#!/bin/sh

# github_issue_sync.sh
# Synchronizes GitHub and Linear issues with Taskwarrior

# Set new line and tab for word splitting
IFS='
	'

# Logger with timestamp
log() {
  echo "[$(date +'%Y-%m-%dT%H:%M:%S%z')]: $*"
}

# Function to trim leading and trailing whitespace using sed
trim_whitespace() {
  input="$1"
  echo "$input" | sed 's/^[ \t]*//;s/[ \t]*$//'
}

# Validate necessary environment variables
validate_env_vars() {
  oldIFS="$IFS"
  IFS=' '
  required_vars="api userid"
  for var in $required_vars; do
    val=$(pass show "api/linear/$var")
    if [ -z "$val" ]; then
      echo "Error: Environment variable $var is not set." >&2
      exit 1
    fi
  done
  IFS="$oldIFS"
}

# Retrieve and format GitHub issues
get_github_issues() {
  issues=$(gh api -X GET /search/issues \
    -f q='is:issue is:open assignee:TheSiahxyz' \
    --jq '.items[] | {id: .number, description: .title, repository: .repository_url, html_url: .html_url}') || {
    echo "Error: Unable to fetch GitHub issues" >&2
    return 1
  }
  echo "$issues"
}

# Retrieve and format Linear issues
get_linear_issues() {
  issues=$(curl -s -X POST \
    -H "Content-Type: application/json" \
    -H "Authorization: $LINEAR_API_KEY" \
    --data '{"query": "query { user(id: \"'"$LINEAR_USER_ID"'\") { id name assignedIssues(filter: { state: { name: { nin: [\"Released\", \"Canceled\"] } } }) { nodes { id title url } } } }"}' \
    https://api.linear.app/graphql | jq -c '.data.user.assignedIssues.nodes[] | {id: .id, description: .title, repository: "linear", html_url: .url}') || {
    echo "Error: Unable to fetch Linear issues" >&2
    return 1
  }
  echo "$issues"
}

# Synchronize a single issue with Taskwarrior
sync_to_taskwarrior() {
  issue_line="$1"
  issue_id=$(echo "$issue_line" | jq -r '.id')
  issue_description=$(echo "$issue_line" | jq -r '.description')
  issue_repo_name=$(echo "$issue_line" | jq -r '.repository' | awk -F/ '{print $NF}')
  issue_url=$(echo "$issue_line" | jq -r '.html_url')

  log "Processing Issue ID: $issue_id, Description: $issue_description"

  task_uuid=$(get_task_id_by_description "$issue_description")

  if [ -z "$task_uuid" ]; then
    log "Creating new task for issue: $issue_description"
    task_uuid=$(create_task "$issue_description" "+$issue_repo_name" "project:$issue_repo_name")

    if [ -n "$task_uuid" ]; then
      annotate_task "$task_uuid" "$issue_url"
      log "Task created and annotated for: $issue_description"
    else
      log "Error: Failed to create task for: $issue_description" >&2
    fi
  else
    log "Task already exists for: $issue_description (UUID: $task_uuid)"
  fi
}

# Mark a GitHub issue as completed in Taskwarrior
sync_github_issue() {
  task_description="$1"
  task_uuid=$(get_task_id_by_description "$task_description")

  if [ -n "$task_uuid" ]; then
    mark_task_completed "$task_uuid"
    log "Task marked as completed: $task_description (UUID: $task_uuid)"
  else
    log "Task UUID not found for: $task_description" >&2
  fi
}

# Compare existing Taskwarrior tasks with current issues and mark as completed if not present
compare_and_display_tasks_not_in_issues() {
  existing_task_descriptions="$1"
  issues_descriptions="$2"

  log "Starting comparison of Taskwarrior tasks and current issues."

  existing_task_descriptions_array=$(echo "$existing_task_descriptions" | tr '\n' ' ')
  issues_descriptions_array=$(echo "$issues_descriptions" | tr '\n' ' ')

  for task_description in $existing_task_descriptions_array; do
    trimmed_task_description=$(trim_whitespace "$task_description")
    issue_exists=false

    for issue_description in $issues_descriptions_array; do
      trimmed_issue_description=$(trim_whitespace "$issue_description")
      if [ "$(echo "$trimmed_task_description" | tr '[:upper:]' '[:lower:]')" = "$(echo "$trimmed_issue_description" | tr '[:upper:]' '[:lower:]')" ]; then
        issue_exists=true
        break
      fi
    done

    if [ "$issue_exists" = false ]; then
      log "No matching issue found for task: $trimmed_task_description. Marking as completed."
      sync_github_issue "$trimmed_task_description"
    fi
  done

  log "Comparison of Taskwarrior tasks and issues completed."
}

# Retrieve existing Taskwarrior task descriptions with +github or +linear tags and pending status
get_existing_task_descriptions() {
  task +github or +linear status:pending export | jq -r '.[] | .description'
}

# Log retrieved issues
log_issues() {
  issue_type="$1"
  issues="$2"
  log "Retrieved $issue_type issues: $(echo "$issues" | jq '.')"
}

# Synchronize all issues to Taskwarrior
sync_issues_to_taskwarrior() {
  issues="$1"
  echo "$issues" | jq -c '.' | while IFS= read -r line; do
    sync_to_taskwarrior "$line"
  done
}

# Main function to orchestrate the synchronization
main() {
  if ! git rev-parse --is-inside-work-tree >/dev/null 2>&1; then
    echo "Not a git repository."
    exit 1
  fi
  validate_env_vars

  github_issues=$(get_github_issues)
  linear_issues=$(get_linear_issues)

  if [ -z "$github_issues" ] && [ -z "$linear_issues" ]; then
    log "No issues retrieved from GitHub or Linear. Exiting."
    exit 0
  fi

  if [ -n "$github_issues" ]; then
    log_issues "GitHub" "$github_issues"
    sync_issues_to_taskwarrior "$github_issues"
  fi

  if [ -n "$linear_issues" ]; then
    log_issues "Linear" "$linear_issues"
    sync_issues_to_taskwarrior "$linear_issues"
  fi

  existing_task_descriptions=$(get_existing_task_descriptions)

  compare_and_display_tasks_not_in_issues "$existing_task_descriptions" "$(
    echo "$github_issues" | jq -r '.description'
    echo "$linear_issues" | jq -r '.description'
  )"
}

main