//! REST HTTP handlers for the gateway: agents, projects, bot configuration, and pipeline.

use crate::service::gateway::{self, GatewayState};
use poem::handler;
use poem::http::StatusCode;
use poem::web::Path as PoemPath;
use poem::web::{Data, Json};
use poem::{Body, Response};
use serde::{Deserialize, Serialize};
use serde_json::{Value, json};
use std::collections::BTreeMap;
use std::sync::Arc;

// ── Agent REST handlers ───────────────────────────────────────────────────────

/// `GET /gateway/mode` — returns `{"mode":"gateway"}`.
#[handler]
pub async fn gateway_mode_handler() -> Response {
    let body = json!({ "mode": "gateway" });
    Response::builder()
        .status(StatusCode::OK)
        .header("Content-Type", "application/json")
        .body(Body::from(serde_json::to_vec(&body).unwrap_or_default()))
}

/// `POST /gateway/tokens` — generate a one-time join token.
#[handler]
pub async fn gateway_generate_token_handler(state: Data<&Arc<GatewayState>>) -> Response {
    let token = gateway::generate_join_token(&state).await;
    let body = json!({ "token": token });
    Response::builder()
        .status(StatusCode::OK)
        .header("Content-Type", "application/json")
        .body(Body::from(serde_json::to_vec(&body).unwrap_or_default()))
}

/// `GET /gateway/agents` — list all alive build agents registered in the CRDT.
#[handler]
pub async fn gateway_list_agents_handler(_state: Data<&Arc<GatewayState>>) -> Response {
    let agents = gateway::list_agents();
    let body = serde_json::to_vec(&agents).unwrap_or_default();
    Response::builder()
        .status(StatusCode::OK)
        .header("Content-Type", "application/json")
        .body(Body::from(body))
}

/// Request body for assigning an agent to a project.
#[derive(Deserialize)]
struct AssignAgentRequest {
    project: Option<String>,
}

/// `POST /gateway/agents/:id/assign` — assign (or unassign) an agent to a project.
#[handler]
pub async fn gateway_assign_agent_handler(
    PoemPath(id): PoemPath<String>,
    body: Json<AssignAgentRequest>,
    state: Data<&Arc<GatewayState>>,
) -> Response {
    match gateway::assign_agent(&state, &id, body.0.project).await {
        Ok(agent) => {
            let body = serde_json::to_vec(&agent).unwrap_or_default();
            Response::builder()
                .status(StatusCode::OK)
                .header("Content-Type", "application/json")
                .body(Body::from(body))
        }
        Err(gateway::Error::ProjectNotFound(msg)) => Response::builder()
            .status(StatusCode::BAD_REQUEST)
            .body(Body::from(msg)),
        Err(_) => Response::builder()
            .status(StatusCode::NOT_FOUND)
            .body(Body::from("agent not found")),
    }
}

// ── Gateway Web UI ────────────────────────────────────────────────────────────

/// `GET /api/gateway` — returns the list of registered projects and the active project.
#[handler]
pub async fn gateway_api_handler(state: Data<&Arc<GatewayState>>) -> Response {
    let active = state.active_project.read().await.clone();
    let projects: Vec<Value> = state
        .projects
        .read()
        .await
        .iter()
        .map(|(name, entry)| {
            json!({
                "name": name,
                "url": entry.url,
            })
        })
        .collect();

    let body = json!({ "active": active, "projects": projects });
    Response::builder()
        .status(StatusCode::OK)
        .header("Content-Type", "application/json")
        .body(Body::from(serde_json::to_vec(&body).unwrap_or_default()))
}

/// Request body for `POST /api/gateway/switch`.
#[derive(Deserialize)]
struct SwitchRequest {
    project: String,
}

