#!/usr/bin/env bash
# migrate.sh — bring an existing ECHO vault up to the plugin's current schema.
#
# Reads the marker's schema_version and applies each intervening migration in order.
# Migrations are idempotent and additive; every destructive step (DELETE) is gated
# behind --apply AND prints what it will do first. Default mode is a DRY-RUN plan.
#
# Usage:
#   migrate.sh            # print the migration plan (no changes)
#   migrate.sh --apply    # perform the migration (moves/deletes included)
#
# Env: ECHO_BASE, ECHO_KEY (via echo.sh).

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
ECHO="$SCRIPT_DIR/echo.sh"
CURRENT_SCHEMA=2
APPLY=0
[ "${1:-}" = "--apply" ] && APPLY=1

[ -x "$ECHO" ] || chmod +x "$ECHO" 2>/dev/null || true
say() { echo "migrate: $*"; }
do_or_show() {  # do_or_show "<human description>" cmd args...
  local desc="$1"; shift
  if [ "$APPLY" = "1" ]; then say "APPLY  $desc"; "$@"; else say "PLAN   $desc"; fi
}

# ---- Read current schema -----------------------------------------------------
if ! marker="$("$ECHO" get _agent/echo-vault.md 2>/dev/null)"; then
  say "marker missing — vault not bootstrapped. Run bootstrap.sh, not migrate.sh."
  exit 3
fi
FROM="$(printf '%s' "$marker" | sed -n 's/^schema_version:[[:space:]]*//p' | head -1)"
FROM="${FROM:-0}"
say "vault schema_version=$FROM, plugin schema=$CURRENT_SCHEMA $([ "$APPLY" = 1 ] && echo '(APPLY)' || echo '(dry-run)')"

if [ "$FROM" -ge "$CURRENT_SCHEMA" ] 2>/dev/null; then
  say "up to date — nothing to do."
  exit 0
fi

ls_files() { "$ECHO" ls "$1" 2>/dev/null | python3 -c 'import sys,json;print("\n".join(json.load(sys.stdin).get("files",[])))' 2>/dev/null || true; }
move() {  # move SRC DST preserving content (PUT dst <- get src, then delete src)
  local src="$1" dst="$2"
  "$ECHO" get "$src" 2>/dev/null | "$ECHO" put "$dst" - >/dev/null
  "$ECHO" delete "$src" >/dev/null
}

# ---- 0 -> 1 : control docs moved into the plugin -----------------------------
mig_0_1() {
  say "[0->1] retire in-vault control docs (CLAUDE/BOOTSTRAP/STRUCTURE/index.md)"
  for f in CLAUDE.md BOOTSTRAP.md STRUCTURE.md index.md; do
    if ECHO_VERIFY=0 "$ECHO" get "$f" >/dev/null 2>&1; then
      do_or_show "delete vault/$f (back it up outside the vault first)" "$ECHO" delete "$f"
    fi
  done
  say "[0->1] reminder: scrub dangling [[CLAUDE]]/[[BOOTSTRAP]]/[[STRUCTURE]]/[[index]] links from ## Related sections (manual/agent step)."
}

# ---- 1 -> 2 : reviews/ folded into journal/ + _agent/health/ -----------------
mig_1_2() {
  say "[1->2] fold reviews/ into journal/ and _agent/health/"
  for f in $(ls_files reviews/weekly); do
    [ "${f%.md}" != "$f" ] || continue
    dst="journal/weekly/$(printf '%s' "$f" | sed 's/-review\.md$/.md/')"
    do_or_show "move reviews/weekly/$f -> $dst" move "reviews/weekly/$f" "$dst"
  done
  for f in $(ls_files reviews/monthly); do
    [ "${f%.md}" != "$f" ] || continue
    case "$f" in
      *vault-health.md) dst="_agent/health/$f" ;;
      *)                dst="journal/monthly/$f" ;;
    esac
    do_or_show "move reviews/monthly/$f -> $dst" move "reviews/monthly/$f" "$dst"
  done
  for period in quarterly annual; do
    for f in $(ls_files "reviews/$period"); do
      [ "${f%.md}" != "$f" ] || continue
      do_or_show "move reviews/$period/$f -> journal/$period/$f" move "reviews/$period/$f" "journal/$period/$f"
    done
  done
  say "[1->2] reminder: update inbound [[reviews/...]] wikilinks in ## Related sections (manual/agent step)."
}

[ "$FROM" -lt 1 ] && mig_0_1
[ "$FROM" -lt 2 ] && mig_1_2

# ---- Stamp the marker --------------------------------------------------------
do_or_show "set _agent/echo-vault.md schema_version -> $CURRENT_SCHEMA" \
  "$ECHO" fm _agent/echo-vault.md schema_version "$CURRENT_SCHEMA"

if [ "$APPLY" = "1" ]; then
  say "migration complete -> schema $CURRENT_SCHEMA. Run vault-lint.sh to confirm invariants."
else
  say "dry-run only. Re-run with --apply to perform the moves/deletes above."
fi