use super::{models::*, AppState};
use crate::auth::Claims;
use crate::discord_bot::{send_domain_approval_request, DomainRegistration};
use base64::{engine::general_purpose, Engine as _};
use gurt::prelude::*;
use rand::{rngs::OsRng, Rng};
use sha2::{Digest, Sha256};
use std::time::{SystemTime, UNIX_EPOCH};
use std::{collections::HashMap, env};

const VALID_DNS_RECORD_TYPES: &[&str] = &["A", "AAAA", "CNAME", "TXT"];

fn parse_query_string(query: &str) -> HashMap<String, String> {
    let mut params = HashMap::new();
    for pair in query.split('&') {
        if let Some((key, value)) = pair.split_once('=') {
            params.insert(key.to_string(), value.to_string());
        }
    }
    params
}

pub(crate) async fn index(_app_state: AppState) -> Result<GurtResponse> {
    let current_dir = std::env::current_dir()
        .map_err(|_| GurtError::invalid_message("Failed to get current directory"))?;
    let frontend_dir = current_dir.join("frontend");
    let index_path = frontend_dir.join("index.html");
    
    match tokio::fs::read_to_string(&index_path).await {
        Ok(content) => {
            Ok(GurtResponse::ok()
                .with_header("Content-Type", "text/html")
                .with_string_body(&content))
        }
        Err(_) => {
            let body = format!(
                "GurtDNS v{}!\n\nThe available endpoints are:\n\n - [GET] /domains\n - [GET] /domain/{{name}}/{{tld}}\n - [POST] /domain\n - [PUT] /domain/{{key}}\n - [DELETE] /domain/{{key}}\n - [GET] /tlds\n\nRatelimits are as follows: 5 requests per 10 minutes on `[POST] /domain`.\n\nCode link: https://github.com/outpoot/gurted",
                env!("CARGO_PKG_VERSION")
            );
            Ok(GurtResponse::ok().with_string_body(&body))
        }
    }
}

pub(crate) async fn create_logic(domain: Domain, user_id: i32, app: &AppState) -> Result<Domain> {
    if !app.config.tld_list().contains(&domain.tld.as_str())
        || !domain.name.chars().all(|c| c.is_alphabetic() || c == '-')
        || domain.name.len() > 24
        || domain.name.is_empty()
        || domain.name.starts_with('-')
        || domain.name.ends_with('-')
    {
        return Err(GurtError::invalid_message(
            "Invalid name, non-existent TLD, or name too long (24 chars).",
        ));
    }

    if app
        .config
        .offen_words()
        .iter()
        .any(|word| domain.name.contains(word))
    {
        return Err(GurtError::invalid_message(
            "The given domain name is offensive.",
        ));
    }

    let existing_count: i64 =
        sqlx::query_scalar("SELECT COUNT(*) FROM domains WHERE name = $1 AND tld = $2")
            .bind(&domain.name)
            .bind(&domain.tld)
            .fetch_one(&app.db)
            .await
            .map_err(|_| GurtError::invalid_message("Database error"))?;

    if existing_count > 0 {
        return Err(GurtError::invalid_message("Domain already exists"));
    }

    let user: (String,) = sqlx::query_as("SELECT username FROM users WHERE id = $1")
        .bind(user_id)
        .fetch_one(&app.db)
        .await
        .map_err(|_| GurtError::invalid_message("User not found"))?;

    let username = user.0;

    let domain_row: (i32,) = sqlx::query_as(
        "INSERT INTO domains (name, tld, user_id, status) VALUES ($1, $2, $3, 'pending') RETURNING id"
    )
    .bind(&domain.name)
    .bind(&domain.tld)
    .bind(user_id)
    .fetch_one(&app.db)
    .await
    .map_err(|_| GurtError::invalid_message("Failed to create domain"))?;

    let domain_id = domain_row.0;

    let affected_rows = sqlx::query(
        "UPDATE users SET registrations_remaining = registrations_remaining - 1 WHERE id = $1 AND registrations_remaining > 0",
    )
    .bind(user_id)
    .execute(&app.db)
    .await
    .map_err(|_| GurtError::invalid_message("Failed to update user registrations"))?
    .rows_affected();

    if affected_rows == 0 {
        sqlx::query("DELETE FROM domains WHERE id = $1")
            .bind(domain_id)
            .execute(&app.db)
            .await
            .map_err(|_| GurtError::invalid_message("Database cleanup error"))?;
        return Err(GurtError::invalid_message("No registrations remaining"));
    }

    if !app.config.discord.bot_token.is_empty() && app.config.discord.channel_id != 0 {
        let domain_registration = DomainRegistration {
            id: domain_id,
            domain_name: domain.name.clone(),
            tld: domain.tld.clone(),
            user_id,
            username: username.clone(),
        };

        let channel_id = app.config.discord.channel_id;
        let bot_token = app.config.discord.bot_token.clone();

        tokio::spawn(async move {
            if let Err(e) =
                send_domain_approval_request(channel_id, domain_registration, &bot_token).await
            {
                log::error!("Failed to send Discord notification: {}", e);
            }
        });
    }

