//! Midtrans payment provider — Core API (v2/charge).
//!
//! Gateway-agnostic design: the payments service calls into this module when
//! Midtrans credentials are configured (`MIDTRANS_*` env). It returns the
//! provider-specific reference that gets persisted into `app_payments.external_ref`:
//! a VA number for `va`, or the QR string payload for `qris`.

use imphnen_utils::AppError;
use serde_json::json;

/// Query transaction status for an order via Midtrans Core API.
///
/// Returns the raw `transaction_status` string (e.g. "capture", "settlement",
/// "pending", "expire", ...).
pub async fn get_status(
	order_id: &str,
	server_key: &str,
) -> Result<String, AppError> {
	let client = reqwest::Client::new();
	let url = format!("{}/{}/status", status_base(), order_id);
	let resp = client
		.get(&url)
		.basic_auth(server_key, Some(""))
		// Midtrans/istio compresses with gzip even when the client cannot
		// decompress; reqwest auto-decompress can return an empty body here,
		// so ask for identity explicitly.
		.header(reqwest::header::ACCEPT_ENCODING, "identity")
		.send()
		.await
		.map_err(|e| AppError::InternalServerError(format!("Midtrans status request failed: {e}")))?;

	let status = resp.status();
	let hdrs = format!("{:?}", resp.headers());
	let text = resp
		.text()
		.await
		.map_err(|e| AppError::InternalServerError(format!("Midtrans status read failed: {e} (http {}, hdrs {})", status, hdrs)))?;
	let payload: serde_json::Value = serde_json::from_str(&text).map_err(|e| {
		AppError::InternalServerError(format!(
			"Midtrans status parse failed: {e} (http {}, hdrs {}, body-len {})",
			status,
			hdrs,
			text.len()
		))
	})?;

	if !status.is_success() {
		return Err(AppError::InternalServerError(format!(
			"Midtrans status error ({}): {}",
			status,
			payload["status_message"].as_str().unwrap_or("unknown")
		)));
	}

	Ok(
		payload["transaction_status"]
			.as_str()
			.unwrap_or("unknown")
			.to_string(),
	)
}

fn status_base() -> &'static str {
	if std::env::var("RUST_ENV").as_deref() == Ok("production") {
		"https://api.midtrans.com/v2"
	} else {
		"https://api.sandbox.midtrans.com/v2"
	}
}

/// Sandbox vs production endpoint for charge. Sandbox is the default and safe for demo.
fn charge_url() -> &'static str {
	if std::env::var("RUST_ENV").as_deref() == Ok("production") {
		"https://api.midtrans.com/v2/charge"
	} else {
		"https://api.sandbox.midtrans.com/v2/charge"
	}
}

/// Create a bank-transfer (Virtual Account) charge via Midtrans Core API.
///
/// Returns the VA number to display to the mentee.
pub async fn create_va_charge(
	order_id: &str,
	gross_amount: i64,
	bank: &str,
	server_key: &str,
) -> Result<String, AppError> {
	let client = reqwest::Client::new();
	let body = json!({
		"payment_type": "bank_transfer",
		"transaction_details": {
			"order_id": order_id,
			"gross_amount": gross_amount,
		},
		"bank_transfer": {
			"bank": bank,
		}
	});

	let resp = client
		.post(charge_url())
		.basic_auth(server_key, Some(""))
		.json(&body)
		.send()
		.await
		.map_err(|e| AppError::InternalServerError(format!("Midtrans request failed: {e}")))?;

	let status = resp.status();
	let payload: serde_json::Value = resp
		.json()
		.await
		.map_err(|e| AppError::InternalServerError(format!("Midtrans response parse failed: {e}")))?;

	if !status.is_success() {
		return Err(AppError::InternalServerError(format!(
			"Midtrans charge error ({}): {}",
			status,
			payload["status_message"]
				.as_str()
				.unwrap_or("unknown error")
		)));
	}

	payload["va_numbers"][0]["va_number"]
		.as_str()
		.map(|s| s.to_string())
		.ok_or_else(|| AppError::InternalServerError("Midtrans response missing va_number".into()))
}

/// Create a QRIS charge via Midtrans Core API.
///
/// Returns the QR string payload (renderable as a QR code).
pub async fn create_qris_charge(
	order_id: &str,
	gross_amount: i64,
	server_key: &str,
) -> Result<String, AppError> {
	let client = reqwest::Client::new();
	let body = json!({
		"payment_type": "qris",
		"transaction_details": {
			"order_id": order_id,
			"gross_amount": gross_amount,
		},
		"qris": {
			"acquirer": "gopay",
		}
	});

	let resp = client
		.post(charge_url())
		.basic_auth(server_key, Some(""))
		.json(&body)
		.send()
		.await
		.map_err(|e| AppError::InternalServerError(format!("Midtrans request failed: {e}")))?;

	let status = resp.status();
	let payload: serde_json::Value = resp
		.json()
		.await
		.map_err(|e| AppError::InternalServerError(format!("Midtrans response parse failed: {e}")))?;

	if !status.is_success() {
		return Err(AppError::InternalServerError(format!(
			"Midtrans charge error ({}): {}",
			status,
			payload["status_message"]
				.as_str()
				.unwrap_or("unknown error")
		)));
	}

	payload["qr_string"]
		.as_str()
		.map(|s| s.to_string())
		.ok_or_else(|| AppError::InternalServerError("Midtrans response missing qr_string".into()))
}