#!/usr/bin/env bash
set -euo pipefail
#
# session-resume.sh — Crash recovery for dead orchestrator sessions
#
# Usage:
#   session-resume.sh [--project <path>] [--clean-lock]

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/_lib.sh"

# ─── Parse arguments ─────────────────────────────────────────────────────────

PROJECT="."
CLEAN_LOCK=false

while [[ $# -gt 0 ]]; do
  case "$1" in
    --project)      PROJECT="$2"; shift 2 ;;
    --clean-lock)   CLEAN_LOCK=true; shift ;;
    -h|--help)
      echo "Usage: session-resume.sh [--project <path>] [--clean-lock]"
      exit 0
      ;;
    *) echo "Unknown option: $1" >&2; exit 1 ;;
  esac
done

_require_jq

# ─── Check session lock ─────────────────────────────────────────────────────

lock_data=""
has_lock=false
if lock_data="$(session_lock_read "$PROJECT" 2>/dev/null)"; then
  has_lock=true
fi

if [[ "$has_lock" == true ]]; then
  lock_pid="$(echo "$lock_data" | jq -r '.pid // 0')"
  lock_sid="$(echo "$lock_data" | jq -r '.session_id // "unknown"')"
  lock_rt="$(echo "$lock_data" | jq -r '.runtime // "unknown"')"
  lock_start="$(echo "$lock_data" | jq -r '.started_at // ""')"
  lock_milestone="$(echo "$lock_data" | jq -r '.milestone_id // ""')"

  if is_pid_alive "$lock_pid"; then
    echo -e "${C_YELLOW}Session $lock_sid is still running (PID $lock_pid).${C_RESET}"
    echo "Use 'mosaic coord status' to check session health."
    exit 0
  fi

  # Session is dead
  echo ""
  echo -e "${C_RED}${C_BOLD}CRASH RECOVERY — Session $lock_sid ($lock_rt)${C_RESET}"
  echo "==========================================="
  echo ""

  if [[ -n "$lock_start" ]]; then
    echo -e "  ${C_CYAN}Session started:${C_RESET}  $lock_start"
  fi
  echo -e "  ${C_CYAN}Session died:${C_RESET}     PID $lock_pid is not running"
  [[ -n "$lock_milestone" ]] && echo -e "  ${C_CYAN}Active milestone:${C_RESET} $lock_milestone"
  echo ""

else
  # No lock — check mission.json for last session info
  if [[ -f "$(mission_path "$PROJECT")" ]]; then
    mission="$(load_mission "$PROJECT")"
    session_count="$(echo "$mission" | jq '.sessions | length')"
    if (( session_count > 0 )); then
      last_idx=$(( session_count - 1 ))
      last_sid="$(echo "$mission" | jq -r ".sessions[$last_idx].session_id")"
      last_reason="$(echo "$mission" | jq -r ".sessions[$last_idx].ended_reason // \"unknown\"")"
      echo -e "${C_DIM}No session lock found. Last session: $last_sid (ended: $last_reason)${C_RESET}"
      echo "Use 'mosaic coord continue' to generate a continuation prompt."
      exit 0
    fi
  fi
  echo -e "${C_DIM}No session state found.${C_RESET}"
  exit 4
fi

# ─── Detect dirty state ─────────────────────────────────────────────────────

echo -e "${C_BOLD}Dirty State:${C_RESET}"

dirty_files=""
if git -C "$PROJECT" rev-parse --is-inside-work-tree &>/dev/null; then
  dirty_files="$(git -C "$PROJECT" status --porcelain 2>/dev/null || true)"
fi

if [[ -n "$dirty_files" ]]; then
  echo "  Modified files:"
  echo "$dirty_files" | head -20 | while IFS= read -r line; do
    echo "    $line"
  done
  file_count="$(echo "$dirty_files" | wc -l)"
  if (( file_count > 20 )); then
    echo "    ... and $(( file_count - 20 )) more"
  fi
else
  echo -e "  ${C_GREEN}Working tree is clean.${C_RESET}"
fi

