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

# ─────────────────────────────────────────────────────────────────────
# Mobile AI Assets Installer  v2.0.0
#
# One script to install skills, agents, and instructions.
# Agents and instructions are discovered automatically from directories.
# Skills are read from simple text files (one install entry per line).
#
# Local:   ./assets/setup.sh all ios
# Remote:  export ASSETS_BASE_URL="https://gitlab.com/<org>/repo/-/raw/develop/assets"
#          bash <(curl -fsSL "$ASSETS_BASE_URL/setup.sh") all ios
# ─────────────────────────────────────────────────────────────────────

VERSION="2.0.0"

# ── Configuration (override with env vars) ───────────────────────────
ASSETS_BASE_URL="${ASSETS_BASE_URL:-}"
AGENTS_DIR="${AGENTS_DIR:-$HOME/.copilot/agents}"
INSTRUCTIONS_DIR="${INSTRUCTIONS_DIR:-./instructions}"
REPO_TOKEN="${REPO_TOKEN:-}"

# ── Colors ───────────────────────────────────────────────────────────
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
BLUE='\033[0;34m'
BOLD='\033[1m'
NC='\033[0m'

# ── Helpers ──────────────────────────────────────────────────────────
info()    { printf "${BLUE}▸${NC} %s\n" "$*"; }
ok()      { printf "${GREEN}✓${NC} %s\n" "$*"; }
warn()    { printf "${YELLOW}!${NC} %s\n" "$*"; }
fail()    { printf "${RED}✗${NC} %s\n" "$*" >&2; exit 1; }
heading() { printf "\n${BOLD}── %s ──${NC}\n" "$*"; }

# ── Mode Detection ───────────────────────────────────────────────────
MODE=""
ASSETS_DIR=""

detect_mode() {
  local script_dir
  script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" 2>/dev/null && pwd)" || script_dir=""

  if [[ -n "$script_dir" && -d "$script_dir/agents" ]]; then
    MODE="local"
    ASSETS_DIR="$script_dir"
  elif [[ -n "$ASSETS_BASE_URL" ]]; then
    MODE="remote"
  else
    fail "Set ASSETS_BASE_URL to run without a clone.
  export ASSETS_BASE_URL=\"https://gitlab.com/org/repo/-/raw/develop/assets\"
  bash <(curl -fsSL \"\$ASSETS_BASE_URL/setup.sh\") agents"
  fi
}

# ── Remote File Discovery ───────────────────────────────────────────
# Build the hosting platform API URL from the raw-file base URL.
# Supports GitLab and GitHub URL formats.
derive_api_url() {
  local subdir="$1"

  # GitLab: https://gitlab.com/<project>/-/raw/<branch>/<path>
  if [[ "$ASSETS_BASE_URL" =~ ^(https?://[^/]+)/(.+)/-/raw/([^/]+)/(.+)$ ]]; then
    local host="${BASH_REMATCH[1]}"
    local project="${BASH_REMATCH[2]}"
    local branch="${BASH_REMATCH[3]}"
    local base_path="${BASH_REMATCH[4]}"
    local encoded
    encoded=$(python3 -c "import urllib.parse; print(urllib.parse.quote('$project', safe=''))" 2>/dev/null) || return 1
    echo "${host}/api/v4/projects/${encoded}/repository/tree?path=${base_path}/${subdir}&ref=${branch}&per_page=100"
    return 0
  fi

  # GitHub: https://raw.githubusercontent.com/<owner>/<repo>/<branch>/<path>
  if [[ "$ASSETS_BASE_URL" =~ ^https://raw\.githubusercontent\.com/([^/]+/[^/]+)/([^/]+)/(.+)$ ]]; then
    local owner_repo="${BASH_REMATCH[1]}"
    local branch="${BASH_REMATCH[2]}"
    local base_path="${BASH_REMATCH[3]}"
    echo "https://api.github.com/repos/${owner_repo}/contents/${base_path}/${subdir}?ref=${branch}"
    return 0
  fi

  return 1
}

# Query the hosting API to list files in a remote directory.
list_remote_files() {
  local subdir="$1" ext="$2"

  local api_url
  api_url=$(derive_api_url "$subdir") || fail "Cannot parse ASSETS_BASE_URL into an API URL.
  Supported formats:
    GitLab: https://gitlab.com/<project>/-/raw/<branch>/assets
    GitHub: https://raw.githubusercontent.com/<owner>/<repo>/<branch>/assets"

  local auth_header=""
  [[ -n "$REPO_TOKEN" ]] && auth_header="Authorization: Bearer $REPO_TOKEN"

  local response
  response=$(curl -fsSL ${auth_header:+-H "$auth_header"} "$api_url" 2>/dev/null) \
    || fail "API request failed. If the repo is private, set REPO_TOKEN.
  export REPO_TOKEN=\"glpat-...\"   # GitLab personal access token
  export REPO_TOKEN=\"ghp_...\"     # GitHub personal access token"

  # Extract filenames from JSON. Works for both GitLab and GitHub responses.
  local files
  files=$(echo "$response" \
    | grep -o '"name":"[^"]*"' \
    | sed 's/"name":"//;s/"//' \
    | grep "${ext}\$" || true)

  echo "$files"
}

# ── Fetch / Download ────────────────────────────────────────────────
fetch() {
  local path="$1"
  if [[ "$MODE" == "local" ]]; then
    cat "$ASSETS_DIR/$path"
  else
    curl -fsSL ${REPO_TOKEN:+-H "Authorization: Bearer $REPO_TOKEN"} "$ASSETS_BASE_URL/$path"
  fi
}

download_to() {
  local src="$1" dest="$2"
  mkdir -p "$(dirname "$dest")"
  if [[ "$MODE" == "local" ]]; then
    cp "$ASSETS_DIR/$src" "$dest"
  else
    curl -fsSL ${REPO_TOKEN:+-H "Authorization: Bearer $REPO_TOKEN"} "$ASSETS_BASE_URL/$src" -o "$dest"
  fi
}

