import { Router, type Request, type RequestHandler, type Response } from 'express'
import { login, requireAuth, requireOwner } from './auth'
import type { DB } from './db'
import {
  createClient, getClient, listClients, updateClient,
  type ClientInput, type ClientPatch,
} from './repos-clients'
import {
  assignModule, createModule, getClientModule, getModule, listClientModules,
  listModules, listPrices, setPrice, updateClientModule, updateModule,
  type AssignModuleInput, type ClientModulePatch, type ModuleInput, type ModulePatch,
  type PriceInput,
} from './repos-modules'
import {
  cancelDocument, convertDocument, createCreditNote, createDraft, getDocument,
  issueDocument, listDocumentEvents, listDocuments, markStatus,
  type DocumentFilter, type DraftInput, type DraftLineInput,
} from './repos-documents'
import {
  clientLedger, modulePaidView, recordPayment, type RecordPaymentInput,
} from './repos-payments'
import { documentHtml } from './templates'
import { renderPdf } from './pdf'
import { emailStatus } from './repos-email'
import { sendDocumentEmail, type GmailDeps } from './gmail'

const staffId = (res: Response): string => (res.locals['staff'] as { id: string }).id

export function apiRouter(db: DB, gmailDeps?: Partial<GmailDeps>): Router {
  const r = Router()
  const companySettings = (): Record<string, string> => {
    const rows = db.prepare(
      `SELECT key, value FROM setting WHERE key LIKE 'company.%'`,
    ).all() as { key: string; value: string }[]
    return Object.fromEntries(rows.map((row) => [row.key, row.value]))
  }
  // Env read at request time so gmail-connect can run without a restart.
  const gmail = (): GmailDeps => ({
    f: gmailDeps?.f ?? fetch,
    clientId: gmailDeps?.clientId ?? process.env['GOOGLE_CLIENT_ID'] ?? '',
    clientSecret: gmailDeps?.clientSecret ?? process.env['GOOGLE_CLIENT_SECRET'] ?? '',
    keyHex: gmailDeps?.keyHex ?? process.env['HQ_SECRET_KEY'] ?? '',
  })
  r.get('/health', (_req, res) => {
    res.json({ ok: true, service: 'sims-hq', version: '0.1.0' })
  })
  r.post('/auth/login', (req, res) => {
    const { email, password } = req.body as { email?: string; password?: string }
    const out = typeof email === 'string' && typeof password === 'string' ? login(db, email, password) : null
    if (!out) { res.status(401).json({ ok: false, error: 'Invalid email or password' }); return }
    res.json({ ok: true, ...out })
  })

  // ---------- clients ----------
  r.get('/clients', requireAuth, (req, res) => {
    const q = typeof req.query['q'] === 'string' ? req.query['q'] : undefined
    res.json({ ok: true, clients: listClients(db, q) })
  })
  r.post('/clients', requireAuth, (req, res) => {
    try {
      const client = createClient(db, staffId(res), req.body as ClientInput)
      res.json({ ok: true, client })
    } catch (err) {
      res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
    }
  })
  r.get('/clients/:id', requireAuth, (req, res) => {
    const client = getClient(db, String(req.params['id'] ?? ''))
    if (client === null) { res.status(404).json({ ok: false, error: 'Client not found' }); return }
    res.json({ ok: true, client })
  })
  r.patch('/clients/:id', requireAuth, (req, res) => {
    const id = String(req.params['id'] ?? '')
    if (getClient(db, id) === null) {
      res.status(404).json({ ok: false, error: 'Client not found' }); return
    }
    try {
      const client = updateClient(db, staffId(res), id, req.body as ClientPatch)
      res.json({ ok: true, client })
    } catch (err) {
      res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
    }
  })