# Check for in-progress tasks
inprog_count=0
task_counts="$(count_tasks_md "$PROJECT")"
inprog_count="$(echo "$task_counts" | jq '.in_progress')"
if (( inprog_count > 0 )); then
  echo -e "  ${C_YELLOW}$inprog_count task(s) still marked in-progress in TASKS.md${C_RESET}"
fi

echo ""

# ─── Recovery actions ────────────────────────────────────────────────────────

echo -e "${C_BOLD}Recovery Actions:${C_RESET}"
if [[ -n "$dirty_files" ]]; then
  echo "  1. Review changes:  git diff"
  echo "  2. If good:         git add -A && git commit -m \"wip: partial work from crashed session\""
  echo "  3. If bad:          git checkout ."
fi
echo "  4. Clean lock:      mosaic coord resume --clean-lock"
echo "  5. Generate prompt: mosaic coord continue"
echo ""

# ─── Clean lock if requested ─────────────────────────────────────────────────

if [[ "$CLEAN_LOCK" == true ]]; then
  echo -e "${C_CYAN}Cleaning session lock...${C_RESET}"

  # Update mission.json with crash info
  mp="$(mission_path "$PROJECT")"
  if [[ -f "$mp" && "$has_lock" == true ]]; then
    updated="$(jq \
      --arg sid "$lock_sid" \
      --arg ts "$(iso_now)" \
      '(.sessions[] | select(.session_id == $sid)) |= . + {
        ended_at: $ts,
        ended_reason: "crashed"
      }' "$mp")"
    write_json "$mp" "$updated"
    echo "  Updated mission.json: session $lock_sid marked as crashed"
  fi

  session_lock_clear "$PROJECT"
  echo "  Cleared session.lock"
  echo ""
  echo -e "${C_GREEN}Lock cleared. Generate continuation prompt with: mosaic coord continue${C_RESET}"
fi

# ─── Generate resume prompt ─────────────────────────────────────────────────

if [[ "$CLEAN_LOCK" != true ]]; then
  echo "---"
  echo ""
  echo -e "${C_BOLD}Resume Prompt (paste to new session):${C_RESET}"
  echo ""

  mission_name=""
  mission_id=""
  if [[ -f "$(mission_path "$PROJECT")" ]]; then
    mission="$(load_mission "$PROJECT")"
    mission_name="$(echo "$mission" | jq -r '.name')"
    mission_id="$(echo "$mission" | jq -r '.mission_id')"
    quality_gates="$(echo "$mission" | jq -r '.quality_gates // "—"')"
    project_path="$(echo "$mission" | jq -r '.project_path')"
  fi

  task_counts="$(count_tasks_md "$PROJECT")"
  tasks_done="$(echo "$task_counts" | jq '.done')"
  tasks_total="$(echo "$task_counts" | jq '.total')"
  next_task="$(find_next_task "$PROJECT")"

  cat <<EOF
## Crash Recovery Mission

Recovering **${mission_name:-Unknown Mission}** from crashed session ${lock_sid:-unknown}.

### WARNING: Dirty State Detected
The previous session left uncommitted changes. Before continuing:
1. Run \`git diff\` to review uncommitted changes
2. Decide: commit (if good) or discard (if broken)
3. Then proceed with the mission

## Setup

- **Project:** ${project_path:-$PROJECT}
- **State:** docs/TASKS.md (${tasks_done}/${tasks_total} tasks complete)
- **Manifest:** docs/MISSION-MANIFEST.md
- **Scratchpad:** docs/scratchpads/${mission_id:-mission}.md
- **Protocol:** ~/.config/mosaic/guides/ORCHESTRATOR.md
- **Quality gates:** ${quality_gates:-—}

## Resume Point

- **Next task:** ${next_task:-check TASKS.md}

## Instructions

1. Read \`docs/MISSION-MANIFEST.md\` for mission scope
2. Read \`docs/scratchpads/${mission_id:-mission}.md\` for session history
3. Review and resolve any uncommitted changes first
4. Read \`docs/TASKS.md\` for current task state
5. Continue execution from the next pending task
6. You are the SOLE writer of \`docs/TASKS.md\`
EOF
fi