use axum::{
    extract::{Path, State},
    response::Json,
};
use serde::Deserialize;
use serde_json;
use sqlx::Row;
use std::collections::HashMap;
use tracing::warn;

use super::{ApiResponse, DashboardState};
use crate::utils::crypto;

#[derive(Deserialize)]
pub(super) struct UpdateProviderRequest {
    pub(super) enabled: bool,
    pub(super) base_url: Option<String>,
    pub(super) api_key: Option<String>,
    pub(super) credit_balance: Option<f64>,
    pub(super) low_credit_threshold: Option<f64>,
    pub(super) billing_mode: Option<String>,
}

pub(super) async fn handle_get_providers(State(state): State<DashboardState>) -> Json<ApiResponse<serde_json::Value>> {
    let registry = &state.app_state.model_registry;
    let config = &state.app_state.config;
    let pool = &state.app_state.db_pool;

    // Load all overrides from database (including billing_mode)
    let db_configs_result = sqlx::query(
        "SELECT id, enabled, base_url, credit_balance, low_credit_threshold, billing_mode FROM provider_configs",
    )
    .fetch_all(pool)
    .await;

    let mut db_configs = HashMap::new();
    if let Ok(rows) = db_configs_result {
        for row in rows {
            let id: String = row.get("id");
            let enabled: bool = row.get("enabled");
            let base_url: Option<String> = row.get("base_url");
            let balance: f64 = row.get("credit_balance");
            let threshold: f64 = row.get("low_credit_threshold");
            let billing_mode: Option<String> = row.get("billing_mode");
            db_configs.insert(id, (enabled, base_url, balance, threshold, billing_mode));
        }
    }

    let mut providers_json = Vec::new();

    // Define the list of providers we support
    let provider_ids = vec!["openai", "gemini", "deepseek", "grok", "ollama"];

    for id in provider_ids {
        // Get base config
        let (mut enabled, mut base_url, display_name) = match id {
            "openai" => (
                config.providers.openai.enabled,
                config.providers.openai.base_url.clone(),
                "OpenAI",
            ),
            "gemini" => (
                config.providers.gemini.enabled,
                config.providers.gemini.base_url.clone(),
                "Google Gemini",
            ),
            "deepseek" => (
                config.providers.deepseek.enabled,
                config.providers.deepseek.base_url.clone(),
                "DeepSeek",
            ),
            "grok" => (
                config.providers.grok.enabled,
                config.providers.grok.base_url.clone(),
                "xAI Grok",
            ),
            "ollama" => (
                config.providers.ollama.enabled,
                config.providers.ollama.base_url.clone(),
                "Ollama",
            ),
            _ => (false, "".to_string(), "Unknown"),
        };

        let mut balance = 0.0;
        let mut threshold = 5.0;
        let mut billing_mode: Option<String> = None;

        // Apply database overrides
        if let Some((db_enabled, db_url, db_balance, db_threshold, db_billing)) = db_configs.get(id) {
            enabled = *db_enabled;
            if let Some(url) = db_url {
                base_url = url.clone();
            }
            balance = *db_balance;
            threshold = *db_threshold;
            billing_mode = db_billing.clone();
        }

        // Find models for this provider in registry
        // NOTE: registry provider IDs differ from internal IDs for some providers.
        let registry_key = match id {
            "gemini" => "google",
            "grok" => "xai",
            _ => id,
        };

        let mut models = Vec::new();
        if let Some(p_info) = registry.providers.get(registry_key) {
            models = p_info.models.keys().cloned().collect();
        } else if id == "ollama" {
            models = config.providers.ollama.models.clone();
        }

        // Determine status
        let status = if !enabled {
            "disabled"
        } else {
            // Check if it's actually initialized in the provider manager
            if state.app_state.provider_manager.get_provider(id).await.is_some() {
                // Check circuit breaker
                if state
                    .app_state
                    .rate_limit_manager
                    .check_provider_request(id)
                    .await
                    .unwrap_or(true)
                {
                    "online"
                } else {
                    "degraded"
                }
            } else {
                "error" // Enabled but failed to initialize (e.g. missing API key)
            }
        };

        providers_json.push(serde_json::json!({
            "id": id,
            "name": display_name,
            "enabled": enabled,
            "status": status,
            "models": models,
            "base_url": base_url,
            "credit_balance": balance,
            "low_credit_threshold": threshold,
            "billing_mode": billing_mode,
            "last_used": None::<String>,
        }));
    }

