From 64b3a3c75334790fb9f41559e074c740e204d039 Mon Sep 17 00:00:00 2001
From: Tim Van Baak <tim.vanbaak@gmail.com>
Date: Wed, 2 Jun 2021 18:08:56 -0700
Subject: [PATCH] Add index backend

---
 amanuensis/backend/index.py | 74 +++++++++++++++++++++++++++++++++++++
 tests/test_index.py         | 50 +++++++++++++++++++++++++
 2 files changed, 124 insertions(+)
 create mode 100644 amanuensis/backend/index.py
 create mode 100644 tests/test_index.py

diff --git a/amanuensis/backend/index.py b/amanuensis/backend/index.py
new file mode 100644
index 0000000..7f108ec
--- /dev/null
+++ b/amanuensis/backend/index.py
@@ -0,0 +1,74 @@
+"""
+Index query interface
+"""
+
+import re
+from typing import Optional
+
+from amanuensis.db import DbContext, ArticleIndex, IndexType
+from amanuensis.errors import ArgumentError
+
+
+def create(
+    db: DbContext,
+    lexicon_id: int,
+    index_type: IndexType,
+    pattern: str,
+    logical_order: int,
+    display_order: int,
+    capacity: Optional[int],
+) -> ArticleIndex:
+    """
+    Create a new index in a lexicon.
+    """
+    # Verify argument types are correct
+    if not isinstance(lexicon_id, int):
+        raise ArgumentError("lexicon_id")
+    if not isinstance(index_type, IndexType):
+        raise ArgumentError("index_type")
+    if not isinstance(pattern, str):
+        raise ArgumentError("pattern")
+    if not isinstance(logical_order, int):
+        raise ArgumentError("logical_order")
+    if not isinstance(display_order, int):
+        raise ArgumentError("display_order")
+    if capacity is not None and not isinstance(capacity, int):
+        raise ArgumentError("capacity")
+
+    # Verify the pattern is valid for the index type:
+    if index_type == IndexType.CHAR:
+        if len(pattern) < 1:
+            raise ArgumentError(
+                f"Pattern '{pattern}' too short for index type {index_type}"
+            )
+    elif index_type == IndexType.RANGE:
+        range_def = re.match(r"^(.)-(.)$", pattern)
+        if not range_def:
+            raise ArgumentError(f"Pattern '{pattern}' is not a valid range format")
+        start_char, end_char = range_def.group(1), range_def.group(2)
+        if start_char >= end_char:
+            raise ArgumentError(
+                f"Range start '{start_char}' is not before range end '{end_char}'"
+            )
+    elif index_type == IndexType.PREFIX:
+        if len(pattern) < 1:
+            raise ArgumentError(
+                f"Pattern '{pattern}' too short for index type {index_type}"
+            )
+    elif index_type == IndexType.ETC:
+        if len(pattern) < 1:
+            raise ArgumentError(
+                f"Pattern '{pattern}' too short for index type {index_type}"
+            )
+
+    new_index = ArticleIndex(
+        lexicon_id=lexicon_id,
+        index_type=index_type,
+        pattern=pattern,
+        logical_order=logical_order,
+        display_order=display_order,
+        capacity=capacity,
+    )
+    db.session.add(new_index)
+    db.session.commit()
+    return new_index
diff --git a/tests/test_index.py b/tests/test_index.py
new file mode 100644
index 0000000..c5a2ac7
--- /dev/null
+++ b/tests/test_index.py
@@ -0,0 +1,50 @@
+from amanuensis.db.models import IndexType
+import pytest
+
+import amanuensis.backend.index as indq
+from amanuensis.db import DbContext, Lexicon, User
+
+from amanuensis.errors import ArgumentError
+
+
+def test_create_index(db: DbContext, make):
+    """Test new index creation"""
+    lexicon: Lexicon = make.lexicon()
+    defaults: dict = {
+        "db": db,
+        "lexicon_id": lexicon.id,
+        "index_type": IndexType.ETC,
+        "pattern": "&c.",
+        "logical_order": 0,
+        "display_order": 0,
+        "capacity": 0,
+    }
+    kwargs: dict
+
+    # Character indexes require nonempty patterns
+    with pytest.raises(ArgumentError):
+        kwargs = {**defaults, "index_type": IndexType.CHAR, "pattern": ""}
+        indq.create(**kwargs)
+    kwargs = {**defaults, "index_type": IndexType.CHAR, "pattern": "ABC"}
+    assert indq.create(**kwargs)
+
+    # Range indexes must follow the 1-2 format
+    with pytest.raises(ArgumentError):
+        kwargs = {**defaults, "index_type": IndexType.RANGE, "pattern": "ABC"}
+        indq.create(**kwargs)
+    kwargs = {**defaults, "index_type": IndexType.RANGE, "pattern": "A-F"}
+    assert indq.create(**kwargs)
+
+    # Prefix indexes require nonempty patterns
+    with pytest.raises(ArgumentError):
+        kwargs = {**defaults, "index_type": IndexType.CHAR, "pattern": ""}
+        indq.create(**kwargs)
+    kwargs = {**defaults, "index_type": IndexType.CHAR, "pattern": "Prefix:"}
+    assert indq.create(**kwargs)
+
+    # Etc indexes require nonempty patterns
+    with pytest.raises(ArgumentError):
+        kwargs = {**defaults, "index_type": IndexType.CHAR, "pattern": ""}
+        indq.create(**kwargs)
+    kwargs = {**defaults, "index_type": IndexType.CHAR, "pattern": "&c."}
+    assert indq.create(**kwargs)