stats: Add histogram generator

An SVG histogram can now be generated into a configurable path
(static/histogram.svg by default) by using the `hist` CLI command.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

.gitignore

@@ -1,3 +1,4 @@
+histogram.svg
 cache
 bans
 thumbs

chanbans/__main__.py

@@ -4,6 +4,7 @@ import logging
 
 from .pull import pull
 from .http import run_app
+from .hist import generate_histogram_svg
 
 
 def parse_args():
@@ -30,6 +31,14 @@ def parse_args():
         "pull",
         help="Pull bans from 4chan, save thumbnails, update the database, and exit",
     )
+
+    _histogram_parser = add_subcommand(
+        "hist",
+        help="Generate histogram file.",
+        # This doesn't work as expected for some reason. Doesn't get parsed correctly
+        #aliases=["histogram"],
+    )
+
     _serve_parser = add_subcommand("serve", help="Start HTTP server")
     _help_parser = add_subcommand("help", help="Show this help message")
 
@@ -57,6 +66,8 @@ def main():
             asyncio.run(pull())
         case "serve":
             run_app()
+        case "hist":
+            generate_histogram_svg()
         case command:
             assert (
                 False

chanbans/config.py

@@ -47,3 +47,5 @@ STATIC_LOCAL_FOLLOW_SYMLINKS = one_of_default(
     "STATIC_LOCAL_FOLLOW_SYMLINKS", ("yes", "true", "1", "no", "false", "0"), "true"
 ) in ("yes", "true", "1")
 STATIC_ROOT = default("STATIC_ROOT", "/static")
+
+HISTOGRAM_PATH = Path(default("HISTOGRAM_PATH", "static/histogram.svg"))

chanbans/hist.py

@@ -0,0 +1,35 @@
+from .db import get_db
+from .config import HISTOGRAM_PATH
+from pathlib import Path
+
+
+def histogram_svg():
+    db = get_db()
+    cursor = db.cursor()
+
+    cursor.execute("SELECT board, COUNT(*) AS count FROM bans GROUP BY board")
+    data = list(cursor.fetchall())
+
+    max_count = max(data, key=lambda x: x["count"])["count"]
+    scale_factor = 200 / max_count
+
+    bar_width = 30
+    bar_padding = 5
+    svg_width = (bar_width + bar_padding) * len(data)
+
+    svg = f'<svg width="{svg_width}" height="300" xmlns="http://www.w3.org/2000/svg">'
+    for i, row in enumerate(data):
+        board = row["board"]
+        count = row["count"]
+        x = i * (bar_width + bar_padding)
+        y = 250 - (count * scale_factor)
+        svg += f'<rect x="{x}" y="{y}" width="{bar_width}" height="{count * scale_factor}" fill="blue" />'
+        svg += f'<text x="{x + 15}" y="280" font-size="12" text-anchor="middle">{board}</text>'
+        svg += f'<text x="{x + 15}" y="{y - 5}" font-size="12" text-anchor="middle">{count}</text>'
+    svg += "</svg>"
+    return svg
+
+
+def generate_histogram_svg(path: Path = HISTOGRAM_PATH):
+    svg = histogram_svg()
+    path = path.write_text(svg)