"""
Demo routes — each /demo/step/N page shows one Tink API call
with the live JSON response and a curl example.
"""

import json
import uuid
import secrets
from typing import Optional

from fastapi import APIRouter, Request, Form, HTTPException
from fastapi.responses import HTMLResponse, RedirectResponse
from fastapi.templating import Jinja2Templates

from src.tink.client import TinkClient
from src.config import get_settings
from src import demo_data

router = APIRouter()
templates = Jinja2Templates(directory="src/templates")


def _client(log_cb=None) -> TinkClient:
    s = get_settings()
    return TinkClient(
        client_id=s.tink_client_id,
        client_secret=s.tink_client_secret,
        redirect_uri=s.tink_redirect_uri,
        api_base=s.tink_api_base,
        link_base=s.tink_link_base,
        on_request=log_cb,
    )


def _session(request: Request) -> dict:
    return request.session.setdefault("demo", {})


def _ctx(request: Request, extra: dict) -> dict:
    """Base template context — always includes session_customer."""
    sess = _session(request)
    return {"request": request, "session_customer": sess.get("external_user_id", ""), **extra}


def _logger(sess: dict):
    """Returns a callback that appends log entries to sess['api_log']."""
    def cb(entry: dict):
        log = sess.setdefault("api_log", [])
        log.append(entry)
        # keep last 50 entries
        if len(log) > 50:
            sess["api_log"] = log[-50:]
    return cb


# ---------------------------------------------------------------------------
# Landing
# ---------------------------------------------------------------------------

@router.get("/", response_class=HTMLResponse)
async def index(request: Request):
    return templates.TemplateResponse("index.html", {"request": request})


@router.get("/demo/reset")
async def reset_demo(request: Request):
    """Clear all demo session state and restart from Step 1."""
    request.session.pop("demo", None)
    return RedirectResponse("/demo/step/1")


# ---------------------------------------------------------------------------
# Step 1 — Authenticate (client credentials)
# ---------------------------------------------------------------------------

@router.get("/demo/step/1", response_class=HTMLResponse)
async def step1(request: Request):
    sess = _session(request)
    client = _client(log_cb=_logger(sess))
    s = get_settings()
    error = None
    result = None
    curl_example = (
        f"curl -X POST https://api.tink.com/api/v1/oauth/token \\\n"
        f"  -d 'client_id={s.tink_client_id}' \\\n"
        f"  -d 'client_secret=***' \\\n"
        f"  -d 'grant_type=client_credentials' \\\n"
        f"  -d 'scope=user:create'"
    )
    try:
        result = await client.get_app_token(scope="user:create")
        sess["app_token"] = result["access_token"]
    except Exception as e:
        error = str(e)

    return templates.TemplateResponse("step.html", _ctx(request, {
        "step": 1,
        "title": "Authenticate",
        "subtitle": "Client Credentials Flow",
        "endpoint": "POST /api/v1/oauth/token",
        "api_version": "v1",
        "description": "Vi starter med at hente et app-level access token via Client Credentials flow. Dette token bruges til at oprette brugere.",
        "curl_example": curl_example,
        "result": result,
        "error": error,
        "next_step": 2,
        "prev_step": None,
    }))


# ---------------------------------------------------------------------------
# Step 2 — Create User
# ---------------------------------------------------------------------------

@router.get("/demo/step/2", response_class=HTMLResponse)
async def step2_get(request: Request):
    sess = _session(request)
    s = get_settings()
    app_token = sess.get("app_token", "")
    error = None

    if not app_token:
        error = "Mangler app token — gå tilbage til Step 1 og kør authentication først."

    # If user already created this session, skip the form
    existing_user_id = sess.get("user_id", "")
    existing_external_id = sess.get("external_user_id", "")

    return templates.TemplateResponse("step2.html", _ctx(request, {
        "step": 2,
        "error": error,
        "existing_user_id": existing_user_id,
        "existing_external_id": existing_external_id,
        "app_token_ok": bool(app_token),
        "next_step": 3,
        "prev_step": 1,
    }))


@router.post("/demo/step/2", response_class=HTMLResponse)
async def step2_post(request: Request,
                     customer_name: str = Form(default=""),
                     market: str = Form(default="DK")):
    sess = _session(request)
    s = get_settings()
    app_token = sess.get("app_token", "")
    error = None
    result = None

