import { getServiceSupabase } from "@/lib/supabase/client";

export interface Task {
  id: string;
  title: string;
  description?: string;
  type: "idea" | "task" | "bug" | "research" | "plan";
  status: "open" | "todo" | "blocked" | "in-progress" | "review" | "validate" | "archived" | "canceled" | "done";
  priority: "low" | "medium" | "high" | "urgent";
  projectId: string;
  sprintId?: string;
  createdAt: string;
  updatedAt: string;
  createdById?: string;
  createdByName?: string;
  createdByAvatarUrl?: string;
  updatedById?: string;
  updatedByName?: string;
  updatedByAvatarUrl?: string;
  assigneeId?: string;
  assigneeName?: string;
  assigneeEmail?: string;
  assigneeAvatarUrl?: string;
  dueDate?: string;
  comments: unknown[];
  tags: string[];
  attachments: unknown[];
}

const TASK_STATUSES: Task["status"][] = ["open", "todo", "blocked", "in-progress", "review", "validate", "archived", "canceled", "done"];

function isTaskStatus(value: unknown): value is Task["status"] {
  return typeof value === "string" && TASK_STATUSES.includes(value as Task["status"]);
}

function toNonEmptyString(value: unknown): string | undefined {
  return typeof value === "string" && value.trim().length > 0 ? value : undefined;
}

function mapTaskRow(row: Record<string, unknown>): Task {
  const fallbackDate = new Date().toISOString();
  return {
    id: String(row.id ?? ""),
    title: toNonEmptyString(row.title) ?? "",
    description: toNonEmptyString(row.description),
    type: (toNonEmptyString(row.type) as Task["type"]) ?? "task",
    status: isTaskStatus(row.status) ? row.status : "todo",
    priority: (toNonEmptyString(row.priority) as Task["priority"]) ?? "medium",
    projectId: String(row.project_id ?? ""),
    sprintId: toNonEmptyString(row.sprint_id),
    createdAt: toNonEmptyString(row.created_at) ?? fallbackDate,
    updatedAt: toNonEmptyString(row.updated_at) ?? fallbackDate,
    createdById: toNonEmptyString(row.created_by_id),
    createdByName: toNonEmptyString(row.created_by_name),
    createdByAvatarUrl: toNonEmptyString(row.created_by_avatar_url),
    updatedById: toNonEmptyString(row.updated_by_id),
    updatedByName: toNonEmptyString(row.updated_by_name),
    updatedByAvatarUrl: toNonEmptyString(row.updated_by_avatar_url),
    assigneeId: toNonEmptyString(row.assignee_id),
    assigneeName: toNonEmptyString(row.assignee_name),
    assigneeEmail: toNonEmptyString(row.assignee_email),
    assigneeAvatarUrl: toNonEmptyString(row.assignee_avatar_url),
    dueDate: toNonEmptyString(row.due_date),
    comments: Array.isArray(row.comments) ? row.comments : [],
    tags: Array.isArray(row.tags) ? row.tags.filter((tag): tag is string => typeof tag === "string") : [],
    attachments: Array.isArray(row.attachments) ? row.attachments : [],
  };
}

/**
 * Fetch all tasks from Supabase
 */
export async function fetchAllTasks(): Promise<Task[]> {
  const supabase = getServiceSupabase();
  const { data, error } = await supabase
    .from("tasks")
    .select("*")
    .order("created_at", { ascending: true });

  if (error) {
    console.error("Error fetching tasks:", error);
    throw new Error(`Failed to fetch tasks: ${error.message}`);
  }

  return (data || []).map((row) => mapTaskRow(row as Record<string, unknown>));
}

/**
 * Fetch active tasks (status != 'done')
 */
export async function fetchActiveTasks(): Promise<Task[]> {
  const supabase = getServiceSupabase();
  const { data, error } = await supabase
    .from("tasks")
    .select("*")
    .neq("status", "done")
    .order("created_at", { ascending: true });

  if (error) {
    console.error("Error fetching active tasks:", error);
    throw new Error(`Failed to fetch active tasks: ${error.message}`);
  }

  return (data || []).map((row) => mapTaskRow(row as Record<string, unknown>));
}

/**
 * Count active tasks
 */
export async function countActiveTasks(): Promise<number> {
  const supabase = getServiceSupabase();
  const { count, error } = await supabase
    .from("tasks")
    .select("*", { count: "exact", head: true })
    .neq("status", "done");

