use crate::AppState;
use axum::{
    extract::{Path, Query, State},
    http::StatusCode,
    response::IntoResponse,
    routing::{get, patch},
    Json, Router,
};
use chrono::{DateTime, Utc};
use contracts::auth_middleware::AuthUser;
use serde::{Deserialize, Serialize};
use uuid::Uuid;

pub fn router() -> Router<AppState> {
    Router::new()
        .route("/", get(list_companies))
        .route("/{id}", get(get_company))
        .route("/{id}/approve", patch(approve_company))
        .route("/{id}/reject", patch(reject_company))
        .route("/{id}/suspend", patch(suspend_company))
        .route("/jobs", get(list_jobs))
        .route("/applications", get(list_applications))
}

#[derive(Deserialize)]
pub struct ListQuery {
    pub q: Option<String>,
}

#[derive(Serialize)]
pub struct AdminCompanyRow {
    pub id: Uuid,
    pub user_id: Uuid,
    pub company_name: String,
    pub registration_number: Option<String>,
    pub industry: Option<String>,
    pub status: String,
    pub created_at: chrono::DateTime<chrono::Utc>,
    pub updated_at: chrono::DateTime<chrono::Utc>,
}

#[derive(Serialize)]
pub struct AdminCompanyDetail {
    pub id: Uuid,
    pub user_id: Uuid,
    pub company_name: String,
    pub registration_number: Option<String>,
    pub industry: Option<String>,
    pub website_url: Option<String>,
    pub employee_count: Option<i32>,
    pub business_type: Option<String>,
    pub gst_number: Option<String>,
    pub contact_name: Option<String>,
    pub contact_email: Option<String>,
    pub contact_phone: Option<String>,
    pub address_line1: Option<String>,
    pub city: Option<String>,
    pub state: Option<String>,
    pub country: String,
    pub postal_code: Option<String>,
    pub status: String,
    pub free_job_slots: i32,
    pub purchased_job_slots: i32,
    pub free_contact_views: i32,
    pub purchased_contact_views: i32,
    pub created_at: chrono::DateTime<chrono::Utc>,
    pub updated_at: chrono::DateTime<chrono::Utc>,
}

#[derive(Deserialize)]
pub struct ApproveRejectRequest {
    pub reason: Option<String>,
}

#[derive(Serialize)]
pub struct AdminJobRow {
    pub id: Uuid,
    pub title: String,
    pub description: Option<String>,
    pub company_id: Uuid,
    pub company_name: String,
    pub location: Option<String>,
    pub job_type: Option<String>,
    pub salary_min: Option<i32>,
    pub salary_max: Option<i32>,
    pub status: String,
    pub is_featured: bool,
    pub applications_count: i64,
    pub posted_at: Option<DateTime<Utc>>,
    pub expires_at: Option<DateTime<Utc>>,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
}

#[derive(Serialize)]
pub struct AdminApplicationRow {
    pub id: Uuid,
    pub job_id: Uuid,
    pub job_title: String,
    pub company_id: Uuid,
    pub company_name: String,
    pub applicant_id: Uuid,
    pub applicant_name: String,
    pub applicant_email: String,
    pub status: String,
    pub cover_letter: Option<String>,
    pub resume_url: Option<String>,
    pub applied_at: DateTime<Utc>,
    pub created_at: DateTime<Utc>,
}

async fn list_companies(
    _auth: AuthUser,
    State(state): State<AppState>,
    Query(q): Query<ListQuery>,
) -> Result<impl IntoResponse, (StatusCode, String)> {
    let search = q.q.as_deref().unwrap_or_default().to_lowercase();
    
    let companies = sqlx::query_as!(
        AdminCompanyRow,
        r#"
            SELECT 
                id, user_id, company_name, registration_number, industry, 
                status, created_at, updated_at
            FROM company_profiles
            WHERE ($1 = '' OR LOWER(company_name) LIKE '%' || $1 || '%')
            ORDER BY created_at DESC
            LIMIT 100
        "#,
        search
    )
    .fetch_all(&state.pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("DB error: {e}")))?;

    Ok(Json(companies))
}

async fn get_company(
    _auth: AuthUser,
    State(state): State<AppState>,
    Path(id): Path<Uuid>,
) -> Result<impl IntoResponse, (StatusCode, String)> {
    let company = sqlx::query_as!(
        AdminCompanyDetail,
        r#"
            SELECT 
                id, user_id, company_name, registration_number, industry,
                website_url, employee_count, business_type, gst_number,
                contact_name, contact_email, contact_phone, address_line1,
                city, state, country, postal_code, status,
                free_job_slots, purchased_job_slots, free_contact_views, purchased_contact_views,
                created_at, updated_at
            FROM company_profiles
            WHERE id = $1
        "#,
        id
    )
    .fetch_optional(&state.pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("DB error: {e}")))?;

    match company {
        Some(c) => Ok(Json(c)),
        None => Err((StatusCode::NOT_FOUND, "Company not found".to_string())),
    }
}

async fn approve_company(
    _auth: AuthUser,
    State(state): State<AppState>,
    Path(id): Path<Uuid>,
    Json(_payload): Json<ApproveRejectRequest>,
) -> Result<impl IntoResponse, (StatusCode, String)> {
    let company = sqlx::query!(
        "SELECT id, user_id, status FROM company_profiles WHERE id = $1",
        id
    )
    .fetch_optional(&state.pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("DB error: {e}")))?;

    let company = match company {
        Some(c) => c,
        None => return Err((StatusCode::NOT_FOUND, "Company not found".to_string())),
    };

    if company.status == "APPROVED" {
        return Err((StatusCode::BAD_REQUEST, "Company is already approved".to_string()));
    }

    sqlx::query!(
        "UPDATE company_profiles SET status = 'APPROVED', updated_at = NOW() WHERE id = $1",
        id
    )
    .execute(&state.pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("DB error: {e}")))?;

