"""Detect orphan templates (never rendered) and orphan static assets."""
from __future__ import annotations

import os
import re

# Walk up until we find the project root (robust to the tool living in a
# nested folder such as docs/tools/).
_here = os.path.dirname(os.path.abspath(__file__))
while _here != os.path.dirname(_here) and not os.path.isdir(os.path.join(_here, 'app')):
    _here = os.path.dirname(_here)
REPO = _here
APP = os.path.join(REPO, 'app')
TPL = os.path.join(APP, 'templates')


def read(p):
    return open(p, encoding='utf-8', errors='replace').read()


# gather all render_template('x.html') calls
rendered = set()
for root, dirs, files in os.walk(APP):
    dirs[:] = [d for d in dirs if d not in ('__pycache__', 'templates')]
    for f in files:
        if f.endswith('.py'):
            s = read(os.path.join(root, f))
            rendered |= set(re.findall(r"render_template\(\s*['\"]([^'\"]+)['\"]", s))
            # render_template with variable name - note it
            rendered |= set(re.findall(r"render_template\(\s*([a-z_]+)", s)) - {'f'}

# gather extends/include/import references
refs = set()
for root, dirs, files in os.walk(TPL):
    for f in files:
        if f.endswith('.html'):
            s = read(os.path.join(root, f))
            for pat in (r"{%\s*extends\s*['\"]([^'\"]+)['\"]",
                        r"{%\s*include\s*['\"]([^'\"]+)['\"]",
                        r"{%\s*import\s*['\"]([^'\"]+)['\"]",
                        r"render_template\(\s*['\"]([^'\"]+)['\"]"):
                refs |= set(re.findall(pat, s))

all_tpl = []
for root, dirs, files in os.walk(TPL):
    for f in files:
        if f.endswith('.html'):
            all_tpl.append(os.path.relpath(os.path.join(root, f), TPL))

referenced = rendered | refs
orphans = []
for t in sorted(all_tpl):
    base = os.path.basename(t)
    if t in referenced or base in referenced:
        continue
    # macro/library files are referenced dynamically sometimes
    orphans.append(t)

print(f'templates total     : {len(all_tpl)}')
print(f'referenced          : {len([t for t in all_tpl if t not in orphans])}')
print(f'ORPHAN templates    : {len(orphans)}')
print()
for o in orphans:
    lines = len(read(os.path.join(TPL, o)).splitlines())
    print(f'   ✗ {o:<58} {lines} lines')