    Ok(domain)
}

pub(crate) async fn create_domain(
    ctx: &ServerContext,
    app_state: AppState,
    claims: Claims,
) -> Result<GurtResponse> {
    let domain: Domain = serde_json::from_slice(ctx.body())
        .map_err(|_| GurtError::invalid_message("Invalid JSON"))?;

    match create_logic(domain.clone(), claims.user_id, &app_state).await {
        Ok(created_domain) => Ok(GurtResponse::ok().with_json_body(&created_domain)?),
        Err(e) => Ok(GurtResponse::bad_request().with_json_body(&Error {
            msg: "Failed to create domain",
            error: e.to_string(),
        })?),
    }
}

pub(crate) async fn get_domain(
    ctx: &ServerContext,
    app_state: AppState,
    claims: Claims,
) -> Result<GurtResponse> {
    let path_parts: Vec<&str> = ctx.path().split('/').collect();
    if path_parts.len() < 3 {
        return Ok(GurtResponse::bad_request()
            .with_string_body("Invalid path format. Expected /domain/{domainName}"));
    }

    let domain_name = path_parts[2];

    let domain_parts: Vec<&str> = domain_name.split('.').collect();
    if domain_parts.len() < 2 {
        return Ok(GurtResponse::bad_request()
            .with_string_body("Invalid domain format. Expected name.tld"));
    }

    let name = domain_parts[0];
    let tld = domain_parts[1];

    let domain: Option<Domain> = sqlx::query_as::<_, Domain>(
        "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE name = $1 AND tld = $2 AND user_id = $3"
    )
    .bind(name)
    .bind(tld)
    .bind(claims.user_id)
    .fetch_optional(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    match domain {
        Some(domain) => {
            let response_domain = DomainDetail {
                name: domain.name,
                tld: domain.tld,
                status: domain.status,
            };
            Ok(GurtResponse::ok().with_json_body(&response_domain)?)
        }
        None => Ok(GurtResponse::not_found().with_string_body("Domain not found")),
    }
}

pub(crate) async fn get_domains(ctx: &ServerContext, app_state: AppState) -> Result<GurtResponse> {
    // Parse pagination from query parameters
    let path = ctx.path();
    let query_params = if let Some(query_start) = path.find('?') {
        let query_string = &path[query_start + 1..];
        parse_query_string(query_string)
    } else {
        HashMap::new()
    };

    let page = query_params
        .get("page")
        .and_then(|p| p.parse::<u32>().ok())
        .unwrap_or(1)
        .max(1); // Ensure page is at least 1

    let page_size = query_params
        .get("limit")
        .and_then(|l| l.parse::<u32>().ok())
        .unwrap_or(100)
        .clamp(1, 1000); // Limit between 1 and 1000

    let offset = (page - 1) * page_size;

    let domains: Vec<Domain> = sqlx::query_as::<_, Domain>(
        "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE status = 'approved' ORDER BY created_at DESC LIMIT $1 OFFSET $2"
    )
    .bind(page_size as i64)
    .bind(offset as i64)
    .fetch_all(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    let response_domains: Vec<ResponseDomain> = domains
        .into_iter()
        .map(|domain| ResponseDomain {
            name: domain.name,
            tld: domain.tld,
            records: None,
        })
        .collect();

    let response = PaginationResponse {
        domains: response_domains,
        page,
        limit: page_size,
    };

    Ok(GurtResponse::ok().with_json_body(&response)?)
}

pub(crate) async fn get_tlds(app_state: AppState) -> Result<GurtResponse> {
    Ok(GurtResponse::ok().with_json_body(&app_state.config.tld_list())?)
}

pub(crate) async fn check_domain(ctx: &ServerContext, app_state: AppState) -> Result<GurtResponse> {
    let path = ctx.path();
    let query_params = if let Some(query_start) = path.find('?') {
        let query_string = &path[query_start + 1..];
        parse_query_string(query_string)
    } else {
        return Ok(GurtResponse::bad_request()
            .with_string_body("Missing query parameters. Expected ?name=<name>&tld=<tld>"));
    };

    let name = query_params
        .get("name")
        .ok_or_else(|| GurtError::invalid_message("Missing 'name' parameter"))?;
    let tld = query_params
        .get("tld")
        .ok_or_else(|| GurtError::invalid_message("Missing 'tld' parameter"))?;

    let domain: Option<Domain> = sqlx::query_as::<_, Domain>(
        "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE name = $1 AND tld = $2"
    )
    .bind(name)
    .bind(tld)
    .fetch_optional(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    let domain_list = DomainList {
        domain: format!("{}.{}", name, tld),
        taken: domain.is_some(),
    };

