import { Hono } from 'hono';
import { HTTPException } from 'hono/http-exception';
import type { Db } from '../db/index.ts';
import { tickets, transactions, customFieldValues, customFields, queues, lifecycles, queueCustomFields, teamMembers } from '../db/schema.ts';
import { and, eq, asc, or, ilike, isNull, inArray, exists, sql } from 'drizzle-orm';
import { CreateTicketSchema, UpdateTicketSchema, CommentSchema } from '../models/ticket.ts';
import { ScripEngine } from '../scrip/engine.ts';
import { LifecycleValidator } from '../lifecycle/validator.ts';
import type { LifecycleDefinition } from '../lifecycle/validator.ts';

export function createTicketsRouter(db: Db): Hono {
  const router = new Hono();
  const scripEngine = new ScripEngine(db);
  const lifecycleValidator = new LifecycleValidator();

  function statusClass(def: LifecycleDefinition, status: string): 'initial' | 'active' | 'inactive' | 'unknown' {
    if (def.statuses.initial.includes(status)) return 'initial';
    if (def.statuses.active.includes(status)) return 'active';
    if (def.statuses.inactive.includes(status)) return 'inactive';
    return 'unknown';
  }

  // GET / — list tickets
  router.get('/', async (c) => {
    const params = new URL(c.req.url).searchParams;
    const queueId = c.req.query('queue_id');
    const status = c.req.query('status');
    const ownerId = c.req.query('owner_id');
    const teamId = c.req.query('team_id');
    const query = c.req.query('q')?.trim() ?? '';
    const limit = c.req.query('limit') ? Number(c.req.query('limit')) : undefined;
    const cfFilters = [...params.entries()]
      .filter(([key, value]) => key.startsWith('cf.') && value.trim())
      .map(([key, value]) => ({
        key: key.slice(3),
        value: value.trim(),
      }));

    // Build SQL WHERE conditions
    const conditions: ReturnType<typeof eq>[] = [];

    if (queueId) {
      conditions.push(eq(tickets.queue_id, queueId));
    }
    if (status) {
      conditions.push(eq(tickets.status, status));
    }
    if (ownerId) {
      conditions.push(
        ownerId === 'unassigned' ? isNull(tickets.owner_id) : eq(tickets.owner_id, ownerId)
      );
    }
    if (teamId) {
      // Resolve team members and filter tickets by those owner_ids
      const members = await db.query.teamMembers.findMany({
        where: eq(teamMembers.team_id, teamId),
      });
      const memberIds = members.map((m) => m.user_id);
      if (memberIds.length > 0) {
        conditions.push(inArray(tickets.owner_id, memberIds));
      } else {
        conditions.push(isNull(tickets.owner_id)); // empty team = no results
      }
    }

    // Text search: push to SQL via ilike on ticket columns + queue name join
    if (query) {
      const pattern = `%${query}%`;
      conditions.push(
        or(
          ilike(tickets.subject, pattern),
          ilike(tickets.status, pattern),
          sql`${tickets.id}::text ILIKE ${pattern}`
        )!
      );
      // Queue name search requires join — keep as post-filter
    }

    // Custom field filters: use EXISTS subquery
    for (const cf of cfFilters) {
      conditions.push(
        exists(
          db.select({ n: sql`1` })
            .from(customFieldValues)
            .innerJoin(customFields, eq(customFieldValues.custom_field_id, customFields.id))
            .where(
              and(
                eq(customFieldValues.ticket_id, tickets.id),
                eq(customFields.key, cf.key),
                eq(customFieldValues.value, cf.value)
              )
            )
        )
      );
    }

    const result = await db.query.tickets.findMany({
      where: conditions.length > 0 ? and(...conditions) : undefined,
      orderBy: asc(tickets.created_at),
      limit,
    });

    // Post-filter for queue name text search (requires in-memory join)
    let filtered = result;
    if (query) {
      const queuesForSearch = await db.query.queues.findMany();
      const queueNameById = new Map(queuesForSearch.map((queue) => [queue.id, queue.name]));
      filtered = result.filter((ticket) =>
        (queueNameById.get(ticket.queue_id) ?? '').toLowerCase().includes(query.toLowerCase())
      );
    }

    return c.json(filtered);
  });

