/**
 * Outreach: a workspace's list of public accounts to contact one by one.
 *
 * The Hub stores the contact, a drafted message and where the conversation
 * stands (todo → sent → replied/declined). It never sends anything: the
 * person copies the text, opens the profile and writes from the platform's
 * own DM box. Platforms forbid or rate-limit unsolicited bulk DMs, so
 * sending stays human and the API has no provider calls here.
 *
 * Audit entries record status changes and membership of the list, never the
 * message text.
 */
import { BadRequestException, Injectable, NotFoundException } from "@nestjs/common";
import { appendTenantAudit } from "../audit/audit.service.js";
import { withTenant } from "../db/client.js";

export const OUTREACH_STATUSES = ["todo", "sent", "replied", "declined"] as const;
export type OutreachStatus = (typeof OUTREACH_STATUSES)[number];

/** One import call; larger lists go in several requests. */
export const OUTREACH_MAX_IMPORT = 500;
export const OUTREACH_MAX_LIST = 2000;

export interface OutreachContactInput {
  name: string;
  platform: string;
  handle: string;
  profileUrl: string;
  category?: string;
  language?: string;
  message?: string;
  notes?: string;
}

export interface OutreachContactPatch {
  message?: string;
  notes?: string;
  status?: OutreachStatus;
}

export interface OutreachContact {
  id: string;
  name: string;
  platform: string;
  handle: string;
  profileUrl: string;
  category: string | null;
  language: string | null;
  message: string;
  notes: string;
  status: OutreachStatus;
  sentAt: string | null;
  repliedAt: string | null;
  createdAt: string;
  updatedAt: string;
}

export interface OutreachActor {
  userId: string;
  role: string;
}

interface OutreachRow {
  id: string;
  name: string;
  platform: string;
  handle: string;
  profile_url: string;
  category: string | null;
  language: string | null;
  message: string;
  notes: string;
  status: OutreachStatus;
  sent_at: Date | null;
  replied_at: Date | null;
  created_at: Date;
  updated_at: Date;
}

const COLUMNS = "id, name, platform, handle, profile_url, category, language, message, notes, status, sent_at, replied_at, created_at, updated_at";

function fromRow(row: OutreachRow): OutreachContact {
  return {
    id: row.id,
    name: row.name,
    platform: row.platform,
    handle: row.handle,
    profileUrl: row.profile_url,
    category: row.category,
    language: row.language,
    message: row.message,
    notes: row.notes,
    status: row.status,
    sentAt: row.sent_at?.toISOString() ?? null,
    repliedAt: row.replied_at?.toISOString() ?? null,
    createdAt: row.created_at.toISOString(),
    updatedAt: row.updated_at.toISOString(),
  };
}

export function isOutreachStatus(value: unknown): value is OutreachStatus {
  return typeof value === "string" && (OUTREACH_STATUSES as readonly string[]).includes(value);
}

@Injectable()
export class OutreachService {
  async list(workspaceId: string, status?: OutreachStatus): Promise<OutreachContact[]> {
    return withTenant(workspaceId, async (client) => {
      const result = await client.query<OutreachRow>(
        `SELECT ${COLUMNS} FROM outreach_contacts
         WHERE ($1::text IS NULL OR status = $1)
         ORDER BY lower(name), platform
         LIMIT ${OUTREACH_MAX_LIST}`,
        [status ?? null],
      );
      return result.rows.map(fromRow);
    });
  }