    Json(ApiResponse::success(serde_json::json!(providers_json)))
}

pub(super) async fn handle_get_provider(
    State(state): State<DashboardState>,
    Path(name): Path<String>,
) -> Json<ApiResponse<serde_json::Value>> {
    let registry = &state.app_state.model_registry;
    let config = &state.app_state.config;
    let pool = &state.app_state.db_pool;

    // Validate provider name
    let (mut enabled, mut base_url, display_name) = match name.as_str() {
        "openai" => (
            config.providers.openai.enabled,
            config.providers.openai.base_url.clone(),
            "OpenAI",
        ),
        "gemini" => (
            config.providers.gemini.enabled,
            config.providers.gemini.base_url.clone(),
            "Google Gemini",
        ),
        "deepseek" => (
            config.providers.deepseek.enabled,
            config.providers.deepseek.base_url.clone(),
            "DeepSeek",
        ),
        "grok" => (
            config.providers.grok.enabled,
            config.providers.grok.base_url.clone(),
            "xAI Grok",
        ),
        "ollama" => (
            config.providers.ollama.enabled,
            config.providers.ollama.base_url.clone(),
            "Ollama",
        ),
        _ => return Json(ApiResponse::error(format!("Unknown provider '{}'", name))),
    };

    let mut balance = 0.0;
    let mut threshold = 5.0;
    let mut billing_mode: Option<String> = None;

    // Apply database overrides
    let db_config = sqlx::query(
        "SELECT enabled, base_url, credit_balance, low_credit_threshold, billing_mode FROM provider_configs WHERE id = ?",
    )
    .bind(&name)
    .fetch_optional(pool)
    .await;

    if let Ok(Some(row)) = db_config {
        enabled = row.get::<bool, _>("enabled");
        if let Some(url) = row.get::<Option<String>, _>("base_url") {
            base_url = url;
        }
        balance = row.get::<f64, _>("credit_balance");
        threshold = row.get::<f64, _>("low_credit_threshold");
        billing_mode = row.get::<Option<String>, _>("billing_mode");
    }

    // Find models for this provider
    // NOTE: registry provider IDs differ from internal IDs for some providers.
    let registry_key = match name.as_str() {
        "gemini" => "google",
        "grok" => "xai",
        _ => name.as_str(),
    };

    let mut models = Vec::new();
    if let Some(p_info) = registry.providers.get(registry_key) {
        models = p_info.models.keys().cloned().collect();
    } else if name == "ollama" {
        models = config.providers.ollama.models.clone();
    }

    // Determine status
    let status = if !enabled {
        "disabled"
    } else if state.app_state.provider_manager.get_provider(&name).await.is_some() {
        if state
            .app_state
            .rate_limit_manager
            .check_provider_request(&name)
            .await
            .unwrap_or(true)
        {
            "online"
        } else {
            "degraded"
        }
    } else {
        "error"
    };

    Json(ApiResponse::success(serde_json::json!({
        "id": name,
        "name": display_name,
        "enabled": enabled,
        "status": status,
        "models": models,
        "base_url": base_url,
        "credit_balance": balance,
        "low_credit_threshold": threshold,
        "billing_mode": billing_mode,
        "last_used": None::<String>,
    })))
}

pub(super) async fn handle_update_provider(
    State(state): State<DashboardState>,
    headers: axum::http::HeaderMap,
    Path(name): Path<String>,
    Json(payload): Json<UpdateProviderRequest>,
) -> Json<ApiResponse<serde_json::Value>> {
    let (session, _) = match super::auth::require_admin(&state, &headers).await {
        Ok((session, new_token)) => (session, new_token),
        Err(e) => return e,
    };

    let pool = &state.app_state.db_pool;

    // Prepare API key encryption if provided
    let (api_key_to_store, api_key_encrypted_flag) = match &payload.api_key {
        Some(key) if !key.is_empty() => {
            match crypto::encrypt(key) {
                Ok(encrypted) => (Some(encrypted), Some(true)),
                Err(e) => {
                    warn!("Failed to encrypt API key for provider {}: {}", name, e);
                    return Json(ApiResponse::error(format!("Failed to encrypt API key: {}", e)));
                }
            }
        }
        Some(_) => {
            // Empty string means clear the key
            (None, Some(false))
        }
        None => {
            // Keep existing key, we'll rely on COALESCE in SQL
            (None, None)
        }
    };