  // POST / — create ticket
  router.post('/', async (c) => {
    const body = await c.req.json();
    const parsed = CreateTicketSchema.parse(body);
    const creatorId = '00000000-0000-0000-0000-000000000000';
    const customFieldInput = parsed.custom_fields ?? {};
    const customFieldEntries = Object.entries(customFieldInput)
      .map(([fieldId, value]) => [fieldId, value.trim()] as const)
      .filter(([, value]) => value);
    const queue = await db.query.queues.findFirst({
      where: eq(queues.id, parsed.queue_id),
    });

    if (!queue) {
      throw new HTTPException(422, { message: 'Queue not found' });
    }

    let initialStatus = 'new';
    if (queue.lifecycle_id) {
      const lifecycle = await db.query.lifecycles.findFirst({
        where: eq(lifecycles.id, queue.lifecycle_id),
      });
      const definition = lifecycle?.definition as LifecycleDefinition | undefined;
      initialStatus = definition?.statuses.initial[0] ?? initialStatus;
    }

    let assignedFields: typeof customFields.$inferSelect[] = [];
    if (customFieldEntries.length > 0) {
      const assignments = await db.query.queueCustomFields.findMany({
        where: eq(queueCustomFields.queue_id, parsed.queue_id),
      });
      const assignedIds = new Set(assignments.map((assignment) => assignment.custom_field_id));
      const requestedIds = customFieldEntries.map(([fieldId]) => fieldId);

      for (const fieldId of requestedIds) {
        if (!assignedIds.has(fieldId)) {
          throw new HTTPException(422, { message: 'Custom field is not assigned to this queue' });
        }
      }

      assignedFields = await db.query.customFields.findMany({
        where: (table, { inArray }) => inArray(table.id, requestedIds),
      });
      const fieldById = new Map(assignedFields.map((field) => [field.id, field]));

      for (const [fieldId, value] of customFieldEntries) {
        const field = fieldById.get(fieldId);
        if (!field) {
          throw new HTTPException(422, { message: 'Custom field not found' });
        }
        if (Array.isArray(field.values) && field.values.length > 0) {
          const allowed = new Set(field.values.map((option) => String(option)));
          if (!allowed.has(value)) {
            throw new HTTPException(422, { message: `${field.name}: value is not an allowed option` });
          }
        }
        if (field.pattern) {
          const regex = new RegExp(field.pattern);
          if (!regex.test(value)) {
            throw new HTTPException(422, { message: `${field.name}: value does not match the required pattern` });
          }
        }
      }
    }

    const [ticket] = await db.insert(tickets).values({
      subject: parsed.subject,
      queue_id: parsed.queue_id,
      status: initialStatus,
      creator_id: creatorId,
      team_id: (queue as any).team_id ?? null,
    }).returning();

    if (!ticket) {
      throw new HTTPException(500, { message: 'Failed to create ticket' });
    }

    const txList = [
      {
        ticket_id: ticket.id,
        transaction_type: 'Create',
        field: 'status',
        new_value: initialStatus,
        creator_id: creatorId,
      },
    ];

    if (parsed.description) {
      txList.push({
        ticket_id: ticket.id,
        transaction_type: 'Correspond',
        field: null,
        new_value: null,
        data: { body: parsed.description },
        creator_id: creatorId,
      } as any);
    }

    const fieldById = new Map(assignedFields.map((field) => [field.id, field]));
    for (const [fieldId, value] of customFieldEntries) {
      await db.insert(customFieldValues).values({
        ticket_id: ticket.id,
        custom_field_id: fieldId,
        value,
      });
      txList.push({
        ticket_id: ticket.id,
        transaction_type: 'CustomFieldChange',
        field: fieldById.get(fieldId)?.key ?? fieldId,
        new_value: value,
        creator_id: creatorId,
      } as any);
    }

    const createdTransactions = await db.insert(transactions).values(txList as any).returning();
    const prepared = await scripEngine.prepare(ticket.id, createdTransactions as any);
    const results = await scripEngine.commit(prepared);

    return c.json({ ticket, scrip_results: results }, 201);
  });

  // GET /:id — get ticket with custom field values
  router.get('/:id', async (c) => {
    const id = Number(c.req.param('id'));

    const ticket = await db.query.tickets.findFirst({
      where: eq(tickets.id, id),
    });

    if (!ticket) {
      throw new HTTPException(404, { message: 'Ticket not found' });
    }

    const cfValues = await db.query.customFieldValues.findMany({
      where: eq(customFieldValues.ticket_id, id),
    });

    const cfIds = [...new Set(cfValues.map(v => v.custom_field_id))];
    const cfRecords = cfIds.length > 0
      ? await db.query.customFields.findMany({
          where: (fields, { inArray }) => inArray(fields.id, cfIds),
        })
      : [];
    const cfMap = new Map(cfRecords.map(cf => [cf.id, cf]));
    const customFieldsMapped = cfValues.map(v => ({
      ...v,
      custom_field: cfMap.get(v.custom_field_id) ?? null,
    }));

    return c.json({ ...ticket, custom_fields: customFieldsMapped });
  });

  // PATCH /:id — update ticket
  router.patch('/:id', async (c) => {
    const id = Number(c.req.param('id'));
    const body = await c.req.json();
    const parsed = UpdateTicketSchema.parse(body);

    const ticket = await db.query.tickets.findFirst({
      where: eq(tickets.id, id),
    });

    if (!ticket) {
      throw new HTTPException(404, { message: 'Ticket not found' });
    }

    let lifecycleDef: LifecycleDefinition | null = null;