  if (error) {
    console.error("Error counting active tasks:", error);
    return 0;
  }

  return count || 0;
}

/**
 * Count total tasks
 */
export async function countTotalTasks(): Promise<number> {
  const supabase = getServiceSupabase();
  const { count, error } = await supabase
    .from("tasks")
    .select("*", { count: "exact", head: true });

  if (error) {
    console.error("Error counting total tasks:", error);
    return 0;
  }

  return count || 0;
}

/**
 * Get task counts by status
 */
export interface TaskStatusCounts {
  open: number;
  inProgress: number;
  review: number;
  done: number;
  total: number;
}

export async function getTaskStatusCounts(): Promise<TaskStatusCounts> {
  const supabase = getServiceSupabase();
  
  // Get all tasks and count by status
  const { data, error } = await supabase
    .from("tasks")
    .select("status");

  if (error) {
    console.error("Error fetching task status counts:", error);
    return { open: 0, inProgress: 0, review: 0, done: 0, total: 0 };
  }

  const counts = { open: 0, inProgress: 0, review: 0, done: 0, total: 0 };
  
  for (const row of data || []) {
    counts.total++;
    const status = row.status;
    if (status === "open" || status === "todo" || status === "blocked") {
      counts.open++;
    } else if (status === "in-progress") {
      counts.inProgress++;
    } else if (status === "review" || status === "validate") {
      counts.review++;
    } else if (status === "done") {
      counts.done++;
    }
  }

  return counts;
}

/**
 * Count high priority tasks (high or urgent priority, not done)
 */
export async function countHighPriorityTasks(): Promise<number> {
  const supabase = getServiceSupabase();
  const { count, error } = await supabase
    .from("tasks")
    .select("*", { count: "exact", head: true })
    .in("priority", ["high", "urgent"])
    .neq("status", "done");

  if (error) {
    console.error("Error counting high priority tasks:", error);
    return 0;
  }

  return count || 0;
}

/**
 * Count overdue tasks (due date in the past, not done)
 */
export async function countOverdueTasks(): Promise<number> {
  const supabase = getServiceSupabase();
  const today = new Date().toISOString().split("T")[0];
  
  const { count, error } = await supabase
    .from("tasks")
    .select("*", { count: "exact", head: true })
    .lt("due_date", today)
    .neq("status", "done")
    .not("due_date", "is", null);

  if (error) {
    console.error("Error counting overdue tasks:", error);
    return 0;
  }

  return count || 0;
}

/**
 * Fetch recently updated tasks (last 5)
 */
export async function fetchRecentlyUpdatedTasks(limit = 5): Promise<Task[]> {
  const supabase = getServiceSupabase();
  const { data, error } = await supabase
    .from("tasks")
    .select("*")
    .order("updated_at", { ascending: false })
    .limit(limit);

  if (error) {
    console.error("Error fetching recently updated tasks:", error);
    return [];
  }

  return (data || []).map((row) => mapTaskRow(row as Record<string, unknown>));
}

/**
 * Fetch recently completed tasks (last 5)
 */
export async function fetchRecentlyCompletedTasks(limit = 5): Promise<Task[]> {
  const supabase = getServiceSupabase();
  const { data, error } = await supabase
    .from("tasks")
    .select("*")
    .eq("status", "done")
    .order("updated_at", { ascending: false })
    .limit(limit);

  if (error) {
    console.error("Error fetching recently completed tasks:", error);
    return [];
  }

  return (data || []).map((row) => mapTaskRow(row as Record<string, unknown>));
}

/**
 * Fetch high priority open tasks (top 5)
 */
export async function fetchHighPriorityOpenTasks(limit = 5): Promise<Task[]> {
  const supabase = getServiceSupabase();
  const { data, error } = await supabase
    .from("tasks")
    .select("*")
    .in("priority", ["high", "urgent"])
    .neq("status", "done")
    .order("updated_at", { ascending: false })
    .limit(limit);

  if (error) {
    console.error("Error fetching high priority open tasks:", error);
    return [];
  }

  return (data || []).map((row) => mapTaskRow(row as Record<string, unknown>));
}