"""Metrologist blueprint - SPC statistics dashboard and API proxies."""
import requests as http_requests

from flask import Blueprint, jsonify, render_template, request, session
from flask_babel import gettext as _

from blueprints.auth import login_required, role_required
from config import Config
from services.api_client import api_client

statistics_bp = Blueprint("statistics", __name__)


# ============================================================================
# PAGINE
# ============================================================================

@statistics_bp.route("/dashboard")
@login_required
@role_required("Metrologist")
def dashboard():
    """SPC dashboard overview — loads recipes for filter dropdown."""
    # #37.6: a single per_page=100 call silently dropped every recipe past
    # the 100th from the filter dropdown. 100 is the backend's max per_page
    # (routers/recipes.py), so a full listing needs a page loop, not a
    # bigger number.
    recipes = []
    page = 1
    while True:
        resp = api_client.get("/api/recipes", params={"per_page": 100, "page": page})
        if isinstance(resp, dict) and resp.get("error"):
            break
        page_items = resp.get("items", []) if isinstance(resp, dict) else []
        recipes.extend(page_items)
        total_pages = resp.get("pages", 1) if isinstance(resp, dict) else 1
        if page >= total_pages or not page_items:
            break
        page += 1

    return render_template("statistics/dashboard.html", recipes=recipes)


# ============================================================================
# PROXY API AJAX → FastAPI
# ============================================================================

def _proxy_statistics(endpoint: str):
    """Forward query params to a FastAPI statistics endpoint."""
    params = {}
    for key in [
        "recipe_id", "version_id", "subtask_id",
        "date_from", "date_to", "operator_id",
        "lot_number", "serial_number", "n_bins", "production_run_id",  # #58
    ]:
        val = request.args.get(key)
        if val is not None and val != "":
            params[key] = val

    resp = api_client.get(f"/api/statistics/{endpoint}", params=params)

    if isinstance(resp, dict) and resp.get("error"):
        error_body = {"error": True, "detail": resp.get("detail", "")}
        if resp.get("session_expired"):
            error_body["session_expired"] = True
        return jsonify(error_body), resp.get("status_code", 500)

    return jsonify(resp)


@statistics_bp.route("/api/summary")
@login_required
@role_required("Metrologist")
def api_summary():
    """Proxy: summary pass/fail/warning."""
    return _proxy_statistics("summary")


@statistics_bp.route("/api/capability")
@login_required
@role_required("Metrologist")
def api_capability():
    """Proxy: capability indices."""
    return _proxy_statistics("capability")


@statistics_bp.route("/api/control-chart")
@login_required
@role_required("Metrologist")
def api_control_chart():
    """Proxy: control chart data."""
    return _proxy_statistics("control-chart")


@statistics_bp.route("/api/histogram")
@login_required
@role_required("Metrologist")
def api_histogram():
    """Proxy: histogram data."""
    return _proxy_statistics("histogram")


@statistics_bp.route("/api/subtasks")
@login_required
@role_required("Metrologist")
def api_subtasks():
    """Proxy: get subtasks for recipe filter."""
    params = {}
    recipe_id = request.args.get("recipe_id")
    if recipe_id:
        params["recipe_id"] = recipe_id
    version_id = request.args.get("version_id")
    if version_id:
        params["version_id"] = version_id

    resp = api_client.get("/api/statistics/subtasks", params=params)

    if isinstance(resp, dict) and resp.get("error"):
        error_body = {"error": True, "detail": resp.get("detail", "")}
        if resp.get("session_expired"):
            error_body["session_expired"] = True
        return jsonify(error_body), resp.get("status_code", 500)

    # Response is a list
    if isinstance(resp, list):
        return jsonify(resp)

    return jsonify(resp)


@statistics_bp.route("/api/runs")
@login_required
@role_required("Metrologist")
def api_runs():
    """Proxy: production runs of a recipe (#58, "Sessione" filter)."""
    params = {}
    recipe_id = request.args.get("recipe_id")
    if recipe_id:
        params["recipe_id"] = recipe_id

    resp = api_client.get("/api/statistics/runs", params=params)

    if isinstance(resp, dict) and resp.get("error"):
        error_body = {"error": True, "detail": resp.get("detail", "")}
        if resp.get("session_expired"):
            error_body["session_expired"] = True
        return jsonify(error_body), resp.get("status_code", 500)

    return jsonify(resp)


# ============================================================================
# PROXY REPORT PDF → FastAPI
# ============================================================================

def _proxy_report(endpoint: str):
    """Forward query params to a FastAPI reports endpoint and return PDF."""
    params = {}
    for key in [
        "recipe_id", "version_id", "subtask_id",
        "date_from", "date_to", "operator_id",
        "lot_number", "serial_number", "production_run_id",  # #58
    ]:
        val = request.args.get(key)
        if val is not None and val != "":
            params[key] = val

    base_url = Config.API_SERVER_URL.rstrip("/")
    headers = {}
    api_key = session.get("api_key")
    if api_key:
        headers["X-API-Key"] = api_key

    try:
        resp = http_requests.get(
            f"{base_url}/api/reports/{endpoint}",
            headers=headers,
            params=params,
            timeout=120,
        )
    except (http_requests.ConnectionError, http_requests.Timeout) as e:
        return jsonify({"error": True, "detail": str(e)}), 502

    if not resp.ok:
        try:
            err = resp.json()
            detail = err.get("detail", f"HTTP {resp.status_code}")
        except Exception:
            detail = f"HTTP {resp.status_code}"
        return jsonify({"error": True, "detail": detail}), resp.status_code

    from flask import Response as FlaskResponse
    return FlaskResponse(
        resp.content,
        mimetype="application/pdf",
        headers={
            "Content-Disposition": resp.headers.get(
                "Content-Disposition", f'attachment; filename="report.pdf"'
            )
        },
    )


@statistics_bp.route("/api/report-spc")
@login_required
@role_required("Metrologist")
def api_report_spc():
    """Proxy: download SPC PDF report."""
    return _proxy_report("spc")


@statistics_bp.route("/api/report-measurements")
@login_required
@role_required("Metrologist")
def api_report_measurements():
    """Proxy: download measurements PDF report."""
    return _proxy_report("measurements")