#!/usr/bin/env bash
set -euo pipefail

# En Croissant + lc0 + Maia + Stockfish setup script
# Targets Arch Linux. No sudo required (prerequisites must be pre-installed).

APPIMAGE_DIR="$HOME/.local/bin"
APPIMAGE_PATH="$APPIMAGE_DIR/en-croissant.AppImage"
LC0_BIN="$HOME/.local/bin/lc0"
MAIA_WEIGHTS_DIR="$HOME/.local/share/maia"
MAIA_BASE_URL="https://github.com/CSSLab/maia-chess/releases/download/v1.0"
STOCKFISH_TAR_URL="https://github.com/official-stockfish/Stockfish/releases/latest/download/stockfish-ubuntu-x86-64-avx2.tar"
STOCKFISH_DIR="$HOME/.local/share/org.encroissant.app/engines/stockfish"
STOCKFISH_BIN="$STOCKFISH_DIR/stockfish-ubuntu-x86-64-avx2"
ENGINES_JSON="$HOME/.local/share/org.encroissant.app/engines/engines.json"
DESKTOP_FILE="$HOME/.local/share/applications/en-croissant.desktop"

info()  { printf '\033[1;34m==> %s\033[0m\n' "$*"; }
ok()    { printf '\033[1;32m  -> %s\033[0m\n' "$*"; }
skip()  { printf '\033[1;33m  -> %s (skipped)\033[0m\n' "$*"; }
err()   { printf '\033[1;31mERROR: %s\033[0m\n' "$*" >&2; }

# ---------------------------------------------------------------------------
# 1. Check prerequisites
# ---------------------------------------------------------------------------
info "Checking prerequisites"

missing=()
for cmd in git meson ninja python3 curl; do
    command -v "$cmd" &>/dev/null || missing+=("$cmd")
done
# Check libraries via pacman
for pkg in openblas eigen; do
    pacman -Qi "$pkg" &>/dev/null || missing+=("$pkg")
done

if (( ${#missing[@]} )); then
    err "Missing packages: ${missing[*]}"
    echo "Install them with:  sudo pacman -S ${missing[*]}"
    exit 1
fi
ok "All prerequisites found"

# ---------------------------------------------------------------------------
# 2. Install En Croissant AppImage
# ---------------------------------------------------------------------------
info "Installing En Croissant AppImage"

if [[ -f "$APPIMAGE_PATH" ]]; then
    skip "Already exists at $APPIMAGE_PATH"
else
    mkdir -p "$APPIMAGE_DIR"
    # Get latest release AppImage URL from GitHub API
    appimage_url=$(curl -sL "https://api.github.com/repos/franciscoBSalgueiro/en-croissant/releases/latest" \
        | python3 -c "import sys,json; assets=json.load(sys.stdin)['assets']; print([a['browser_download_url'] for a in assets if a['name'].endswith('_amd64.AppImage')][0])")
    echo "  Downloading: $appimage_url"
    curl -L -o "$APPIMAGE_PATH" "$appimage_url"
    chmod +x "$APPIMAGE_PATH"
    ok "Installed to $APPIMAGE_PATH"
fi

# ---------------------------------------------------------------------------
# 3. Build and install lc0 from source
# ---------------------------------------------------------------------------
info "Building lc0"

if [[ -x "$LC0_BIN" ]]; then
    skip "Already exists at $LC0_BIN"
else
    LC0_BUILD_DIR=$(mktemp -d /tmp/lc0-build.XXXXXX)
    echo "  Cloning to $LC0_BUILD_DIR"
    git clone --recurse-submodules https://github.com/LeelaChessZero/lc0.git "$LC0_BUILD_DIR/lc0"
    pushd "$LC0_BUILD_DIR/lc0" >/dev/null
    INSTALL_PREFIX="$HOME/.local" ./build.sh
    popd >/dev/null
    mkdir -p "$HOME/.local/bin"
    cp "$LC0_BUILD_DIR/lc0/build/release/lc0" "$LC0_BIN"
    chmod +x "$LC0_BIN"
    ok "Installed to $LC0_BIN"
    rm -rf "$LC0_BUILD_DIR"
fi

# ---------------------------------------------------------------------------
# 4. Download Maia weights
# ---------------------------------------------------------------------------
info "Downloading Maia weights"
mkdir -p "$MAIA_WEIGHTS_DIR"

for elo in 1100 1200 1300 1400 1500 1600 1700 1800 1900; do
    file="maia-${elo}.pb.gz"
    dest="$MAIA_WEIGHTS_DIR/$file"
    if [[ -f "$dest" ]]; then
        skip "$file already exists"
    else
        echo "  Downloading $file"
        curl -sL -o "$dest" "$MAIA_BASE_URL/$file"
        ok "$file"
    fi
done

