use axum::{
    extract::{Path, State},
    http::StatusCode,
    routing::{get, post},
    Json, Router,
};
use serde_json::json;
use std::sync::Arc;
use uuid::Uuid;

use crate::{
    auth::{auth_middleware, create_jwt},
    db,
    models::*,
};

pub struct AppState {
    pub pool: sqlx::PgPool,
    pub jwt_secret: String,
}

pub fn create_router(state: Arc<AppState>) -> Router {
    let public_routes = Router::new()
        .route("/health", get(health_check))
        .route("/login", post(login));

    let protected_routes = Router::new()
        .route("/accounts", get(list_accounts).post(create_account_handler))
        .route("/accounts/:id", get(get_account_handler))
        .route("/journal-entries", get(list_journal_entries).post(create_journal_entry_handler))
        .route("/journal-entries/:id", get(get_journal_entry_handler))
        .route("/trial-balance", get(get_trial_balance_legacy))
        .route_layer(axum::middleware::from_fn(auth_middleware));

    let api_routes = Router::new()
        .nest("/api/v1", protected_routes);

    // Legacy /api/ledger routes for Ouroboros UI compatibility
    let ledger_routes = Router::new()
        .route("/journal", get(list_journal_entries_legacy))
        .route("/trial-balance", get(get_trial_balance_legacy))
        .route_layer(axum::middleware::from_fn(auth_middleware));

    Router::new()
        .merge(public_routes)
        .merge(api_routes)
        .nest("/api/ledger", ledger_routes)
        .with_state(state)
}

async fn health_check() -> Json<serde_json::Value> {
    Json(json!({"status": "ok"}))
}

async fn login(
    State(state): State<Arc<AppState>>,
    Json(req): Json<LoginRequest>,
) -> Result<Json<LoginResponse>, (StatusCode, Json<serde_json::Value>)> {
    // Simplified auth - in production, verify password hash against database
    if req.password != "password" {
        return Err((
            StatusCode::UNAUTHORIZED,
            Json(json!({"error": "Invalid credentials"})),
        ));
    }

    let token = create_jwt(&state.jwt_secret, &req.username).map_err(|e| {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(json!({"error": format!("Failed to create token: {}", e)})),
        )
    })?;

    Ok(Json(LoginResponse { token }))
}

async fn list_accounts(
    State(state): State<Arc<AppState>>,
) -> Result<Json<Vec<Account>>, (StatusCode, Json<serde_json::Value>)> {
    let accounts = db::get_accounts(&state.pool).await.map_err(|e| {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(json!({"error": format!("Database error: {}", e)})),
        )
    })?;

    Ok(Json(accounts))
}

async fn create_account_handler(
    State(state): State<Arc<AppState>>,
    Json(req): Json<CreateAccount>,
) -> Result<(StatusCode, Json<Account>), (StatusCode, Json<serde_json::Value>)> {
    let account = db::create_account(&state.pool, &req).await.map_err(|e| {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(json!({"error": format!("Database error: {}", e)})),
        )
    })?;

    Ok((StatusCode::CREATED, Json(account)))
}

async fn get_account_handler(
    State(state): State<Arc<AppState>>,
    Path(id): Path<Uuid>,
) -> Result<Json<Account>, (StatusCode, Json<serde_json::Value>)> {
    let account = db::get_account_by_id(&state.pool, id).await.map_err(|e| {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(json!({"error": format!("Database error: {}", e)})),
        )
    })?;

    match account {
        Some(account) => Ok(Json(account)),
        None => Err((
            StatusCode::NOT_FOUND,
            Json(json!({"error": "Account not found"})),
        )),
    }
}

async fn list_journal_entries(
    State(state): State<Arc<AppState>>,
) -> Result<Json<Vec<JournalEntry>>, (StatusCode, Json<serde_json::Value>)> {
    let entries = db::get_journal_entries(&state.pool).await.map_err(|e| {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(json!({"error": format!("Database error: {}", e)})),
        )
    })?;

