#!/usr/bin/env bash
#
# battlenet-update-proton.sh
#
# Lists available GE-Proton releases from GitHub, downloads the chosen version
# into ~/.local/share/Steam/compatibilitytools.d/, and updates the battlenet
# launch script to point at it.
#
# Usage:
#   ./battlenet-update-proton.sh              # interactive picker
#   ./battlenet-update-proton.sh --latest     # auto-install the latest release
#   ./battlenet-update-proton.sh --list       # list available releases and exit
#   ./battlenet-update-proton.sh --version=GE-Proton9-20  # install a specific release
# END_HELP

set -euo pipefail

# ---------- config ----------
PROTON_DIR="${PROTON_INSTALL_DIR:-$HOME/.local/share/Steam/compatibilitytools.d}"
LAUNCH_SCRIPT="${BATTLENET_LAUNCH_SCRIPT:-$HOME/.local/bin/battlenet}"
GITHUB_API="https://api.github.com/repos/GloriousEggroll/proton-ge-custom/releases"
LIST_COUNT=10   # how many recent releases to show in the picker

ASSUME_LATEST=0
LIST_ONLY=0
PINNED_VERSION=""

# ---------- helpers ----------
c_reset=$'\033[0m'; c_blue=$'\033[1;34m'; c_green=$'\033[1;32m'
c_yellow=$'\033[1;33m'; c_red=$'\033[1;31m'; c_dim=$'\033[2m'

log()  { printf '%s==>%s %s\n' "$c_blue"   "$c_reset" "$*"; }
ok()   { printf '%s✓%s %s\n'   "$c_green"  "$c_reset" "$*"; }
warn() { printf '%s!%s %s\n'   "$c_yellow" "$c_reset" "$*"; }
err()  { printf '%s✗%s %s\n'   "$c_red"    "$c_reset" "$*" >&2; }
skip() { printf '  %s(skip) %s%s\n' "$c_dim" "$*" "$c_reset"; }
die()  { err "$*"; exit 1; }

# ---------- arg parsing ----------
for arg in "$@"; do
    case "$arg" in
        --latest)       ASSUME_LATEST=1 ;;
        --list)         LIST_ONLY=1 ;;
        --version=*)    PINNED_VERSION="${arg#*=}" ;;
        -h|--help)
            sed -n '/^# Usage:/,/^# END_HELP/p' "$0" | sed 's/^# \{0,1\}//'
            exit 0
            ;;
        *) die "Unknown argument: $arg" ;;
    esac
done

# ---------- preflight ----------
command -v curl >/dev/null || die "curl not installed. Run: sudo pacman -S curl"
command -v tar  >/dev/null || die "tar not installed."

# ---------- fetch release list ----------
log "Fetching GE-Proton release list from GitHub"

RELEASES_JSON=$(curl -fsSL "$GITHUB_API?per_page=$LIST_COUNT")

# Extract tag names (GE-ProtonX-Y format)
mapfile -t RELEASE_TAGS < <(
    printf '%s' "$RELEASES_JSON" \
    | grep '"tag_name"' \
    | sed 's/.*"tag_name": *"\([^"]*\)".*/\1/'
)

[[ ${#RELEASE_TAGS[@]} -gt 0 ]] || die "No releases found — GitHub API may be rate-limited. Try again shortly."

if [[ $LIST_ONLY -eq 1 ]]; then
    echo "Recent GE-Proton releases:"
    for tag in "${RELEASE_TAGS[@]}"; do
        installed=""
        [[ -d "$PROTON_DIR/$tag" ]] && installed="  ${c_green}(installed)${c_reset}"
        printf "  %s%s\n" "$tag" "$installed"
    done
    exit 0
fi

# ---------- choose version ----------
if [[ -n "$PINNED_VERSION" ]]; then
    TARGET="$PINNED_VERSION"
elif [[ $ASSUME_LATEST -eq 1 ]]; then
    TARGET="${RELEASE_TAGS[0]}"
    log "Latest release: $TARGET"
else
    echo
    echo "Recent GE-Proton releases (${c_green}green = already installed${c_reset}):"
    i=1
    for tag in "${RELEASE_TAGS[@]}"; do
        installed=""
        [[ -d "$PROTON_DIR/$tag" ]] && installed="  ${c_green}✓${c_reset}"
        printf "  %2d) %s%s\n" "$i" "$tag" "$installed"
        (( i++ ))
    done
    echo
    printf "Enter number (1-%d) or a version tag [default: 1 = %s]: " "${#RELEASE_TAGS[@]}" "${RELEASE_TAGS[0]}"
    read -r choice
    if [[ -z "$choice" ]]; then
        TARGET="${RELEASE_TAGS[0]}"
    elif [[ "$choice" =~ ^[0-9]+$ ]] && (( choice >= 1 && choice <= ${#RELEASE_TAGS[@]} )); then
        TARGET="${RELEASE_TAGS[$(( choice - 1 ))]}"
    else
        TARGET="$choice"
    fi
fi

log "Target: $TARGET"

# ---------- download ----------
INSTALL_PATH="$PROTON_DIR/$TARGET"

if [[ -d "$INSTALL_PATH" ]]; then
    skip "$TARGET already installed at $INSTALL_PATH"
else
    # Find the .tar.gz asset URL for this release
    log "Resolving download URL for $TARGET"
    ASSET_URL=$(
        curl -fsSL "$GITHUB_API/tags/$TARGET" \
        | grep '"browser_download_url"' \
        | grep '\.tar\.gz"' \
        | head -1 \
        | sed 's/.*"browser_download_url": *"\([^"]*\)".*/\1/'
    )
    [[ -n "$ASSET_URL" ]] || die "Could not find a .tar.gz asset for $TARGET. Check the version name."

    log "Downloading $TARGET"
    TMPFILE=$(mktemp --suffix=.tar.gz)
    trap 'rm -f "$TMPFILE"' EXIT

    curl -L --fail --progress-bar -o "$TMPFILE" "$ASSET_URL"

    log "Extracting to $PROTON_DIR"
    mkdir -p "$PROTON_DIR"
    tar -xzf "$TMPFILE" -C "$PROTON_DIR"
    ok "$TARGET installed to $INSTALL_PATH"
fi

# ---------- update launch script ----------
if [[ ! -f "$LAUNCH_SCRIPT" ]]; then
    warn "Launch script not found at $LAUNCH_SCRIPT — skipping update."
    warn "Run battlenet-umu-setup.sh first, or set BATTLENET_LAUNCH_SCRIPT."
else
    CURRENT=$(grep '^export PROTONPATH=' "$LAUNCH_SCRIPT" 2>/dev/null | head -1 | sed 's/.*="\?\([^"]*\)"\?.*/\1/' || echo "(not set)")
    if [[ "$CURRENT" == "$TARGET" ]]; then
        skip "Launch script already points to $TARGET"
    else
        log "Updating launch script: $CURRENT → $TARGET"
        sed -i \
            -e "s|^# Proton version:.*|# Proton version: $TARGET|" \
            -e "s|^export PROTONPATH=.*|export PROTONPATH=\"$TARGET\"|" \
            "$LAUNCH_SCRIPT"
        ok "Launch script updated"
    fi
fi

# ---------- done ----------
echo
ok "Done. Active Proton: $TARGET"
echo
echo "  Installed at: $INSTALL_PATH"
echo "  Launch script: $LAUNCH_SCRIPT"
echo
echo "Restart Battle.net to use the new Proton version."
echo "If anything regresses, re-run with --version=<older-tag> to roll back."