use std::sync::Arc;

use axum::body::Body;
use axum::extract::Request;
use axum::http::header;
use axum::middleware::Next;
use axum::response::Response;

use crate::state::AppState;

const OG_PLACEHOLDER: &str =
    r#"<meta name="x-og-placeholder" content="__PERFECT_POSTCODE_OG_TAGS__"/>"#;

pub async fn og_middleware(request: Request, next: Next) -> Response {
    let path = request.uri().path().to_string();
    // Capture the query string before passing the request through
    let query_string = request.uri().query().unwrap_or("").to_string();

    // Get state from extensions
    let state = request.extensions().get::<Arc<AppState>>().cloned();

    let response = next.run(request).await;

    // Only inject OG tags into SPA HTML responses, not proxied PocketBase responses
    if path.starts_with("/pb/") || path.starts_with("/api/") {
        return response;
    }

    let content_type = response
        .headers()
        .get(header::CONTENT_TYPE)
        .and_then(|val| val.to_str().ok())
        .unwrap_or("");

    if !content_type.contains("text/html") {
        return response;
    }

    let state = match state {
        Some(st) => st,
        None => return response,
    };

    let index_html = match &state.index_html {
        Some(html) => html,
        None => return response,
    };

    // Build OG-injected HTML (og=1 triggers heading overlay on screenshot)
    let is_invite = path.starts_with("/invite/");

    let og_image_url = if is_invite {
        // Include path= so the screenshot service navigates to /invite/CODE
        if query_string.is_empty() {
            format!("{}/api/screenshot?og=1&path={}", state.public_url, path)
        } else {
            format!(
                "{}/api/screenshot?og=1&path={}&{}",
                state.public_url, path, query_string
            )
        }
    } else if query_string.is_empty() {
        format!("{}/api/screenshot?og=1", state.public_url)
    } else {
        format!("{}/api/screenshot?og=1&{}", state.public_url, query_string)
    };

    let og_url = if query_string.is_empty() {
        format!("{}{}", state.public_url, path)
    } else {
        format!("{}{}?{}", state.public_url, path, query_string)
    };

    let og_logo = format!("{}/favicon.svg", state.public_url);

    let (og_title, og_description) = if is_invite {
        (
            "You\u{2019}re invited to Perfect Postcode",
            "Accept your invitation to explore property prices, energy ratings, crime stats, school ratings, and more across England.",
        )
    } else {
        (
            "Perfect Postcode \u{2014} Every neighbourhood in England",
            "Explore property prices, energy ratings, crime stats, school ratings, and more across England on one interactive map.",
        )
    };

    let og_tags = format!(
        r#"<meta property="og:title" content="{og_title}" />
    <meta property="og:description" content="{og_description}" />
    <meta property="og:type" content="website" />
    <meta property="og:url" content="{og_url}" />
    <meta property="og:logo" content="{og_logo}" />
    <meta property="og:image" content="{og_image_url}" />
    <meta property="og:image:width" content="1200" />
    <meta property="og:image:height" content="630" />
    <meta name="twitter:card" content="summary_large_image" />
    <meta name="twitter:title" content="{og_title}" />
    <meta name="twitter:description" content="{og_description}" />"#
    );

    let html = index_html.replace(OG_PLACEHOLDER, &og_tags);

    let (parts, _body) = response.into_parts();
    Response::from_parts(parts, Body::from(html))
}