"""
E-Ink Photo Frame Server

Serves photos for the ESP32 photo frame and provides a web UI for management.
Tracks frame status via heartbeat reports from the ESP32.

Endpoints:
    GET  /              Web UI — gallery, upload, frame status
    GET  /photo         Random JPEG resized to 800x480 (called by ESP32)
    POST /heartbeat     ESP32 reports what it displayed
    GET  /api/status    Frame status (for Home Assistant REST sensor)
    GET  /api/photos    List all photos as JSON
    POST /api/upload    Upload new photos
    DELETE /api/photos/<name>  Delete a photo
    GET  /health        Health check
"""

import argparse
import io
import json
import random
import sys
import time
from datetime import datetime, timezone
from pathlib import Path

from flask import Flask, Response, jsonify, request, render_template_string
from werkzeug.utils import secure_filename

from PIL import Image

app = Flask(__name__)

PHOTOS_DIR: Path = Path(".")
TARGET_WIDTH = 800
TARGET_HEIGHT = 480
SUPPORTED_EXTENSIONS = {".jpg", ".jpeg", ".png", ".webp", ".heic", ".bmp", ".tiff"}
MAX_UPLOAD_SIZE = 20 * 1024 * 1024  # 20MB

# Frame state — persisted to disk so it survives restarts
STATE_FILE = Path("/data/frame_state.json")

def load_state() -> dict:
    try:
        if STATE_FILE.exists():
            return json.loads(STATE_FILE.read_text())
    except Exception:
        pass
    return {"last_update": None, "current_photo": None, "ip": None, "updates": 0}

def save_state(state: dict):
    try:
        STATE_FILE.parent.mkdir(parents=True, exist_ok=True)
        STATE_FILE.write_text(json.dumps(state))
    except Exception as e:
        print(f"Warning: could not save state: {e}", file=sys.stderr)

frame_state = load_state()


def get_photo_list() -> list[Path]:
    photos = []
    for f in PHOTOS_DIR.rglob("*"):
        if f.suffix.lower() in SUPPORTED_EXTENSIONS and f.is_file():
            photos.append(f)
    return sorted(photos, key=lambda p: p.name)


def resize_and_crop(img: Image.Image) -> Image.Image:
    target_ratio = TARGET_WIDTH / TARGET_HEIGHT
    img_ratio = img.width / img.height

    if img_ratio > target_ratio:
        new_height = TARGET_HEIGHT
        new_width = int(img.width * (TARGET_HEIGHT / img.height))
    else:
        new_width = TARGET_WIDTH
        new_height = int(img.height * (TARGET_WIDTH / img.width))

    img = img.resize((new_width, new_height), Image.LANCZOS)

    left = (new_width - TARGET_WIDTH) // 2
    top = (new_height - TARGET_HEIGHT) // 2
    img = img.crop((left, top, left + TARGET_WIDTH, top + TARGET_HEIGHT))
    return img


def make_thumbnail(img: Image.Image, size: int = 300) -> bytes:
    img.thumbnail((size, size), Image.LANCZOS)
    buf = io.BytesIO()
    img.save(buf, format="JPEG", quality=75)
    return buf.getvalue()


# --- ESP32 endpoints ---

@app.route("/photo")
def random_photo():
    photos = get_photo_list()
    if not photos:
        return jsonify({"error": "No photos found"}), 404

    chosen = random.choice(photos)
    try:
        img = Image.open(chosen)
        img = img.convert("RGB")
        img = resize_and_crop(img)

        buf = io.BytesIO()
        img.save(buf, format="JPEG", quality=85)
        buf.seek(0)

        return Response(buf.getvalue(), mimetype="image/jpeg",
                        headers={"X-Photo-Name": chosen.name})
    except Exception as e:
        print(f"Error processing {chosen}: {e}", file=sys.stderr)
        return jsonify({"error": str(e)}), 500


@app.route("/heartbeat", methods=["POST"])
def heartbeat():
    """ESP32 reports after displaying a photo."""
    global frame_state
    data = request.get_json(silent=True) or {}
    frame_state["last_update"] = datetime.now(timezone.utc).isoformat()
    frame_state["current_photo"] = data.get("photo", None)
    frame_state["ip"] = request.remote_addr
    frame_state["free_heap"] = data.get("free_heap", None)
    frame_state["updates"] = frame_state.get("updates", 0) + 1
    save_state(frame_state)
    return jsonify({"ok": True})