    Ok(GurtResponse::ok().with_json_body(&domain_list)?)
}

pub(crate) async fn update_domain(
    _ctx: &ServerContext,
    _app_state: AppState,
    _claims: Claims,
) -> Result<GurtResponse> {
    return Ok(GurtResponse::bad_request()
        .with_string_body("Domain updates are no longer supported. Use DNS records instead."));
}

pub(crate) async fn delete_domain(
    ctx: &ServerContext,
    app_state: AppState,
    claims: Claims,
) -> Result<GurtResponse> {
    let path_parts: Vec<&str> = ctx.path().split('/').collect();
    if path_parts.len() < 4 {
        return Ok(GurtResponse::bad_request()
            .with_string_body("Invalid path format. Expected /domain/{name}/{tld}"));
    }

    let name = path_parts[2];
    let tld = path_parts[3];

    // Verify user owns this domain
    let domain: Option<Domain> = sqlx::query_as::<_, Domain>(
        "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE name = $1 AND tld = $2 AND user_id = $3"
    )
    .bind(name)
    .bind(tld)
    .bind(claims.user_id)
    .fetch_optional(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    if domain.is_none() {
        return Ok(GurtResponse::not_found().with_string_body("Domain not found or access denied"));
    }

    sqlx::query("DELETE FROM domains WHERE name = $1 AND tld = $2 AND user_id = $3")
        .bind(name)
        .bind(tld)
        .bind(claims.user_id)
        .execute(&app_state.db)
        .await
        .map_err(|_| GurtError::invalid_message("Failed to delete domain"))?;

    Ok(GurtResponse::ok().with_string_body("Domain deleted successfully"))
}

pub(crate) async fn get_user_domains(
    ctx: &ServerContext,
    app_state: AppState,
    claims: Claims,
) -> Result<GurtResponse> {
    // Parse pagination from query parameters
    let path = ctx.path();
    let query_params = if let Some(query_start) = path.find('?') {
        let query_string = &path[query_start + 1..];
        parse_query_string(query_string)
    } else {
        HashMap::new()
    };

    let page = query_params
        .get("page")
        .and_then(|p| p.parse::<u32>().ok())
        .unwrap_or(1)
        .max(1);

    let page_size = query_params
        .get("limit")
        .and_then(|l| l.parse::<u32>().ok())
        .unwrap_or(100)
        .clamp(1, 1000);

    let offset = (page - 1) * page_size;

    let domains: Vec<Domain> = sqlx::query_as::<_, Domain>(
        "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE user_id = $1 ORDER BY created_at DESC LIMIT $2 OFFSET $3"
    )
    .bind(claims.user_id)
    .bind(page_size as i64)
    .bind(offset as i64)
    .fetch_all(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    let response_domains: Vec<UserDomain> = domains
        .into_iter()
        .map(|domain| UserDomain {
            name: domain.name,
            tld: domain.tld,
            status: domain.status.unwrap_or_else(|| "pending".to_string()),
            denial_reason: domain.denial_reason,
        })
        .collect();

    let response = UserDomainResponse {
        domains: response_domains,
        page,
        limit: page_size,
    };

    Ok(GurtResponse::ok().with_json_body(&response)?)
}

pub(crate) async fn get_domain_records(
    ctx: &ServerContext,
    app_state: AppState,
    claims: Claims,
) -> Result<GurtResponse> {
    let path_parts: Vec<&str> = ctx.path().split('/').collect();
    if path_parts.len() < 4 {
        return Ok(GurtResponse::bad_request()
            .with_string_body("Invalid path format. Expected /domain/{domainName}/records"));
    }

    let domain_name = path_parts[2];

    let domain_parts: Vec<&str> = domain_name.split('.').collect();
    if domain_parts.len() < 2 {
        return Ok(GurtResponse::bad_request()
            .with_string_body("Invalid domain format. Expected name.tld"));
    }

    let name = domain_parts[0];
    let tld = domain_parts[1];

    let domain: Option<Domain> = sqlx::query_as::<_, Domain>(
        "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE name = $1 AND tld = $2 AND user_id = $3"
    )
    .bind(name)
    .bind(tld)
    .bind(claims.user_id)
    .fetch_optional(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    let domain = match domain {
        Some(d) => d,
        None => {
            return Ok(
                GurtResponse::not_found().with_string_body("Domain not found or access denied")
            )
        }
    };

