#!/usr/bin/env bash
# Kanban CLI - Task Management with Hierarchy Support
# Part of Epic 335: Kanban Development Pipeline

set -euo pipefail

API_BASE="http://127.0.0.1:5003/api"
TAXONOMY="/tmp/kanban-taxonomy.md"

# Colors
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
NC='\033[0m' # No Color

error() { echo -e "${RED}❌ $*${NC}" >&2; exit 1; }
success() { echo -e "${GREEN}✅ $*${NC}"; }
warn() { echo -e "${YELLOW}⚠️  $*${NC}"; }

usage() {
  cat << EOF
Kanban CLI - Task Management with Hierarchy

USAGE:
  kanban-cli <command> [options]

COMMANDS:
  create <type> <title>      Create task (epic|story|task|subtask)
  update <id>                Update task fields
  link <id> --parent <ref>   Link task to parent (epic:305)
  list [--type <t>]          List tasks
  view <id>                  Show task details
  delete <id>                Delete task
  validate <id>              Validate task structure

OPTIONS:
  --title <text>             Task title
  --description <text>       Task description
  --tags <csv>              Comma-separated tags
  --parent <ref>            Parent reference (epic:335, story:307)
  --priority <0-3>          Priority level
  --status <status>         Task status (queue|in_progress|done)
  --agent <agent>           Agent assignment
  --size <xs|s|m|l|xl>     Task size
  --setup <setup>           Setup requirements

EXAMPLES:
  # Create epic
  kanban-cli create epic "Feature X" --tags "size:xl,agent:nvidia" --priority 3

  # Create story under epic
  kanban-cli create story "Implement API" --parent epic:335 --size l

  # Create task under story
  kanban-cli create task "Write tests" --parent story:336 --size s

  # Link existing task
  kanban-cli link 307 --parent epic:305

  # Update tags
  kanban-cli update 333 --tags "priority:critical,agent:nvidia"

  # List by type
  kanban-cli list --type epic
  kanban-cli list --agent gemini-flash --size s

TAXONOMY:
  type:     epic, story, task, subtask
  size:     xs, s, m, l, xl
  setup:    local, pi, openclaw, external, skill, docs
  agent:    gemini-flash, gemini-pro, nvidia, deepseek, human
  domain:   security, reddit, onboarding, cost, home-automation, development
  priority: 0-3 (low, medium, high, critical)

EOF
  exit 0
}

validate_tag() {
  local tag="$1"
  
  # Extract category and value
  if [[ ! "$tag" =~ ^([a-z-]+):([a-z0-9-]+)$ ]]; then
    warn "Invalid tag format: $tag (expected category:value)"
    return 1
  fi
  
  local cat="${BASH_REMATCH[1]}"
  local val="${BASH_REMATCH[2]}"
  
  # Validate against taxonomy
  case "$cat" in
    type)
      [[ "$val" =~ ^(epic|story|task|subtask)$ ]] || { warn "Invalid type: $val"; return 1; }
      ;;
    size)
      [[ "$val" =~ ^(xs|s|m|l|xl)$ ]] || { warn "Invalid size: $val"; return 1; }
      ;;
    setup)
      [[ "$val" =~ ^(local|pi|openclaw|external|skill|docs)$ ]] || { warn "Invalid setup: $val"; return 1; }
      ;;
    agent)
      [[ "$val" =~ ^(gemini-flash|gemini-pro|nvidia|deepseek|human)$ ]] || { warn "Invalid agent: $val"; return 1; }
      ;;
    domain)
      [[ "$val" =~ ^(security|reddit|onboarding|cost|home-automation|development)$ ]] || { warn "Invalid domain: $val"; return 1; }
      ;;
    priority)
      [[ "$val" =~ ^(low|medium|high|critical)$ ]] || { warn "Invalid priority: $val"; return 1; }
      ;;
    *)
      # Allow unknown categories (for flexibility)
      warn "Unknown category: $cat (allowed but not in taxonomy)"
      ;;
  esac
  
  return 0
}

validate_tags() {
  local tags="$1"
  IFS=',' read -ra TAG_ARRAY <<< "$tags"
  
