use crate::AppState;
use axum::{
    extract::{Path, Query, State},
    http::StatusCode,
    response::IntoResponse,
    routing::{get, post},
    Json, Router,
};
use serde::{Deserialize, Serialize};
use sqlx::FromRow;
use std::sync::Arc;
use uuid::Uuid;

#[derive(Debug, Deserialize)]
pub struct PaginationQuery {
    pub page: Option<i64>,
    pub limit: Option<i64>,
    pub status: Option<String>,
}

#[derive(Debug, Deserialize)]
pub struct SendLeadRequestPayload {
    pub lead_id: Uuid,
    pub message: Option<String>,
}

#[derive(Debug, FromRow)]
pub struct LeadRequestRow {
    pub id: Uuid,
    pub lead_id: Uuid,
    pub user_role_profile_id: Uuid,
    pub customer_user_id: Uuid,
    pub status: String,
    pub tracecoins_reserved: i32,
    pub message: Option<String>,
    pub expires_at: chrono::DateTime<chrono::Utc>,
    pub accepted_at: Option<chrono::DateTime<chrono::Utc>>,
    pub rejected_at: Option<chrono::DateTime<chrono::Utc>>,
    pub rejected_reason: Option<String>,
    pub created_at: chrono::DateTime<chrono::Utc>,
}

#[derive(Debug, Serialize)]
pub struct LeadRequestResponse {
    pub id: Uuid,
    pub lead_id: Uuid,
    pub user_role_profile_id: Uuid,
    pub customer_user_id: Uuid,
    pub professional_name: Option<String>,
    pub professional_role: Option<String>,
    pub customer_name: Option<String>,
    pub lead_title: Option<String>,
    pub status: String,
    pub tracecoins_reserved: i32,
    pub message: Option<String>,
    pub expires_at: chrono::DateTime<chrono::Utc>,
    pub accepted_at: Option<chrono::DateTime<chrono::Utc>>,
    pub rejected_at: Option<chrono::DateTime<chrono::Utc>>,
    pub rejected_reason: Option<String>,
    pub created_at: chrono::DateTime<chrono::Utc>,
}

pub fn router() -> Router<Arc<AppState>> {
    Router::new()
        .route("/", get(list_lead_requests))
        .route("/send", post(send_lead_request))
        .route("/{id}/accept", post(accept_lead_request))
        .route("/{id}/reject", post(reject_lead_request))
        .route("/my-requests", get(my_requests))
        .route("/my-pending", get(my_pending_requests))
        .route("/customer/{lead_id}", get(get_customer_lead_requests))
}

fn lead_request_to_response(row: LeadRequestRow) -> LeadRequestResponse {
    LeadRequestResponse {
        id: row.id,
        lead_id: row.lead_id,
        user_role_profile_id: row.user_role_profile_id,
        customer_user_id: row.customer_user_id,
        professional_name: None,
        professional_role: None,
        customer_name: None,
        lead_title: None,
        status: row.status,
        tracecoins_reserved: row.tracecoins_reserved,
        message: row.message,
        expires_at: row.expires_at,
        accepted_at: row.accepted_at,
        rejected_at: row.rejected_at,
        rejected_reason: row.rejected_reason,
        created_at: row.created_at,
    }
}

async fn list_lead_requests(
    State(state): State<Arc<AppState>>,
    Query(q): Query<PaginationQuery>,
) -> impl IntoResponse {
    let page = q.page.unwrap_or(1);
    let limit = q.limit.unwrap_or(20);
    let offset = (page - 1) * limit;

    let status_filter = q.status
        .as_ref()
        .map(|s| format!("AND lr.status = '{}'", s))
        .unwrap_or_default();

    let requests = match sqlx::query_as::<_, LeadRequestRow>(&format!(
        r#"
        SELECT lr.* FROM lead_requests lr
        WHERE 1=1 {}
        ORDER BY lr.created_at DESC
        LIMIT {} OFFSET {}
        "#,
        status_filter, limit, offset
    ))
    .fetch_all(&state.pool)
    .await
    {
        Ok(r) => r,
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    let requests: Vec<LeadRequestResponse> = requests.into_iter().map(lead_request_to_response).collect();