    // Validate lifecycle transition if status is changing
    if (parsed.status) {
      const queue = await db.query.queues.findFirst({
        where: eq(queues.id, ticket.queue_id),
      });

      if (queue?.lifecycle_id) {
        const lifecycle = await db.query.lifecycles.findFirst({
          where: eq(lifecycles.id, queue.lifecycle_id!),
        });

        if (lifecycle) {
          lifecycleDef = lifecycle.definition as LifecycleDefinition;
          const result = lifecycleValidator.validateTransition(lifecycleDef, ticket.status, parsed.status);
          if (!result.valid) {
            throw new HTTPException(422, { message: result.error ?? 'Invalid transition' });
          }
        }
      }
    }

    const txList = [];

    if (parsed.subject && parsed.subject !== ticket.subject) {
      txList.push({
        ticket_id: id,
        transaction_type: 'StatusChange' as const,
        field: 'subject',
        old_value: ticket.subject,
        new_value: parsed.subject,
        creator_id: '00000000-0000-0000-0000-000000000000',
      });
    }

    if (parsed.status && parsed.status !== ticket.status) {
      txList.push({
        ticket_id: id,
        transaction_type: 'StatusChange' as const,
        field: 'status',
        old_value: ticket.status,
        new_value: parsed.status,
        creator_id: '00000000-0000-0000-0000-000000000000',
      });
    }

    if (parsed.owner_id !== undefined && parsed.owner_id !== ticket.owner_id) {
      txList.push({
        ticket_id: id,
        transaction_type: 'SetOwner' as const,
        field: 'owner_id',
        old_value: ticket.owner_id ?? null,
        new_value: parsed.owner_id,
        creator_id: '00000000-0000-0000-0000-000000000000',
      });
    }

    if (parsed.team_id !== undefined && parsed.team_id !== (ticket as any).team_id) {
      txList.push({
        ticket_id: id,
        transaction_type: 'SetTeam' as const,
        field: 'team_id',
        old_value: (ticket as any).team_id ?? null,
        new_value: parsed.team_id,
        creator_id: '00000000-0000-0000-0000-000000000000',
      });
    }

    // Update the ticket
    const updateData: Record<string, unknown> = {};
    if (parsed.subject) updateData.subject = parsed.subject;
    if (parsed.status) {
      updateData.status = parsed.status;

      if (lifecycleDef && parsed.status !== ticket.status) {
        const fromClass = statusClass(lifecycleDef, ticket.status);
        const toClass = statusClass(lifecycleDef, parsed.status);
        const now = new Date();

        if (fromClass === 'initial' && (toClass === 'active' || toClass === 'inactive') && !ticket.started_at) {
          updateData.started_at = now;
        }

        if ((fromClass === 'initial' || fromClass === 'active') && toClass === 'inactive') {
          updateData.resolved_at = now;
        }

        if (fromClass === 'inactive' && toClass !== 'inactive') {
          updateData.resolved_at = null;
        }
      }
    }
    if (parsed.owner_id !== undefined) updateData.owner_id = parsed.owner_id;
    if (parsed.team_id !== undefined) updateData.team_id = parsed.team_id;
    updateData.updated_at = new Date();

    const [updated] = await db.update(tickets)
      .set(updateData as any)
      .where(eq(tickets.id, id))
      .returning();

    // Insert transactions
    if (txList.length > 0) {
      await db.insert(transactions).values(txList as any);
    }

    // Run scrips
    const prepared = await scripEngine.prepare(id, txList as any);
    const results = await scripEngine.commit(prepared);

    return c.json({ ticket: updated, scrip_results: results });
  });

  // POST /:id/preview — dry-run scrips
  router.post('/:id/preview', async (c) => {
    const id = Number(c.req.param('id'));
    const body = await c.req.json();
    const parsed = UpdateTicketSchema.parse(body);

    const ticket = await db.query.tickets.findFirst({
      where: eq(tickets.id, id),
    });

    if (!ticket) {
      throw new HTTPException(404, { message: 'Ticket not found' });
    }

    if (parsed.status) {
      const queue = await db.query.queues.findFirst({
        where: eq(queues.id, ticket.queue_id),
      });

      if (queue?.lifecycle_id) {
        const lifecycle = await db.query.lifecycles.findFirst({
          where: eq(lifecycles.id, queue.lifecycle_id),
        });

        if (lifecycle) {
          const lifecycleDef = lifecycle.definition as LifecycleDefinition;
          const result = lifecycleValidator.validateTransition(lifecycleDef, ticket.status, parsed.status);
          if (!result.valid) {
            throw new HTTPException(422, { message: result.error ?? 'Invalid transition' });
          }
        }
      }
    }

