hm_ems_report/server.py

"""
Flask server for H&M EMS Product Review Tool.

Serves the review UI and provides API endpoints for:
- Listing available JSON campaign files
- Loading campaign data with image mappings
- Approving/saving edits back to the master JSON with change logging

Configuration (environment variables):
    IMAGE_BASE_PATH  – root folder containing year/campaign/Automation_LR images
                       (defaults to ./campaign_images)
    MASTER_JSON_DIR  – folder containing campaign JSON files
                       (defaults to ./Master_Json)
    PORT             – server port (defaults to 5000)

Usage:
    python3 server.py
    Then open http://localhost:5000
"""

import os
import json
import threading
from datetime import datetime
from flask import Flask, jsonify, request, send_from_directory, abort

from html_generator import (
    LANGUAGE_DISPLAY_NAMES,
    _get_campaign_prefix,
    _get_main_image_filename,
    _get_all_image_filenames,
)

# ========== Config ==========
BASE_DIR = os.path.dirname(os.path.abspath(__file__))
MASTER_JSON_DIR = os.environ.get(
    "MASTER_JSON_DIR",
    os.path.join(BASE_DIR, "Master_Json"),
)
IMAGE_BASE_PATH = os.environ.get(
    "IMAGE_BASE_PATH",
    os.path.join(BASE_DIR, "campaign_images"),
)

# Thread lock for safe JSON read/write
file_lock = threading.Lock()

app = Flask(__name__, static_folder="static")


# ========== Static UI ==========
@app.route("/")
def index():
    return send_from_directory("static", "index.html")


# ========== API: List available JSON files ==========
@app.route("/api/files")
def list_files():
    files = []
    for f in sorted(os.listdir(MASTER_JSON_DIR)):
        if f.endswith(".json") and not f.endswith("_changelog.json"):
            campaign = _get_campaign_prefix(f)
            files.append({"filename": f, "campaign": campaign})
    return jsonify(files)


# ========== API: Load campaign data ==========
@app.route("/api/load/<filename>")
def load_campaign(filename):
    # Security: strip path components
    filename = os.path.basename(filename)
    filepath = os.path.join(MASTER_JSON_DIR, filename)

    if not os.path.isfile(filepath):
        abort(404, description=f"File not found: {filename}")

    with open(filepath, "r", encoding="utf-8") as f:
        data = json.load(f)

    campaign_prefix = _get_campaign_prefix(filename)

    # Derive year from Season field (first 4 chars, e.g. "202502" -> "2025")
    season = data[0].get("Season", "") if data else ""
    year = season[:4] if len(season) >= 4 else "2025"

    image_source_dir = os.path.join(IMAGE_BASE_PATH, year, campaign_prefix, "Automation_LR")

    # Build image map: Article id -> list of server image URLs
    image_map = {}
    for record in data:
        article_id = record.get("Article id", "")
        if article_id in image_map:
            continue
        img_names = _get_all_image_filenames(record.get("Filename", ""))
        urls = []
        for img_name in img_names:
            if os.path.isfile(os.path.join(image_source_dir, img_name)):
                urls.append(f"/hm-ems-report/images/{year}/{campaign_prefix}/{img_name}")
        image_map[article_id] = urls if urls else None

    # Build language display names for languages present in data
    languages = sorted(set(
        r.get("Language", "").lower() for r in data if r.get("Language")
    ))
    lang_display = {}
    for lang in languages:
        lang_display[lang] = LANGUAGE_DISPLAY_NAMES.get(lang, lang)

    # Derive campaign info
    campaign_name = data[0].get("Campaign", campaign_prefix) if data else campaign_prefix
    season = data[0].get("Season", "") if data else ""

    # Load existing approvals from changelog
    approvals = _load_approvals(filename)

    return jsonify({
        "data": data,
        "image_map": image_map,
        "lang_display": lang_display,
        "campaign": campaign_name,
        "season": season,
        "filename": filename,
        "approvals": approvals,
    })


# ========== API: Approve / save edits ==========
@app.route("/api/approve", methods=["POST"])
def approve():
    body = request.get_json()
    if not body:
        abort(400, description="Missing JSON body")

    filename = os.path.basename(body.get("filename", ""))
    article_id = body.get("article_id", "")
    language = body.get("language", "")
    edits = body.get("edits", {})
    action = body.get("action", "approve")  # "approve" or "unapprove"

    if not filename or not article_id or not language:
        abort(400, description="Missing required fields: filename, article_id, language")

    filepath = os.path.join(MASTER_JSON_DIR, filename)
    if not os.path.isfile(filepath):
        abort(404, description=f"File not found: {filename}")

    with file_lock:
        # Load master JSON
        with open(filepath, "r", encoding="utf-8") as f:
            data = json.load(f)