/// `POST /api/gateway/switch` — switch the active project.
#[handler]
pub async fn gateway_switch_handler(
    state: Data<&Arc<GatewayState>>,
    body: Json<SwitchRequest>,
) -> Response {
    match gateway::switch_project(&state, &body.project).await {
        Ok(_) => {
            let body_val = json!({ "ok": true });
            Response::builder()
                .status(StatusCode::OK)
                .header("Content-Type", "application/json")
                .body(Body::from(
                    serde_json::to_vec(&body_val).unwrap_or_default(),
                ))
        }
        Err(e) => {
            let body_val = json!({ "ok": false, "error": e.to_string() });
            Response::builder()
                .status(StatusCode::BAD_REQUEST)
                .header("Content-Type", "application/json")
                .body(Body::from(
                    serde_json::to_vec(&body_val).unwrap_or_default(),
                ))
        }
    }
}

// ── Project management API ────────────────────────────────────────────────────

/// Request body for adding a new project.
#[derive(Deserialize)]
struct AddProjectRequest {
    name: String,
    url: String,
}

/// `POST /api/gateway/projects` — add a new project.
#[handler]
pub async fn gateway_add_project_handler(
    state: Data<&Arc<GatewayState>>,
    body: Json<AddProjectRequest>,
) -> Response {
    match gateway::add_project(&state, &body.name, &body.url).await {
        Ok(()) => {
            let name = body.0.name.trim().to_string();
            let url = body.0.url.trim().to_string();
            let body_val = json!({ "name": name, "url": url });
            Response::builder()
                .status(StatusCode::OK)
                .header("Content-Type", "application/json")
                .body(Body::from(
                    serde_json::to_vec(&body_val).unwrap_or_default(),
                ))
        }
        Err(gateway::Error::DuplicateToken(_)) => Response::builder()
            .status(StatusCode::CONFLICT)
            .body(Body::from(format!(
                "project '{}' already exists",
                body.0.name.trim()
            ))),
        Err(e) => Response::builder()
            .status(StatusCode::BAD_REQUEST)
            .body(Body::from(e.to_string())),
    }
}

/// `DELETE /api/gateway/projects/:name` — remove a project.
#[handler]
pub async fn gateway_remove_project_handler(
    PoemPath(name): PoemPath<String>,
    state: Data<&Arc<GatewayState>>,
) -> Response {
    match gateway::remove_project(&state, &name).await {
        Ok(()) => Response::builder()
            .status(StatusCode::NO_CONTENT)
            .body(Body::empty()),
        Err(gateway::Error::ProjectNotFound(msg)) => Response::builder()
            .status(StatusCode::NOT_FOUND)
            .body(Body::from(msg)),
        Err(e) => Response::builder()
            .status(StatusCode::BAD_REQUEST)
            .body(Body::from(e.to_string())),
    }
}

// ── Bot configuration API ─────────────────────────────────────────────────────

/// Request/response body for the bot configuration API.
#[derive(Deserialize, Serialize, Default)]
pub(crate) struct BotConfigPayload {
    transport: String,
    homeserver: Option<String>,
    username: Option<String>,
    password: Option<String>,
    slack_bot_token: Option<String>,
    slack_signing_secret: Option<String>,
}

/// `GET /api/gateway/bot-config` — return current bot.toml fields as JSON.
#[handler]
pub async fn gateway_bot_config_get_handler(state: Data<&Arc<GatewayState>>) -> Response {
    let fields = gateway::io::read_bot_config_raw(&state.config_dir);
    let payload = BotConfigPayload {
        transport: fields.transport,
        homeserver: fields.homeserver,
        username: fields.username,
        password: fields.password,
        slack_bot_token: fields.slack_bot_token,
        slack_signing_secret: fields.slack_signing_secret,
    };
    Response::builder()
        .status(StatusCode::OK)
        .header("Content-Type", "application/json")
        .body(Body::from(serde_json::to_vec(&payload).unwrap_or_default()))
}

