#!/bin/bash
# next-task — print the ID of the next PENDING task to run, or nothing if none.
#
# Selection logic:
#   1. Find the most recently updated COMPLETED or READY task.
#   2. If READY, run its first PENDING child (subtask) to begin the series.
#   3. If COMPLETED, run its next PENDING sibling to continue the series.
#   4. If neither yields a task, fall back to highest-priority oldest PENDING
#      task across the whole queue.
#
# Usage: next_id=$(scripts/next-task)
# Example: scripts/start-next-task

DB_PATH="${DB_PATH:-/site/doot.terst.org/data/claudomator.db}"

# 1. Fetch the most recently updated COMPLETED or READY task
target=$(sqlite3 "$DB_PATH" "SELECT id, state, parent_task_id FROM tasks WHERE state IN ('COMPLETED', 'READY') ORDER BY updated_at DESC LIMIT 1;")

if [ -z "$target" ]; then
    exit 0
fi

IFS='|' read -r id state parent_id <<< "$target"

if [ "$state" == "READY" ]; then
    # 2. READY = parent task; run its first PENDING child to begin the series
    next_task=$(sqlite3 "$DB_PATH" "SELECT id FROM tasks WHERE parent_task_id = '$id' AND state = 'PENDING' ORDER BY created_at ASC LIMIT 1;")
elif [ "$state" == "COMPLETED" ]; then
    # 3. Find next PENDING sibling to continue the series
    next_task=$(sqlite3 "$DB_PATH" "SELECT id FROM tasks WHERE parent_task_id = '$parent_id' AND state = 'PENDING' ORDER BY created_at ASC LIMIT 1;")
fi

if [ -z "$next_task" ]; then
    # 4. No child/sibling found: fall back to highest-priority oldest PENDING task
    #    Exclude tasks that have a rejection comment or have already been executed
    #    to avoid auto-approving rejected tasks.
    FALLBACK_SQL="SELECT id FROM tasks WHERE (state = 'PENDING' AND (rejection_comment IS NULL OR rejection_comment = '') AND id NOT IN (SELECT task_id FROM executions)) OR state = 'QUEUED'
        ORDER BY
            CASE priority
                WHEN 'critical' THEN 4
                WHEN 'high'     THEN 3
                WHEN 'normal'   THEN 2
                WHEN 'low'      THEN 1
                ELSE 0
            END DESC,
            created_at ASC
        LIMIT 1;"
    next_task=$(sqlite3 "$DB_PATH" "$FALLBACK_SQL")
fi

echo "$next_task"