        # Find matching record
        record = None
        for r in data:
            if (r.get("Article id") == article_id and
                    r.get("Language", "").lower() == language.lower()):
                record = r
                break

        if not record:
            abort(404, description=f"Record not found: {article_id} / {language}")

        # Build changelog entry
        changelog_entry = {
            "timestamp": datetime.now().isoformat(),
            "article_id": article_id,
            "language": language,
            "country": record.get("Country", ""),
            "product_id": record.get("Product id", ""),
            "action": action,
            "edits": [],
        }

        # Apply edits if approving
        if action == "approve" and edits:
            for field in ["Product name", "Price"]:
                if field in edits and edits[field] is not None:
                    old_val = record.get(field, "")
                    new_val = edits[field]
                    if str(old_val) != str(new_val):
                        changelog_entry["edits"].append({
                            "field": field,
                            "old": old_val,
                            "new": new_val,
                        })
                        record[field] = new_val

        # Write master JSON back
        with open(filepath, "w", encoding="utf-8") as f:
            json.dump(data, f, indent=2, ensure_ascii=False)

        # Write changelog
        _append_changelog(filename, changelog_entry)

    return jsonify({"status": "ok", "action": action})


# ========== API: Unapprove ==========
@app.route("/api/unapprove", methods=["POST"])
def unapprove():
    body = request.get_json()
    if not body:
        abort(400)
    body["action"] = "unapprove"
    # Reuse the approve logic for logging
    return _handle_approval(body)


# ========== Image serving ==========
@app.route("/images/<year>/<campaign_prefix>/<path:filename>")
def serve_image(year, campaign_prefix, filename):
    # Security: no path traversal
    year = os.path.basename(year)
    campaign_prefix = os.path.basename(campaign_prefix)
    filename = os.path.basename(filename)
    image_dir = os.path.join(IMAGE_BASE_PATH, year, campaign_prefix, "Automation_LR")
    if not os.path.isdir(image_dir):
        abort(404)
    return send_from_directory(image_dir, filename)


# ========== Changelog helpers ==========
def _changelog_path(filename):
    stem = os.path.splitext(filename)[0]
    return os.path.join(MASTER_JSON_DIR, f"{stem}_changelog.json")


def _append_changelog(filename, entry):
    path = _changelog_path(filename)
    if os.path.isfile(path):
        with open(path, "r", encoding="utf-8") as f:
            log = json.load(f)
    else:
        log = []
    log.append(entry)
    with open(path, "w", encoding="utf-8") as f:
        json.dump(log, f, indent=2, ensure_ascii=False)


def _load_approvals(filename):
    """Load approval state from changelog - returns dict of approved keys."""
    path = _changelog_path(filename)
    approvals = {}
    if not os.path.isfile(path):
        return approvals
    with open(path, "r", encoding="utf-8") as f:
        log = json.load(f)
    for entry in log:
        key = entry["article_id"] + "::" + entry["language"].lower()
        if entry.get("action") == "approve":
            approvals[key] = True
        elif entry.get("action") == "unapprove":
            approvals.pop(key, None)
    return approvals


def _handle_approval(body):
    """Shared logic for approve/unapprove."""
    filename = os.path.basename(body.get("filename", ""))
    article_id = body.get("article_id", "")
    language = body.get("language", "")
    action = body.get("action", "approve")

    if not filename or not article_id or not language:
        abort(400)

    filepath = os.path.join(MASTER_JSON_DIR, filename)
    if not os.path.isfile(filepath):
        abort(404)

    with file_lock:
        changelog_entry = {
            "timestamp": datetime.now().isoformat(),
            "article_id": article_id,
            "language": language,
            "action": action,
            "edits": [],
        }
        _append_changelog(filename, changelog_entry)

    return jsonify({"status": "ok", "action": action})


# ========== Run ==========
if __name__ == "__main__":
    port = int(os.environ.get("PORT", 5000))
    print(f"Master JSON folder: {MASTER_JSON_DIR}")
    print(f"Image base path:    {IMAGE_BASE_PATH}")
    print(f"Starting server at  http://localhost:{port}")
    app.run(host="0.0.0.0", port=port, debug=False)