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

SOURCE_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
TARGET_DIR="${MOSAIC_HOME:-$HOME/.config/mosaic}"
INSTALL_MODE="${MOSAIC_INSTALL_MODE:-prompt}" # prompt|keep|overwrite
PRESERVE_PATHS=("SOUL.md" "USER.md" "TOOLS.md" "memory")

# Colors (disabled if not a terminal)
if [[ -t 1 ]]; then
  GREEN='\033[0;32m' YELLOW='\033[0;33m' RED='\033[0;31m'
  CYAN='\033[0;36m' BOLD='\033[1m' RESET='\033[0m'
else
  GREEN='' YELLOW='' RED='' CYAN='' BOLD='' RESET=''
fi

ok()   { echo -e "  ${GREEN}✓${RESET} $1"; }
warn() { echo -e "  ${YELLOW}⚠${RESET} $1" >&2; }
fail() { echo -e "  ${RED}✗${RESET} $1" >&2; }
step() { echo -e "\n${BOLD}$1${RESET}"; }

is_existing_install() {
  [[ -d "$TARGET_DIR" ]] || return 1
  [[ -f "$TARGET_DIR/bin/mosaic" || -f "$TARGET_DIR/AGENTS.md" || -f "$TARGET_DIR/SOUL.md" ]]
}

select_install_mode() {
  case "$INSTALL_MODE" in
    keep|overwrite|prompt) ;;
    *)
      fail "Invalid MOSAIC_INSTALL_MODE='$INSTALL_MODE'. Use: prompt, keep, overwrite."
      exit 1
      ;;
  esac

  if ! is_existing_install; then
    INSTALL_MODE="overwrite"
    return
  fi

  case "$INSTALL_MODE" in
    keep|overwrite)
      ;;
    prompt)
      if [[ -t 0 ]]; then
        echo ""
        echo "Existing Mosaic install detected at: $TARGET_DIR"
        echo "Choose reinstall mode:"
        echo "  1) keep      Keep local files (SOUL.md, USER.md, TOOLS.md, memory/) while updating framework"
        echo "  2) overwrite Replace everything in $TARGET_DIR"
        echo "  3) cancel    Abort install"
        printf "Selection [1/2/3] (default: 1): "
        read -r selection

        case "${selection:-1}" in
          1|k|K|keep|KEEP) INSTALL_MODE="keep" ;;
          2|o|O|overwrite|OVERWRITE) INSTALL_MODE="overwrite" ;;
          3|c|C|cancel|CANCEL|n|N|no|NO)
            fail "Install cancelled."
            exit 1
            ;;
          *)
            warn "Unrecognized selection '$selection'; defaulting to keep."
            INSTALL_MODE="keep"
            ;;
        esac
      else
        warn "Existing install detected without interactive input; defaulting to keep local files."
        INSTALL_MODE="keep"
      fi
      ;;
  esac
}

sync_framework() {
  local source_real target_real
  source_real="$(cd "$SOURCE_DIR" && pwd -P)"
  target_real="$(mkdir -p "$TARGET_DIR" && cd "$TARGET_DIR" && pwd -P)"

  if [[ "$source_real" == "$target_real" ]]; then
    warn "Source and target are the same directory; skipping file sync."
    return
  fi

  if command -v rsync >/dev/null 2>&1; then
    local rsync_args=(-a --delete --exclude ".git")

    if [[ "$INSTALL_MODE" == "keep" ]]; then
      local path
      for path in "${PRESERVE_PATHS[@]}"; do
        rsync_args+=(--exclude "$path")
      done
    fi

    rsync "${rsync_args[@]}" "$SOURCE_DIR/" "$TARGET_DIR/"
    return
  fi

  local preserve_tmp=""
  if [[ "$INSTALL_MODE" == "keep" ]]; then
    preserve_tmp="$(mktemp -d "${TMPDIR:-/tmp}/mosaic-preserve-XXXXXX")"
    local path
    for path in "${PRESERVE_PATHS[@]}"; do
      if [[ -e "$TARGET_DIR/$path" ]]; then
        mkdir -p "$preserve_tmp/$(dirname "$path")"
        cp -R "$TARGET_DIR/$path" "$preserve_tmp/$path"
      fi
    done
  fi

  find "$TARGET_DIR" -mindepth 1 -maxdepth 1 ! -name ".git" -exec rm -rf {} +
  cp -R "$SOURCE_DIR"/. "$TARGET_DIR"/
  rm -rf "$TARGET_DIR/.git"

  if [[ -n "$preserve_tmp" ]]; then
    local path
    for path in "${PRESERVE_PATHS[@]}"; do
      if [[ -e "$preserve_tmp/$path" ]]; then
        rm -rf "$TARGET_DIR/$path"
        mkdir -p "$TARGET_DIR/$(dirname "$path")"
        cp -R "$preserve_tmp/$path" "$TARGET_DIR/$path"
      fi
    done
    rm -rf "$preserve_tmp"
  fi
}

step "Installing Mosaic framework"

