module main

import net.http
import time
import json
import crypto.hmac
import crypto.sha256
import encoding.hex
import sources
import os


pub struct Stats {
pub mut:
	total_notifications int
	errors              int
	by_source           map[string]int
}

pub struct App {
pub mut:
	cfg            Config
	logger         Logger
	ntfy           NtfyClient
	dedup          Dedup
	stats          Stats
	start_time     time.Time
	poll_state     map[string]bool // url -> is_down
	webhook_routes map[string]WebhookRoute
	recent_events  []RecentEvent
	shutdown_flag  bool
	dashboard_html string // cached dashboard HTML
}

pub struct RecentEvent {
	timestamp time.Time
	source    string
	name      string
	topic     string
	priority  int
	message   string
	success   bool
}

const recent_events_max = 100

pub fn new_app(cfg Config, quiet bool) App {
	// json_mode = quiet — when running as a systemd service (quiet mode),
	// use JSON structured logging; otherwise use human-readable console output
	logger := new_logger(.info, quiet)
	dashboard := load_dashboard_html(logger)
	return App{
		cfg:            cfg
		logger:         logger
		ntfy:           new_ntfy_client(cfg.server, logger)
		dedup:          new_dedup(cfg.dedup)
		stats:          Stats{
			by_source: map[string]int{}
		}
		start_time:     time.now()
		poll_state:     map[string]bool{}
		webhook_routes: build_webhook_routes(cfg)
		recent_events:  []RecentEvent{}
		shutdown_flag:  false
		dashboard_html: dashboard
	}
}

fn load_dashboard_html(logger Logger) string {
	// Try dashboard.html from current working directory
	if os.exists('dashboard.html') {
		content := os.read_file('dashboard.html') or {
			logger.warn('server', 'dashboard', 'failed to read dashboard.html, using fallback')
			return dashboard_fallback_html()
		}
		logger.info('server', 'dashboard', 'loaded dashboard.html (${content.len} bytes)')
		return content
	}

	logger.warn('server', 'dashboard', 'dashboard.html not found, using fallback')
	return dashboard_fallback_html()
}

fn dashboard_fallback_html() string {
	return '<!DOCTYPE html><html><head><title>ntfy-bridge</title><style>body{background:#0f172a;color:#e2e8f0;font-family:system-ui,sans-serif;display:flex;align-items:center;justify-content:center;min-height:100vh;margin:0}.msg{text-align:center}.msg h1{font-size:1.5rem}.msg p{color:#94a3b8;margin-top:8px}code{background:#1e293b;padding:2px 8px;border-radius:4px;font-size:.875rem}</style></head><body><div class=msg><h1>🔔 ntfy-bridge</h1><p>Dashboard file not found.</p><p>Place <code>dashboard.html</code> in the working directory.</p></div></body></html>'
}

pub fn (mut app App) run() ! {
	app.start_background_tasks()

	app.logger.info('server', 'start', 'listening on ${app.cfg.server.listen}')

	// Graceful shutdown via signal handling on Unix
	$if linux || macos {
		spawn app.handle_signals()
	}

	mut s := http.Server{
		addr:    app.cfg.server.listen
		handler: app
	}
	s.listen_and_serve()
}

$if linux || macos {
	fn (mut app App) handle_signals() {
		sigch := os.new_signal_channel(.int, .term)
		_ := <-sigch
		app.logger.info('server', 'shutdown', 'received signal, shutting down...')
		app.shutdown_flag = true
		time.sleep(500 * time.millisecond)
		exit(0)
	}
}

fn (mut app App) start_background_tasks() {
	if app.cfg.sources.http_poll.len > 0 {
		spawn app.http_poll_loop()
	}
	if app.cfg.sources.docker.len > 0 {
		spawn app.docker_watch_loop()
	}
}