    # Build external_user_id from customer name
    if customer_name.strip():
        slug = customer_name.strip().lower().replace(" ", "-")
        import re
        slug = re.sub(r"[^a-z0-9\-]", "", slug)
        external_user_id = f"moneycapp-{slug}"
    else:
        external_user_id = f"moneycapp-demo-{secrets.token_hex(4)}"

    body = json.dumps({"external_user_id": external_user_id, "market": market, "locale": "da_DK"}, indent=2)
    curl_example = (
        f"curl -X POST https://api.tink.com/api/v1/user/create \\\n"
        f"  -H 'Authorization: Bearer $APP_TOKEN' \\\n"
        f"  -H 'Content-Type: application/json' \\\n"
        f"  -d '{body}'"
    )

    if not app_token:
        error = "Mangler app token — gå tilbage til Step 1."
    else:
        try:
            client = _client(log_cb=_logger(sess))
            result = await client.create_user(app_token, external_user_id, market=market)
            sess["user_id"] = result.get("user_id", "")
            sess["external_user_id"] = external_user_id
        except Exception as e:
            error = str(e)

    return templates.TemplateResponse("step.html", _ctx(request, {
        "step": 2,
        "title": "Opret Bruger",
        "subtitle": f"Kunde: {external_user_id}",
        "endpoint": "POST /api/v1/user/create",
        "api_version": "v1",
        "description": f"Oprettet Tink-bruger med external_user_id <code class='text-violet-300 font-mono'>{external_user_id}</code> — dette er dit interne kunde-ID. Tink returnerer et user_id som bruges i næste kald.",
        "curl_example": curl_example,
        "result": result,
        "error": error,
        "next_step": 3,
        "prev_step": 1,
    }))


# ---------------------------------------------------------------------------
# Step 3 — Connect Bank (Tink Link redirect)
# ---------------------------------------------------------------------------

CONSOLE_CALLBACK = "https://console.tink.com/callback"


@router.get("/demo/step/3", response_class=HTMLResponse)
async def step3_get(request: Request):
    sess = _session(request)
    s = get_settings()
    client = _client()

    tink_link_url = client.get_tink_link_url(market="DK")
    dev_tink_link_url = client.get_tink_link_url(
        market="DK", redirect_uri_override=CONSOLE_CALLBACK
    )
    error = None
    credentials = None
    cb_success = request.query_params.get("cb_success")
    cb_error = request.query_params.get("cb_error")

    # Demo mode: auto-mark as connected with mock data
    if s.demo_mode and not sess.get("user_token"):
        sess["user_token"] = "demo-mode-token"
        sess["demo_mode"] = True

    # Check if already connected (returning from callback)
    user_token = sess.get("user_token", "")
    if user_token:
        if sess.get("demo_mode"):
            credentials = demo_data.MOCK_CREDENTIALS
            cb_success = cb_success or "demo"
        else:
            try:
                credentials = await client.list_credentials(user_token)
            except Exception as e:
                # credentials:read may not be granted in simple Tink Link flow — not fatal
                if "403" in str(e):
                    credentials = {"note": "credentials:read kræver authorization-grant flow"}
                else:
                    error = str(e)

    curl_example = (
        "# Simpelt Tink Link flow — ingen pre-oprettet bruger nødvendig\n"
        f"# Redirect brugeren direkte til:\n"
        f"https://link.tink.com/1.0/transactions/connect-accounts\n"
        f"  ?client_id=$CLIENT_ID\n"
        f"  &redirect_uri=$REDIRECT_URI\n"
        f"  &market=DK\n"
        f"  &scope=accounts:read,transactions:read,credentials:read\n\n"
        "# Tink Link redirecter tilbage med ?code=... som du exchangeer for user token:\n"
        "curl -X POST https://api.tink.com/api/v1/oauth/token \\\n"
        "  -d 'grant_type=authorization_code' \\\n"
        "  -d 'client_id=$CLIENT_ID' \\\n"
        "  -d 'client_secret=$CLIENT_SECRET' \\\n"
        "  -d 'code=$CODE'"
    )

    return templates.TemplateResponse("step.html", _ctx(request, {
        "step": 3,
        "title": "Tilslut Bank",
        "subtitle": "Tink Link — Bank Connection",
        "endpoint": "Tink Link /1.0/transactions/connect-accounts",
        "api_version": "Link v1",
        "description": "Brugeren åbner Tink Link, vælger Tink Demo Bank og logger ind med test-credentials fra Console. Tink redirecter tilbage med en authorization_code som automatisk exchang'es til et user token.",
        "curl_example": curl_example,
        "result": credentials,
        "tink_link_url": tink_link_url,
        "dev_tink_link_url": dev_tink_link_url,
        "error": error or (f"Callback fejl: {cb_error}" if cb_error else None),
        "cb_success": cb_success,
        "next_step": 4,
        "prev_step": 2,
    }))


