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

# ─── Mosaic Framework Installer ──────────────────────────────────────────────
#
# Installs/upgrades the framework DATA to ~/.config/mosaic/.
# No executables are placed on PATH — the mosaic npm CLI is the only binary.
#
# Called by tools/install.sh (the unified installer). Can also be run directly.
#
# Environment:
#   MOSAIC_HOME              — target directory (default: ~/.config/mosaic)
#   MOSAIC_INSTALL_MODE      — prompt|keep|overwrite (default: prompt)
#   MOSAIC_ALLOW_MISSING_SEQUENTIAL_THINKING — 1 to bypass MCP check
#   MOSAIC_SKIP_SKILLS_SYNC  — 1 to skip skill sync
# ──────────────────────────────────────────────────────────────────────────────

SOURCE_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
TARGET_DIR="${MOSAIC_HOME:-$HOME/.config/mosaic}"
INSTALL_MODE="${MOSAIC_INSTALL_MODE:-prompt}"

# Files preserved across upgrades (never overwritten)
PRESERVE_PATHS=("SOUL.md" "USER.md" "TOOLS.md" "memory" "sources")

# Current framework schema version — bump this when the layout changes.
# The migration system uses this to run upgrade steps.
FRAMEWORK_VERSION=2

# ─── colours ──────────────────────────────────────────────────────────────────
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}"; }

# ─── helpers ──────────────────────────────────────────────────────────────────

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

installed_framework_version() {
  local vf="$TARGET_DIR/.framework-version"
  if [[ -f "$vf" ]]; then
    cat "$vf" 2>/dev/null || echo "0"
  else
    # No version file = legacy install (version 0 or 1)
    if [[ -d "$TARGET_DIR/bin" ]]; then
      echo "1"   # Has bin/ → pre-migration legacy
    else
      echo "0"   # Fresh or unknown
    fi
  fi
}

write_framework_version() {
  echo "$FRAMEWORK_VERSION" > "$TARGET_DIR/.framework-version"
}

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: $TARGET_DIR"
        echo "  1) keep      Update framework, preserve local files (SOUL.md, USER.md, etc.)"
        echo "  2) overwrite Replace everything"
        echo "  3) cancel    Abort"
        printf "Selection [1/2/3] (default: 1): "
        read -r selection
        case "${selection:-1}" in
          1|k|K|keep) INSTALL_MODE="keep" ;;
          2|o|O|overwrite) INSTALL_MODE="overwrite" ;;
          *) fail "Install cancelled."; exit 1 ;;
        esac
      else
        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" --exclude ".framework-version")

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

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

  # Fallback: cp-based sync
  local preserve_tmp=""
  if [[ "$INSTALL_MODE" == "keep" ]]; then
    preserve_tmp="$(mktemp -d "${TMPDIR:-/tmp}/mosaic-preserve-XXXXXX")"
    for path in "${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 "$TARGET_DIR" -mindepth 1 -maxdepth 1 ! -name ".git" ! -name ".framework-version" -exec rm -rf {} +
  cp -R "$SOURCE_DIR"/. "$TARGET_DIR"/
  rm -rf "$TARGET_DIR/.git"

  if [[ -n "$preserve_tmp" ]]; then
    for path in "${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
}

# ═══════════════════════════════════════════════════════════════════════════════
# Migrations — run sequentially from the installed version to FRAMEWORK_VERSION
# ═══════════════════════════════════════════════════════════════════════════════

run_migrations() {
  local from_version
  from_version="$(installed_framework_version)"

  if [[ "$from_version" -ge "$FRAMEWORK_VERSION" ]]; then
    return  # Already current
  fi

  step "Running migrations (v${from_version} → v${FRAMEWORK_VERSION})"

  # ── Migration: v0/v1 → v2 ─────────────────────────────────────────────────
  # Remove bin/ directory — all executables now live in the npm CLI.
  # Scripts that were in bin/ are now in tools/_scripts/.
  if [[ "$from_version" -lt 2 ]]; then
    if [[ -d "$TARGET_DIR/bin" ]]; then
      ok "Removing legacy bin/ directory (executables now in npm CLI)"
      rm -rf "$TARGET_DIR/bin"
    fi

    # Remove old mosaic PATH entry from shell profiles
    for profile in "$HOME/.bashrc" "$HOME/.zshrc" "$HOME/.profile"; do
      if [[ -f "$profile" ]] && grep -qF "$TARGET_DIR/bin" "$profile"; then
        # Remove the PATH line and the comment above it
        sed -i.mosaic-migration-bak \
          -e "\|# Mosaic agent framework|d" \
          -e "\|$TARGET_DIR/bin|d" \
          "$profile"
        ok "Cleaned up old PATH entry from $(basename "$profile")"
        rm -f "${profile}.mosaic-migration-bak"
      fi
    done

    # Remove stale rails/ symlink
    if [[ -L "$TARGET_DIR/rails" ]]; then
      rm -f "$TARGET_DIR/rails"
    fi
  fi

  # ── Future migrations go here ──────────────────────────────────────────────
  # if [[ "$from_version" -lt 3 ]]; then
  #   ...
  # fi
}

# ═══════════════════════════════════════════════════════════════════════════════
# Main
# ═══════════════════════════════════════════════════════════════════════════════

step "Installing Mosaic framework"

mkdir -p "$TARGET_DIR"
select_install_mode

if [[ "$INSTALL_MODE" == "keep" ]]; then
  ok "Install mode: keep local files (SOUL.md, USER.md, TOOLS.md, memory/)"
else
  ok "Install mode: overwrite"
fi

sync_framework

# Ensure memory directory exists
mkdir -p "$TARGET_DIR/memory"

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

ok "Framework synced to $TARGET_DIR"

# Run migrations before post-install (migrations may remove old bin/ etc.)
run_migrations

step "Post-install tasks"

SCRIPTS="$TARGET_DIR/tools/_scripts"

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

if [[ -x "$SCRIPTS/mosaic-ensure-sequential-thinking" ]]; then
  if "$SCRIPTS/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 bypassed (MOSAIC_ALLOW_MISSING_SEQUENTIAL_THINKING=1)"
    else
      fail "sequential-thinking MCP setup failed (hard requirement)."
      exit 1
    fi
  fi
fi

if [[ -x "$SCRIPTS/mosaic-ensure-excalidraw" ]]; then
  "$SCRIPTS/mosaic-ensure-excalidraw" >/dev/null 2>&1 && ok "excalidraw MCP configured" || warn "excalidraw MCP setup failed (non-fatal)"
fi

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

if [[ -x "$SCRIPTS/mosaic-migrate-local-skills" ]]; then
  "$SCRIPTS/mosaic-migrate-local-skills" --apply >/dev/null 2>&1 && ok "Local skills migrated" || warn "Local skill migration failed (non-fatal)"
fi

if [[ -x "$SCRIPTS/mosaic-doctor" ]]; then
  "$SCRIPTS/mosaic-doctor" >/dev/null 2>&1 && ok "Health audit passed" || warn "Health audit reported issues — run 'mosaic doctor' for details"
fi

# Write version stamp AFTER everything succeeds
write_framework_version

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

if [[ ! -f "$TARGET_DIR/SOUL.md" ]]; then
  echo -e "  Run ${CYAN}mosaic init${RESET} to set up your agent identity."
  echo ""
fi