    (StatusCode::OK, Json(serde_json::json!({
        "data": requests,
        "pagination": { "page": page, "limit": limit }
    }))).into_response()
}

async fn send_lead_request(
    State(state): State<Arc<AppState>>,
    axum::extract::ConnectInfo(addr): axum::extract::ConnectInfo<std::net::SocketAddr>,
    Json(payload): Json<SendLeadRequestPayload>,
) -> impl IntoResponse {
    let user_id = Uuid::parse_str("00000000-0000-0000-0000-000000000001").unwrap_or_default();
    
    let user_role_profile_id = match sqlx::query_scalar::<_, Uuid>(
        "SELECT id FROM user_role_profiles WHERE user_id = $1 LIMIT 1"
    )
    .bind(user_id)
    .fetch_optional(&state.pool)
    .await
    {
        Ok(Some(id)) => id,
        Ok(None) => return (StatusCode::NOT_FOUND, "Professional profile not found. Please complete your profile first.").into_response(),
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    let lead = match sqlx::query_as::<_, (Uuid, String, Uuid, String, i32)>(
        "SELECT id, title, customer_user_id, status, COALESCE(current_acceptances, 0) FROM leads WHERE id = $1"
    )
    .bind(payload.lead_id)
    .fetch_optional(&state.pool)
    .await
    {
        Ok(Some(l)) => l,
        Ok(None) => return (StatusCode::NOT_FOUND, "Lead not found").into_response(),
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    if lead.3 != "OPEN" {
        return (StatusCode::BAD_REQUEST, "Lead is not open for requests").into_response();
    }

    if lead.4 >= 10 {
        return (StatusCode::BAD_REQUEST, "Lead has reached maximum acceptances").into_response();
    }

    let duplicate = match sqlx::query_scalar::<_, Uuid>(
        "SELECT id FROM lead_requests WHERE lead_id = $1 AND user_role_profile_id = $2 AND status IN ('PENDING', 'ACCEPTED')"
    )
    .bind(payload.lead_id)
    .bind(user_role_profile_id)
    .fetch_optional(&state.pool)
    .await
    {
        Ok(Some(_)) => true,
        Ok(None) => false,
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    if duplicate {
        return (StatusCode::CONFLICT, "You have already sent a request for this lead").into_response();
    }

    let request_count: (i64,) = match sqlx::query_as(
        "SELECT COUNT(*) FROM lead_requests WHERE lead_id = $1 AND status IN ('PENDING', 'ACCEPTED')"
    )
    .bind(payload.lead_id)
    .fetch_one(&state.pool)
    .await
    {
        Ok(c) => c,
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    if request_count.0 >= 20 {
        return (StatusCode::CONFLICT, "Lead has reached maximum requests").into_response();
    }

    let wallet = match sqlx::query_as::<_, (Uuid, i64)>(
        "SELECT id, balance FROM tracecoin_wallets WHERE user_id = $1"
    )
    .bind(user_id)
    .fetch_optional(&state.pool)
    .await
    {
        Ok(Some(w)) => w,
        Ok(None) => return (StatusCode::BAD_REQUEST, "Wallet not found. Please contact support.").into_response(),
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    let tracecoins_cost = 25;
    if wallet.1 < tracecoins_cost as i64 {
        return (StatusCode::PAYMENT_REQUIRED, format!("Insufficient balance. You need at least {} Tracecoins.", tracecoins_cost)).into_response();
    }

    let expires_at = chrono::Utc::now() + chrono::Duration::hours(24);

    let result = sqlx::query_as::<_, LeadRequestRow>(
        r#"
        INSERT INTO lead_requests (lead_id, user_role_profile_id, customer_user_id, status, tracecoins_reserved, message, expires_at)
        VALUES ($1, $2, $3, 'PENDING', $4, $5, $6)
        RETURNING *
        "#
    )
    .bind(payload.lead_id)
    .bind(user_role_profile_id)
    .bind(lead.2)
    .bind(tracecoins_cost)
    .bind(&payload.message)
    .bind(expires_at)
    .fetch_one(&state.pool)
    .await;

    match result {
        Ok(req) => {
            let _ = sqlx::query(
                r#"
                UPDATE tracecoin_wallets SET
                    balance = balance - $1,
                    reserved = COALESCE(reserved, 0) + $1,
                    updated_at = NOW()
                WHERE user_id = $2
                "#
            )
            .bind(tracecoins_cost as i64)
            .bind(user_id)
            .execute(&state.pool)
            .await;

            let _ = sqlx::query(
                r#"
                INSERT INTO notifications (user_id, title, body, notification_type, reference_id)
                VALUES ($1, $2, $3, $4, $5)
                "#
            )
            .bind(lead.2)
            .bind("New Lead Request")
            .bind("You have a new lead request. Please review and respond within 24 hours.")
            .bind("LEAD_REQUEST")
            .bind(req.id)
            .execute(&state.pool)
            .await;

            let response = lead_request_to_response(req);
            (StatusCode::CREATED, Json(response)).into_response()
        }
        Err(e) => (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    }
}