    let records: Vec<DnsRecord> = sqlx::query_as::<_, DnsRecord>(
        "SELECT id, domain_id, record_type, name, value, ttl, priority, created_at FROM dns_records WHERE domain_id = $1 ORDER BY created_at ASC"
    )
    .bind(domain.id.unwrap())
    .fetch_all(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    let response_records: Vec<ResponseDnsRecord> = records
        .into_iter()
        .map(|record| ResponseDnsRecord {
            id: record.id.unwrap(),
            record_type: record.record_type,
            name: record.name,
            value: record.value,
            ttl: record.ttl,
            priority: record.priority,
        })
        .collect();

    Ok(GurtResponse::ok().with_json_body(&response_records)?)
}

pub(crate) async fn create_domain_record(
    ctx: &ServerContext,
    app_state: AppState,
    claims: Claims,
) -> Result<GurtResponse> {
    let path_parts: Vec<&str> = ctx.path().split('/').collect();
    if path_parts.len() < 4 {
        return Ok(GurtResponse::bad_request()
            .with_string_body("Invalid path format. Expected /domain/{domainName}/records"));
    }

    let domain_name = path_parts[2];

    let domain_parts: Vec<&str> = domain_name.split('.').collect();
    if domain_parts.len() < 2 {
        return Ok(GurtResponse::bad_request()
            .with_string_body("Invalid domain format. Expected name.tld"));
    }

    let name = domain_parts[0];
    let tld = domain_parts[1];

    let domain: Option<Domain> = sqlx::query_as::<_, Domain>(
        "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE name = $1 AND tld = $2 AND user_id = $3"
    )
    .bind(name)
    .bind(tld)
    .bind(claims.user_id)
    .fetch_optional(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    let domain = match domain {
        Some(d) => d,
        None => {
            return Ok(
                GurtResponse::not_found().with_string_body("Domain not found or access denied")
            )
        }
    };

    let record_data: CreateDnsRecord = {
        let body_bytes = ctx.body();
        let body_str = std::str::from_utf8(body_bytes).unwrap_or("<invalid utf8>");
        log::info!("Received JSON body: {}", body_str);

        serde_json::from_slice(body_bytes).map_err(|e| {
            log::error!("JSON parsing error: {} for body: {}", e, body_str);
            GurtError::invalid_message("Invalid JSON")
        })?
    };

    if record_data.record_type.is_empty() {
        return Ok(GurtResponse::bad_request().with_string_body("Record type is required"));
    }

    if !VALID_DNS_RECORD_TYPES.contains(&record_data.record_type.as_str()) {
        return Ok(GurtResponse::bad_request().with_string_body(
            "Invalid record type. Only A, AAAA, CNAME, and TXT records are supported.",
        ));
    }

    let record_name = record_data.name.unwrap_or_else(|| "@".to_string());
    let ttl = record_data.ttl.filter(|t| *t > 0);

    match record_data.record_type.as_str() {
        "A" => {
            if !record_data.value.parse::<std::net::Ipv4Addr>().is_ok() {
                return Ok(GurtResponse::bad_request()
                    .with_string_body("Invalid IPv4 address for A record"));
            }
        }
        "AAAA" => {
            if !record_data.value.parse::<std::net::Ipv6Addr>().is_ok() {
                return Ok(GurtResponse::bad_request()
                    .with_string_body("Invalid IPv6 address for AAAA record"));
            }
        }
        "CNAME" => {
            if record_data.value.is_empty() || !record_data.value.contains('.') {
                return Ok(GurtResponse::bad_request()
                    .with_string_body("CNAME records must contain a valid domain name"));
            }
        }
        "TXT" => {
            // TXT records can contain any text
        }
        _ => {
            return Ok(GurtResponse::bad_request().with_string_body("Invalid record type"));
        }
    }

    let record_id: (i32,) = sqlx::query_as(
        "INSERT INTO dns_records (domain_id, record_type, name, value, ttl, priority) VALUES ($1, $2, $3, $4, $5, $6) RETURNING id"
    )
    .bind(domain.id.unwrap())
    .bind(&record_data.record_type)
    .bind(&record_name)
    .bind(&record_data.value)
    .bind(ttl)
    .bind(record_data.priority)
    .fetch_one(&app_state.db)
    .await
    .map_err(|e| {
        log::error!("Failed to create DNS record: {}", e);
        GurtError::invalid_message("Failed to create DNS record")
    })?;

    let response_record = ResponseDnsRecord {
        id: record_id.0,
        record_type: record_data.record_type,
        name: record_name,
        value: record_data.value,
        ttl: Some(ttl.unwrap_or(3600)),
        priority: record_data.priority,
    };

