use crate::state::AppState;
use axum::{
    Json,
    extract::{Query, State},
    http::StatusCode,
    response::{IntoResponse, Response},
};
use bcrypt::verify;
use serde::{Deserialize, Serialize};
use serde_json::json;
use tracing::{error, info, warn};

#[derive(Deserialize)]
pub struct GetServiceAuthParams {
    pub aud: String,
    pub lxm: Option<String>,
    pub exp: Option<i64>,
}

#[derive(Serialize)]
pub struct GetServiceAuthOutput {
    pub token: String,
}

pub async fn get_service_auth(
    State(state): State<AppState>,
    headers: axum::http::HeaderMap,
    Query(params): Query<GetServiceAuthParams>,
) -> Response {
    let auth_header = headers.get("Authorization");
    if auth_header.is_none() {
        return (
            StatusCode::UNAUTHORIZED,
            Json(json!({"error": "AuthenticationRequired"})),
        )
            .into_response();
    }

    let token = auth_header
        .unwrap()
        .to_str()
        .unwrap_or("")
        .replace("Bearer ", "");

    let session = sqlx::query!(
        r#"
        SELECT s.did, k.key_bytes
        FROM sessions s
        JOIN users u ON s.did = u.did
        JOIN user_keys k ON u.id = k.user_id
        WHERE s.access_jwt = $1
        "#,
        token
    )
    .fetch_optional(&state.db)
    .await;

    let (did, key_bytes) = match session {
        Ok(Some(row)) => (row.did, row.key_bytes),
        Ok(None) => {
            return (
                StatusCode::UNAUTHORIZED,
                Json(json!({"error": "AuthenticationFailed"})),
            )
                .into_response();
        }
        Err(e) => {
            error!("DB error in get_service_auth: {:?}", e);
            return (
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(json!({"error": "InternalError"})),
            )
                .into_response();
        }
    };

    if let Err(_) = crate::auth::verify_token(&token, &key_bytes) {
        return (
            StatusCode::UNAUTHORIZED,
            Json(json!({"error": "AuthenticationFailed", "message": "Invalid token signature"})),
        )
            .into_response();
    }

    let lxm = params.lxm.as_deref().unwrap_or("*");

    let service_token = match crate::auth::create_service_token(&did, &params.aud, lxm, &key_bytes)
    {
        Ok(t) => t,
        Err(e) => {
            error!("Failed to create service token: {:?}", e);
            return (
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(json!({"error": "InternalError"})),
            )
                .into_response();
        }
    };

    (StatusCode::OK, Json(GetServiceAuthOutput { token: service_token })).into_response()
}

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

#[derive(Serialize)]
#[serde(rename_all = "camelCase")]
pub struct CreateSessionOutput {
    pub access_jwt: String,
    pub refresh_jwt: String,
    pub handle: String,
    pub did: String,
}

pub async fn create_session(
    State(state): State<AppState>,
    Json(input): Json<CreateSessionInput>,
) -> Response {
    info!("create_session: identifier='{}'", input.identifier);

    let user_row = sqlx::query!(
        "SELECT u.id, u.did, u.handle, u.password_hash, k.key_bytes FROM users u JOIN user_keys k ON u.id = k.user_id WHERE u.handle = $1 OR u.email = $1",
        input.identifier
    )
        .fetch_optional(&state.db)
        .await;

    match user_row {
        Ok(Some(row)) => {
            let user_id = row.id;
            let stored_hash = &row.password_hash;
            let did = &row.did;
            let handle = &row.handle;
            let key_bytes = &row.key_bytes;

            let password_valid = if verify(&input.password, stored_hash).unwrap_or(false) {
                true
            } else {
                let app_pass_rows = sqlx::query!("SELECT password_hash FROM app_passwords WHERE user_id = $1", user_id)
                    .fetch_all(&state.db)
                    .await
                    .unwrap_or_default();

                app_pass_rows.iter().any(|row| {
                    verify(&input.password, &row.password_hash).unwrap_or(false)
                })
            };

            if password_valid {
                let access_jwt = match crate::auth::create_access_token(&did, &key_bytes) {
                    Ok(t) => t,
                    Err(e) => {
                        error!("Failed to create access token: {:?}", e);
                        return (
                            StatusCode::INTERNAL_SERVER_ERROR,
                            Json(json!({"error": "InternalError"})),
                        )
                            .into_response();
                    }
                };