@router.post("/demo/step/3", response_class=HTMLResponse)
async def step3_post(request: Request, code: str = Form(...)):
    """Manual code entry — exchange a code obtained via console.tink.com/callback."""
    sess = _session(request)
    try:
        client = _client(log_cb=_logger(sess))
        tokens = await client.exchange_code_for_token(
            code=code.strip(),
            redirect_uri=CONSOLE_CALLBACK,
        )
        sess["user_token"] = tokens.get("access_token", "")
        return RedirectResponse("/demo/step/3?cb_success=1", status_code=303)
    except Exception as e:
        return RedirectResponse(f"/demo/step/3?cb_error={str(e)}", status_code=303)


@router.get("/callback", response_class=HTMLResponse)
async def tink_callback(request: Request, code: Optional[str] = None,
                        error: Optional[str] = None,
                        credentials_id: Optional[str] = None):
    """Tink Link OAuth callback — exchange code for user token."""
    sess = _session(request)
    if error:
        return RedirectResponse(f"/demo/step/3?error={error}")
    if code:
        try:
            client = _client(log_cb=_logger(sess))
            tokens = await client.exchange_code_for_token(code)
            sess["user_token"] = tokens.get("access_token", "")
            return RedirectResponse("/demo/step/3?cb_success=1", status_code=303)
        except Exception as e:
            return RedirectResponse(f"/demo/step/3?cb_error={str(e)}", status_code=303)
    return RedirectResponse("/demo/step/3", status_code=303)


# ---------------------------------------------------------------------------
# Step 4 — Accounts (v2)
# ---------------------------------------------------------------------------

@router.get("/demo/step/4", response_class=HTMLResponse)
async def step4(request: Request):
    sess = _session(request)
    s = get_settings()
    user_token = sess.get("user_token", "")
    error = None
    result = None
    is_demo = sess.get("demo_mode") or s.demo_mode

    curl_example = (
        "curl https://api.tink.com/data/v2/accounts \\\n"
        "  -H 'Authorization: Bearer $USER_TOKEN'"
    )

    if not user_token and not is_demo:
        error = "Mangler user token — tilslut en bank i Step 3 først."
    elif is_demo:
        result = demo_data.MOCK_ACCOUNTS
    else:
        try:
            client = _client(log_cb=_logger(sess))
            result = await client.list_accounts(user_token)
            # Fall back to demo data if no accounts connected yet
            if not result.get("accounts"):
                result = demo_data.MOCK_ACCOUNTS
                sess["demo_mode"] = True
        except Exception as e:
            error = str(e)

    return templates.TemplateResponse("step.html", _ctx(request, {
        "step": 4,
        "title": "Konti",
        "subtitle": "Account List with Balances",
        "endpoint": "GET /data/v2/accounts",
        "api_version": "v2 ✦",
        "description": "Henter brugerens konti via det nye v2 data endpoint. Returnerer account type, balance, currency og IBAN.",
        "curl_example": curl_example,
        "result": result,
        "error": error,
        "is_demo": is_demo or (result == demo_data.MOCK_ACCOUNTS),
        "next_step": 5,
        "prev_step": 3,
    }))


# ---------------------------------------------------------------------------
# Step 5 — Transactions (v2)
# ---------------------------------------------------------------------------

@router.get("/demo/step/5", response_class=HTMLResponse)
async def step5(request: Request, account_id: Optional[str] = None):
    sess = _session(request)
    s = get_settings()
    user_token = sess.get("user_token", "")
    is_demo = sess.get("demo_mode") or s.demo_mode
    error = None
    result = None

    curl_example = (
        "curl 'https://api.tink.com/data/v2/transactions?pageSize=25' \\\n"
        "  -H 'Authorization: Bearer $USER_TOKEN'"
    )

    if not user_token and not is_demo:
        error = "Mangler user token — tilslut en bank i Step 3 først."
    elif is_demo:
        result = demo_data.MOCK_TRANSACTIONS
    else:
        try:
            client = _client(log_cb=_logger(sess))
            result = await client.list_transactions(user_token, account_id=account_id)
            if not result.get("transactions"):
                result = demo_data.MOCK_TRANSACTIONS
                sess["demo_mode"] = True
        except Exception as e:
            error = str(e)

    return templates.TemplateResponse("step.html", _ctx(request, {
        "step": 5,
        "title": "Transaktioner",
        "subtitle": "Transaction History",
        "endpoint": "GET /data/v2/transactions",
        "api_version": "v2 ✦",
        "description": "Henter transaktioner via v2 endpoint med paginering. Returnerer amount, description, status (BOOKED/PENDING), og kategorisering.",
        "curl_example": curl_example,
        "result": result,
        "error": error,
        "is_demo": is_demo or (result == demo_data.MOCK_TRANSACTIONS),
        "next_step": 6,
        "prev_step": 4,
    }))