    Ok(GurtResponse::ok().with_json_body(&response_record)?)
}

pub(crate) async fn delete_domain_record(
    ctx: &ServerContext,
    app_state: AppState,
    claims: Claims,
) -> Result<GurtResponse> {
    let path_parts: Vec<&str> = ctx.path().split('/').collect();
    if path_parts.len() < 5 {
        return Ok(GurtResponse::bad_request().with_string_body(
            "Invalid path format. Expected /domain/{domainName}/records/{recordId}",
        ));
    }

    let domain_name = path_parts[2];
    let record_id_str = path_parts[4];

    let record_id: i32 = record_id_str
        .parse()
        .map_err(|_| GurtError::invalid_message("Invalid record ID"))?;

    let domain_parts: Vec<&str> = domain_name.split('.').collect();
    if domain_parts.len() < 2 {
        return Ok(GurtResponse::bad_request()
            .with_string_body("Invalid domain format. Expected name.tld"));
    }

    let name = domain_parts[0];
    let tld = domain_parts[1];

    let domain: Option<Domain> = sqlx::query_as::<_, Domain>(
        "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE name = $1 AND tld = $2 AND user_id = $3"
    )
    .bind(name)
    .bind(tld)
    .bind(claims.user_id)
    .fetch_optional(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    let domain = match domain {
        Some(d) => d,
        None => {
            return Ok(
                GurtResponse::not_found().with_string_body("Domain not found or access denied")
            )
        }
    };

    let rows_affected = sqlx::query("DELETE FROM dns_records WHERE id = $1 AND domain_id = $2")
        .bind(record_id)
        .bind(domain.id.unwrap())
        .execute(&app_state.db)
        .await
        .map_err(|_| GurtError::invalid_message("Database error"))?
        .rows_affected();

    if rows_affected == 0 {
        return Ok(GurtResponse::not_found().with_string_body("DNS record not found"));
    }

    Ok(GurtResponse::ok().with_string_body("DNS record deleted successfully"))
}

pub(crate) async fn resolve_domain(
    ctx: &ServerContext,
    app_state: AppState,
) -> Result<GurtResponse> {
    let resolution_request: DnsResolutionRequest = serde_json::from_slice(ctx.body())
        .map_err(|_| GurtError::invalid_message("Invalid JSON"))?;

    let full_domain = format!("{}.{}", resolution_request.name, resolution_request.tld);

    // Try to resolve with enhanced subdomain and delegation support
    match resolve_dns_with_delegation(&full_domain, &app_state).await {
        Ok(response) => Ok(GurtResponse::ok().with_json_body(&response)?),
        Err(_) => Ok(GurtResponse::not_found().with_json_body(&Error {
            msg: "Domain not found",
            error: "Domain not found, not approved, or delegation failed".into(),
        })?),
    }
}

async fn resolve_dns_with_delegation(
    query_name: &str,
    app_state: &AppState,
) -> Result<DnsResolutionResponse> {
    // Parse the query domain
    let parts: Vec<&str> = query_name.split('.').collect();
    if parts.len() < 2 {
        return Err(GurtError::invalid_message("Invalid domain format"));
    }

    let tld = parts.last().unwrap();

    // Try to find exact match first
    if let Some(response) = try_exact_match(query_name, tld, app_state).await? {
        return Ok(response);
    }

    // Try to find delegation by checking parent domains
    if let Some(response) = try_delegation_match(query_name, tld, app_state).await? {
        return Ok(response);
    }

    Err(GurtError::invalid_message(
        "No matching records or delegation found",
    ))
}

async fn try_exact_match(
    query_name: &str,
    tld: &str,
    app_state: &AppState,
) -> Result<Option<DnsResolutionResponse>> {
    let parts: Vec<&str> = query_name.split('.').collect();
    if parts.len() < 2 {
        return Ok(None);
    }

    // For a query like "api.blog.example.com", try different combinations
    for i in (1..parts.len()).rev() {
        let domain_name = parts[parts.len() - i - 1];
        let subdomain_parts = &parts[0..parts.len() - i - 1];
        let subdomain = if subdomain_parts.is_empty() {
            "@".to_string()
        } else {
            subdomain_parts.join(".")
        };