# ---------------------------------------------------------------------------
# 5. Create Maia wrapper scripts
# ---------------------------------------------------------------------------
info "Creating Maia wrapper scripts"
mkdir -p "$HOME/.local/bin"

for elo in 1100 1200 1300 1400 1500 1600 1700 1800 1900; do
    wrapper="$HOME/.local/bin/maia-${elo}"
    cat > "$wrapper" <<SCRIPT
#!/bin/sh
exec "$LC0_BIN" --weights="$MAIA_WEIGHTS_DIR/maia-${elo}.pb.gz" "\$@"
SCRIPT
    chmod +x "$wrapper"
done
ok "Created 9 wrapper scripts in ~/.local/bin/"

# ---------------------------------------------------------------------------
# 6. Download Stockfish binary
# ---------------------------------------------------------------------------
info "Installing Stockfish"

if [[ -x "$STOCKFISH_BIN" ]]; then
    skip "Already exists at $STOCKFISH_BIN"
else
    mkdir -p "$STOCKFISH_DIR"
    echo "  Downloading Stockfish"
    curl -sL "$STOCKFISH_TAR_URL" | tar -xf - -C "$STOCKFISH_DIR" --strip-components=1
    chmod +x "$STOCKFISH_BIN"
    ok "Installed to $STOCKFISH_BIN"
fi

# ---------------------------------------------------------------------------
# 7. Write engines.json
# ---------------------------------------------------------------------------
info "Writing engines.json"
mkdir -p "$(dirname "$ENGINES_JSON")"

# Generate a UUID via python3
genuuid() { python3 -c "import uuid; print(uuid.uuid4())"; }

# Build the JSON with python3 for correctness
python3 - "$STOCKFISH_BIN" "$HOME/.local/bin" <<'PYEOF' > "$ENGINES_JSON"
import json, sys, uuid

stockfish_bin = sys.argv[1]
maia_bin_dir = sys.argv[2]

engines = []

# Stockfish
engines.append({
    "type": "local",
    "id": str(uuid.uuid4()),
    "name": "Stockfish",
    "version": "",
    "path": stockfish_bin,
    "image": "https://upload.wikimedia.org/wikipedia/commons/3/3a/NewLogoSF.png",
    "elo": 3635,
    "downloadSize": 79953920,
    "downloadLink": "https://github.com/official-stockfish/Stockfish/releases/latest/download/stockfish-ubuntu-x86-64-avx2.tar",
    "loaded": True,
    "go": {"t": "Infinite"},
    "settings": [
        {"name": "Threads", "value": 1},
        {"name": "Hash", "value": 16},
        {"name": "MultiPV", "value": 1}
    ]
})

# Maia engines
for elo in range(1100, 2000, 100):
    engines.append({
        "type": "local",
        "id": str(uuid.uuid4()),
        "name": f"Maia {elo}",
        "version": "1.0",
        "path": f"{maia_bin_dir}/maia-{elo}",
        "image": None,
        "elo": elo,
        "loaded": True,
        "go": {"t": "Nodes", "c": 1},
        "settings": [
            {"name": "MultiPV", "value": 1}
        ]
    })

print(json.dumps(engines, indent=4))
PYEOF

ok "Wrote $ENGINES_JSON with 10 engines"

# ---------------------------------------------------------------------------
# 8. Create .desktop file
# ---------------------------------------------------------------------------
info "Creating .desktop file"
mkdir -p "$(dirname "$DESKTOP_FILE")"

cat > "$DESKTOP_FILE" <<EOF
[Desktop Entry]
Name=En Croissant
Comment=Chess GUI for analysis, puzzles, and play
Exec=$APPIMAGE_PATH
Icon=chess
Type=Application
Categories=Game;BoardGame;
StartupWMClass=En Croissant
EOF

update-desktop-database "$HOME/.local/share/applications/" 2>/dev/null || true
ok "Created $DESKTOP_FILE"

# ---------------------------------------------------------------------------
# Done
# ---------------------------------------------------------------------------
echo ""
info "Setup complete!"
echo "  En Croissant: $APPIMAGE_PATH"
echo "  lc0:          $LC0_BIN"
echo "  Stockfish:    $STOCKFISH_BIN"
echo "  Maia weights: $MAIA_WEIGHTS_DIR/"
echo "  engines.json: $ENGINES_JSON"
echo ""
echo "  Launch with:  $APPIMAGE_PATH"