    Ok(Json(serde_json::json!({
        "id": id,
        "status": "APPROVED",
        "message": "Company approved successfully"
    })))
}

async fn reject_company(
    _auth: AuthUser,
    State(state): State<AppState>,
    Path(id): Path<Uuid>,
    Json(payload): Json<ApproveRejectRequest>,
) -> Result<impl IntoResponse, (StatusCode, String)> {
    let reason = payload.reason.as_deref().unwrap_or("No reason provided");

    let company = sqlx::query!(
        "SELECT id, user_id, status FROM company_profiles WHERE id = $1",
        id
    )
    .fetch_optional(&state.pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("DB error: {e}")))?;

    let company = match company {
        Some(c) => c,
        None => return Err((StatusCode::NOT_FOUND, "Company not found".to_string())),
    };

    if company.status == "REJECTED" {
        return Err((StatusCode::BAD_REQUEST, "Company is already rejected".to_string()));
    }

    sqlx::query!(
        "UPDATE company_profiles SET status = 'REJECTED', updated_at = NOW() WHERE id = $1",
        id
    )
    .execute(&state.pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("DB error: {e}")))?;

    Ok(Json(serde_json::json!({
        "id": id,
        "status": "REJECTED",
        "reason": reason,
        "message": "Company rejected"
    })))
}

async fn suspend_company(
    _auth: AuthUser,
    State(state): State<AppState>,
    Path(id): Path<Uuid>,
    Json(payload): Json<ApproveRejectRequest>,
) -> Result<impl IntoResponse, (StatusCode, String)> {
    let reason = payload.reason.as_deref().unwrap_or("No reason provided");

    let company = sqlx::query!(
        "SELECT id, user_id, status FROM company_profiles WHERE id = $1",
        id
    )
    .fetch_optional(&state.pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("DB error: {e}")))?;

    let company = match company {
        Some(c) => c,
        None => return Err((StatusCode::NOT_FOUND, "Company not found".to_string())),
    };

    if company.status == "SUSPENDED" {
        return Err((StatusCode::BAD_REQUEST, "Company is already suspended".to_string()));
    }

    sqlx::query!(
        "UPDATE company_profiles SET status = 'SUSPENDED', updated_at = NOW() WHERE id = $1",
        id
    )
    .execute(&state.pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("DB error: {e}")))?;

    Ok(Json(serde_json::json!({
        "id": id,
        "status": "SUSPENDED",
        "reason": reason,
        "message": "Company suspended"
    })))
}

async fn list_jobs(
    _auth: AuthUser,
    State(state): State<AppState>,
    Query(q): Query<ListQuery>,
) -> Result<impl IntoResponse, (StatusCode, String)> {
    let search = q.q.as_deref().unwrap_or_default().to_lowercase();

    let jobs = sqlx::query_as!(
        AdminJobRow,
        r#"
            SELECT 
                j.id, j.title, j.description, j.company_id, cp.company_name,
                j.location, j.job_type, j.salary_min, j.salary_max,
                j.status, j.is_featured,
                COUNT(a.id) AS "applications_count!",
                j.posted_at, j.expires_at,
                j.created_at, j.updated_at
            FROM jobs j
            JOIN company_profiles cp ON j.company_id = cp.id
            LEFT JOIN applications a ON a.job_id = j.id
            WHERE ($1 = '' OR LOWER(j.title) LIKE '%' || $1 || '%')
            GROUP BY j.id, cp.company_name
            ORDER BY j.created_at DESC
            LIMIT 100
        "#,
        search
    )
    .fetch_all(&state.pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("DB error: {e}")))?;

    Ok(Json(jobs))
}

async fn list_applications(
    _auth: AuthUser,
    State(state): State<AppState>,
    Query(q): Query<ListQuery>,
) -> Result<impl IntoResponse, (StatusCode, String)> {
    let search = q.q.as_deref().unwrap_or_default().to_lowercase();

    let applications = sqlx::query_as!(
        AdminApplicationRow,
        r#"
            SELECT 
                a.id, a.job_id, j.title AS "job_title!", a.company_id, cp.company_name,
                a.user_id AS "applicant_id!", COALESCE(u.first_name, '') || ' ' || COALESCE(u.last_name, '') AS "applicant_name!",
                u.email AS "applicant_email!",
                a.status, a.cover_letter, a.resume_url,
                a.applied_at, a.created_at
            FROM applications a
            JOIN jobs j ON a.job_id = j.id
            JOIN company_profiles cp ON j.company_id = cp.id
            JOIN users u ON a.user_id = u.id
            WHERE ($1 = '' OR LOWER(j.title) LIKE '%' || $1 || '%' OR LOWER(u.first_name) LIKE '%' || $1 || '%' OR LOWER(u.last_name) LIKE '%' || $1 || '%')
            ORDER BY a.applied_at DESC
            LIMIT 100
        "#,
        search
    )
    .fetch_all(&state.pool)
    .await
    .map_err(|e| (StatusCode::INTERNAL_SERVER_ERROR, format!("DB error: {e}")))?;

    Ok(Json(applications))
}