/// `POST /api/gateway/bot-config` — write new bot.toml and restart the bot.
#[handler]
pub async fn gateway_bot_config_save_handler(
    state: Data<&Arc<GatewayState>>,
    body: Json<BotConfigPayload>,
) -> Response {
    let content = gateway::config::serialize_bot_config(
        &body.transport,
        body.homeserver.as_deref(),
        body.username.as_deref(),
        body.password.as_deref(),
        body.slack_bot_token.as_deref(),
        body.slack_signing_secret.as_deref(),
    );

    match gateway::save_bot_config_and_restart(&state, &content).await {
        Ok(()) => {
            let ok = json!({ "ok": true });
            Response::builder()
                .status(StatusCode::OK)
                .header("Content-Type", "application/json")
                .body(Body::from(serde_json::to_vec(&ok).unwrap_or_default()))
        }
        Err(e) => {
            let err = json!({ "ok": false, "error": e.to_string() });
            Response::builder()
                .status(StatusCode::INTERNAL_SERVER_ERROR)
                .header("Content-Type", "application/json")
                .body(Body::from(serde_json::to_vec(&err).unwrap_or_default()))
        }
    }
}

/// `GET /api/gateway/pipeline` — fetch pipeline status from all registered projects.
#[handler]
pub async fn gateway_all_pipeline_handler(state: Data<&Arc<GatewayState>>) -> Response {
    let project_urls: BTreeMap<String, String> = state
        .projects
        .read()
        .await
        .iter()
        .map(|(n, e)| (n.clone(), e.url.clone()))
        .collect();

    let results =
        gateway::io::fetch_all_project_pipeline_statuses(&project_urls, &state.client).await;

    let active = state.active_project.read().await.clone();
    let body = json!({ "active": active, "projects": results });
    Response::builder()
        .status(StatusCode::OK)
        .header("Content-Type", "application/json")
        .body(Body::from(serde_json::to_vec(&body).unwrap_or_default()))
}

// ── Bot config page ───────────────────────────────────────────────────────────