  /** Bulk add; an account already on the list (same platform + handle) is skipped. */
  async import(workspaceId: string, contacts: OutreachContactInput[], actor: OutreachActor): Promise<{ added: number; skipped: number }> {
    if (contacts.length === 0) throw new BadRequestException("contacts must not be empty");
    if (contacts.length > OUTREACH_MAX_IMPORT) {
      throw new BadRequestException(`at most ${OUTREACH_MAX_IMPORT} contacts per import`);
    }
    const added = await withTenant(workspaceId, async (client) => {
      const result = await client.query<{ id: string }>(
        `INSERT INTO outreach_contacts
           (workspace_id, name, platform, handle, profile_url, category, language, message, notes, created_by)
         SELECT $1, c.name, c.platform, c.handle, c.profile_url, c.category, c.language,
                coalesce(c.message, ''), coalesce(c.notes, ''), $2
         FROM jsonb_to_recordset($3::jsonb) AS c(
           name text, platform text, handle text, profile_url text,
           category text, language text, message text, notes text)
         ON CONFLICT (workspace_id, platform, lower(handle)) DO NOTHING
         RETURNING id`,
        [workspaceId, actor.userId, JSON.stringify(contacts.map(toRecord))],
      );
      return result.rowCount ?? result.rows.length;
    });
    if (added > 0) {
      await appendTenantAudit(workspaceId, {
        actorUserId: actor.userId,
        actorRole: actor.role,
        action: "outreach.imported",
        targetType: "outreach_contact",
        targetId: workspaceId,
        diff: { added, skipped: contacts.length - added },
      });
    }
    return { added, skipped: contacts.length - added };
  }

  /**
   * Edit the draft/notes or move the status. Marking `sent` stamps who and
   * when; `replied` stamps when; going back to `todo` clears both.
   */
  async update(workspaceId: string, id: string, patch: OutreachContactPatch, actor: OutreachActor): Promise<OutreachContact> {
    const { contact, previous } = await withTenant(workspaceId, async (client) => {
      const current = await client.query<{ status: OutreachStatus }>(
        "SELECT status FROM outreach_contacts WHERE id = $1 FOR UPDATE",
        [id],
      );
      const before = current.rows[0];
      if (before === undefined) throw new NotFoundException(`outreach contact ${id} not found`);
      const status = patch.status ?? before.status;
      const changed = status !== before.status;
      const result = await client.query<OutreachRow>(
        `UPDATE outreach_contacts SET
           message = coalesce($2, message),
           notes = coalesce($3, notes),
           status = $4,
           sent_at = CASE WHEN NOT $5 THEN sent_at WHEN $4 = 'todo' THEN NULL WHEN $4 = 'sent' THEN now() ELSE coalesce(sent_at, now()) END,
           sent_by = CASE WHEN NOT $5 THEN sent_by WHEN $4 = 'todo' THEN NULL WHEN $4 = 'sent' THEN $6::uuid ELSE coalesce(sent_by, $6::uuid) END,
           replied_at = CASE WHEN NOT $5 THEN replied_at WHEN $4 = 'replied' THEN now() ELSE NULL END,
           updated_at = now()
         WHERE id = $1
         RETURNING ${COLUMNS}`,
        [id, patch.message ?? null, patch.notes ?? null, status, changed, actor.userId],
      );
      const row = result.rows[0];
      if (row === undefined) throw new NotFoundException(`outreach contact ${id} not found`);
      return { contact: fromRow(row), previous: before.status };
    });
    if (contact.status !== previous) {
      await appendTenantAudit(workspaceId, {
        actorUserId: actor.userId,
        actorRole: actor.role,
        action: `outreach.${contact.status}`,
        targetType: "outreach_contact",
        targetId: contact.id,
        diff: { from: previous, to: contact.status, platform: contact.platform, handle: contact.handle },
      });
    }
    return contact;
  }

  async remove(workspaceId: string, id: string, actor: OutreachActor): Promise<void> {
    const removed = await withTenant(workspaceId, async (client) => {
      const result = await client.query<{ platform: string; handle: string }>(
        "DELETE FROM outreach_contacts WHERE id = $1 RETURNING platform, handle",
        [id],
      );
      return result.rows[0];
    });
    if (removed === undefined) throw new NotFoundException(`outreach contact ${id} not found`);
    await appendTenantAudit(workspaceId, {
      actorUserId: actor.userId,
      actorRole: actor.role,
      action: "outreach.removed",
      targetType: "outreach_contact",
      targetId: id,
      diff: { platform: removed.platform, handle: removed.handle },
    });
  }
}

function toRecord(contact: OutreachContactInput): Record<string, string | null> {
  return {
    name: contact.name,
    platform: contact.platform,
    handle: contact.handle,
    profile_url: contact.profileUrl,
    category: contact.category ?? null,
    language: contact.language ?? null,
    message: contact.message ?? null,
    notes: contact.notes ?? null,
  };
}