import json
import os
import subprocess
from functools import wraps
from pathlib import Path

from flask import Flask, jsonify, redirect, render_template, request, send_file, url_for

app = Flask(__name__)

CONFIG_FILE = "/data/proxy_config.json"
NGINX_CONF_DIR = "/etc/nginx/conf.d"
NGINX_UPSTREAM_CONF = f"{NGINX_CONF_DIR}/proxy-targets.conf"

USERNAME = os.environ.get("WEBUI_USERNAME", "admin")
PASSWORD = os.environ.get("WEBUI_PASSWORD", "admin123")


def load_config():
    if os.path.exists(CONFIG_FILE):
        with open(CONFIG_FILE) as f:
            return json.load(f)
    return {"targets": []}


def save_config(config):
    os.makedirs(os.path.dirname(CONFIG_FILE), exist_ok=True)
    with open(CONFIG_FILE, "w") as f:
        json.dump(config, f, indent=2)


def generate_nginx_config(config):
    """Generate nginx upstream/server blocks from config."""
    lines = []

    for i, target in enumerate(config.get("targets", [])):
        name = target.get("name", f"target_{i}")
        target_host = target.get("target_host", "")
        target_port = target.get("target_port", 80)
        listen_port = target.get("listen_port", 0)
        domains = target.get("domains", [])
        target_scheme = target.get("target_scheme", "http")

        if not target_host or not target.get("enabled", True):
            continue

        upstream_name = f"upstream_{name}"
        lines.append(f"upstream {upstream_name} {{")
        lines.append(f"    server {target_host}:{target_port};")
        lines.append("}")
        lines.append("")

        # Domain-based routing
        if domains:
            for domain_entry in domains:
                domain = domain_entry.get("domain", "")
                domain_port = domain_entry.get("port", 443)
                if not domain:
                    continue
                lines.append("server {")
                lines.append(f"    listen {domain_port} ssl;")
                lines.append(f"    server_name {domain};")
                lines.append("")
                lines.append("    ssl_certificate /certs/server.crt;")
                lines.append("    ssl_certificate_key /certs/server.key;")
                lines.append("    ssl_protocols TLSv1.2 TLSv1.3;")
                lines.append("")
                lines.append(f"    location / {{")
                lines.append(f"        proxy_pass {target_scheme}://{upstream_name};")
                lines.append("        proxy_set_header Host $host;")
                lines.append("        proxy_set_header X-Real-IP $remote_addr;")
                lines.append("        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;")
                lines.append("        proxy_set_header X-Forwarded-Proto $scheme;")
                lines.append("        proxy_http_version 1.1;")
                lines.append('        proxy_set_header Upgrade $http_upgrade;')
                lines.append('        proxy_set_header Connection "upgrade";')
                lines.append("    }")
                lines.append("}")
                lines.append("")

        # IP/Port-based routing
        if listen_port:
            lines.append("server {")
            lines.append(f"    listen {listen_port} ssl;")
            lines.append(f"    server_name _;")
            lines.append("")
            lines.append("    ssl_certificate /certs/server.crt;")
            lines.append("    ssl_certificate_key /certs/server.key;")
            lines.append("    ssl_protocols TLSv1.2 TLSv1.3;")
            lines.append("")
            lines.append(f"    location / {{")
            lines.append(f"        proxy_pass {target_scheme}://{upstream_name};")
            lines.append("        proxy_set_header Host $host;")
            lines.append("        proxy_set_header X-Real-IP $remote_addr;")
            lines.append("        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;")
            lines.append("        proxy_set_header X-Forwarded-Proto $scheme;")
            lines.append("        proxy_http_version 1.1;")
            lines.append('        proxy_set_header Upgrade $http_upgrade;')
            lines.append('        proxy_set_header Connection "upgrade";')
            lines.append("    }")
            lines.append("}")
            lines.append("")

    conf_content = "\n".join(lines)
    os.makedirs(NGINX_CONF_DIR, exist_ok=True)
    with open(NGINX_UPSTREAM_CONF, "w") as f:
        f.write(conf_content)

    return conf_content


def reload_nginx():
    """Reload nginx configuration."""
    try:
        result = subprocess.run(
            ["nginx", "-t"],
            capture_output=True, text=True, timeout=10
        )
        if result.returncode != 0:
            return False, f"Nginx config test failed: {result.stderr}"

        result = subprocess.run(
            ["nginx", "-s", "reload"],
            capture_output=True, text=True, timeout=10
        )
        if result.returncode != 0:
            return False, f"Nginx reload failed: {result.stderr}"

        return True, "Nginx reloaded successfully"
    except Exception as e:
        return False, str(e)


def check_auth(f):
    @wraps(f)
    def decorated(*args, **kwargs):
        auth = request.authorization
        if not auth or auth.username != USERNAME or auth.password != PASSWORD:
            return (
                "Authentication required",
                401,
                {"WWW-Authenticate": 'Basic realm="Proxy Admin"'},
            )
        return f(*args, **kwargs)
    return decorated


# ==================== WebUI Routes ====================

@app.route("/")
@check_auth
def index():
    config = load_config()
    return render_template("index.html", config=config)