    Ok(Json(entries))
}

async fn create_journal_entry_handler(
    State(state): State<Arc<AppState>>,
    Json(req): Json<CreateJournalEntry>,
) -> Result<(StatusCode, Json<JournalEntryWithLines>), (StatusCode, Json<serde_json::Value>)> {
    // Validate that debits equal credits
    let total_debit: f64 = req
        .lines
        .iter()
        .filter_map(|l| l.debit)
        .fold(0.0, |acc, val| acc + val);

    let total_credit: f64 = req
        .lines
        .iter()
        .filter_map(|l| l.credit)
        .fold(0.0, |acc, val| acc + val);

    if (total_debit - total_credit).abs() > 0.01 {
        return Err((
            StatusCode::BAD_REQUEST,
            Json(json!({"error": format!("Total debits ({:.2}) must equal total credits ({:.2})", total_debit, total_credit)})),
        ));
    }

    let entry = db::create_journal_entry(&state.pool, &req, "system")
        .await
        .map_err(|e| {
            (
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(json!({"error": format!("Database error: {}", e)})),
            )
        })?;

    Ok((StatusCode::CREATED, Json(entry)))
}

async fn get_journal_entry_handler(
    State(state): State<Arc<AppState>>,
    Path(id): Path<Uuid>,
) -> Result<Json<JournalEntryWithLines>, (StatusCode, Json<serde_json::Value>)> {
    let entry = db::get_journal_entry_by_id(&state.pool, id).await.map_err(|e| {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(json!({"error": format!("Database error: {}", e)})),
        )
    })?;

    match entry {
        Some(entry) => Ok(Json(entry)),
        None => Err((
            StatusCode::NOT_FOUND,
            Json(json!({"error": "Journal entry not found"})),
        )),
    }
}

async fn get_trial_balance_handler(
    State(state): State<Arc<AppState>>,
) -> Result<Json<Vec<TrialBalanceRow>>, (StatusCode, Json<serde_json::Value>)> {
    let rows = db::get_trial_balance(&state.pool).await.map_err(|e| {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(json!({"error": format!("Database error: {}", e)})),
        )
    })?;

    Ok(Json(rows))
}

// Legacy handler for /api/ledger/journal - returns format compatible with Ouroboros UI
async fn list_journal_entries_legacy(
    State(state): State<Arc<AppState>>,
) -> Result<Json<serde_json::Value>, (StatusCode, Json<serde_json::Value>)> {
    let entries = db::get_journal_entries(&state.pool).await.map_err(|e| {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(json!({"error": format!("Database error: {}", e)})),
        )
    })?;

    // Format compatible with Ouroboros UI
    let formatted_entries: Vec<serde_json::Value> = entries
        .into_iter()
        .map(|e| {
            json!({
                "entry_number": e.entry_number,
                "entry_date": e.entry_date,
                "description": e.description,
                "reference": e.entry_number,
                "rader": []
            })
        })
        .collect();

    Ok(Json(json!({
        "ok": true,
        "entries": formatted_entries
    })))
}

// Legacy handler for /api/ledger/trial-balance - returns format compatible with Ouroboros UI
async fn get_trial_balance_legacy(
    State(state): State<Arc<AppState>>,
) -> Result<Json<serde_json::Value>, (StatusCode, Json<serde_json::Value>)> {
    let rows = db::get_trial_balance(&state.pool).await.map_err(|e| {
        (
            StatusCode::INTERNAL_SERVER_ERROR,
            Json(json!({"error": format!("Database error: {}", e)})),
        )
    })?;

    // Format compatible with Ouroboros UI
    let accounts: Vec<serde_json::Value> = rows
        .into_iter()
        .map(|r| {
            json!({
                "account_number": r.account_code,
                "account_name": r.account_name,
                "balance": r.balance.unwrap_or(0.0)
            })
        })
        .collect();

    Ok(Json(json!({
        "ok": true,
        "accounts": accounts
    })))
}