# ── Commands ─────────────────────────────────────────────────────────

# -- skills [platform] ────────────────────────────────────────────────
# Reads a plain-text skills file. Each non-empty, non-comment line is
# passed to `npx skills add`.
cmd_skills() {
  local platform="${1:-shared}"
  local manifest="${platform}-skills.txt"

  heading "Skills ($platform)"

  local content
  content="$(fetch "$manifest")" || fail "Could not fetch $manifest"

  local count=0
  while IFS= read -r line; do
    [[ -z "$line" || "$line" == \#* ]] && continue
    info "npx skills add $line"
    read -r -a args <<< "$line"
    npx skills add "${args[@]}"
    count=$((count + 1))
  done <<< "$content"

  if [[ $count -eq 0 ]]; then
    warn "No entries in $manifest — nothing to install."
  else
    ok "$count skill(s) installed. Restart your editor if they don't appear."
  fi
}

# -- agents ───────────────────────────────────────────────────────────
# Discovers .agent.md files automatically (local: find, remote: API).
cmd_agents() {
  heading "Agents → $AGENTS_DIR"
  mkdir -p "$AGENTS_DIR"

  local files count=0

  if [[ "$MODE" == "local" ]]; then
    files=$(find "$ASSETS_DIR/agents" -maxdepth 1 -type f -name '*.agent.md' -exec basename {} \; | sort)
  else
    files=$(list_remote_files "agents" ".agent.md")
  fi

  if [[ -z "$files" ]]; then
    warn "No agent files found."
    return 0
  fi

  while IFS= read -r file; do
    [[ -z "$file" ]] && continue
    info "$file"
    download_to "agents/$file" "$AGENTS_DIR/$file"
    count=$((count + 1))
  done <<< "$files"

  ok "$count agent(s) installed."
}

# -- instructions ─────────────────────────────────────────────────────
# Discovers .instructions.md files automatically.
cmd_instructions() {
  heading "Instructions → $INSTRUCTIONS_DIR"
  mkdir -p "$INSTRUCTIONS_DIR"

  local files count=0

  if [[ "$MODE" == "local" ]]; then
    files=$(find "$ASSETS_DIR/instructions" -maxdepth 1 -type f -name '*.instructions.md' -exec basename {} \; | sort)
  else
    files=$(list_remote_files "instructions" ".instructions.md")
  fi

  if [[ -z "$files" ]]; then
    warn "No instruction files found."
    return 0
  fi

  while IFS= read -r file; do
    [[ -z "$file" ]] && continue
    info "$file"
    download_to "instructions/$file" "$INSTRUCTIONS_DIR/$file"
    count=$((count + 1))
  done <<< "$files"

  ok "$count instruction(s) installed."
}

# -- all [platform] ───────────────────────────────────────────────────
cmd_all() {
  local platform="${1:-shared}"
  cmd_skills "$platform"
  cmd_agents
  cmd_instructions
  printf "\n"
  ok "All done."
}

# -- help ─────────────────────────────────────────────────────────────
cmd_help() {
  cat <<EOF

${BOLD}Mobile AI Assets Installer${NC} v${VERSION}

${BOLD}USAGE${NC}
  setup.sh <command> [platform]

${BOLD}COMMANDS${NC}
  skills [platform]   Install skills from a curated list
  agents              Install all agent prompt files (auto-discovered)
  instructions        Install all instruction files  (auto-discovered)
  all [platform]      Install everything at once
  help                Show this message

${BOLD}PLATFORMS${NC} (for skills)
  ios        iOS-specific skills
  android    Android-specific skills
  shared     Cross-platform skills (default)

${BOLD}EXAMPLES${NC}
  ${GREEN}# Cloned repo${NC}
  ./assets/setup.sh skills ios
  ./assets/setup.sh agents
  ./assets/setup.sh all ios

  ${GREEN}# No clone — run directly from the remote repo${NC}
  export ASSETS_BASE_URL="https://gitlab.com/org/repo/-/raw/develop/assets"
  bash <(curl -fsSL "\$ASSETS_BASE_URL/setup.sh") skills ios
  bash <(curl -fsSL "\$ASSETS_BASE_URL/setup.sh") agents
  bash <(curl -fsSL "\$ASSETS_BASE_URL/setup.sh") all ios

${BOLD}ENVIRONMENT VARIABLES${NC}
  ASSETS_BASE_URL      Base URL for remote downloads (required without clone)
  AGENTS_DIR           Install location for agents       (default: ~/.copilot/agents)
  INSTRUCTIONS_DIR     Install location for instructions (default: ./instructions)
  REPO_TOKEN           Auth token for private repos      (optional)

EOF
}

# ── Main ─────────────────────────────────────────────────────────────
detect_mode

case "${1:-help}" in
  skills)        cmd_skills "${2:-shared}" ;;
  agents)        cmd_agents ;;
  instructions)  cmd_instructions ;;
  all)           cmd_all "${2:-shared}" ;;
  help|--help|-h) cmd_help ;;
  *)             fail "Unknown command: $1. Run 'setup.sh help' for usage." ;;
esac