async fn accept_lead_request(
    State(state): State<Arc<AppState>>,
    Path(id): Path<Uuid>,
    axum::extract::ConnectInfo(addr): axum::extract::ConnectInfo<std::net::SocketAddr>,
) -> impl IntoResponse {
    let user_id = Uuid::parse_str("00000000-0000-0000-0000-000000000001").unwrap_or_default();

    let request = match sqlx::query_as::<_, LeadRequestRow>(
        "SELECT * FROM lead_requests WHERE id = $1 AND status = 'PENDING'"
    )
    .bind(id)
    .fetch_optional(&state.pool)
    .await
    {
        Ok(Some(r)) => r,
        Ok(None) => return (StatusCode::NOT_FOUND, "Lead request not found or already processed").into_response(),
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    if request.customer_user_id != user_id {
        return (StatusCode::FORBIDDEN, "You are not authorized to accept this request").into_response();
    }

    if request.expires_at < chrono::Utc::now() {
        return (StatusCode::BAD_REQUEST, "This request has expired").into_response();
    }

    let lead_acceptances: (i32,) = match sqlx::query_as(
        "SELECT COALESCE(current_acceptances, 0) FROM leads WHERE id = $1"
    )
    .bind(request.lead_id)
    .fetch_optional(&state.pool)
    .await
    {
        Ok(Some(l)) => l,
        Ok(None) => return (StatusCode::NOT_FOUND, "Lead not found").into_response(),
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    if lead_acceptances.0 >= 10 {
        return (StatusCode::BAD_REQUEST, "Lead has reached maximum acceptances").into_response();
    }

    let _ = sqlx::query(
        "UPDATE lead_requests SET status = 'ACCEPTED', accepted_at = NOW(), updated_at = NOW() WHERE id = $1"
    )
    .bind(id)
    .execute(&state.pool)
    .await;

    let _ = sqlx::query(
        "UPDATE leads SET current_acceptances = current_acceptances + 1, updated_at = NOW() WHERE id = $1"
    )
    .bind(request.lead_id)
    .execute(&state.pool)
    .await;

    let _ = sqlx::query(
        r#"
        UPDATE tracecoin_wallets SET
            reserved = reserved - $1,
            updated_at = NOW()
        WHERE user_id = $2
        "#
    )
    .bind(request.tracecoins_reserved as i64)
    .bind(user_id)
    .execute(&state.pool)
    .await;

    if lead_acceptances.0 + 1 >= 10 {
        let _ = sqlx::query("UPDATE leads SET status = 'CLOSED', updated_at = NOW() WHERE id = $1")
            .bind(request.lead_id)
            .execute(&state.pool)
            .await;
    }

    let _ = sqlx::query(
        r#"
        INSERT INTO notifications (user_id, title, body, notification_type, reference_id)
        VALUES ($1, $2, $3, $4, $5)
        "#
    )
    .bind(user_id)
    .bind("Lead Request Accepted")
    .bind("Your lead request has been accepted! Contact details have been shared.")
    .bind("LEAD_REQUEST")
    .bind(id)
    .execute(&state.pool)
    .await;

    (StatusCode::OK, Json(serde_json::json!({
        "message": "Lead request accepted successfully",
        "contact_details_shared": true
    }))).into_response()
}

async fn reject_lead_request(
    State(state): State<Arc<AppState>>,
    Path(id): Path<Uuid>,
    axum::extract::ConnectInfo(addr): axum::extract::ConnectInfo<std::net::SocketAddr>,
) -> impl IntoResponse {
    let user_id = Uuid::parse_str("00000000-0000-0000-0000-000000000001").unwrap_or_default();

    let request = match sqlx::query_as::<_, LeadRequestRow>(
        "SELECT * FROM lead_requests WHERE id = $1 AND status = 'PENDING'"
    )
    .bind(id)
    .fetch_optional(&state.pool)
    .await
    {
        Ok(Some(r)) => r,
        Ok(None) => return (StatusCode::NOT_FOUND, "Lead request not found or already processed").into_response(),
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    if request.customer_user_id != user_id {
        return (StatusCode::FORBIDDEN, "You are not authorized to reject this request").into_response();
    }

    let _ = sqlx::query(
        "UPDATE lead_requests SET status = 'REJECTED', rejected_at = NOW(), rejected_reason = 'Rejected by customer', updated_at = NOW() WHERE id = $1"
    )
    .bind(id)
    .execute(&state.pool)
    .await;

    let _ = sqlx::query(
        r#"
        UPDATE tracecoin_wallets SET
            balance = balance + $1,
            reserved = reserved - $1,
            updated_at = NOW()
        WHERE user_id = $2
        "#
    )
    .bind(request.tracecoins_reserved as i64)
    .bind(user_id)
    .execute(&state.pool)
    .await;

    let _ = sqlx::query(
        r#"
        INSERT INTO notifications (user_id, title, body, notification_type, reference_id)
        VALUES ($1, $2, $3, $4, $5)
        "#
    )
    .bind(user_id)
    .bind("Lead Request Rejected")
    .bind("Your lead request was not accepted. Tracecoins have been refunded.")
    .bind("LEAD_REQUEST")
    .bind(id)
    .execute(&state.pool)
    .await;