# ---------------------------------------------------------------------------
# Step 6 — Events (v2)
# ---------------------------------------------------------------------------

@router.get("/demo/step/6", response_class=HTMLResponse)
async def step6(request: Request):
    sess = _session(request)
    s = get_settings()
    is_demo = sess.get("demo_mode") or s.demo_mode
    error = None
    result_webhooks = None
    webhook_registered = None

    webhook_url = f"{s.app_base_url}/webhooks/tink"

    curl_list = (
        "# List registered webhooks (app-level token)\n"
        "curl 'https://api.tink.com/api/v1/webhooks' \\\n"
        "  -H 'Authorization: Bearer $APP_TOKEN'"
    )
    curl_register = (
        "# Register webhook endpoint\n"
        "curl -X POST 'https://api.tink.com/api/v1/webhooks' \\\n"
        "  -H 'Authorization: Bearer $APP_TOKEN' \\\n"
        "  -H 'Content-Type: application/json' \\\n"
        "  -d '{\n"
        '    "url": "' + webhook_url + '",\n'
        '    "enabledEvents": [\n'
        '      "account-booked-transaction:created",\n'
        '      "account-pending-transaction:created"\n'
        "    ]\n"
        "  }'"
    )

    if is_demo:
        result_webhooks = demo_data.MOCK_EVENTS_BOOKED
        webhook_registered = {
            "id": "wh-demo-001",
            "url": webhook_url,
            "enabledEvents": ["account-booked-transaction:created", "account-pending-transaction:created"],
            "status": "ENABLED",
        }
    else:
        try:
            client = _client(log_cb=_logger(sess))
            app_token_resp = await client.get_app_token(scope="user:create")
            app_token = app_token_resp.get("access_token", "")

            result_webhooks = await client.list_webhooks(app_token)

            # Register our webhook if not already there
            existing = [w for w in result_webhooks.get("webhooks", []) if w.get("url") == webhook_url]
            if not existing:
                webhook_registered = await client.register_webhook(app_token, webhook_url)
            else:
                webhook_registered = existing[0]
        except Exception as e:
            err_str = str(e)
            if "404" in err_str:
                result_webhooks = {"note": "Webhook API ikke tilgængeligt i sandbox — kun i produktion"}
                webhook_registered = {
                    "url": webhook_url,
                    "enabledEvents": ["account-booked-transaction:created", "account-pending-transaction:created"],
                    "status": "ENABLED (eksempel)",
                }
            else:
                error = err_str

    return templates.TemplateResponse("step6.html", _ctx(request, {
        "step": 6,
        "title": "Webhooks & Events",
        "subtitle": "Real-time Event Notifications",
        "error": error,
        "result_webhooks": result_webhooks,
        "webhook_registered": webhook_registered,
        "webhook_url": webhook_url,
        "curl_list": curl_list,
        "curl_register": curl_register,
        "is_demo": is_demo,
        "app_base_url": s.app_base_url,
        "next_step": None,
        "prev_step": 5,
    }))


# ---------------------------------------------------------------------------
# API Request Log
# ---------------------------------------------------------------------------

@router.get("/demo/log", response_class=HTMLResponse)
async def api_log(request: Request):
    sess = _session(request)
    log = sess.get("api_log", [])
    return templates.TemplateResponse("log.html", _ctx(request, {
        "log": list(reversed(log)),  # newest first
        "log_count": len(log),
    }))


@router.post("/demo/log/clear")
async def clear_log(request: Request):
    sess = _session(request)
    sess["api_log"] = []
    return RedirectResponse("/demo/log", status_code=303)


# ---------------------------------------------------------------------------
# Webhook receiver
# ---------------------------------------------------------------------------

@router.post("/webhooks/tink")
async def webhook_receiver(request: Request):
    """Receive Tink webhook events (configure URL in Tink Console)."""
    body = await request.json()
    # In production you'd verify the signature and store events
    print(f"[WEBHOOK] {json.dumps(body, indent=2)}")
    return {"status": "received"}