  // ---------- modules ----------
  r.get('/modules', requireAuth, (_req, res) => {
    res.json({ ok: true, modules: listModules(db) })
  })
  r.post('/modules', requireAuth, requireOwner, (req, res) => {
    try {
      const mod = createModule(db, staffId(res), req.body as ModuleInput)
      res.json({ ok: true, module: mod })
    } catch (err) {
      res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
    }
  })
  r.patch('/modules/:id', requireAuth, requireOwner, (req, res) => {
    const id = String(req.params['id'] ?? '')
    if (getModule(db, id) === null) {
      res.status(404).json({ ok: false, error: 'Module not found' }); return
    }
    try {
      const mod = updateModule(db, staffId(res), id, req.body as ModulePatch)
      res.json({ ok: true, module: mod })
    } catch (err) {
      res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
    }
  })
  r.get('/modules/:id/prices', requireAuth, (req, res) => {
    const id = String(req.params['id'] ?? '')
    if (getModule(db, id) === null) {
      res.status(404).json({ ok: false, error: 'Module not found' }); return
    }
    res.json({ ok: true, prices: listPrices(db, id) })
  })
  r.post('/modules/:id/prices', requireAuth, requireOwner, (req, res) => {
    const id = String(req.params['id'] ?? '')
    if (getModule(db, id) === null) {
      res.status(404).json({ ok: false, error: 'Module not found' }); return
    }
    try {
      setPrice(db, staffId(res), { ...(req.body as Omit<PriceInput, 'moduleId'>), moduleId: id })
      res.json({ ok: true, prices: listPrices(db, id) })
    } catch (err) {
      res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
    }
  })

  // ---------- client modules ----------
  r.get('/clients/:id/modules', requireAuth, (req, res) => {
    const id = String(req.params['id'] ?? '')
    if (getClient(db, id) === null) {
      res.status(404).json({ ok: false, error: 'Client not found' }); return
    }
    res.json({ ok: true, clientModules: listClientModules(db, id) })
  })
  r.post('/clients/:id/modules', requireAuth, (req, res) => {
    const id = String(req.params['id'] ?? '')
    if (getClient(db, id) === null) {
      res.status(404).json({ ok: false, error: 'Client not found' }); return
    }
    try {
      const cm = assignModule(db, staffId(res), {
        ...(req.body as Omit<AssignModuleInput, 'clientId'>), clientId: id,
      })
      res.json({ ok: true, clientModule: cm })
    } catch (err) {
      res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
    }
  })
  r.patch('/client-modules/:id', requireAuth, (req, res) => {
    const id = String(req.params['id'] ?? '')
    if (getClientModule(db, id) === null) {
      res.status(404).json({ ok: false, error: 'Client module not found' }); return
    }
    try {
      const cm = updateClientModule(db, staffId(res), id, req.body as ClientModulePatch)
      res.json({ ok: true, clientModule: cm })
    } catch (err) {
      res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
    }
  })

  // ---------- documents ----------
  r.post('/documents', requireAuth, (req, res) => {
    try {
      const document = createDraft(db, staffId(res), req.body as DraftInput)
      res.json({ ok: true, document })
    } catch (err) {
      res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
    }
  })
  r.get('/documents', requireAuth, (req, res) => {
    const filter: DocumentFilter = {}
    if (typeof req.query['type'] === 'string') filter.type = req.query['type']
    if (typeof req.query['status'] === 'string') filter.status = req.query['status']
    if (typeof req.query['clientId'] === 'string') filter.clientId = req.query['clientId']
    res.json({ ok: true, documents: listDocuments(db, filter) })
  })
  r.get('/documents/:id', requireAuth, (req, res) => {
    const id = String(req.params['id'] ?? '')
    const document = getDocument(db, id)
    if (document === null) { res.status(404).json({ ok: false, error: 'Document not found' }); return }
    const emails = db.prepare(
      `SELECT * FROM email_log WHERE document_id=? ORDER BY id`,
    ).all(id)
    res.json({ ok: true, document, events: listDocumentEvents(db, id), emails })
  })

  const docAction = (fn: (docId: string, res: Response, req: Request) => unknown): RequestHandler =>
    (req, res) => {
      const id = String(req.params['id'] ?? '')
      if (getDocument(db, id) === null) {
        res.status(404).json({ ok: false, error: 'Document not found' }); return
      }
      try {
        res.json({ ok: true, document: fn(id, res, req) })
      } catch (err) {
        res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
      }
    }

  r.get('/documents/:id/pdf', requireAuth, (req, res) => {
    const id = String(req.params['id'] ?? '')
    const document = getDocument(db, id)
    if (document === null) { res.status(404).json({ ok: false, error: 'Document not found' }); return }
    const client = getClient(db, document.clientId)
    if (client === null) { res.status(404).json({ ok: false, error: 'Client not found' }); return }
    const company = companySettings()
    void (async () => {
      try {
        const pdf = await renderPdf(documentHtml(document, client, company))
        res.setHeader('Content-Type', 'application/pdf')
        // docNo contains '/' (QT/26-27-0001) — not legal in a filename.
        const filename = (document.docNo ?? 'draft').replaceAll('/', '-')
        res.setHeader('Content-Disposition', `inline; filename="${filename}.pdf"`)
        res.send(pdf)
      } catch (err) {
        res.status(500).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
      }
    })()
  })

