load_valid_languages()
+
+
+def get_spell_check_enabled(profile_name: str | None = None) -> bool:
+    """Return whether spell check is enabled for a profile."""
+    return get_profile_config(profile_name).get("spell_check_enabled", True)
+
+
+def set_spell_check_enabled(enabled: bool, profile_name: str | None = None) -> None:
+    """Persist spell check enabled state for a profile."""
+    profile = get_profile_config(profile_name)
+    profile["spell_check_enabled"] = enabled
+    save_profile_config(profile, profile_name)
 
 
 def get_active_profile() -> str:
@@ -123,8 +151,16 @@ def migrate_config(config: dict) -> dict:
 def load_config() -> dict:
     """Load configuration from settings.json.
 
-    Automatically migrates legacy configs to v2 format.
+    Migrates legacy configs to v2 format in memory. The migrated config is
+    cached and only written to disk when save_config() is called explicitly
+    (after setup completes), so the user's original file is never overwritten
+    until they finish setup.
     """
+    global _runtime_config, _just_migrated
+
+    if _runtime_config is not None:
+        return _runtime_config
+
     config_path = get_config_path()
     if not config_path.exists():
         return {}
@@ -135,20 +171,21 @@ def load_config() -> dict:
         return {}
 
     if "app_version" not in config and config.get("setup_complete"):
-        global _just_migrated
         _just_migrated = True
         backup_config()
         config = migrate_config(config)
-        save_config(config)
+        _runtime_config = config  # cache in memory; main() saves after setup
 
     return config
 
 
 def save_config(config: dict) -> None:
     """Save configuration to settings.json."""
+    global _runtime_config
     config_path = get_config_path()
     config_path.parent.mkdir(parents=True, exist_ok=True)
     write_text(config_path, json.dumps(config, indent=2))
+    _runtime_config = None  # clear cache; disk is now authoritative
 
 
 def get_profile_config(profile_name: str | None = None) -> dict:
@@ -306,6 +343,16 @@ def set_last_file(path: Path) -> None:
     save_profile_config(profile)
 
 
+def needs_language_setup(profile_name: str | None = None) -> bool:
+    """Return True if this profile has no spell_language set yet."""
+    return "spell_language" not in get_profile_config(profile_name)
+
+
+def profiles_needing_language_setup() -> list[str]:
+    """Return all profile names that have no spell_language set."""
+    return [p for p in list_profiles() if needs_language_setup(p)]
+
+
 def ensure_workspace() -> None:
     """Ensure the workspace structure exists."""
     dirs = [