use crate::core::shared::state::AppState;
use crate::core::urls::ApiUrls;
use axum::{
    extract::{Path, Query, State},
    http::HeaderMap,
    response::{Html, IntoResponse},
    Json,
};
use std::sync::Arc;
use uuid::Uuid;

use super::auth::get_current_user;
use super::models::SaveRequest;
use super::storage::{delete_document_from_drive, list_documents_from_drive, load_document_from_drive, save_document_to_drive};
use super::utils::{format_document_content, format_document_list_item, format_error, format_relative_time};

pub async fn handle_new_document(
    State(state): State<Arc<AppState>>,
    headers: HeaderMap,
) -> impl IntoResponse {
    let (user_id, user_identifier) = match get_current_user(&state, &headers).await {
        Ok(u) => u,
        Err(e) => {
            log::error!("Auth error: {}", e);
            return Html(format_error("Authentication required"));
        }
    };

    let doc_id = Uuid::new_v4().to_string();
    let title = "Untitled".to_string();
    let content = String::new();

    if let Err(e) =
        save_document_to_drive(&state, &user_identifier, &doc_id, &title, &content, false).await
    {
        log::error!("Failed to save new document: {}", e);
    }

    let mut html = String::new();
    html.push_str("<div class=\"paper-new-created\" data-id=\"");
    html.push_str(&super::utils::html_escape(&doc_id));
    html.push_str("\">");

    html.push_str(&format_document_list_item(
        &doc_id, &title, "just now", true,
    ));

    html.push_str("<script>");
    html.push_str("htmx.trigger('#paper-list', 'refresh');");
    html.push_str(&format!("htmx.ajax('GET', '{}', {{target: '#editor-content', swap: 'innerHTML'}});",
        ApiUrls::PAPER_BY_ID.replace(":id", &super::utils::html_escape(&doc_id))));
    html.push_str("</script>");
    html.push_str("</div>");

    log::info!("New document created: {} for user {}", doc_id, user_id);
    Html(html)
}

pub async fn handle_list_documents(
    State(state): State<Arc<AppState>>,
    headers: HeaderMap,
) -> impl IntoResponse {
    let (_user_id, user_identifier) = match get_current_user(&state, &headers).await {
        Ok(u) => u,
        Err(e) => {
            log::error!("Auth error: {}", e);
            return Html(format_error("Authentication required"));
        }
    };

    let documents = match list_documents_from_drive(&state, &user_identifier).await {
        Ok(docs) => docs,
        Err(e) => {
            log::error!("Failed to list documents: {}", e);
            Vec::new()
        }
    };

    let mut html = String::new();
    html.push_str("<div class=\"paper-list\">");

    if documents.is_empty() {
        html.push_str("<div class=\"paper-empty\">");
        html.push_str("<p>No documents yet</p>");
        html.push_str(&format!("<button class=\"btn-new\" hx-post=\"{}\" hx-target=\"#paper-list\" hx-swap=\"afterbegin\">Create your first document</button>", ApiUrls::PAPER_NEW));
        html.push_str("</div>");
    } else {
        for doc in documents {
            let time_str = format_relative_time(doc.updated_at);
            let badge = if doc.storage_type == "named" {
                " 📁"
            } else {
                ""
            };
            html.push_str(&format_document_list_item(
                &doc.id,
                &format!("{}{}", doc.title, badge),
                &time_str,
                false,
            ));
        }
    }

    html.push_str("</div>");
    Html(html)
}

pub async fn handle_search_documents(
    State(state): State<Arc<AppState>>,
    headers: HeaderMap,
    Query(params): Query<super::models::SearchQuery>,
) -> impl IntoResponse {
    let (_user_id, user_identifier) = match get_current_user(&state, &headers).await {
        Ok(u) => u,
        Err(e) => {
            log::error!("Auth error: {}", e);
            return Html(format_error("Authentication required"));
        }
    };

    let query = params.q.unwrap_or_default().to_lowercase();

    let documents = list_documents_from_drive(&state, &user_identifier)
        .await
        .unwrap_or_default();

    let filtered: Vec<_> = if query.is_empty() {
        documents
    } else {
        documents
            .into_iter()
            .filter(|d| d.title.to_lowercase().contains(&query))
            .collect()
    };

    let mut html = String::new();
    html.push_str("<div class=\"paper-search-results\">");