        // Look for the domain in our database
        let domain: Option<Domain> = sqlx::query_as::<_, Domain>(
            "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE name = $1 AND tld = $2 AND status = 'approved'"
        )
        .bind(domain_name)
        .bind(tld)
        .fetch_optional(&app_state.db)
        .await
        .map_err(|_| GurtError::invalid_message("Database error"))?;

        if let Some(domain) = domain {
            // Look for specific records for this subdomain
            let records: Vec<DnsRecord> = sqlx::query_as::<_, DnsRecord>(
                "SELECT id, domain_id, record_type, name, value, ttl, priority, created_at FROM dns_records WHERE domain_id = $1 AND name = $2 ORDER BY created_at ASC"
            )
            .bind(domain.id.unwrap())
            .bind(&subdomain)
            .fetch_all(&app_state.db)
            .await
            .map_err(|_| GurtError::invalid_message("Database error"))?;

            if !records.is_empty() {
                let response_records: Vec<ResponseDnsRecord> = records
                    .into_iter()
                    .map(|record| ResponseDnsRecord {
                        id: record.id.unwrap(),
                        record_type: record.record_type,
                        name: record.name,
                        value: record.value,
                        ttl: record.ttl,
                        priority: record.priority,
                    })
                    .collect();

                return Ok(Some(DnsResolutionResponse {
                    name: query_name.to_string(),
                    tld: tld.to_string(),
                    records: response_records,
                }));
            }
        }
    }

    Ok(None)
}

async fn try_delegation_match(
    query_name: &str,
    tld: &str,
    app_state: &AppState,
) -> Result<Option<DnsResolutionResponse>> {
    let parts: Vec<&str> = query_name.split('.').collect();

    // Try to find NS records for parent domains
    for i in (1..parts.len()).rev() {
        let domain_name = parts[parts.len() - i - 1];
        let subdomain_parts = &parts[0..parts.len() - i - 1];
        let subdomain = if subdomain_parts.is_empty() {
            "@".to_string()
        } else {
            subdomain_parts.join(".")
        };

        // Look for the domain
        let domain: Option<Domain> = sqlx::query_as::<_, Domain>(
            "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE name = $1 AND tld = $2 AND status = 'approved'"
        )
        .bind(domain_name)
        .bind(tld)
        .fetch_optional(&app_state.db)
        .await
        .map_err(|_| GurtError::invalid_message("Database error"))?;

        if let Some(domain) = domain {
            // Look for NS records that match this subdomain or parent
            let ns_records: Vec<DnsRecord> = sqlx::query_as::<_, DnsRecord>(
                "SELECT id, domain_id, record_type, name, value, ttl, priority, created_at FROM dns_records WHERE domain_id = $1 AND record_type = 'NS' AND (name = $2 OR name = $3) ORDER BY created_at ASC"
            )
            .bind(domain.id.unwrap())
            .bind(&subdomain)
            .bind("@")
            .fetch_all(&app_state.db)
            .await
            .map_err(|_| GurtError::invalid_message("Database error"))?;

            if !ns_records.is_empty() {
                // Also look for glue records (A/AAAA records for the NS hosts)
                let mut all_records = ns_records;

                // Get glue records for NS entries that point to subdomains of this zone
                for ns_record in &all_records.clone() {
                    let ns_host = &ns_record.value;
                    if ns_host.ends_with(&format!(".{}.{}", domain_name, tld))
                        || ns_host == &format!("{}.{}", domain_name, tld)
                    {
                        let glue_records: Vec<DnsRecord> = sqlx::query_as::<_, DnsRecord>(
                            "SELECT id, domain_id, record_type, name, value, ttl, priority, created_at FROM dns_records WHERE domain_id = $1 AND (record_type = 'A' OR record_type = 'AAAA') AND value = $2"
                        )
                        .bind(domain.id.unwrap())
                        .bind(ns_host)
                        .fetch_all(&app_state.db)
                        .await
                        .map_err(|_| GurtError::invalid_message("Database error"))?;

                        all_records.extend(glue_records);
                    }
                }

                let response_records: Vec<ResponseDnsRecord> = all_records
                    .into_iter()
                    .map(|record| ResponseDnsRecord {
                        id: record.id.unwrap(),
                        record_type: record.record_type,
                        name: record.name,
                        value: record.value,
                        ttl: record.ttl,
                        priority: record.priority,
                    })
                    .collect();

                return Ok(Some(DnsResolutionResponse {
                    name: query_name.to_string(),
                    tld: tld.to_string(),
                    records: response_records,
                }));
            }
        }
    }

    Ok(None)
}

pub(crate) async fn resolve_full_domain(
    ctx: &ServerContext,
    app_state: AppState,
) -> Result<GurtResponse> {
    #[derive(serde::Deserialize)]
    struct FullDomainRequest {
        domain: String,
        record_type: Option<String>,
    }

    let request: FullDomainRequest = serde_json::from_slice(ctx.body())
        .map_err(|_| GurtError::invalid_message("Invalid JSON"))?;

