#!/usr/bin/env bash
#
# run.sh — E2E test suite for musicfs.
#
# Full distributed path: server in Incus VM serving a generated music library
# over gRPC, local client mounting it as FUSE, tests run against the mountpoint.
#
# Requires: devenv shell (for ffmpeg, metaflac, id3v2, incus, grpcurl, Postgres)
#
# Usage:
#   scripts/e2e/run.sh          full suite (creates VM, runs tests, destroys)
#   KEEP=1 scripts/e2e/run.sh   keep VM + DB alive after run for debugging
#
set -euo pipefail

# ─────────────────────────── config ────────────────────────────────────
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
SCRIPTS_DIR="$(cd "$SCRIPT_DIR/.." && pwd)"
PROJECT_DIR="$(cd "$SCRIPT_DIR/../.." && pwd)"

MNT="$PROJECT_DIR/target/e2e/mnt"
MUSIC_DIR="$PROJECT_DIR/target/e2e/music"
LOG_DIR="$PROJECT_DIR/logs/e2e"
DB_NAME="musicfs_e2e"
VM_NAME="musicfs-e2e"
PORT=50061
KEEP="${KEEP:-0}"
RUST_LOG_VAL="${RUST_LOG:-musicfs=debug}"

CLIENT_PID=""
STARTED_PG=""
. "$SCRIPT_DIR/lib.sh"

log()  { printf '\033[1;34m[e2e]\033[0m %s\n' "$*" >&2; }
die()  { printf '\033[1;31m[e2e error]\033[0m %s\n' "$*" >&2; exit 1; }

# ──────────────────────── postgres ─────────────────────────────────────
ensure_postgres() {
  if pg_isready -h "$PGHOST" >/dev/null 2>&1; then return 0; fi
  log "Postgres not running — starting via devenv…"
  devenv up postgres &
  STARTED_PG=$!
  local i
  for ((i = 0; i < 45; i++)); do
    if pg_isready -h "$PGHOST" >/dev/null 2>&1; then
      log "Postgres ready"
      return 0
    fi
    sleep 1
  done
  die "Postgres did not become ready in 45s"
}

stop_postgres() {
  [[ -n "$STARTED_PG" ]] || return 0
  log "stopping Postgres (started by this script)…"
  kill "$STARTED_PG" 2>/dev/null || true
  wait "$STARTED_PG" 2>/dev/null || true
  STARTED_PG=""
}

# ──────────────────────── VM management ────────────────────────────────
vm_ip() { incus list "$VM_NAME" -f csv -c 4 2>/dev/null | head -1 | awk '{print $1}'; }

start_vm() {
  log "starting VM '$VM_NAME' (port $PORT)…"
  VM_NAME="$VM_NAME" \
  MUSIC_SOURCE="$MUSIC_DIR" \
  LISTEN_PORT="$PORT" \
  RUST_LOG=debug \
  bash "$SCRIPTS_DIR/vm.sh" up

  local ip; ip="$(vm_ip)"
  [[ -n "$ip" ]] || die "could not determine VM IP"
  log "VM IP: $ip"

  log "waiting for health check…"
  local i
  for ((i = 0; i < 45; i++)); do
    if grpcurl -plaintext "$ip:$PORT" grpc.health.v1.Health/Check 2>/dev/null | grep -q SERVING; then
      log "server healthy"
      VM_IP="$ip"
      return
    fi
    sleep 1
  done
  die "server health check timed out"
}

destroy_vm() {
  VM_NAME="$VM_NAME" bash "$SCRIPTS_DIR/vm.sh" destroy 2>/dev/null || true
}

# ──────────────────────── DB management ────────────────────────────────
reset_db() {
  log "resetting database '$DB_NAME'…"
  dropdb --if-exists "$DB_NAME" 2>/dev/null || true
  createdb "$DB_NAME"
  psql -q -d "$DB_NAME" -f "$PROJECT_DIR/db/schema.sql"
}

drop_db() {
  dropdb --if-exists "$DB_NAME" 2>/dev/null || true
}

# ────────────────────── client lifecycle ───────────────────────────────
build_client() {
  log "building client…"
  (cd "$PROJECT_DIR" && cargo build --bin musicfs)
}

start_client() {
  mkdir -p "$MNT" "$LOG_DIR"
  local dsn="postgresql://fujin@localhost/$DB_NAME?host=$PGHOST"

  log "starting client (mountpoint $MNT)…"
  RUST_LOG="$RUST_LOG_VAL" \
  "$PROJECT_DIR/target/debug/musicfs" \
    --source "http://$VM_IP:$PORT" \
    --mountpoint "$MNT" \
    --database "$dsn" \
    --log-dir "$LOG_DIR" &
  CLIENT_PID=$!
  wait_for_mount
}