                let refresh_jwt = match crate::auth::create_refresh_token(&did, &key_bytes) {
                    Ok(t) => t,
                    Err(e) => {
                        error!("Failed to create refresh token: {:?}", e);
                        return (
                            StatusCode::INTERNAL_SERVER_ERROR,
                            Json(json!({"error": "InternalError"})),
                        )
                            .into_response();
                    }
                };

                let session_insert = sqlx::query!(
                    "INSERT INTO sessions (access_jwt, refresh_jwt, did) VALUES ($1, $2, $3)",
                    access_jwt,
                    refresh_jwt,
                    did
                )
                .execute(&state.db)
                .await;

                match session_insert {
                    Ok(_) => {
                        return (
                            StatusCode::OK,
                            Json(CreateSessionOutput {
                                access_jwt,
                                refresh_jwt,
                                handle: handle.clone(),
                                did: did.clone(),
                            }),
                        )
                            .into_response();
                    }
                    Err(e) => {
                        error!("Failed to insert session: {:?}", e);
                        return (
                            StatusCode::INTERNAL_SERVER_ERROR,
                            Json(json!({"error": "InternalError"})),
                        )
                            .into_response();
                    }
                }
            } else {
                warn!(
                    "Password verification failed for identifier: {}",
                    input.identifier
                );
            }
        }
        Ok(None) => {
            warn!("User not found for identifier: {}", input.identifier);
        }
        Err(e) => {
            error!("Database error fetching user: {:?}", e);
            return (
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(json!({"error": "InternalError"})),
            )
                .into_response();
        }
    }

    (
        StatusCode::UNAUTHORIZED,
        Json(json!({"error": "AuthenticationFailed", "message": "Invalid identifier or password"})),
    )
        .into_response()
}

pub async fn get_session(
    State(state): State<AppState>,
    headers: axum::http::HeaderMap,
) -> Response {
    let auth_header = headers.get("Authorization");
    if auth_header.is_none() {
        return (
            StatusCode::UNAUTHORIZED,
            Json(json!({"error": "AuthenticationRequired"})),
        )
            .into_response();
    }

    let token = auth_header
        .unwrap()
        .to_str()
        .unwrap_or("")
        .replace("Bearer ", "");

    let result = sqlx::query!(
        r#"
        SELECT u.handle, u.did, u.email, k.key_bytes
        FROM sessions s
        JOIN users u ON s.did = u.did
        JOIN user_keys k ON u.id = k.user_id
        WHERE s.access_jwt = $1
        "#,
        token
    )
    .fetch_optional(&state.db)
    .await;

    match result {
        Ok(Some(row)) => {
            if let Err(_) = crate::auth::verify_token(&token, &row.key_bytes) {
                return (StatusCode::UNAUTHORIZED, Json(json!({"error": "AuthenticationFailed", "message": "Invalid token signature"}))).into_response();
            }

            return (
                StatusCode::OK,
                Json(json!({
                    "handle": row.handle,
                    "did": row.did,
                    "email": row.email,
                    "didDoc": {}
                })),
            )
                .into_response();
        }
        Ok(None) => {
            return (
                StatusCode::UNAUTHORIZED,
                Json(json!({"error": "AuthenticationFailed"})),
            )
                .into_response();
        }
        Err(e) => {
            error!("Database error in get_session: {:?}", e);
            return (
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(json!({"error": "InternalError"})),
            )
                .into_response();
        }
    }
}

pub async fn delete_session(
    State(state): State<AppState>,
    headers: axum::http::HeaderMap,
) -> Response {
    let auth_header = headers.get("Authorization");
    if auth_header.is_none() {
        return (
            StatusCode::UNAUTHORIZED,
            Json(json!({"error": "AuthenticationRequired"})),
        )
            .into_response();
    }

    let token = auth_header
        .unwrap()
        .to_str()
        .unwrap_or("")
        .replace("Bearer ", "");

    let result = sqlx::query!("DELETE FROM sessions WHERE access_jwt = $1", token)
        .execute(&state.db)
        .await;

    match result {
        Ok(res) => {
            if res.rows_affected() > 0 {
                return (StatusCode::OK, Json(json!({}))).into_response();
            }
        }
        Err(e) => {
            error!("Database error in delete_session: {:?}", e);
        }
    }