    // Try to resolve with enhanced subdomain and delegation support
    match resolve_dns_with_delegation(&request.domain, &app_state).await {
        Ok(mut response) => {
            // Filter by record type if specified
            if let Some(record_type) = request.record_type {
                response.records.retain(|r| r.record_type == record_type);
            }
            Ok(GurtResponse::ok().with_json_body(&response)?)
        }
        Err(_) => Ok(GurtResponse::not_found().with_json_body(&Error {
            msg: "Domain not found",
            error: "Domain not found, not approved, or delegation failed".into(),
        })?),
    }
}

// Certificate Authority endpoints
pub(crate) async fn verify_domain_ownership(
    ctx: &ServerContext,
    app_state: AppState,
) -> Result<GurtResponse> {
    let path_parts: Vec<&str> = ctx.path().split('/').collect();
    if path_parts.len() < 3 {
        return Ok(GurtResponse::bad_request().with_string_body("Invalid path format"));
    }

    let domain = path_parts[2];

    let domain_parts: Vec<&str> = domain.split('.').collect();
    if domain_parts.len() < 2 {
        return Ok(GurtResponse::bad_request().with_string_body("Invalid domain format"));
    }

    let name = domain_parts[0];
    let tld = domain_parts[1];

    let domain_record: Option<Domain> = sqlx::query_as::<_, Domain>(
        "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE name = $1 AND tld = $2 AND status = 'approved'"
    )
    .bind(name)
    .bind(tld)
    .fetch_optional(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    let exists = domain_record.is_some();

    Ok(GurtResponse::ok().with_json_body(&serde_json::json!({
        "domain": domain,
        "exists": exists
    }))?)
}

pub(crate) async fn request_certificate(
    ctx: &ServerContext,
    app_state: AppState,
) -> Result<GurtResponse> {
    #[derive(serde::Deserialize)]
    struct CertRequest {
        domain: String,
        csr: String,
    }

    let cert_request: CertRequest = serde_json::from_slice(ctx.body())
        .map_err(|_| GurtError::invalid_message("Invalid JSON"))?;

    let domain_parts: Vec<&str> = cert_request.domain.split('.').collect();
    if domain_parts.len() < 2 {
        return Ok(GurtResponse::bad_request().with_string_body("Invalid domain format"));
    }

    let name = domain_parts[0];
    let tld = domain_parts[1];

    let domain_record: Option<Domain> = sqlx::query_as::<_, Domain>(
        "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE name = $1 AND tld = $2 AND status = 'approved'"
    )
    .bind(name)
    .bind(tld)
    .fetch_optional(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    if domain_record.is_none() {
        return Ok(GurtResponse::bad_request()
            .with_string_body("Domain does not exist or is not approved"));
    }

    let token = uuid::Uuid::new_v4().to_string();
    let verification_data = generate_challenge_data(&cert_request.domain, &token)?;

    sqlx::query(
        "INSERT INTO certificate_challenges (token, domain, challenge_type, verification_data, csr_pem, expires_at) VALUES ($1, $2, $3, $4, $5, $6)"
    )
    .bind(&token)
    .bind(&cert_request.domain)
    .bind("dns") // Only DNS challenges
    .bind(&verification_data)
    .bind(&cert_request.csr)
    .bind(chrono::Utc::now() + chrono::Duration::hours(1))
    .execute(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Failed to store challenge"))?;

    let challenge = serde_json::json!({
        "token": token,
        "challenge_type": "dns",
        "domain": cert_request.domain,
        "verification_data": verification_data
    });

    Ok(GurtResponse::ok().with_json_body(&challenge)?)
}

pub(crate) async fn get_certificate(
    ctx: &ServerContext,
    app_state: AppState,
) -> Result<GurtResponse> {
    let path_parts: Vec<&str> = ctx.path().split('/').collect();
    if path_parts.len() < 4 {
        return Ok(GurtResponse::bad_request().with_string_body("Invalid path format"));
    }

    let token = path_parts[3];

    let challenge: Option<(String, String, String, Option<String>, chrono::DateTime<chrono::Utc>)> = sqlx::query_as(
        "SELECT domain, challenge_type, verification_data, csr_pem, expires_at FROM certificate_challenges WHERE token = $1"
    )
    .bind(token)
    .fetch_optional(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    let (domain, _challenge_type, verification_data, csr_pem, expires_at) = match challenge {
        Some(c) => c,
        None => return Ok(GurtResponse::not_found().with_string_body("Challenge not found")),
    };

