#!/usr/bin/env bash
# SessionStart hook: inject project state at conversation start.
# Provides current branch, active investigations, and session continuation notes.
set -euo pipefail

REPO_ROOT="$(git rev-parse --show-toplevel 2>/dev/null || echo ".")"
# Reset tool call counter for periodic self-checks (see post-tool-use.sh)
REPO_ID=$(printf '%s' "$REPO_ROOT" | md5sum | cut -c1-8 2>/dev/null || echo "default")
echo "0" > "/tmp/.opencode-tool-count-${REPO_ID}"
BRANCH=$(git -C "$REPO_ROOT" rev-parse --abbrev-ref HEAD 2>/dev/null || echo "unknown")

# Check for active investigation files
active_investigations=""
EXPLORATIONS_DIR="$REPO_ROOT/docs/explorations"
if [[ -d "$EXPLORATIONS_DIR" ]]; then
  inv_files=$(find "$EXPLORATIONS_DIR" -name "*.md" -not -empty 2>/dev/null || true)
  if [[ -n "$inv_files" ]]; then
    inv_count=$(echo "$inv_files" | wc -l)
    inv_names=$(echo "$inv_files" | xargs -I{} basename {} .md | sed 's/^/  - /' || true)
    active_investigations="Active investigation/exploration files (${inv_count}):\n${inv_names}\nReview relevant files before starting related work."
  fi
fi

# Check for session continuation notes
session_notes=""
if [[ -d "/memories/session" ]]; then
  session_files=$(find /memories/session -name "*.md" 2>/dev/null || true)
  if [[ -n "$session_files" ]]; then
    session_names=$(echo "$session_files" | xargs -I{} basename {} .md | sed 's/^/  - /' || true)
    session_notes="Session memory files exist:\n${session_names}\nCheck these for context from previous conversations."
  fi
fi

# Check for dead-ends file from previous debugging sessions
dead_ends=""
DEAD_ENDS_FILE="$REPO_ROOT/.session/dead-ends.md"
if [[ -f "$DEAD_ENDS_FILE" ]]; then
  de_count=$(grep -c '^\s*- \*\*' "$DEAD_ENDS_FILE" 2>/dev/null || echo "0")
  if [[ "$de_count" -gt 0 ]]; then
    dead_ends="Active dead-ends file with ~${de_count} entries — read before debugging to avoid re-testing eliminated hypotheses."
  fi
fi

# Build context message
context="PROJECT STATE | Branch: ${BRANCH}"

if [[ -n "$active_investigations" ]]; then
  context="${context}\n${active_investigations}"
fi

if [[ -n "$session_notes" ]]; then
  context="${context}\n${session_notes}"
fi

if [[ -n "$dead_ends" ]]; then
  context="${context}\n${dead_ends}"
fi

context="${context}\nREMINDERS: (a) Check AGENTS.md and package-level AGENTS.md files for implementation guidance. (b) Ordered markdown lists are auto-renumbered by the editor on save — do not manually renumber after inserting or removing items."

# Prefix with a self-identifying marker so the model cannot confuse the
# injection with project content.
context="[HOOK INJECTION: session-start] System context — injected at session start, not part of any user message or tool output:\n\n${context}"

# Output JSON
json_context=$(printf '%b' "$context" | node -e 'process.stdout.write(JSON.stringify(require("fs").readFileSync("/dev/stdin","utf8")))')
cat <<EOF
{
  "hookSpecificOutput": {
    "hookEventName": "SessionStart",
    "additionalContext": ${json_context}
  }
}
EOF