    (
        StatusCode::UNAUTHORIZED,
        Json(json!({"error": "AuthenticationFailed"})),
    )
        .into_response()
}

pub async fn refresh_session(
    State(state): State<AppState>,
    headers: axum::http::HeaderMap,
) -> Response {
    let auth_header = headers.get("Authorization");
    if auth_header.is_none() {
        return (
            StatusCode::UNAUTHORIZED,
            Json(json!({"error": "AuthenticationRequired"})),
        )
            .into_response();
    }

    let refresh_token = auth_header
        .unwrap()
        .to_str()
        .unwrap_or("")
        .replace("Bearer ", "");

    let session = sqlx::query!(
            "SELECT s.did, k.key_bytes FROM sessions s JOIN users u ON s.did = u.did JOIN user_keys k ON u.id = k.user_id WHERE s.refresh_jwt = $1",
            refresh_token
        )
        .fetch_optional(&state.db)
        .await;

    match session {
        Ok(Some(session_row)) => {
            let did = &session_row.did;
            let key_bytes = &session_row.key_bytes;

            if let Err(_) = crate::auth::verify_token(&refresh_token, &key_bytes) {
                return (StatusCode::UNAUTHORIZED, Json(json!({"error": "AuthenticationFailed", "message": "Invalid refresh token signature"}))).into_response();
            }

            let new_access_jwt = match crate::auth::create_access_token(&did, &key_bytes) {
                Ok(t) => t,
                Err(e) => {
                    error!("Failed to create access token: {:?}", e);
                    return (
                        StatusCode::INTERNAL_SERVER_ERROR,
                        Json(json!({"error": "InternalError"})),
                    )
                        .into_response();
                }
            };
            let new_refresh_jwt = match crate::auth::create_refresh_token(&did, &key_bytes) {
                Ok(t) => t,
                Err(e) => {
                    error!("Failed to create refresh token: {:?}", e);
                    return (
                        StatusCode::INTERNAL_SERVER_ERROR,
                        Json(json!({"error": "InternalError"})),
                    )
                        .into_response();
                }
            };

            let update = sqlx::query!(
                "UPDATE sessions SET access_jwt = $1, refresh_jwt = $2 WHERE refresh_jwt = $3",
                new_access_jwt,
                new_refresh_jwt,
                refresh_token
            )
            .execute(&state.db)
            .await;

            match update {
                Ok(_) => {
                    let user = sqlx::query!("SELECT handle FROM users WHERE did = $1", did)
                        .fetch_optional(&state.db)
                        .await;

                    match user {
                        Ok(Some(u)) => {
                            return (
                                StatusCode::OK,
                                Json(json!({
                                    "accessJwt": new_access_jwt,
                                    "refreshJwt": new_refresh_jwt,
                                    "handle": u.handle,
                                    "did": did
                                })),
                            )
                                .into_response();
                        }
                        Ok(None) => {
                            error!("User not found for existing session: {}", did);
                            return (
                                StatusCode::INTERNAL_SERVER_ERROR,
                                Json(json!({"error": "InternalError"})),
                            )
                                .into_response();
                        }
                        Err(e) => {
                            error!("Database error fetching user: {:?}", e);
                            return (
                                StatusCode::INTERNAL_SERVER_ERROR,
                                Json(json!({"error": "InternalError"})),
                            )
                                .into_response();
                        }
                    }
                }
                Err(e) => {
                    error!("Database error updating session: {:?}", e);
                    return (
                        StatusCode::INTERNAL_SERVER_ERROR,
                        Json(json!({"error": "InternalError"})),
                    )
                        .into_response();
                }
            }
        }
        Ok(None) => {
            return (
                StatusCode::UNAUTHORIZED,
                Json(json!({"error": "AuthenticationFailed", "message": "Invalid refresh token"})),
            )
                .into_response();
        }
        Err(e) => {
            error!("Database error fetching session: {:?}", e);
            return (
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(json!({"error": "InternalError"})),
            )
                .into_response();
        }
    }
}