wait_for_mount() {
  log "waiting for FUSE mount…"
  local i
  for ((i = 0; i < 60; i++)); do
    if [[ -d "$MNT/E2E Artist A" ]]; then
      log "mount ready"
      return
    fi
    if ! kill -0 "$CLIENT_PID" 2>/dev/null; then
      die "client process exited prematurely — check $LOG_DIR"
    fi
    sleep 1
  done
  die "FUSE mount not ready after 60s"
}

stop_client() {
  [[ -n "$CLIENT_PID" ]] || return 0
  kill "$CLIENT_PID" 2>/dev/null || true
  local i
  for ((i = 0; i < 10; i++)); do
    kill -0 "$CLIENT_PID" 2>/dev/null || break
    sleep 1
  done
  kill -9 "$CLIENT_PID" 2>/dev/null || true
  wait "$CLIENT_PID" 2>/dev/null || true
  CLIENT_PID=""
  fusermount -u "$MNT" 2>/dev/null || true
  sleep 1
}

# ─────────────────────────── cleanup ───────────────────────────────────
cleanup() {
  local rv=$?
  log "cleaning up…"
  stop_client || true
  if [[ "$KEEP" != "1" ]]; then
    drop_db
    destroy_vm
    stop_postgres || true
    rm -rf "$MNT"
  else
    log "KEEP=1 — VM, DB, and mount left intact for debugging"
    log "  mountpoint: $MNT"
    log "  VM IP:      ${VM_IP:-<unknown>}"
    log "  logs:       $LOG_DIR"
  fi
  exit $rv
}
trap cleanup EXIT

# ─────────────────────────── paths ─────────────────────────────────────
ALPHA="$MNT/E2E Artist A/E2E Album X/01 - Alpha.flac"
BETA="$MNT/E2E Artist A/E2E Album X/02 - Beta.flac"
GAMMA="$MNT/E2E Artist B/E2E Album Y/01 - Gamma.mp3"
DELTA="$MNT/E2E Artist B/E2E Album Y/02 - Delta.mp3"

# ════════════════════════════════════════════════════════════════════════
# TESTS
# ════════════════════════════════════════════════════════════════════════

test_structural() {
  printf '\n\033[1;36m── structural ──\033[0m\n'

  local root; root="$(ls "$MNT" 2>/dev/null || true)"
  assert_contains "root has Artist A dir" "$root" "E2E Artist A"
  assert_contains "root has Artist B dir" "$root" "E2E Artist B"

  local album_a; album_a="$(ls "$MNT/E2E Artist A/E2E Album X" 2>/dev/null || true)"
  assert_contains "Album X has Alpha.flac" "$album_a" "01 - Alpha.flac"
  assert_contains "Album X has Beta.flac"  "$album_a" "02 - Beta.flac"

  local album_b; album_b="$(ls "$MNT/E2E Artist B/E2E Album Y" 2>/dev/null || true)"
  assert_contains "Album Y has Gamma.mp3" "$album_b" "01 - Gamma.mp3"
  assert_contains "Album Y has Delta.mp3" "$album_b" "02 - Delta.mp3"

  local ftype; ftype="$(stat -c %F "$ALPHA" 2>/dev/null || echo "missing")"
  assert_eq "Alpha is regular file" "regular file" "$ftype"

  local fsize; fsize="$(stat -c %s "$ALPHA" 2>/dev/null || echo 0)"
  assert_gt "Alpha virtual size > 0" "$fsize" 0

  local dtype; dtype="$(stat -c %F "$MNT/E2E Artist A" 2>/dev/null || echo "missing")"
  assert_eq "Artist A is directory" "directory" "$dtype"
}

test_cache() {
  printf '\n\033[1;36m── cache behavior ──\033[0m\n'

  ffprobe -hide_banner -v quiet -show_format "$BETA" >/dev/null 2>&1 || true
  ffprobe -hide_banner -v quiet -show_format "$BETA" >/dev/null 2>&1 || true

  sleep 1
  local log_file=""
  log_file="$(ls -t "$LOG_DIR"/musicfs.*.log 2>/dev/null | head -1)" || true
  local logs=""
  if [[ -n "$log_file" ]]; then
    logs="$(cat "$log_file" 2>/dev/null || true)"
  fi

  assert_contains "cache miss on first read" "$logs" "cache miss"
  assert_contains "cache hit on second read"  "$logs" "cache hit"
}

test_flac_read() {
  printf '\n\033[1;36m── FLAC read ──\033[0m\n'

  local title;  title="$(metaflac --show-tag=TITLE  "$ALPHA" 2>/dev/null || true)"
  local artist; artist="$(metaflac --show-tag=ARTIST "$ALPHA" 2>/dev/null || true)"
  local album;  album="$(metaflac --show-tag=ALBUM  "$ALPHA" 2>/dev/null || true)"

  assert_contains "FLAC TITLE tag"  "$title"  "TITLE=Alpha"
  assert_contains "FLAC ARTIST tag" "$artist" "ARTIST=E2E Artist A"
  assert_contains "FLAC ALBUM tag"  "$album"  "ALBUM=E2E Album X"

