#!/bin/sh
# ============================================
# Chat Switchboard - Frontend Entrypoint
# ============================================
# nginx serves static assets and proxies page
# routes to the Go backend for template rendering.
# API/WS routes are handled by Ingress directly.
#
# Environment (required):
#   BACKEND_URL  - Backend service URL
#                  (e.g. "http://switchboard-be:8080")
#
# Environment (optional):
#   BASE_PATH    - URL prefix (e.g. "/dev", "" for root)
#   ENVIRONMENT  - Environment name for logging
# ============================================
set -e

BASE_PATH="${BASE_PATH:-}"
BACKEND_URL="${BACKEND_URL:?BACKEND_URL is required (e.g. http://switchboard-be:8080)}"
ENVIRONMENT="${ENVIRONMENT:-production}"

# Read version from VERSION file (baked in at build time)
APP_VERSION="dev"
if [ -f /VERSION ]; then
    APP_VERSION=$(cat /VERSION | tr -d '[:space:]')
fi

# Compute build hash from JS file contents (unique per deploy)
BUILD_HASH=$(find /usr/share/nginx/html/js -name '*.js' -exec md5sum {} + 2>/dev/null | sort | md5sum | cut -c1-8)
if [ -z "${BUILD_HASH}" ]; then
    BUILD_HASH=$(date +%s | md5sum | cut -c1-8)
fi

# ── Inject into index.html (redirect page) ──
sed -i \
    -e "s|%%BASE_PATH%%|${BASE_PATH}|g" \
    -e "s|%%APP_VERSION%%|${APP_VERSION}|g" \
    /usr/share/nginx/html/index.html

# Inject version and build hash into service worker
sed -i \
    -e "s|%%APP_VERSION%%|${APP_VERSION}|g" \
    -e "s|%%BUILD_HASH%%|${BUILD_HASH}|g" \
    /usr/share/nginx/html/sw.js

echo "✅ Frontend: BASE_PATH=${BASE_PATH:-/} VERSION=${APP_VERSION} BUILD=${BUILD_HASH} BACKEND=${BACKEND_URL}"

# ── Page route proxy blocks ─────────────────
page_proxy_block() {
    local path="$1"
    cat <<PROXY
    location ${path} {
        proxy_pass ${BACKEND_URL};
        proxy_http_version 1.1;
        proxy_set_header Host \$host;
        proxy_set_header X-Real-IP \$remote_addr;
        proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto \$scheme;
    }
PROXY
}

PAGE_ROUTES=$(cat <<ROUTES
    # ── Page routes → backend ────────────────
$(page_proxy_block "= ${BASE_PATH}/")
$(page_proxy_block "= ${BASE_PATH}/login")
    location ~ ^${BASE_PATH}/chat/[^/]+\$ {
        proxy_pass ${BACKEND_URL};
        proxy_http_version 1.1;
        proxy_set_header Host \$host;
        proxy_set_header X-Real-IP \$remote_addr;
        proxy_set_header X-Forwarded-For \$proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto \$scheme;
    }
$(page_proxy_block "${BASE_PATH}/admin")
$(page_proxy_block "${BASE_PATH}/editor")
$(page_proxy_block "${BASE_PATH}/notes")
$(page_proxy_block "${BASE_PATH}/settings")
$(page_proxy_block "${BASE_PATH}/w")
    # v0.27.0: Extension surface page routes
$(page_proxy_block "${BASE_PATH}/s")
    # v0.27.0: Extension surface static assets (proxied to backend; on-disk at /data/packages/)
$(page_proxy_block "${BASE_PATH}/surfaces")
ROUTES
)

# ── Generate nginx config ───────────────────
if [ -z "${BASE_PATH}" ]; then
    cat > /etc/nginx/conf.d/default.conf <<NGINX
server {
    listen 80;
    server_name _;
    root /usr/share/nginx/html;
    index index.html;

    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_proxied expired no-cache no-store private auth;
    gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml application/javascript;

    location ~* \.(jpg|jpeg|png|gif|ico|css|js|woff|woff2)$ {
        expires 1y;
        add_header Cache-Control "public, immutable";
    }

    location = /sw.js {
        expires off;
        add_header Cache-Control "no-cache, no-store, must-revalidate";
    }

    location /branding/ {
        alias /branding/;
        expires 1h;
        add_header Cache-Control "public";
        try_files \$uri =404;
    }

${PAGE_ROUTES}

    location / {
        try_files \$uri \$uri/ /index.html;
    }

    location = /healthz {
        return 200 'ok';
        add_header Content-Type text/plain;
    }

    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-XSS-Protection "1; mode=block" always;
}
NGINX
else
    cat > /etc/nginx/conf.d/default.conf <<NGINX
server {
    listen 80;
    server_name _;

    gzip on;
    gzip_vary on;
    gzip_min_length 1024;
    gzip_proxied expired no-cache no-store private auth;
    gzip_types text/plain text/css text/xml text/javascript application/x-javascript application/xml application/javascript;

${PAGE_ROUTES}

    location ${BASE_PATH}/ {
        alias /usr/share/nginx/html/;
        try_files \$uri \$uri/ ${BASE_PATH}/index.html;

        location ~* \.(jpg|jpeg|png|gif|ico|css|js|woff|woff2)\$ {
            expires 1y;
            add_header Cache-Control "public, immutable";
        }

        location = ${BASE_PATH}/sw.js {
            alias /usr/share/nginx/html/sw.js;
            expires off;
            add_header Cache-Control "no-cache, no-store, must-revalidate";
        }
    }

    location ${BASE_PATH}/branding/ {
        alias /branding/;
        expires 1h;
        add_header Cache-Control "public";
        try_files \$uri =404;
    }

    location = ${BASE_PATH} {
        return 301 ${BASE_PATH}/;
    }

    location = /healthz {
        return 200 'ok';
        add_header Content-Type text/plain;
    }

    add_header X-Frame-Options "SAMEORIGIN" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-XSS-Protection "1; mode=block" always;
}
NGINX
fi

exec nginx -g 'daemon off;'