  for tag in "${TAG_ARRAY[@]}"; do
    tag=$(echo "$tag" | xargs) # trim whitespace
    validate_tag "$tag" || return 1
  done
  
  return 0
}

cmd_create() {
  local type="$1"; shift
  local title="$1"; shift
  
  # Parse options
  local tags="" description="" parent="" priority=0 status="queue"
  
  while [[ $# -gt 0 ]]; do
    case "$1" in
      --tags) tags="$2"; shift 2;;
      --description) description="$2"; shift 2;;
      --parent) parent="$2"; shift 2;;
      --priority) priority="$2"; shift 2;;
      --status) status="$2"; shift 2;;
      --agent) tags="$tags,agent:$2"; shift 2;;
      --size) tags="$tags,size:$2"; shift 2;;
      --setup) tags="$tags,setup:$2"; shift 2;;
      *) error "Unknown option: $1";;
    esac
  done
  
  # Add type tag
  tags="type:$type${tags:+,$tags}"
  
  # Validate tags
  validate_tags "$tags" || error "Tag validation failed"
  
  # Build JSON
  local json=$(jq -n \
    --arg title "$title" \
    --arg desc "$description" \
    --arg tags "$tags" \
    --arg status "$status" \
    --arg parent "$parent" \
    --argjson priority "$priority" \
    '{
      title: $title,
      description: $desc,
      tags: $tags,
      status: $status,
      external_id: (if $parent == "" then null else $parent end),
      priority: $priority
    }')
  
  # Create task
  local response=$(curl -sS -X POST "$API_BASE/tasks" \
    -H "Content-Type: application/json" \
    -d "$json")
  
  local id=$(echo "$response" | jq -r '.id')
  
  if [[ "$id" == "null" ]]; then
    error "Failed to create task: $(echo "$response" | jq -r '.error // .message // "Unknown error"')"
  fi
  
  success "Created $type [$id]: $title"
  
  # Fetch back to show actual persisted data
  local created=$(curl -sS "$API_BASE/tasks?status=queue" | jq --arg id "$id" '.[] | select(.id == ($id | tonumber))')
  echo "$created" | jq -r '"  Tags: \(.tags // "pending...")\n  Parent: \(.external_id // "none")\n  Priority: \(.priority)"'
}

cmd_update() {
  local id="$1"; shift
  
  # Parse options
  local title="" description="" tags="" status="" priority=""
  
  while [[ $# -gt 0 ]]; do
    case "$1" in
      --title) title="$2"; shift 2;;
      --description) description="$2"; shift 2;;
      --tags) tags="$2"; shift 2;;
      --status) status="$2"; shift 2;;
      --priority) priority="$2"; shift 2;;
      *) error "Unknown option: $1";;
    esac
  done
  
  # Validate tags if provided
  if [[ -n "$tags" ]]; then
    validate_tags "$tags" || error "Tag validation failed"
  fi
  
  # Build JSON
  local json="{}"
  [[ -n "$title" ]] && json=$(jq --arg v "$title" '. + {title: $v}' <<< "$json")
  [[ -n "$description" ]] && json=$(jq --arg v "$description" '. + {description: $v}' <<< "$json")
  [[ -n "$tags" ]] && json=$(jq --arg v "$tags" '. + {tags: $v}' <<< "$json")
  [[ -n "$status" ]] && json=$(jq --arg v "$status" '. + {status: $v}' <<< "$json")
  [[ -n "$priority" ]] && json=$(jq --argjson v "$priority" '. + {priority: $v}' <<< "$json")
  
  # Update task
  local response=$(curl -sS -X PATCH "$API_BASE/tasks/$id" \
    -H "Content-Type: application/json" \
    -d "$json")
  
  local updated_id=$(echo "$response" | jq -r '.id')
  
  if [[ "$updated_id" == "null" ]]; then
    error "Failed to update task: $(echo "$response" | jq -r '.error // .message // "Unknown error"')"
  fi
  
  success "Updated task [$id]"
  echo "$response" | jq -r '"  Title: \(.title)\n  Tags: \(.tags)\n  Status: \(.status)"'
}

cmd_link() {
  local id="$1"
  local parent=""
  
  shift
  while [[ $# -gt 0 ]]; do
    case "$1" in
      --parent) parent="$2"; shift 2;;
      *) error "Unknown option: $1";;
    esac
  done
  