/// Self-contained HTML page for bot configuration.
const GATEWAY_BOT_CONFIG_HTML: &str = r#"<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Bot Configuration &#x2014; Huskies Gateway</title>
<style>
  *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
  body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: #0f172a;
    color: #e2e8f0;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
  }
  .card {
    background: #1e293b;
    border: 1px solid #334155;
    border-radius: 12px;
    padding: 2rem;
    width: 100%;
    max-width: 520px;
    box-shadow: 0 4px 24px rgba(0,0,0,0.4);
  }
  .header {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
  }
  .back {
    color: #64748b;
    text-decoration: none;
    font-size: 0.85rem;
    margin-right: auto;
  }
  .back:hover { color: #94a3b8; }
  .logo { font-size: 1.5rem; }
  h1 { font-size: 1.2rem; font-weight: 600; color: #f8fafc; }
  .field { margin-bottom: 1rem; }
  label {
    display: block;
    font-size: 0.75rem;
    font-weight: 500;
    color: #94a3b8;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.4rem;
  }
  input, select {
    width: 100%;
    padding: 0.625rem 0.875rem;
    background: #0f172a;
    border: 1px solid #334155;
    border-radius: 8px;
    color: #f1f5f9;
    font-size: 0.9rem;
  }
  input:focus, select:focus { outline: none; border-color: #6366f1; box-shadow: 0 0 0 2px rgba(99,102,241,0.25); }
  select {
    cursor: pointer;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2394a3b8' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.875rem center;
    padding-right: 2.5rem;
  }
  .section { margin-top: 1rem; }
  .divider {
    border: none;
    border-top: 1px solid #334155;
    margin: 1.25rem 0;
  }
  button {
    width: 100%;
    padding: 0.75rem;
    background: #6366f1;
    border: none;
    border-radius: 8px;
    color: #fff;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    margin-top: 1.25rem;
  }
  button:hover { background: #4f46e5; }
  button:disabled { background: #334155; color: #64748b; cursor: not-allowed; }
  .status { margin-top: 0.875rem; font-size: 0.8rem; color: #64748b; min-height: 1.25rem; }
  .status.ok { color: #4ade80; }
  .status.err { color: #f87171; }
</style>
</head>
<body>
<div class="card">
  <div class="header">
    <a href="/" class="back">&#x2190; Gateway</a>
    <span class="logo">&#x1F916;</span>
    <h1>Bot Configuration</h1>
  </div>
  <div class="field">
    <label for="transport">Transport</label>
    <select id="transport" onchange="onTransportChange(this.value)">
      <option value="matrix">Matrix</option>
      <option value="slack">Slack</option>
    </select>
  </div>
  <hr class="divider">
  <div id="matrix-fields" class="section">
    <div class="field">
      <label for="homeserver">Homeserver URL</label>
      <input type="text" id="homeserver" placeholder="https://matrix.example.com">
    </div>
    <div class="field">
      <label for="username">Bot Username</label>
      <input type="text" id="username" placeholder="@bot:example.com">
    </div>
    <div class="field">
      <label for="password">Password</label>
      <input type="password" id="password" placeholder="&#x2022;&#x2022;&#x2022;&#x2022;&#x2022;&#x2022;&#x2022;&#x2022;">
    </div>
  </div>
  <div id="slack-fields" class="section" style="display:none">
    <div class="field">
      <label for="slack-bot-token">Bot Token</label>
      <input type="password" id="slack-bot-token" placeholder="xoxb-&#x2026;">
    </div>
    <div class="field">
      <label for="slack-signing-secret">App / Signing Secret</label>
      <input type="password" id="slack-signing-secret" placeholder="Your signing secret">
    </div>
  </div>
  <button id="save-btn" onclick="save()">Save &amp; Restart Bot</button>
  <div id="status" class="status"></div>
</div>
<script>
function onTransportChange(v) {
  document.getElementById('matrix-fields').style.display = v === 'matrix' ? '' : 'none';
  document.getElementById('slack-fields').style.display = v === 'slack' ? '' : 'none';
}
async function loadConfig() {
  try {
    const r = await fetch('/api/gateway/bot-config');
    const d = await r.json();
    document.getElementById('transport').value = d.transport || 'matrix';
    onTransportChange(d.transport || 'matrix');
    document.getElementById('homeserver').value = d.homeserver || '';
    document.getElementById('username').value = d.username || '';
    document.getElementById('password').value = d.password || '';
    document.getElementById('slack-bot-token').value = d.slack_bot_token || '';
    document.getElementById('slack-signing-secret').value = d.slack_signing_secret || '';
  } catch(e) {
    document.getElementById('status').textContent = 'Failed to load config: ' + e;
    document.getElementById('status').className = 'status err';
  }
}
async function save() {
  const btn = document.getElementById('save-btn');
  const statusEl = document.getElementById('status');
  btn.disabled = true;
  btn.textContent = 'Saving\u2026';
  statusEl.className = 'status';
  statusEl.textContent = '';
  const transport = document.getElementById('transport').value;
  const payload = { transport };
  if (transport === 'matrix') {
    payload.homeserver = document.getElementById('homeserver').value;
    payload.username = document.getElementById('username').value;
    payload.password = document.getElementById('password').value;
  } else {
    payload.slack_bot_token = document.getElementById('slack-bot-token').value;
    payload.slack_signing_secret = document.getElementById('slack-signing-secret').value;
  }
  try {
    const r = await fetch('/api/gateway/bot-config', {
      method: 'POST',
      headers: {'Content-Type': 'application/json'},
      body: JSON.stringify(payload)
    });
    const d = await r.json();
    if (d.ok) {
      statusEl.className = 'status ok';
      statusEl.textContent = 'Saved \u2014 bot restarted with new credentials.';
    } else {
      statusEl.className = 'status err';
      statusEl.textContent = d.error || 'Save failed';
    }
  } catch(e) {
    statusEl.className = 'status err';
    statusEl.textContent = 'Error: ' + e;
  }
  btn.disabled = false;
  btn.textContent = 'Save & Restart Bot';
}
loadConfig();
</script>
</body>
</html>
"#;

/// Serve the bot configuration HTML page at `GET /bot-config`.
#[handler]
pub async fn gateway_bot_config_page_handler() -> Response {
    Response::builder()
        .status(StatusCode::OK)
        .header("Content-Type", "text/html; charset=utf-8")
        .body(Body::from(GATEWAY_BOT_CONFIG_HTML))
}