use std::sync::Arc;

use axum::extract::State;
use axum::http::HeaderMap;
use axum::response::IntoResponse;
use axum::routing::{get, post};
use axum::{Json, Router};
use serde::Deserialize;

use crate::auth;
use crate::config;
use crate::database;
use crate::error::http_error;
use crate::state::{self, AppState};

#[derive(Deserialize)]
pub struct PasswordRequest {
    password: String,
}

#[derive(Deserialize)]
pub struct AppConfigRequest {
    #[serde(rename = "BOT_TOKEN")]
    bot_token: Option<String>,
    #[serde(rename = "CHANNEL_NAME")]
    channel_name: Option<String>,
    #[serde(rename = "PASS_WORD")]
    pass_word: Option<String>,
    #[serde(rename = "BASE_URL")]
    base_url: Option<String>,
    #[serde(rename = "PICGO_API_KEY")]
    picgo_api_key: Option<String>,
}

#[derive(Deserialize)]
pub struct VerifyRequest {
    #[serde(rename = "BOT_TOKEN")]
    bot_token: Option<String>,
    #[serde(rename = "CHANNEL_NAME")]
    channel_name: Option<String>,
}

fn validate_config(cfg: &std::collections::HashMap<String, Option<String>>) -> Result<(), (axum::http::StatusCode, &'static str, &'static str)> {
    if let Some(Some(token)) = cfg.get("BOT_TOKEN") {
        let t = token.trim();
        if !t.is_empty() && (!t.contains(':') || t.len() < 20) {
            return Err((axum::http::StatusCode::BAD_REQUEST, "BOT_TOKEN 格式不正确", "invalid_bot_token"));
        }
    }
    if let Some(Some(channel)) = cfg.get("CHANNEL_NAME") {
        let c = channel.trim();
        if !c.is_empty() && !c.starts_with('@') && !c.starts_with("-100") {
            return Err((axum::http::StatusCode::BAD_REQUEST, "CHANNEL_NAME 格式不正确（@username 或 -100...）", "invalid_channel"));
        }
    }
    if let Some(Some(url)) = cfg.get("BASE_URL") {
        let u = url.trim();
        if !u.is_empty() && !u.starts_with("http://") && !u.starts_with("https://") {
            return Err((axum::http::StatusCode::BAD_REQUEST, "BASE_URL 必须以 http:// 或 https:// 开头", "invalid_base_url"));
        }
    }
    Ok(())
}

fn merge_config(
    existing: &std::collections::HashMap<String, Option<String>>,
    incoming: &AppConfigRequest,
) -> Result<
    std::collections::HashMap<String, Option<String>>,
    (axum::http::StatusCode, &'static str, &'static str),
> {
    let mut result = existing.clone();

    if let Some(ref v) = incoming.bot_token {
        let v = v.trim().to_string();
        result.insert("BOT_TOKEN".into(), if v.is_empty() { None } else { Some(v) });
    }
    if let Some(ref v) = incoming.channel_name {
        let v = v.trim().to_string();
        result.insert("CHANNEL_NAME".into(), if v.is_empty() { None } else { Some(v) });
    }
    if let Some(ref v) = incoming.pass_word {
        let v = v.trim().to_string();
        if v.is_empty() {
            result.insert("PASS_WORD".into(), None);
            result.insert("SESSION_TOKEN".into(), None);
        } else {
            // Hash password and compute a cryptographically random session token.
            // The token is independent of the password, so sessions cannot be
            // forged from knowledge of the plaintext or hash. If hashing fails we
            // REJECT the update rather than falling back to plaintext storage.
            match auth::hash_password(&v) {
                Ok(hashed) => {
                    let session_token = auth::generate_session_token();
                    result.insert("PASS_WORD".into(), Some(hashed));
                    result.insert("SESSION_TOKEN".into(), Some(session_token));
                }
                Err(e) => {
                    tracing::error!("密码哈希失败: {}", e);
                    return Err((
                        axum::http::StatusCode::INTERNAL_SERVER_ERROR,
                        "密码哈希失败",
                        "hash_error",
                    ));
                }
            }
        }
    }
    if let Some(ref v) = incoming.base_url {
        let v = v.trim().to_string();
        result.insert("BASE_URL".into(), if v.is_empty() { None } else { Some(v) });
    }
    if let Some(ref v) = incoming.picgo_api_key {
        let v = v.trim().to_string();
        result.insert("PICGO_API_KEY".into(), if v.is_empty() { None } else { Some(v) });
    }
    Ok(result)
}