  r.post('/documents/:id/issue', requireAuth, docAction((id, res) =>
    issueDocument(db, staffId(res), id)))
  r.post('/documents/:id/status', requireAuth, docAction((id, res, req) => {
    const { status } = req.body as { status?: string }
    if (status !== 'sent' && status !== 'accepted' && status !== 'lost') {
      throw new Error(`Status must be one of: sent, accepted, lost`)
    }
    return markStatus(db, staffId(res), id, status)
  }))
  r.post('/documents/:id/convert', requireAuth, docAction((id, res, req) => {
    const { to } = req.body as { to?: string }
    if (to !== 'PROFORMA' && to !== 'INVOICE') {
      throw new Error(`Convert target must be PROFORMA or INVOICE`)
    }
    return convertDocument(db, staffId(res), id, to)
  }))
  r.post('/documents/:id/cancel', requireAuth, docAction((id, res) =>
    cancelDocument(db, staffId(res), id)))
  r.post('/documents/:id/credit-note', requireAuth, docAction((id, res, req) => {
    const { lines } = req.body as { lines?: DraftLineInput[] }
    return createCreditNote(db, staffId(res), id, lines)
  }))

  // ---------- email ----------
  r.get('/email/status', requireAuth, (_req, res) => {
    res.json({ ok: true, ...emailStatus(db) })
  })
  r.post('/documents/:id/send', requireAuth, (req, res) => {
    const id = String(req.params['id'] ?? '')
    const document = getDocument(db, id)
    if (document === null) { res.status(404).json({ ok: false, error: 'Document not found' }); return }
    // Guard before any work: a dead/missing account never attempts a send.
    const status = emailStatus(db)
    if (!status.connected) { res.status(409).json({ ok: false, error: 'gmail-not-connected' }); return }
    if (status.dead) { res.status(409).json({ ok: false, error: 'gmail-token-dead' }); return }
    if (document.docNo === null) {
      res.status(400).json({ ok: false, error: 'Only issued documents can be emailed' }); return
    }
    const client = getClient(db, document.clientId)
    if (client === null) { res.status(404).json({ ok: false, error: 'Client not found' }); return }
    const body = req.body as { to?: string; subject?: string; body?: string }
    const to = body.to ?? client.contacts.find((c) => c.email !== undefined && c.email !== '')?.email
    if (to === undefined || to === '') {
      res.status(400).json({ ok: false, error: 'No recipient: pass "to" or add a contact email to the client' })
      return
    }
    const company = companySettings()
    const companyName = company['company.name'] ?? ''
    const subject = body.subject ?? `${document.docType} ${document.docNo} — ${companyName}`
    const bodyText = body.body ??
      `Dear ${client.name},\n\nPlease find attached ${document.docType} ${document.docNo}.\n\nRegards,\n${companyName}`
    void (async () => {
      try {
        const pdf = await renderPdf(documentHtml(document, client, company))
        const out = await sendDocumentEmail(db, gmail(), {
          documentId: id, to, subject, bodyText, pdf, userId: staffId(res),
        })
        if (!out.ok) {
          res.status(out.error === 'gmail-token-dead' ? 409 : 502).json({ ok: false, error: out.error })
          return
        }
        res.json({ ok: true, document: getDocument(db, id) })
      } catch (err) {
        res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
      }
    })()
  })

  // ---------- payments ----------
  r.post('/payments', requireAuth, (req, res) => {
    try {
      const out = recordPayment(db, staffId(res), req.body as RecordPaymentInput)
      res.json({ ok: true, ...out })
    } catch (err) {
      res.status(400).json({ ok: false, error: err instanceof Error ? err.message : String(err) })
    }
  })
  r.get('/clients/:id/ledger', requireAuth, (req, res) => {
    const id = String(req.params['id'] ?? '')
    if (getClient(db, id) === null) {
      res.status(404).json({ ok: false, error: 'Client not found' }); return
    }
    res.json({ ok: true, ...clientLedger(db, id), modulePaid: modulePaidView(db, id) })
  })

  return r
}