@app.route("/ca.crt")
def download_ca():
    """Download CA certificate - no auth required so devices can easily fetch it."""
    ca_path = "/certs/ca.crt"
    if not os.path.exists(ca_path):
        return "CA certificate not found", 404
    return send_file(ca_path, as_attachment=True, download_name="ca.crt",
                     mimetype="application/x-x509-ca-cert")


@app.route("/target/add", methods=["POST"])
@check_auth
def add_target():
    config = load_config()

    domains = []
    domain_names = request.form.getlist("domain_name[]")
    domain_ports = request.form.getlist("domain_port[]")
    for name, port in zip(domain_names, domain_ports):
        if name.strip():
            domains.append({"domain": name.strip(), "port": int(port) if port else 443})

    target = {
        "name": request.form.get("name", "").strip().replace(" ", "_"),
        "target_host": request.form.get("target_host", "").strip(),
        "target_port": int(request.form.get("target_port", 80)),
        "target_scheme": request.form.get("target_scheme", "http"),
        "listen_port": int(request.form.get("listen_port", 0) or 0),
        "domains": domains,
        "enabled": True,
    }

    if not target["name"] or not target["target_host"]:
        return redirect(url_for("index"))

    config["targets"].append(target)
    save_config(config)
    generate_nginx_config(config)
    reload_nginx()

    return redirect(url_for("index"))


@app.route("/target/<int:idx>/delete", methods=["POST"])
@check_auth
def delete_target(idx):
    config = load_config()
    if 0 <= idx < len(config["targets"]):
        config["targets"].pop(idx)
        save_config(config)
        generate_nginx_config(config)
        reload_nginx()
    return redirect(url_for("index"))


@app.route("/target/<int:idx>/toggle", methods=["POST"])
@check_auth
def toggle_target(idx):
    config = load_config()
    if 0 <= idx < len(config["targets"]):
        config["targets"][idx]["enabled"] = not config["targets"][idx].get("enabled", True)
        save_config(config)
        generate_nginx_config(config)
        reload_nginx()
    return redirect(url_for("index"))


@app.route("/target/<int:idx>/edit", methods=["POST"])
@check_auth
def edit_target(idx):
    config = load_config()
    if 0 <= idx < len(config["targets"]):
        domains = []
        domain_names = request.form.getlist("domain_name[]")
        domain_ports = request.form.getlist("domain_port[]")
        for name, port in zip(domain_names, domain_ports):
            if name.strip():
                domains.append({"domain": name.strip(), "port": int(port) if port else 443})

        config["targets"][idx] = {
            "name": request.form.get("name", "").strip().replace(" ", "_"),
            "target_host": request.form.get("target_host", "").strip(),
            "target_port": int(request.form.get("target_port", 80)),
            "target_scheme": request.form.get("target_scheme", "http"),
            "listen_port": int(request.form.get("listen_port", 0) or 0),
            "domains": domains,
            "enabled": config["targets"][idx].get("enabled", True),
        }
        save_config(config)
        generate_nginx_config(config)
        reload_nginx()
    return redirect(url_for("index"))


# ==================== API Routes ====================

@app.route("/api/targets", methods=["GET"])
@check_auth
def api_list_targets():
    config = load_config()
    return jsonify(config)


@app.route("/api/targets", methods=["POST"])
@check_auth
def api_add_target():
    config = load_config()
    target = request.get_json()
    if not target:
        return jsonify({"error": "Invalid JSON"}), 400
    if not target.get("name") or not target.get("target_host"):
        return jsonify({"error": "name and target_host are required"}), 400

    target.setdefault("target_port", 80)
    target.setdefault("target_scheme", "http")
    target.setdefault("listen_port", 0)
    target.setdefault("domains", [])
    target.setdefault("enabled", True)

    config["targets"].append(target)
    save_config(config)
    generate_nginx_config(config)
    success, msg = reload_nginx()

    return jsonify({"status": "ok" if success else "warning", "message": msg, "target": target}), 201


@app.route("/api/targets/<int:idx>", methods=["PUT"])
@check_auth
def api_update_target(idx):
    config = load_config()
    if idx < 0 or idx >= len(config["targets"]):
        return jsonify({"error": "Target not found"}), 404

    target = request.get_json()
    if not target:
        return jsonify({"error": "Invalid JSON"}), 400

    config["targets"][idx] = target
    save_config(config)
    generate_nginx_config(config)
    success, msg = reload_nginx()

    return jsonify({"status": "ok" if success else "warning", "message": msg})


@app.route("/api/targets/<int:idx>", methods=["DELETE"])
@check_auth
def api_delete_target(idx):
    config = load_config()
    if idx < 0 or idx >= len(config["targets"]):
        return jsonify({"error": "Target not found"}), 404

    removed = config["targets"].pop(idx)
    save_config(config)
    generate_nginx_config(config)
    success, msg = reload_nginx()

    return jsonify({"status": "ok" if success else "warning", "message": msg, "removed": removed})


@app.route("/api/reload", methods=["POST"])
@check_auth
def api_reload():
    config = load_config()
    generate_nginx_config(config)
    success, msg = reload_nginx()
    return jsonify({"status": "ok" if success else "error", "message": msg})


if __name__ == "__main__":
    app.run(host="0.0.0.0", port=5000, debug=True)