fn is_https(headers: &HeaderMap) -> bool {
    headers
        .get("x-forwarded-proto")
        .and_then(|v| v.to_str().ok())
        .map_or(false, |v| v == "https")
}

async fn get_app_config(State(state): State<Arc<AppState>>) -> impl IntoResponse {
    let settings = config::get_app_settings(&state.settings, &state.db_pool);
    let bot = state.bot_state.lock().await;

    Json(serde_json::json!({
        "status": "ok",
        "cfg": {
            "BOT_TOKEN_SET": settings.get("BOT_TOKEN").and_then(|v| v.as_deref()).map_or(false, |v| !v.is_empty()),
            "CHANNEL_NAME": settings.get("CHANNEL_NAME").and_then(|v| v.as_deref()).unwrap_or(""),
            "PASS_WORD_SET": settings.get("PASS_WORD").and_then(|v| v.as_deref()).map_or(false, |v| !v.is_empty()),
            "BASE_URL": settings.get("BASE_URL").and_then(|v| v.as_deref()).unwrap_or(""),
            "PICGO_API_KEY_SET": settings.get("PICGO_API_KEY").and_then(|v| v.as_deref()).map_or(false, |v| !v.is_empty()),
        },
        "bot": {
            "ready": bot.bot_ready,
            "running": bot.bot_running,
            "error": bot.bot_error,
        }
    }))
}

async fn save_config_only(
    State(state): State<Arc<AppState>>,
    Json(payload): Json<AppConfigRequest>,
) -> Result<impl IntoResponse, impl IntoResponse> {
    let existing = database::get_app_settings_from_db(&state.db_pool).unwrap_or_default();
    let merged = merge_config(&existing, &payload)
        .map_err(|(status, msg, code)| http_error(status, msg, code))?;

    if let Err((status, msg, code)) = validate_config(&merged) {
        return Err(http_error(status, msg, code));
    }

    database::save_app_settings_to_db(&state.db_pool, &merged).map_err(|e| {
        tracing::error!("保存配置失败: {}", e);
        http_error(
            axum::http::StatusCode::INTERNAL_SERVER_ERROR,
            "保存配置失败",
            "save_error",
        )
    })?;

    tracing::info!("配置已保存（未应用）");
    Ok(Json(serde_json::json!({
        "status": "ok",
        "message": "已保存（未应用）"
    })))
}

async fn save_and_apply(
    State(state): State<Arc<AppState>>,
    headers: HeaderMap,
    Json(payload): Json<AppConfigRequest>,
) -> Result<impl IntoResponse, impl IntoResponse> {
    let existing = database::get_app_settings_from_db(&state.db_pool).unwrap_or_default();
    let merged = merge_config(&existing, &payload)
        .map_err(|(status, msg, code)| http_error(status, msg, code))?;

    if let Err((status, msg, code)) = validate_config(&merged) {
        return Err(http_error(status, msg, code));
    }

    database::save_app_settings_to_db(&state.db_pool, &merged).map_err(|e| {
        tracing::error!("保存配置失败: {}", e);
        http_error(
            axum::http::StatusCode::INTERNAL_SERVER_ERROR,
            "保存配置失败",
            "save_error",
        )
    })?;

    let _ = state::apply_runtime_settings(state.clone(), true).await;

    let bot = state.bot_state.lock().await;