    if filtered.is_empty() {
        html.push_str("<div class=\"paper-empty\">");
        html.push_str("<p>No documents found</p>");
        html.push_str("</div>");
    } else {
        for doc in filtered {
            let time_str = format_relative_time(doc.updated_at);
            html.push_str(&format_document_list_item(
                &doc.id, &doc.title, &time_str, false,
            ));
        }
    }

    html.push_str("</div>");
    Html(html)
}

pub async fn handle_get_document(
    State(state): State<Arc<AppState>>,
    headers: HeaderMap,
    Path(id): Path<String>,
) -> impl IntoResponse {
    let (_user_id, user_identifier) = match get_current_user(&state, &headers).await {
        Ok(u) => u,
        Err(e) => {
            log::error!("Auth error: {}", e);
            return Html(format_error("Authentication required"));
        }
    };

    match load_document_from_drive(&state, &user_identifier, &id).await {
        Ok(Some(doc)) => Html(format_document_content(&doc.title, &doc.content)),
        Ok(None) => Html(format_document_content("Untitled", "")),
        Err(e) => {
            log::error!("Failed to load document {}: {}", id, e);
            Html(format_document_content("Untitled", ""))
        }
    }
}

pub async fn handle_save_document(
    State(state): State<Arc<AppState>>,
    headers: HeaderMap,
    Json(payload): Json<SaveRequest>,
) -> impl IntoResponse {
    let (_user_id, user_identifier) = match get_current_user(&state, &headers).await {
        Ok(u) => u,
        Err(e) => {
            log::error!("Auth error: {}", e);
            return Html(format_error("Authentication required"));
        }
    };

    let doc_id = payload.id.unwrap_or_else(|| Uuid::new_v4().to_string());
    let title = payload.title.unwrap_or_else(|| "Untitled".to_string());
    let content = payload.content.unwrap_or_default();
    let is_named = payload.save_as_named.unwrap_or(false);

    match save_document_to_drive(
        &state,
        &user_identifier,
        &doc_id,
        &title,
        &content,
        is_named,
    )
    .await
    {
        Ok(path) => {
            log::info!("Document saved: {} at {}", doc_id, path);
            let mut html = String::new();
            html.push_str("<div class=\"save-success\">");
            html.push_str("<span class=\"save-icon\">*</span>");
            html.push_str("<span>Saved</span>");
            html.push_str("</div>");
            Html(html)
        }
        Err(e) => {
            log::error!("Failed to save document: {}", e);
            Html(format_error("Failed to save document"))
        }
    }
}

pub async fn handle_autosave(
    State(state): State<Arc<AppState>>,
    headers: HeaderMap,
    Json(payload): Json<SaveRequest>,
) -> impl IntoResponse {
    let (_user_id, user_identifier) = match get_current_user(&state, &headers).await {
        Ok(u) => u,
        Err(e) => {
            log::error!("Auth error: {}", e);
            return Html(String::new());
        }
    };

    let doc_id = payload.id.unwrap_or_else(|| Uuid::new_v4().to_string());
    let title = payload.title.unwrap_or_else(|| "Untitled".to_string());
    let content = payload.content.unwrap_or_default();

    if let Err(e) =
        save_document_to_drive(&state, &user_identifier, &doc_id, &title, &content, false).await
    {
        log::warn!("Autosave failed for {}: {}", doc_id, e);
    }

    Html("<span class=\"autosave-indicator\">Auto-saved</span>".to_string())
}

pub async fn handle_delete_document(
    State(state): State<Arc<AppState>>,
    headers: HeaderMap,
    Path(id): Path<String>,
) -> impl IntoResponse {
    let (_user_id, user_identifier) = match get_current_user(&state, &headers).await {
        Ok(u) => u,
        Err(e) => {
            log::error!("Auth error: {}", e);
            return Html(format_error("Authentication required"));
        }
    };

    match delete_document_from_drive(&state, &user_identifier, &id).await {
        Ok(()) => {
            log::info!("Document deleted: {}", id);
            Html(format!("<div class=\"delete-success\" hx-trigger=\"load\" hx-get=\"{}\" hx-target=\"#paper-list\" hx-swap=\"innerHTML\"></div>", ApiUrls::PAPER_LIST))
        }
        Err(e) => {
            log::error!("Failed to delete document {}: {}", id, e);
            Html(format_error("Failed to delete document"))
        }
    }
}