  [[ -z "$parent" ]] && error "Parent reference required (--parent epic:305)"
  
  # Update external_id
  local response=$(curl -sS -X PATCH "$API_BASE/tasks/$id" \
    -H "Content-Type: application/json" \
    -d "{\"external_id\": \"$parent\"}")
  
  local updated_id=$(echo "$response" | jq -r '.id')
  
  if [[ "$updated_id" == "null" ]]; then
    error "Failed to link task: $(echo "$response" | jq -r '.error // .message // "Unknown error"')"
  fi
  
  success "Linked task [$id] → $parent"
}

cmd_list() {
  local filters="status=queue"
  
  while [[ $# -gt 0 ]]; do
    case "$1" in
      --type) filters="$filters&type=$2"; shift 2;;
      --agent) filters="$filters&agent=$2"; shift 2;;
      --size) filters="$filters&size=$2"; shift 2;;
      --status) filters="${filters/status=queue/status=$2}"; shift 2;;
      *) error "Unknown filter: $1";;
    esac
  done
  
  curl -sS "$API_BASE/tasks?$filters" | \
    jq -r '.[] | "[\(.id)] \(.title)\n  Tags: \(.tags // "none")\n  Parent: \(.external_id // "none")\n"'
}

cmd_view() {
  local id="$1"
  
  # Use batch endpoint (single-task GET is broken)
  curl -sS "$API_BASE/tasks?status=queue" | \
    jq -r --arg id "$id" '.[] | select(.id == ($id | tonumber)) | 
    "[\(.id)] \(.title)\n\nDescription:\n\(.description // "none")\n\nTags: \(.tags // "none")\nParent: \(.external_id // "none")\nStatus: \(.status)\nPriority: \(.priority)\nCreated: \(.created_at)\nUpdated: \(.updated_at)"'
}

cmd_delete() {
  local id="$1"
  
  echo "Delete task $id? (y/N)"
  read -r confirm
  
  if [[ "${confirm,,}" != "y" ]]; then
    echo "Aborted"
    exit 0
  fi
  
  curl -sS -X DELETE "$API_BASE/tasks/$id"
  success "Deleted task [$id]"
}

cmd_validate() {
  local id="$1"
  
  # Get task (use batch endpoint)
  local task=$(curl -sS "$API_BASE/tasks?status=queue" | jq --arg id "$id" '.[] | select(.id == ($id | tonumber))')
  local title=$(echo "$task" | jq -r '.title')
  local tags=$(echo "$task" | jq -r '.tags // ""')
  local parent=$(echo "$task" | jq -r '.external_id // ""')
  
  echo "Validating task [$id]: $title"
  echo ""
  
  # Check tags
  if [[ -z "$tags" ]]; then
    warn "No tags set"
  else
    echo "Validating tags..."
    validate_tags "$tags" && success "Tags valid" || error "Tags invalid"
  fi
  
  # Check parent link
  if [[ -n "$parent" ]]; then
    echo "Checking parent link: $parent"
    local parent_id=$(echo "$parent" | grep -oP ':\K[0-9]+')
    if curl -sS "$API_BASE/tasks?status=queue" | jq --arg id "$parent_id" '.[] | select(.id == ($id | tonumber))' | jq -e '.id' >/dev/null 2>&1; then
      success "Parent exists"
    else
      error "Parent not found: $parent"
    fi
  fi
  
  success "Task validated"
}

# Main
if [[ $# -eq 0 ]]; then usage; fi

cmd="$1"; shift

case "$cmd" in
  create) cmd_create "$@";;
  update) cmd_update "$@";;
  link) cmd_link "$@";;
  list) cmd_list "$@";;
  view) cmd_view "$@";;
  delete) cmd_delete "$@";;
  validate) cmd_validate "$@";;
  help|--help|-h) usage;;
  *) error "Unknown command: $cmd (try 'help')";;
esac