    const txList: any[] = [];

    if (parsed.status && parsed.status !== ticket.status) {
      txList.push({
        id: '00000000-0000-0000-0000-000000000000',
        ticket_id: id,
        transaction_type: 'StatusChange',
        field: 'status',
        old_value: ticket.status,
        new_value: parsed.status,
        creator_id: '00000000-0000-0000-0000-000000000000',
      });
    }

    const prepared = await scripEngine.prepare(id, txList);
    const preparedWithDryRun = prepared.map((p) => ({ ...p, dryRun: true }));
    const results = await scripEngine.commit(preparedWithDryRun);

    return c.json({ prepared_scrips: results });
  });

  // GET /:id/transactions — list transactions for ticket
  router.get('/:id/transactions', async (c) => {
    const id = Number(c.req.param('id'));

    const result = await db.query.transactions.findMany({
      where: eq(transactions.ticket_id, id),
      orderBy: asc(transactions.created_at),
    });

    return c.json(result);
  });

  // POST /:id/comment — add a comment (reply or internal note)
  router.post('/:id/comment', async (c) => {
    const id = Number(c.req.param('id'));
    const body = await c.req.json();
    const parsed = CommentSchema.parse(body);

    const ticket = await db.query.tickets.findFirst({
      where: eq(tickets.id, id),
    });

    if (!ticket) {
      throw new HTTPException(404, { message: 'Ticket not found' });
    }

    const transactionType = parsed.internal ? 'Comment' : 'Correspond';

    const [tx] = await db.insert(transactions).values({
      ticket_id: id,
      transaction_type: transactionType,
      data: { body: parsed.body },
      creator_id: parsed.creator_id,
    }).returning();

    if (!tx) {
      throw new HTTPException(500, { message: 'Failed to create comment' });
    }

    // Run scrips
    const txList = [tx];
    const prepared = await scripEngine.prepare(id, txList as any);
    await scripEngine.commit(prepared);

    return c.json(tx, 201);
  });

  // PATCH /:id/custom-fields/:fieldId — set or clear a custom field value
  router.patch('/:id/custom-fields/:fieldId', async (c) => {
    const id = Number(c.req.param('id'));
    const fieldId = c.req.param('fieldId');
    const body = await c.req.json();
    const value = typeof body.value === 'string' ? body.value.trim() : '';

    const ticket = await db.query.tickets.findFirst({
      where: eq(tickets.id, id),
    });

    if (!ticket) {
      throw new HTTPException(404, { message: 'Ticket not found' });
    }

    const assignment = await db.query.queueCustomFields.findFirst({
      where: and(
        eq(queueCustomFields.queue_id, ticket.queue_id),
        eq(queueCustomFields.custom_field_id, fieldId),
      ),
    });

    if (!assignment) {
      throw new HTTPException(422, { message: 'Custom field is not assigned to this ticket queue' });
    }

    const field = await db.query.customFields.findFirst({
      where: eq(customFields.id, fieldId),
    });

    if (!field) {
      throw new HTTPException(404, { message: 'Custom field not found' });
    }

    if (value && Array.isArray(field.values) && field.values.length > 0) {
      const allowed = new Set(field.values.map((option) => String(option)));
      if (!allowed.has(value)) {
        throw new HTTPException(422, { message: `${field.name}: value is not an allowed option` });
      }
    }

    if (value && field.pattern) {
      const regex = new RegExp(field.pattern);
      if (!regex.test(value)) {
        throw new HTTPException(422, { message: `${field.name}: value does not match the required pattern` });
      }
    }

    const existing = await db.query.customFieldValues.findMany({
      where: and(
        eq(customFieldValues.ticket_id, id),
        eq(customFieldValues.custom_field_id, fieldId),
      ),
    });
    const oldValue = existing.map((item) => item.value).join(', ');

    await db.delete(customFieldValues).where(and(
      eq(customFieldValues.ticket_id, id),
      eq(customFieldValues.custom_field_id, fieldId),
    ));

    if (value) {
      await db.insert(customFieldValues).values({
        ticket_id: id,
        custom_field_id: fieldId,
        value,
      });
    }

    await db.update(tickets)
      .set({ updated_at: new Date() } as any)
      .where(eq(tickets.id, id));

    const [tx] = await db.insert(transactions).values({
      ticket_id: id,
      transaction_type: 'CustomFieldChange',
      field: field.key,
      old_value: oldValue || null,
      new_value: value || null,
      creator_id: '00000000-0000-0000-0000-000000000000',
    }).returning();

    const prepared = await scripEngine.prepare(id, [tx] as any);
    await scripEngine.commit(prepared);

    return c.json(tx, 200);
  });

  return router;
}