    // Handle password cookie using the server-side random session token.
    // We honor x-forwarded-proto so cookies get the Secure flag when a
    // trusted reverse proxy terminates TLS; the COOKIE_SECURE env var
    // (handled inside build_cookie) can force Secure regardless.
    let session_token = merged
        .get("SESSION_TOKEN")
        .and_then(|v| v.as_deref())
        .unwrap_or("");
    let pwd = merged
        .get("PASS_WORD")
        .and_then(|v| v.as_deref())
        .unwrap_or("");
    let secure = is_https(&headers);
    let cookie = if !pwd.is_empty() && !session_token.is_empty() {
        auth::build_cookie(session_token, secure)
    } else {
        // No password set OR no session token — clear any stale cookie.
        auth::build_clear_cookie()
    };

    Ok((
        [(axum::http::header::SET_COOKIE, cookie)],
        Json(serde_json::json!({
            "status": "ok",
            "message": "已保存并应用",
            "bot": {
                "ready": bot.bot_ready,
                "running": bot.bot_running,
            }
        })),
    ))
}

async fn reset_config(State(state): State<Arc<AppState>>) -> impl IntoResponse {
    database::reset_app_settings_in_db(&state.db_pool).ok();
    let _ = state::apply_runtime_settings(state.clone(), true).await;
    tracing::warn!("配置已重置");

    let cookie = crate::auth::build_clear_cookie();

    (
        [(axum::http::header::SET_COOKIE, cookie)],
        Json(serde_json::json!({
            "status": "ok",
            "message": "配置已重置"
        })),
    )
}

async fn set_password(
    State(state): State<Arc<AppState>>,
    Json(payload): Json<PasswordRequest>,
) -> Result<Json<serde_json::Value>, crate::error::AppError> {
    let db_pool = &state.db_pool;
    let password = payload.password.trim().to_string();

    // Hash the password with argon2 and compute session token
    let hashed = auth::hash_password(&password).map_err(|e| {
        tracing::error!("密码哈希失败: {}", e);
        crate::error::AppError::new(
            axum::http::StatusCode::INTERNAL_SERVER_ERROR,
            "密码哈希失败",
            "hash_error",
        )
    })?;
    // Random session token, independent of the password.
    let session_token = auth::generate_session_token();

    let mut current = database::get_app_settings_from_db(db_pool).unwrap_or_default();
    current.insert("PASS_WORD".into(), Some(hashed));
    current.insert("SESSION_TOKEN".into(), Some(session_token));

    database::save_app_settings_to_db(db_pool, &current).map_err(|_| {
        crate::error::AppError::new(
            axum::http::StatusCode::INTERNAL_SERVER_ERROR,
            "无法写入密码。",
            "write_password_failed",
        )
    })?;

    let _ = state::apply_runtime_settings(state.clone(), false).await;
    tracing::info!("密码已成功设置");

    Ok(Json(serde_json::json!({
        "status": "ok",
        "message": "密码已成功设置。"
    })))
}

async fn verify_bot(
    State(state): State<Arc<AppState>>,
    Json(payload): Json<VerifyRequest>,
) -> impl IntoResponse {
    let app_settings = config::get_app_settings(&state.settings, &state.db_pool);
    let token = payload
        .bot_token
        .or_else(|| app_settings.get("BOT_TOKEN").and_then(|v| v.clone()))
        .unwrap_or_default();

    if token.is_empty() {
        return Json(serde_json::json!({
            "status": "ok",
            "ok": false,
            "available": false,
            "message": "未提供 BOT_TOKEN"
        }));
    }

    let url = format!("https://api.telegram.org/bot{}/getMe", token);
    let client = reqwest::Client::builder()
        .timeout(std::time::Duration::from_secs(10))
        .build()
        .unwrap();