  local pics; pics="$(metaflac --list --block-type=PICTURE "$ALPHA" 2>/dev/null || true)"
  assert_contains "FLAC has cover art" "$pics" "PICTURE"
}

test_flac_write() {
  printf '\n\033[1;36m── FLAC write ──\033[0m\n'

  metaflac --remove-tag=ARTIST --set-tag="ARTIST=Modified FLAC" "$BETA" 2>/dev/null

  local artist; artist="$(metaflac --show-tag=ARTIST "$BETA" 2>/dev/null || true)"
  assert_contains "FLAC write — ARTIST updated" "$artist" "ARTIST=Modified FLAC"

  local title; title="$(metaflac --show-tag=TITLE "$BETA" 2>/dev/null || true)"
  assert_contains "FLAC write — TITLE preserved" "$title" "TITLE=Beta"
}

test_mp3_read() {
  printf '\n\033[1;36m── MP3 read ──\033[0m\n'

  local info; info="$(id3v2 --list "$GAMMA" 2>/dev/null || true)"

  assert_contains "MP3 TITLE tag"  "$info" "Gamma"
  assert_contains "MP3 ARTIST tag" "$info" "E2E Artist B"
  assert_contains "MP3 ALBUM tag"  "$info" "E2E Album Y"
}

test_mp3_write() {
  printf '\n\033[1;36m── MP3 write ──\033[0m\n'

  id3v2 --song "Modified Delta" --artist "Modified MP3" "$DELTA" 2>/dev/null

  local info; info="$(id3v2 --list "$DELTA" 2>/dev/null || true)"
  assert_contains "MP3 write — TIT2 updated" "$info" "Modified Delta"
  assert_contains "MP3 write — TPE1 updated" "$info" "Modified MP3"
}

test_chunked_write() {
  printf '\n\033[1;36m── chunked write resilience ──\033[0m\n'

  # Write at offset 8192 — well past any metadata blocks for both formats.
  # The write handler should ignore it (no tag pattern match) and the
  # metadata structure remains parseable.

  local title_before; title_before="$(metaflac --show-tag=TITLE "$ALPHA" 2>/dev/null || true)"
  printf 'XXXX' | dd of="$ALPHA" bs=1 seek=8192 count=4 conv=notrunc 2>/dev/null || true
  sleep 0.5
  local title_after; title_after="$(metaflac --show-tag=TITLE "$ALPHA" 2>/dev/null || true)"
  assert_eq "FLAC tags unchanged after non-metadata write" "$title_before" "$title_after"

  local mp3_before; mp3_before="$(id3v2 --list "$GAMMA" 2>/dev/null | grep -i 'title' || true)"
  printf 'YYYY' | dd of="$GAMMA" bs=1 seek=8192 count=4 conv=notrunc 2>/dev/null || true
  sleep 0.5
  local mp3_after; mp3_after="$(id3v2 --list "$GAMMA" 2>/dev/null | grep -i 'title' || true)"
  assert_eq "MP3 tags unchanged after non-metadata write" "$mp3_before" "$mp3_after"
}

test_persistence() {
  printf '\n\033[1;36m── persistence (client restart) ──\033[0m\n'

  metaflac --remove-tag=ARTIST --set-tag="ARTIST=Persisted Artist" "$ALPHA" 2>/dev/null

  local before; before="$(metaflac --show-tag=ARTIST "$ALPHA" 2>/dev/null || true)"
  assert_contains "persistence — write before restart" "$before" "ARTIST=Persisted Artist"

  log "restarting client…"
  stop_client
  start_client

  local after; after="$(metaflac --show-tag=ARTIST "$ALPHA" 2>/dev/null || true)"
  assert_contains "persistence — read after restart" "$after" "ARTIST=Persisted Artist"
}

# ════════════════════════════════════════════════════════════════════════
# MAIN
# ════════════════════════════════════════════════════════════════════════

main() {
  [[ -n "${PGHOST:-}" ]] || die "PGHOST not set — run inside devenv shell"
  ensure_postgres
  command -v incus    >/dev/null || die "incus not found"
  command -v grpcurl  >/dev/null || die "grpcurl not found"
  command -v metaflac >/dev/null || die "metaflac not found"
  command -v id3v2    >/dev/null || die "id3v2 not found"
  command -v ffprobe  >/dev/null || die "ffprobe not found"

  log "=== E2E suite start ==="

  # Phase 0: fixtures
  bash "$SCRIPT_DIR/make-fixtures.sh" "$MUSIC_DIR"

  # Phase 1: server
  start_vm

  # Phase 2: client
  build_client
  reset_db
  start_client

  # Phase 3-8: tests (read-only first, mutating last)
  test_structural
  test_cache
  test_flac_read
  test_flac_write
  test_mp3_read
  test_mp3_write
  test_chunked_write
  test_persistence

  # Summary
  printf '\n'
  summary
  local rv=$?
  log "=== E2E suite done ==="
  exit $rv
}

main "$@"