// ---- HTTP Handler ----

pub fn (mut app App) handle(req http.Request) http.Response {
	match req.method {
		.get {
			if req.url == '/' || req.url == '/dashboard' {
				return app.dashboard_response()
			}
			if req.url == '/health' {
				return app.health_response()
			}
			if req.url == '/stats' {
				return app.stats_response()
			}
			if req.url == '/api/config' {
				return app.config_api_response()
			}
			if req.url == '/api/status' {
				return app.status_api_response()
			}
			if req.url == '/api/history' {
				return app.history_api_response()
			}
		}
		.post {
			return app.handle_webhook(req)
		}
		else {}
	}

	return new_json_response(.not_found, '{"error":"not found"}')
}

// ---- Health & Stats ----

fn (mut app App) health_response() http.Response {
	uptime := time.now().unix() - app.start_time.unix()
	body := '{"status":"ok","uptime_seconds":${uptime},"total_notifications":${app.stats.total_notifications}}'
	return new_json_response(.ok, body)
}

fn (mut app App) stats_response() http.Response {
	mut parts := []string{}
	for source, count in app.stats.by_source {
		parts << '"${source}":${count}'
	}
	by_source := '{' + parts.join(',') + '}'
	body := '{"total":${app.stats.total_notifications},"errors":${app.stats.errors},"by_source":${by_source}}'
	return new_json_response(.ok, body)
}

// ---- API endpoints for dashboard ----

fn (mut app App) config_api_response() http.Response {
	mut safe := map[string]string{}
	safe['server_url'] = app.cfg.server.url
	safe['listen'] = app.cfg.server.listen
	safe['dedup_enabled'] = app.cfg.dedup.enabled.str()
	safe['dedup_ttl'] = app.cfg.dedup.ttl_seconds.str()
	safe['default_priority'] = app.cfg.defaults.priority.str()
	safe['gitea_sources'] = app.cfg.sources.gitea.len.str()
	safe['uptime_kuma_sources'] = app.cfg.sources.uptime_kuma.len.str()
	safe['docker_sources'] = app.cfg.sources.docker.len.str()
	safe['http_poll_sources'] = app.cfg.sources.http_poll.len.str()
	safe['cron_sources'] = app.cfg.sources.cron.len.str()
	safe['generic_sources'] = app.cfg.sources.generic.len.str()

	return new_json_response(.ok, json.encode(safe))
}

fn (mut app App) status_api_response() http.Response {
	mut items := []map[string]string{}
	for src in app.cfg.sources.http_poll {
		for check in src.checks {
			is_down := app.poll_state[check.url] or { false }
			status := if is_down { 'up' } else { 'down' }
			items << {
				'name':   check.url
				'status': status
			}
		}
	}
	return new_json_response(.ok, json.encode(items))
}

fn (mut app App) history_api_response() http.Response {
	mut entries := []map[string]string{}
	for ev in app.recent_events {
		entries << {
			'timestamp': ev.timestamp.format_rfc3339()
			'source':    ev.source
			'name':      ev.name
			'topic':     ev.topic
			'priority':  ev.priority.str()
			'message':   ev.message
			'success':   ev.success.str()
		}
	}
	return new_json_response(.ok, json.encode(entries))
}

// ---- Webhook handling (O(1) dispatch) ----

fn (mut app App) handle_webhook(req http.Request) http.Response {
	path := req.url
	route := app.webhook_routes[path] or {
		return new_json_response(.not_found, '{"error":"unknown webhook"}')
	}

	// HMAC validation (if secret is configured)
	if app.cfg.server.hmac_secret != '' {
		sig_header := req.header.get_custom('X-Hub-Signature-256') or { '' }
		if sig_header == '' || !app.verify_hmac(req.data, sig_header) {
			app.logger.warn('server', 'webhook', 'HMAC validation failed for ${path}')
			return new_json_response(.unauthorized, '{"error":"invalid signature"}')
		}
	}

	mut event_opt := ?sources.Event(none)
	match route.kind {
		.gitea {
			src := app.cfg.sources.gitea[route.index]
			event_opt = sources.transform_gitea(req.data, src)
		}
		.uptime_kuma {
			src := app.cfg.sources.uptime_kuma[route.index]
			event_opt = sources.transform_uptime_kuma(req.data, src)
		}
		.cron {
			src := app.cfg.sources.cron[route.index]
			event_opt = sources.transform_cron(req.data, src)
		}
		.generic {
			src := app.cfg.sources.generic[route.index]
			event_opt = sources.transform_generic(req.data, src)
		}
	}