    match client.get(&url).send().await {
        Ok(resp) => match resp.json::<serde_json::Value>().await {
            Ok(data) => {
                if data["ok"].as_bool() == Some(true) {
                    let username = data["result"]["username"]
                        .as_str()
                        .unwrap_or("unknown");
                    Json(serde_json::json!({
                        "status": "ok",
                        "ok": true,
                        "available": true,
                        "result": { "username": username }
                    }))
                } else {
                    Json(serde_json::json!({
                        "status": "ok",
                        "ok": false,
                        "available": false,
                        "message": data["description"].as_str().unwrap_or("Unknown error")
                    }))
                }
            }
            Err(e) => {
                tracing::warn!("verify_bot parse error: {}", e);
                Json(serde_json::json!({
                    "status": "ok",
                    "ok": false,
                    "available": false,
                    "message": "解析响应失败"
                }))
            }
        },
        Err(e) => {
            tracing::warn!("verify_bot connect error: {}", e);
            Json(serde_json::json!({
                "status": "ok",
                "ok": false,
                "available": false,
                "message": "连接失败"
            }))
        },
    }
}

async fn verify_channel(
    State(state): State<Arc<AppState>>,
    Json(payload): Json<VerifyRequest>,
) -> impl IntoResponse {
    let app_settings = config::get_app_settings(&state.settings, &state.db_pool);
    let token = payload
        .bot_token
        .or_else(|| app_settings.get("BOT_TOKEN").and_then(|v| v.clone()))
        .unwrap_or_default();
    let channel = payload
        .channel_name
        .or_else(|| app_settings.get("CHANNEL_NAME").and_then(|v| v.clone()))
        .unwrap_or_default();

    if token.is_empty() || channel.is_empty() {
        return Json(serde_json::json!({
            "status": "ok",
            "available": false,
            "message": "缺少 BOT_TOKEN 或 CHANNEL_NAME"
        }));
    }

    let url = format!("https://api.telegram.org/bot{}/sendMessage", token);
    let client = reqwest::Client::builder()
        .timeout(std::time::Duration::from_secs(10))
        .build()
        .unwrap();

    match client
        .post(&url)
        .json(&serde_json::json!({
            "chat_id": channel,
            "text": "tgState channel check"
        }))
        .send()
        .await
    {
        Ok(resp) => match resp.json::<serde_json::Value>().await {
            Ok(data) => {
                if data["ok"].as_bool() == Some(true) {
                    // Try to delete test message
                    if let Some(msg_id) = data["result"]["message_id"].as_i64() {
                        let del_url =
                            format!("https://api.telegram.org/bot{}/deleteMessage", token);
                        let _ = client
                            .post(&del_url)
                            .json(&serde_json::json!({
                                "chat_id": channel,
                                "message_id": msg_id
                            }))
                            .send()
                            .await;
                    }
                    Json(serde_json::json!({
                        "status": "ok",
                        "available": true
                    }))
                } else {
                    Json(serde_json::json!({
                        "status": "ok",
                        "available": false,
                        "message": data["description"].as_str().unwrap_or("Unknown error")
                    }))
                }
            }
            Err(e) => {
                tracing::warn!("verify_channel parse error: {}", e);
                Json(serde_json::json!({
                    "status": "ok",
                    "available": false,
                    "message": "解析响应失败"
                }))
            }
        },
        Err(e) => {
            tracing::warn!("verify_channel connect error: {}", e);
            Json(serde_json::json!({
                "status": "ok",
                "available": false,
                "message": "连接失败"
            }))
        },
    }
}

pub fn router() -> Router<Arc<AppState>> {
    Router::new()
        .route("/api/app-config", get(get_app_config))
        .route("/api/app-config/save", post(save_config_only))
        .route("/api/app-config/apply", post(save_and_apply))
        .route("/api/reset-config", post(reset_config))
        .route("/api/set-password", post(set_password))
        .route("/api/verify/bot", post(verify_bot))
        .route("/api/verify/channel", post(verify_channel))
}