"""
dashboard/app.py
----------------
Flask backend for the BATL CARLA Orchestrator Dashboard.
Serves the HTML UI, exposes REST endpoints, and streams
real-time simulation output via Server-Sent Events (SSE).

NOTE: This file lives inside the /dashboard sub-folder.
      PROJECT_ROOT is therefore TWO levels up: dashboard/app.py → dashboard/ → Fox/
"""

import os
import sys
from flask import Flask, render_template, request, jsonify, Response
import subprocess

# ------------------------------------------------------------------
# Path bootstrapping — make the project root importable regardless
# of which directory the user launches from.
# ------------------------------------------------------------------
PROJECT_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
if PROJECT_ROOT not in sys.path:
    sys.path.insert(0, PROJECT_ROOT)

import config
from src.scenario_loader import list_scenarios

# ------------------------------------------------------------------
# Flask app — templates and static assets are siblings of this file.
# ------------------------------------------------------------------
DASHBOARD_DIR = os.path.dirname(os.path.abspath(__file__))

app = Flask(
    __name__,
    template_folder=os.path.join(DASHBOARD_DIR, "templates"),
    static_folder=os.path.join(DASHBOARD_DIR, "static"),
)


# ── Routes ────────────────────────────────────────────────────────

@app.route("/")
def index():
    return render_template("index.html")


@app.route("/api/config", methods=["GET"])
def get_config():
    scenarios = list_scenarios()
    return jsonify({
        "scenarios": scenarios,
        "default_scenario": getattr(config, "DEFAULT_SCENARIO", "braking"),
        "default_frames":   getattr(config, "MAX_FRAMES", 200),
        "default_weather":  getattr(config, "DEFAULT_WEATHER", "ClearNoon"),
        "weather_options":  [
            "ClearNoon", "CloudyNoon", "WetNoon",
            "SoftRainNoon", "HardRainNoon", "ClearSunset", "Night"
        ],
    })


@app.route("/api/scenario_params/<scenario_name>", methods=["GET"])
def get_scenario_params(scenario_name):
    from src.scenario_loader import load_scenario
    try:
        scenario = load_scenario(scenario_name)
        tunable_params = {}
        # Convention: tunable constants are UPPERCASE class-level attributes
        for attr in dir(scenario):
            if attr.isupper() and not attr.startswith("_"):
                val = getattr(scenario, attr)
                if isinstance(val, (int, float, str, bool)):
                    tunable_params[attr] = val
        return jsonify({"success": True, "params": tunable_params})
    except Exception as e:
        return jsonify({"success": False, "error": str(e)})


@app.route("/api/run", methods=["POST"])
def run_simulation():
    data      = request.json or {}
    scenario  = data.get("scenario") or "braking"
    frames    = data.get("frames")   or ""
    weather   = data.get("weather")  or ""
    no_record = bool(data.get("no_record"))
    params    = data.get("params")   or ""

    # Build the command — run.bat lives in PROJECT_ROOT
    cmd = ["cmd.exe", "/c", "run.bat", scenario]
    if frames:
        cmd.extend(["--frames", str(frames)])
    if weather:
        cmd.extend(["--weather", weather])
    if no_record:
        cmd.append("--no-record")
    if params:
        cmd.extend(["--params", f'"{params}"'])

    def generate():
        try:
            # cwd = project root so that run.bat is reachable
            env = os.environ.copy()
            env["PYTHONUNBUFFERED"] = "1"
            
            process = subprocess.Popen(
                cmd,
                stdout=subprocess.PIPE,
                stderr=subprocess.STDOUT,
                text=True,
                bufsize=1,
                cwd=PROJECT_ROOT,
                env=env,
                creationflags=subprocess.CREATE_NEW_PROCESS_GROUP,
            )

            yield f"data: [INFO] Starting command: {' '.join(cmd)}\n\n"

            for line in iter(process.stdout.readline, ""):
                if line:
                    yield f"data: {line.rstrip()}\n\n"

            process.stdout.close()
            return_code = process.wait()
            yield f"data: [PROCESS_COMPLETED] Exit Code: {return_code}\n\n"

        except Exception as e:
            yield f"data: [ERROR] Failed to start process: {str(e)}\n\n"

    return Response(generate(), mimetype="text/event-stream")


# ── Entry point ───────────────────────────────────────────────────

if __name__ == "__main__":
    print("Starting BATL CARLA Dashboard orchestrator...")
    print(f"  Project root : {PROJECT_ROOT}")
    print(f"  Dashboard dir: {DASHBOARD_DIR}")
    app.run(host="0.0.0.0", port=5000, debug=True)