# --- API endpoints ---

@app.route("/api/status")
def api_status():
    """Frame status for Home Assistant REST sensor."""
    photos = get_photo_list()
    return jsonify({
        "state": "online" if frame_state.get("last_update") else "waiting",
        "last_update": frame_state.get("last_update"),
        "current_photo": frame_state.get("current_photo"),
        "frame_ip": frame_state.get("ip"),
        "total_photos": len(photos),
        "total_updates": frame_state.get("updates", 0),
    })


@app.route("/api/photos")
def api_photos():
    photos = get_photo_list()
    return jsonify([{"name": p.name, "size": p.stat().st_size} for p in photos])


@app.route("/api/upload", methods=["POST"])
def api_upload():
    uploaded = []
    for f in request.files.getlist("photos"):
        if not f.filename:
            continue
        fname = secure_filename(f.filename)
        ext = Path(fname).suffix.lower()
        if ext not in SUPPORTED_EXTENSIONS:
            continue
        dest = PHOTOS_DIR / fname
        f.save(str(dest))
        uploaded.append(fname)
    return jsonify({"uploaded": uploaded, "count": len(uploaded)})


@app.route("/api/photos/<name>", methods=["DELETE"])
def api_delete(name: str):
    fname = secure_filename(name)
    path = PHOTOS_DIR / fname
    if not path.exists():
        return jsonify({"error": "not found"}), 404
    path.unlink()
    return jsonify({"deleted": fname})


@app.route("/thumb/<name>")
def thumbnail(name: str):
    fname = secure_filename(name)
    path = PHOTOS_DIR / fname
    if not path.exists():
        return "", 404
    try:
        img = Image.open(path).convert("RGB")
        data = make_thumbnail(img)
        return Response(data, mimetype="image/jpeg")
    except Exception:
        return "", 500


# --- Web UI ---

@app.route("/")
def index():
    photos = get_photo_list()
    return render_template_string(WEB_UI, photos=photos, state=frame_state,
                                  photo_count=len(photos))


@app.route("/health")
def health():
    photos = get_photo_list()
    return jsonify({"status": "ok", "photo_count": len(photos)})


WEB_UI = """<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Photo Frame</title>
<style>
  :root { --bg: #111; --card: #1a1a1a; --text: #eee; --accent: #6c8; --border: #333; }
  * { box-sizing: border-box; margin: 0; padding: 0; }
  body { font-family: -apple-system, system-ui, sans-serif; background: var(--bg); color: var(--text); min-height: 100vh; }
  .container { max-width: 960px; margin: 0 auto; padding: 1.5rem; }
  h1 { font-size: 1.5rem; margin-bottom: 1.5rem; }
  h1 span { color: var(--accent); }

  .status-card {
    background: var(--card); border: 1px solid var(--border); border-radius: 8px;
    padding: 1rem 1.25rem; margin-bottom: 1.5rem; display: flex; gap: 2rem; flex-wrap: wrap;
  }
  .status-card .item { display: flex; flex-direction: column; gap: 0.2rem; }
  .status-card .label { font-size: 0.75rem; text-transform: uppercase; color: #888; }
  .status-card .value { font-size: 0.95rem; }
  .status-card .online { color: var(--accent); }
  .status-card .waiting { color: #f80; }

  .upload-area {
    background: var(--card); border: 2px dashed var(--border); border-radius: 8px;
    padding: 2rem; text-align: center; margin-bottom: 1.5rem; cursor: pointer;
    transition: border-color 0.2s;
  }
  .upload-area:hover, .upload-area.dragover { border-color: var(--accent); }
  .upload-area input { display: none; }

  .gallery { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 0.75rem; }
  .photo-card {
    background: var(--card); border: 1px solid var(--border); border-radius: 6px;
    overflow: hidden; position: relative;
  }
  .photo-card img { width: 100%; aspect-ratio: 5/3; object-fit: cover; display: block; }
  .photo-card .info {
    padding: 0.5rem 0.6rem; display: flex; justify-content: space-between; align-items: center;
    font-size: 0.8rem;
  }
  .photo-card .name { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; max-width: 70%; }
  .photo-card .delete {
    background: none; border: none; color: #f55; cursor: pointer; font-size: 0.85rem;
    padding: 0.2rem 0.4rem; border-radius: 4px;
  }
  .photo-card .delete:hover { background: rgba(255,85,85,0.15); }
  .photo-card.current { border-color: var(--accent); }