    (StatusCode::OK, Json(serde_json::json!({
        "message": "Lead request rejected. Tracecoins refunded.",
        "refunded": request.tracecoins_reserved
    }))).into_response()
}

async fn my_requests(
    State(state): State<Arc<AppState>>,
    Query(q): Query<PaginationQuery>,
    axum::extract::ConnectInfo(addr): axum::extract::ConnectInfo<std::net::SocketAddr>,
) -> impl IntoResponse {
    let user_id = Uuid::parse_str("00000000-0000-0000-0000-000000000001").unwrap_or_default();
    let page = q.page.unwrap_or(1);
    let limit = q.limit.unwrap_or(20);
    let offset = (page - 1) * limit;

    let status_filter = q.status
        .as_ref()
        .map(|s| format!("AND lr.status = '{}'", s))
        .unwrap_or_default();

    let requests = match sqlx::query_as::<_, LeadRequestRow>(&format!(
        r#"
        SELECT lr.* FROM lead_requests lr
        JOIN user_role_profiles urp ON urp.id = lr.user_role_profile_id
        WHERE urp.user_id = $1 {}
        ORDER BY lr.created_at DESC
        LIMIT {} OFFSET {}
        "#,
        status_filter, limit, offset
    ))
    .bind(user_id)
    .fetch_all(&state.pool)
    .await
    {
        Ok(r) => r,
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    let requests: Vec<LeadRequestResponse> = requests.into_iter().map(lead_request_to_response).collect();

    (StatusCode::OK, Json(serde_json::json!({
        "data": requests,
        "pagination": { "page": page, "limit": limit }
    }))).into_response()
}

async fn my_pending_requests(
    State(state): State<Arc<AppState>>,
    axum::extract::ConnectInfo(addr): axum::extract::ConnectInfo<std::net::SocketAddr>,
) -> impl IntoResponse {
    let user_id = Uuid::parse_str("00000000-0000-0000-0000-000000000001").unwrap_or_default();

    let requests = match sqlx::query_as::<_, LeadRequestRow>(
        r#"
        SELECT lr.* FROM lead_requests lr
        WHERE lr.customer_user_id = $1 AND lr.status = 'PENDING'
        ORDER BY lr.expires_at ASC
        "#
    )
    .bind(user_id)
    .fetch_all(&state.pool)
    .await
    {
        Ok(r) => r,
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    let requests: Vec<LeadRequestResponse> = requests.into_iter().map(lead_request_to_response).collect();

    (StatusCode::OK, Json(serde_json::json!({
        "data": requests
    }))).into_response()
}

async fn get_customer_lead_requests(
    State(state): State<Arc<AppState>>,
    Path(lead_id): Path<Uuid>,
    Query(q): Query<PaginationQuery>,
    axum::extract::ConnectInfo(addr): axum::extract::ConnectInfo<std::net::SocketAddr>,
) -> impl IntoResponse {
    let user_id = Uuid::parse_str("00000000-0000-0000-0000-000000000001").unwrap_or_default();
    let page = q.page.unwrap_or(1);
    let limit = q.limit.unwrap_or(20);
    let offset = (page - 1) * limit;

    let requests = match sqlx::query_as::<_, LeadRequestRow>(&format!(
        r#"
        SELECT lr.* FROM lead_requests lr
        WHERE lr.lead_id = $1 AND lr.customer_user_id = $2
        ORDER BY lr.created_at DESC
        LIMIT {} OFFSET {}
        "#,
        limit, offset
    ))
    .bind(lead_id)
    .bind(user_id)
    .fetch_all(&state.pool)
    .await
    {
        Ok(r) => r,
        Err(e) => return (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response(),
    };

    let requests: Vec<LeadRequestResponse> = requests.into_iter().map(lead_request_to_response).collect();

    (StatusCode::OK, Json(serde_json::json!({
        "data": requests,
        "pagination": { "page": page, "limit": limit }
    }))).into_response()
}