"""Convert every PDF in examples/ into a static HTML/CSS site under output/.

Shells out to poppler-utils (pdftocairo, pdftotext, pdfinfo). No third-party deps.
Usage: python main.py    (or: uv run python main.py)
"""

from __future__ import annotations

import html
import re
import shutil
import subprocess
import sys
from pathlib import Path

ROOT = Path(__file__).parent
EXAMPLES_DIR = ROOT / "examples"
OUTPUT_DIR = ROOT / "output"

DPI_FULL = 150
DPI_THUMB = 30
JPEG_QUALITY_FULL = 85
JPEG_QUALITY_THUMB = 80

REQUIRED_BINARIES = ("pdftocairo", "pdftotext", "pdfinfo")


def main() -> int:
    missing = [b for b in REQUIRED_BINARIES if shutil.which(b) is None]
    if missing:
        print(f"error: missing poppler-utils binaries: {', '.join(missing)}", file=sys.stderr)
        print("install with: sudo apt install poppler-utils", file=sys.stderr)
        return 1

    if not EXAMPLES_DIR.is_dir():
        print(f"error: {EXAMPLES_DIR} does not exist", file=sys.stderr)
        return 1

    pdfs = sorted(EXAMPLES_DIR.glob("*.pdf"))
    if not pdfs:
        print(f"error: no PDFs found in {EXAMPLES_DIR}", file=sys.stderr)
        return 1

    OUTPUT_DIR.mkdir(exist_ok=True)
    write_shared_css()

    issues = []
    for pdf in pdfs:
        print(f"converting {pdf.name} ...")
        issues.append(convert_pdf(pdf))

    write_root_index(issues)
    print(f"\ndone. open {OUTPUT_DIR / 'index.html'} in a browser.")
    return 0


def convert_pdf(pdf_path: Path) -> dict:
    stem = pdf_path.stem
    out = OUTPUT_DIR / stem
    reset_dir(out)

    page_count = pdf_page_count(pdf_path)
    page_texts = extract_text_per_page(pdf_path, page_count)

    for n in range(1, page_count + 1):
        render_jpeg(pdf_path, out / f"page-{n:02d}", n, DPI_FULL, JPEG_QUALITY_FULL)
        render_jpeg(pdf_path, out / f"thumb-{n:02d}", n, DPI_THUMB, JPEG_QUALITY_THUMB)
        write_page_html(out, stem, n, page_count, page_texts[n - 1])

    write_issue_index(out, stem, page_count)
    return {"stem": stem, "title": stem, "pages": page_count}


def reset_dir(path: Path) -> None:
    if path.exists():
        shutil.rmtree(path)
    path.mkdir(parents=True)


def pdf_page_count(pdf_path: Path) -> int:
    out = subprocess.run(
        ["pdfinfo", str(pdf_path)], check=True, capture_output=True, text=True
    ).stdout
    m = re.search(r"^Pages:\s+(\d+)", out, re.MULTILINE)
    if not m:
        raise RuntimeError(f"could not parse page count from pdfinfo for {pdf_path}")
    return int(m.group(1))


def extract_text_per_page(pdf_path: Path, page_count: int) -> list[str]:
    """Return a list of page texts. pdftotext separates pages with form-feed (\\f)."""
    out = subprocess.run(
        ["pdftotext", "-layout", str(pdf_path), "-"],
        check=True,
        capture_output=True,
        text=True,
    ).stdout
    pages = out.split("\f")
    # pdftotext appends a trailing form-feed → one extra empty element; trim it.
    if pages and pages[-1] == "":
        pages.pop()
    # Pad/truncate so the list matches page_count exactly (defensive).
    while len(pages) < page_count:
        pages.append("")
    return pages[:page_count]


def render_jpeg(pdf_path: Path, out_stem: Path, page: int, dpi: int, quality: int) -> None:
    """pdftocairo always appends -<page>.jpg unless -singlefile is used.

    We render one page at a time with -singlefile so the output filename is exact.
    """
    subprocess.run(
        [
            "pdftocairo",
            "-jpeg",
            "-jpegopt",
            f"quality={quality}",
            "-r",
            str(dpi),
            "-f",
            str(page),
            "-l",
            str(page),
            "-singlefile",
            str(pdf_path),
            str(out_stem),  # pdftocairo appends .jpg automatically
        ],
        check=True,
        capture_output=True,
    )


# ---------- HTML emission ----------


def write_shared_css() -> None:
    (OUTPUT_DIR / "styles.css").write_text(SHARED_CSS, encoding="utf-8")


def write_root_index(issues: list[dict]) -> None:
    cards = "\n".join(
        f"""    <a class="card" href="{html.escape(i['stem'])}/index.html">
      <img src="{html.escape(i['stem'])}/thumb-01.jpg" alt="Cover of {html.escape(i['title'])}">
      <h2>{html.escape(i['title'])}</h2>
      <p>{i['pages']} pages</p>
    </a>"""
        for i in issues
    )
    page = PAGE_SHELL.format(
        title="NETgazet archive",
        css_href="styles.css",
        body=f"""  <header>
    <h1>NETgazet archive</h1>
    <p>Static HTML rendering of the available editions.</p>
  </header>
  <main class="card-grid">
{cards}
  </main>""",
    )
    (OUTPUT_DIR / "index.html").write_text(page, encoding="utf-8")