  .empty { text-align: center; padding: 3rem; color: #666; }
</style>
</head>
<body>
<div class="container">
  <h1><span>&#9632;</span> Photo Frame</h1>

  <div class="status-card">
    <div class="item">
      <span class="label">Frame Status</span>
      <span class="value {{ 'online' if state.get('last_update') else 'waiting' }}">
        {{ 'Online' if state.get('last_update') else 'Waiting for first update' }}
      </span>
    </div>
    {% if state.get('last_update') %}
    <div class="item">
      <span class="label">Last Update</span>
      <span class="value" data-utc="{{ state.last_update }}">{{ state.last_update[:19] }}</span>
    </div>
    <div class="item">
      <span class="label">Showing</span>
      <span class="value">{{ state.get('current_photo', 'Unknown') }}</span>
    </div>
    {% endif %}
    <div class="item">
      <span class="label">Photos</span>
      <span class="value">{{ photo_count }}</span>
    </div>
    <div class="item">
      <span class="label">Total Refreshes</span>
      <span class="value">{{ state.get('updates', 0) }}</span>
    </div>
  </div>

  <div class="upload-area" id="upload-area" onclick="document.getElementById('file-input').click()">
    <input type="file" id="file-input" multiple accept="image/*">
    <p>Drop photos here or click to upload</p>
  </div>

  {% if photos %}
  <div class="gallery">
    {% for p in photos %}
    <div class="photo-card {{ 'current' if state.get('current_photo') == p.name else '' }}" data-name="{{ p.name }}">
      <img src="/thumb/{{ p.name }}" loading="lazy" alt="{{ p.name }}">
      <div class="info">
        <span class="name" title="{{ p.name }}">{{ p.name }}</span>
        <button class="delete" onclick="deletePhoto('{{ p.name }}')" title="Delete">&times;</button>
      </div>
    </div>
    {% endfor %}
  </div>
  {% else %}
  <div class="empty">No photos yet. Upload some!</div>
  {% endif %}
</div>

<script>
const area = document.getElementById('upload-area');
const input = document.getElementById('file-input');

['dragenter','dragover'].forEach(e => area.addEventListener(e, ev => { ev.preventDefault(); area.classList.add('dragover'); }));
['dragleave','drop'].forEach(e => area.addEventListener(e, ev => { ev.preventDefault(); area.classList.remove('dragover'); }));

area.addEventListener('drop', ev => { uploadFiles(ev.dataTransfer.files); });
input.addEventListener('change', () => { uploadFiles(input.files); });

function uploadFiles(files) {
  const fd = new FormData();
  for (const f of files) fd.append('photos', f);
  fetch('/api/upload', { method: 'POST', body: fd })
    .then(r => r.json())
    .then(d => { if (d.count > 0) location.reload(); });
}

function deletePhoto(name) {
  if (!confirm('Delete ' + name + '?')) return;
  fetch('/api/photos/' + encodeURIComponent(name), { method: 'DELETE' })
    .then(r => r.json())
    .then(() => {
      document.querySelector('[data-name="' + name + '"]')?.remove();
    });
}

// Convert UTC timestamps to local time
document.querySelectorAll('[data-utc]').forEach(el => {
  const d = new Date(el.dataset.utc);
  el.textContent = d.toLocaleString();
});
</script>
</body>
</html>
"""


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="E-Ink Photo Frame Server")
    parser.add_argument("--port", type=int, default=8473)
    parser.add_argument("--photos-dir", type=str, default="./photos")
    args = parser.parse_args()

    PHOTOS_DIR = Path(args.photos_dir)
    if not PHOTOS_DIR.exists():
        PHOTOS_DIR.mkdir(parents=True, exist_ok=True)

    print(f"Serving photos from: {PHOTOS_DIR.resolve()}")
    print(f"Found {len(get_photo_list())} photos")
    print(f"Listening on port {args.port}")

    app.run(host="0.0.0.0", port=args.port)