    // Update or insert into database (include billing_mode and api_key_encrypted)
    let result = sqlx::query(
        r#"
        INSERT INTO provider_configs (id, display_name, enabled, base_url, api_key, api_key_encrypted, credit_balance, low_credit_threshold, billing_mode)
        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)
        ON CONFLICT(id) DO UPDATE SET
            enabled = excluded.enabled,
            base_url = excluded.base_url,
            api_key = COALESCE(excluded.api_key, provider_configs.api_key),
            api_key_encrypted = COALESCE(excluded.api_key_encrypted, provider_configs.api_key_encrypted),
            credit_balance = COALESCE(excluded.credit_balance, provider_configs.credit_balance),
            low_credit_threshold = COALESCE(excluded.low_credit_threshold, provider_configs.low_credit_threshold),
            billing_mode = COALESCE(excluded.billing_mode, provider_configs.billing_mode),
            updated_at = CURRENT_TIMESTAMP
        "#,
    )
    .bind(&name)
    .bind(name.to_uppercase())
    .bind(payload.enabled)
    .bind(&payload.base_url)
    .bind(&api_key_to_store)
    .bind(api_key_encrypted_flag)
    .bind(payload.credit_balance)
    .bind(payload.low_credit_threshold)
    .bind(payload.billing_mode)
    .execute(pool)
    .await;

    match result {
        Ok(_) => {
            // Re-initialize provider in manager
            if let Err(e) = state
                .app_state
                .provider_manager
                .initialize_provider(&name, &state.app_state.config, &state.app_state.db_pool)
                .await
            {
                warn!("Failed to re-initialize provider {}: {}", name, e);
                return Json(ApiResponse::error(format!(
                    "Provider settings saved but initialization failed: {}",
                    e
                )));
            }

            Json(ApiResponse::success(
                serde_json::json!({ "message": "Provider updated and re-initialized" }),
            ))
        }
        Err(e) => {
            warn!("Failed to update provider config: {}", e);
            Json(ApiResponse::error(format!("Failed to update provider: {}", e)))
        }
    }
}

pub(super) async fn handle_test_provider(
    State(state): State<DashboardState>,
    Path(name): Path<String>,
) -> Json<ApiResponse<serde_json::Value>> {
    let start = std::time::Instant::now();

    let provider = match state.app_state.provider_manager.get_provider(&name).await {
        Some(p) => p,
        None => {
            return Json(ApiResponse::error(format!(
                "Provider '{}' not found or not enabled",
                name
            )));
        }
    };

    // Pick a real model for this provider from the registry
    // NOTE: registry provider IDs differ from internal IDs for some providers.
    let registry_key = match name.as_str() {
        "gemini" => "google",
        "grok" => "xai",
        _ => name.as_str(),
    };

    let test_model = state
        .app_state
        .model_registry
        .providers
        .get(registry_key)
        .and_then(|p| p.models.keys().next().cloned())
        .unwrap_or_else(|| name.clone());

    let test_request = crate::models::UnifiedRequest {
        client_id: "system-test".to_string(),
        model: test_model,
        messages: vec![crate::models::UnifiedMessage {
            role: "user".to_string(),
            content: vec![crate::models::ContentPart::Text { text: "Hi".to_string() }],
            reasoning_content: None,
            tool_calls: None,
            name: None,
            tool_call_id: None,
        }],
        temperature: None,
        top_p: None,
        top_k: None,
        n: None,
        stop: None,
        max_tokens: Some(5),
        presence_penalty: None,
        frequency_penalty: None,
        stream: false,
        has_images: false,
        tools: None,
        tool_choice: None,
    };

    match provider.chat_completion(test_request).await {
        Ok(_) => {
            let latency = start.elapsed().as_millis();
            Json(ApiResponse::success(serde_json::json!({
                "success": true,
                "latency": latency,
                "message": "Connection test successful"
            })))
        }
        Err(e) => Json(ApiResponse::error(format!("Provider test failed: {}", e))),
    }
}