def write_issue_index(out: Path, stem: str, page_count: int) -> None:
    thumbs = "\n".join(
        f"""    <a class="thumb" href="page-{n:02d}.html">
      <img src="thumb-{n:02d}.jpg" alt="Page {n}" loading="lazy">
      <span>Page {n}</span>
    </a>"""
        for n in range(1, page_count + 1)
    )
    page = PAGE_SHELL.format(
        title=html.escape(stem),
        css_href="../styles.css",
        body=f"""  <header>
    <p><a href="../index.html">← all editions</a></p>
    <h1>{html.escape(stem)}</h1>
    <p>{page_count} pages — tap a thumbnail to read.</p>
  </header>
  <main class="thumb-grid">
{thumbs}
  </main>""",
    )
    (out / "index.html").write_text(page, encoding="utf-8")


def write_page_html(out: Path, stem: str, n: int, total: int, text: str) -> None:
    prev_link = (
        f'<a href="page-{n - 1:02d}.html" rel="prev">← Page {n - 1}</a>'
        if n > 1
        else '<span class="nav-disabled">← Page</span>'
    )
    next_link = (
        f'<a href="page-{n + 1:02d}.html" rel="next">Page {n + 1} →</a>'
        if n < total
        else '<span class="nav-disabled">Page →</span>'
    )
    text_block = (
        f"""  <details class="page-text">
    <summary>Show page text</summary>
    <pre>{html.escape(text)}</pre>
  </details>"""
        if text.strip()
        else ""
    )
    body = f"""  <header>
    <p><a href="index.html">← {html.escape(stem)}</a> · <a href="../index.html">all editions</a></p>
    <h1>Page {n} <span class="of">of {total}</span></h1>
  </header>
  <nav class="pager">
    {prev_link}
    <a href="index.html" class="nav-up">Index</a>
    {next_link}
  </nav>
  <main>
    <figure class="page">
      <img src="page-{n:02d}.jpg" alt="Page {n} of {html.escape(stem)}">
    </figure>
{text_block}
  </main>
  <nav class="pager pager-bottom">
    {prev_link}
    <a href="index.html" class="nav-up">Index</a>
    {next_link}
  </nav>"""
    page = PAGE_SHELL.format(
        title=f"{html.escape(stem)} — page {n}",
        css_href="../styles.css",
        body=body,
    )
    (out / f"page-{n:02d}.html").write_text(page, encoding="utf-8")


# ---------- Templates ----------

PAGE_SHELL = """<!doctype html>
<html lang="nl">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>{title}</title>
  <link rel="stylesheet" href="{css_href}">
</head>
<body>
{body}
</body>
</html>
"""

SHARED_CSS = """:root {
  --fg: #1a1a1a;
  --muted: #666;
  --bg: #fafafa;
  --card: #fff;
  --border: #e2e2e2;
  --accent: #1a4480;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--fg);
  background: var(--bg);
  line-height: 1.45;
  max-width: 1000px;
  margin: 0 auto;
  padding: 1rem;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
header { margin-bottom: 1.5rem; }
header h1 { margin: 0.25rem 0; font-size: 1.5rem; }
header p { margin: 0.25rem 0; color: var(--muted); }
.of { color: var(--muted); font-weight: normal; font-size: 0.85em; }

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1.25rem;
}
.card {
  display: block;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.75rem;
  color: inherit;
}
.card:hover { border-color: var(--accent); text-decoration: none; }
.card img { border: 1px solid var(--border); margin-bottom: 0.5rem; }
.card h2 { margin: 0.25rem 0; font-size: 1.05rem; }
.card p { margin: 0; color: var(--muted); font-size: 0.9rem; }

.thumb-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 1rem;
}
.thumb {
  display: block;
  text-align: center;
  color: inherit;
}
.thumb img {
  border: 1px solid var(--border);
  border-radius: 3px;
  margin: 0 auto 0.25rem;
}
.thumb:hover img { border-color: var(--accent); }
.thumb span { font-size: 0.85rem; color: var(--muted); }

.pager {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: space-between;
  align-items: center;
  margin: 1rem 0;
  padding: 0.5rem 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
}
.pager .nav-up { font-weight: 600; }
.pager .nav-disabled { color: #bbb; }
.pager-bottom { margin-top: 1rem; }

.page { margin: 0; }
.page img {
  border: 1px solid var(--border);
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
  margin: 0 auto;
}

.page-text {
  margin-top: 1rem;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.5rem 0.75rem;
}
.page-text summary {
  cursor: pointer;
  color: var(--accent);
  font-size: 0.95rem;
}
.page-text pre {
  white-space: pre-wrap;
  word-wrap: break-word;
  font-size: 0.85rem;
  line-height: 1.4;
  margin: 0.75rem 0 0;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

@media (max-width: 480px) {
  body { padding: 0.5rem; }
  header h1 { font-size: 1.25rem; }
  .pager { font-size: 0.85rem; }
}
"""


if __name__ == "__main__":
    sys.exit(main())