mkdir -p "$TARGET_DIR"
select_install_mode

if [[ "$INSTALL_MODE" == "keep" ]]; then
  ok "Install mode: keep local SOUL.md/USER.md/TOOLS.md/memory while updating framework"
else
  ok "Install mode: overwrite existing files"
fi

sync_framework

# Ensure memory directory exists (preserved across upgrades, may not exist on fresh install)
mkdir -p "$TARGET_DIR/memory"

chmod +x "$TARGET_DIR"/bin/*
chmod +x "$TARGET_DIR"/install.sh

# Ensure tool scripts are executable
find "$TARGET_DIR/tools" -name "*.sh" -exec chmod +x {} + 2>/dev/null || true

# Create backward-compat symlink: rails/ → tools/
if [[ -d "$TARGET_DIR/tools" ]]; then
  if [[ -d "$TARGET_DIR/rails" ]] && [[ ! -L "$TARGET_DIR/rails" ]]; then
    rm -rf "$TARGET_DIR/rails"
  fi
  ln -sfn "tools" "$TARGET_DIR/rails"
fi

ok "Framework installed to $TARGET_DIR"

step "Post-install tasks"

if "$TARGET_DIR/bin/mosaic-link-runtime-assets" >/dev/null 2>&1; then
  ok "Runtime assets linked"
else
  warn "Runtime asset linking failed (non-fatal)"
fi

if "$TARGET_DIR/bin/mosaic-ensure-sequential-thinking" >/dev/null 2>&1; then
  ok "sequential-thinking MCP configured"
else
  if [[ "${MOSAIC_ALLOW_MISSING_SEQUENTIAL_THINKING:-0}" == "1" ]]; then
    warn "sequential-thinking MCP setup failed but bypassed (MOSAIC_ALLOW_MISSING_SEQUENTIAL_THINKING=1)"
  else
    fail "sequential-thinking MCP setup failed (hard requirement)."
    fail "Set MOSAIC_ALLOW_MISSING_SEQUENTIAL_THINKING=1 only for temporary bypass scenarios."
    exit 1
  fi
fi

if [[ "${MOSAIC_SKIP_SKILLS_SYNC:-0}" == "1" ]]; then
  ok "Skills sync skipped (MOSAIC_SKIP_SKILLS_SYNC=1)"
else
  if "$TARGET_DIR/bin/mosaic-sync-skills" >/dev/null 2>&1; then
    ok "Skills synced"
  else
    warn "Skills sync failed (non-fatal)"
  fi
fi

if "$TARGET_DIR/bin/mosaic-migrate-local-skills" --apply >/dev/null 2>&1; then
  ok "Local skills migrated"
else
  warn "Local skill migration failed (non-fatal)"
fi

if "$TARGET_DIR/bin/mosaic-doctor" >/dev/null 2>&1; then
  ok "Health audit passed"
else
  warn "Health audit reported issues — run 'mosaic doctor' for details"
fi

step "PATH configuration"

PATH_LINE="export PATH=\"$TARGET_DIR/bin:\$PATH\""

# Find the right shell profile
if [[ -n "${ZSH_VERSION:-}" ]] || [[ "$(basename "${SHELL:-}")" == "zsh" ]]; then
  SHELL_PROFILE="$HOME/.zshrc"
elif [[ -f "$HOME/.bashrc" ]]; then
  SHELL_PROFILE="$HOME/.bashrc"
elif [[ -f "$HOME/.profile" ]]; then
  SHELL_PROFILE="$HOME/.profile"
else
  SHELL_PROFILE="$HOME/.profile"
fi

PATH_CHANGED=false
if grep -qF "$TARGET_DIR/bin" "$SHELL_PROFILE" 2>/dev/null; then
  ok "Already in PATH via $SHELL_PROFILE"
else
  {
    echo ""
    echo "# Mosaic agent framework"
    echo "$PATH_LINE"
  } >> "$SHELL_PROFILE"
  ok "Added to PATH in $SHELL_PROFILE"
  PATH_CHANGED=true
fi

# ── Summary ──────────────────────────────────────────────────
echo ""
echo -e "${GREEN}${BOLD}  Mosaic installed successfully.${RESET}"
echo ""

# Collect next steps
NEXT_STEPS=()

if [[ "$PATH_CHANGED" == "true" ]]; then
  NEXT_STEPS+=("Run ${CYAN}source $SHELL_PROFILE${RESET} or log out and back in to activate PATH.")
fi

if [[ ! -f "$TARGET_DIR/SOUL.md" ]]; then
  NEXT_STEPS+=("Run ${CYAN}mosaic init${RESET} to set up your agent identity (SOUL.md), user profile (USER.md), and tool config (TOOLS.md).")
elif grep -q "not configured" "$TARGET_DIR/USER.md" 2>/dev/null; then
  NEXT_STEPS+=("Run ${CYAN}mosaic init${RESET} to personalize your user profile (USER.md) and tool config (TOOLS.md).")
fi

if [[ ${#NEXT_STEPS[@]} -gt 0 ]]; then
  echo -e "  ${BOLD}Next steps:${RESET}"
  for i in "${!NEXT_STEPS[@]}"; do
    echo -e "  $((i+1)). ${NEXT_STEPS[$i]}"
  done
  echo ""
fi