	event := event_opt or {
		app.logger.warn('server', 'webhook', 'failed to transform: ${path}')
		return new_json_response(.bad_request, '{"error":"bad request"}')
	}
	app.publish(event)
	return new_json_response(.ok, '{"ok":true}')
}

fn (mut app App) verify_hmac(payload string, sig_header string) bool {
	if !sig_header.starts_with('sha256=') {
		return false
	}
	expected_hex := sig_header[7..] // strip "sha256=" prefix

	key := app.cfg.server.hmac_secret.bytes()
	data := payload.bytes()
	computed := hmac.new(key, data, sha256.sum, sha256.block_size)
	computed_hex := hex.encode(computed)

	return computed_hex == expected_hex
}

// ---- Publish pipeline ----

pub fn (mut app App) publish(event sources.Event) {
	mut e := apply_defaults(event, app.cfg.defaults)
	if !app.dedup.allow(e) {
		app.logger.debug('server', 'dedup', 'dropped event ${e.source}:${e.name}')
		return
	}

	now := time.now()
	app.ntfy.publish(e) or {
		app.logger.error('server', 'publish', 'failed to publish: ${err}')
		app.stats.errors++
		app.add_recent_event(now, e, false)
		return
	}
	app.stats.total_notifications++
	mut count := app.stats.by_source[e.source] or { 0 }
	count++
	app.stats.by_source[e.source] = count
	app.logger.info('server', 'publish', '${e.source}:${e.name} → ${e.topic}')
	app.add_recent_event(now, e, true)
}

fn (mut app App) add_recent_event(ts time.Time, event sources.Event, success bool) {
	app.recent_events << RecentEvent{
		timestamp: ts
		source:    event.source
		name:      event.name
		topic:     event.topic
		priority:  event.priority
		message:   event.message
		success:   success
	}
	if app.recent_events.len > recent_events_max {
		app.recent_events = app.recent_events[app.recent_events.len - recent_events_max..]
	}
}

// ---- HTTP Poll Loop ----

fn (mut app App) http_poll_loop() {
	for {
		if app.shutdown_flag {
			break
		}
		for src in app.cfg.sources.http_poll {
			for check in src.checks {
				app.run_http_check(check)
			}
		}
		mut min_interval := 60
		for src in app.cfg.sources.http_poll {
			if src.interval > 0 && src.interval < min_interval {
				min_interval = src.interval
			}
		}
		time.sleep(min_interval * time.second)
	}
}

fn (mut app App) run_http_check(check sources.HttpCheck) {
	resp := http.fetch(http.FetchConfig{
		url:          check.url
		method:       .get
		read_timeout: check.timeout * time.second
	}) or {
		app.handle_http_result(check, false, err.msg())
		return
	}
	is_up := resp.status_code == check.expect_status
	app.handle_http_result(check, is_up, 'status ${resp.status_code}')
}

fn (mut app App) handle_http_result(check sources.HttpCheck, is_up bool, detail string) {
	was_up := app.poll_state[check.url] or { true }
	if is_up && !was_up {
		app.publish(sources.transform_http_up(check))
		app.poll_state[check.url] = true
	} else if !is_up && was_up {
		app.publish(sources.transform_http_down(check, detail))
		app.poll_state[check.url] = false
	}
}

// ---- Helpers ----

fn new_json_response(status http.Status, body string) http.Response {
	mut header := http.Header{}
	header.add_custom('Content-Type', 'application/json') or { panic(err) }
	return http.new_response(http.ResponseConfig{
		status: status
		body:   body
		header: header
	})
}

fn (mut app App) dashboard_response() http.Response {
	mut header := http.Header{}
	header.add_custom('Content-Type', 'text/html; charset=utf-8') or { panic(err) }
	return http.new_response(http.ResponseConfig{
		status: .ok
		body:   app.dashboard_html
		header: header
	})
}