    let csr_pem = match csr_pem {
        Some(csr) => csr,
        None => {
            return Ok(
                GurtResponse::bad_request().with_string_body("CSR not found for this challenge")
            )
        }
    };

    if chrono::Utc::now() > expires_at {
        return Ok(GurtResponse::bad_request().with_string_body("Challenge expired"));
    }

    let challenge_domain = format!("_gurtca-challenge.{}", domain);
    let domain_parts: Vec<&str> = challenge_domain.split('.').collect();
    if domain_parts.len() < 3 {
        return Ok(GurtResponse::bad_request().with_string_body("Invalid domain format"));
    }

    let record_name = "_gurtca-challenge";
    let base_domain_name = domain_parts[domain_parts.len() - 2];
    let tld = domain_parts[domain_parts.len() - 1];

    let domain_record: Option<Domain> = sqlx::query_as::<_, Domain>(
        "SELECT id, name, tld, ip, user_id, status, denial_reason, created_at FROM domains WHERE name = $1 AND tld = $2 AND status = 'approved'"
    )
    .bind(base_domain_name)
    .bind(tld)
    .fetch_optional(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    let domain_record = match domain_record {
        Some(d) => d,
        None => {
            return Ok(
                GurtResponse::bad_request().with_string_body("Domain not found or not approved")
            )
        }
    };

    let txt_records: Vec<DnsRecord> = sqlx::query_as::<_, DnsRecord>(
        "SELECT id, domain_id, record_type, name, value, ttl, priority, created_at FROM dns_records WHERE domain_id = $1 AND record_type = 'TXT' AND name = $2 AND value = $3"
    )
    .bind(domain_record.id.unwrap())
    .bind(record_name)
    .bind(&verification_data)
    .fetch_all(&app_state.db)
    .await
    .map_err(|_| GurtError::invalid_message("Database error"))?;

    if txt_records.is_empty() {
        return Ok(GurtResponse::new(gurt::GurtStatusCode::Accepted)
            .with_string_body("Challenge not completed yet"));
    }

    let ca_cert = super::ca::get_or_create_ca(&app_state.db)
        .await
        .map_err(|e| {
            log::error!("Failed to get CA certificate: {}", e);
            GurtError::invalid_message("CA certificate error")
        })?;

    let cert_pem = crate::crypto::sign_csr_with_ca(
        &csr_pem,
        &ca_cert.ca_cert_pem,
        &ca_cert.ca_key_pem,
        &domain,
    )
    .map_err(|e| {
        log::error!("Failed to sign certificate: {}", e);
        GurtError::invalid_message("Certificate signing failed")
    })?;

    let certificate = serde_json::json!({
        "cert_pem": cert_pem,
        "chain_pem": ca_cert.ca_cert_pem,
        "expires_at": (chrono::Utc::now() + chrono::Duration::days(90)).to_rfc3339()
    });

    // Delete the challenge as it's completed
    sqlx::query("DELETE FROM certificate_challenges WHERE token = $1")
        .bind(token)
        .execute(&app_state.db)
        .await
        .map_err(|_| GurtError::invalid_message("Failed to cleanup challenge"))?;

    Ok(GurtResponse::ok().with_json_body(&certificate)?)
}

pub(crate) async fn get_ca_certificate(
    _ctx: &ServerContext,
    app_state: AppState,
) -> Result<GurtResponse> {
    let ca_cert = super::ca::get_or_create_ca(&app_state.db)
        .await
        .map_err(|e| {
            log::error!("Failed to get CA certificate: {}", e);
            GurtError::invalid_message("CA certificate error")
        })?;

    Ok(GurtResponse::ok()
        .with_header("Content-Type", "application/x-pem-file")
        .with_header(
            "Content-Disposition",
            "attachment; filename=\"gurted-ca.crt\"",
        )
        .with_string_body(ca_cert.ca_cert_pem))
}

fn generate_challenge_data(domain: &str, token: &str) -> Result<String> {
    let timestamp = SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map_err(|_| GurtError::invalid_message("System time error"))?
        .as_nanos();

    let mut rng = OsRng;
    let random_bytes: [u8; 32] = rng.gen();
    let secure_entropy = general_purpose::STANDARD.encode(random_bytes);

    let uuid_entropy = uuid::Uuid::new_v4().to_string();

    let data = format!(
        "{}:{}:{}:{}:{}",
        domain, token, timestamp, secure_entropy, uuid_entropy
    );
    let mut hasher = Sha256::new();
    hasher.update(data.as_bytes());
    let hash = hasher.finalize();

    Ok(general_purpose::STANDARD.encode(hash))
}

#[derive(serde::Serialize)]
struct Error {
    msg: &'static str,
    error: String,
}