package api

import (
	"net/http"
	"strings"
	"time"

	"github.com/loyaly/behavision-server/internal/auth"
)

func (s *Server) handleVisitors(w http.ResponseWriter, r *http.Request) {
	p := PrincipalFrom(r.Context())
	q := trim(r.URL.Query().Get("q"))
	limit := queryInt(r, "limit", 50, 500)

	out, err := s.Store.SearchVisitors(r.Context(), p.ClientID, q, limit)
	if err != nil {
		s.serverError(w, "search visitors", err)
		return
	}
	if out == nil {
		out = []Customer{}
	}
	writeJSON(w, http.StatusOK, out)
}

func (s *Server) handleVisitorHistory(w http.ResponseWriter, r *http.Request) {
	p := PrincipalFrom(r.Context())
	// 404, not 400: to the caller a reference that is malformed and one that
	// names nobody are the same thing - the customer is not there.
	id, ok := s.resolveVisitor(w, r, r.PathValue("id"))
	if !ok {
		return
	}
	rows, err := s.Store.VisitorHistory(r.Context(), p.ClientID, id,
		queryInt(r, "limit", 100, 1000))
	if err != nil {
		s.serverError(w, "visitor history", err)
		return
	}
	if rows == nil {
		rows = []VisitRow{}
	}
	writeJSON(w, http.StatusOK, rows)
}

// handleSaveProfile attaches a name, a phone number and a consent record to a
// face the system already knows.
//
// PUT, and idempotent on visitor_id: staff fill this in on a shop floor with
// bad wifi, and a resubmit must correct the record rather than create a second
// one for the same person.
func (s *Server) handleSaveProfile(w http.ResponseWriter, r *http.Request) {
	p := PrincipalFrom(r.Context())
	if !p.CanWriteProfiles() {
		writeErr(w, http.StatusForbidden, "forbidden",
			"Your account cannot edit customer details.")
		return
	}
	var body Profile
	if err := decode(w, r, &body); err != nil {
		badRequest(w, err.Error())
		return
	}
	// The path wins over the body. Trusting the body would let a client PUT to
	// one customer's URL and write to another's record.
	visitorID, ok := s.resolveVisitor(w, r, r.PathValue("id"))
	if !ok {
		return
	}
	body.VisitorID = visitorID
	body.FullName = clip(trim(body.FullName), 200)
	body.Phone = clip(trim(body.Phone), 40)
	body.Email = auth.NormalizeEmail(body.Email)
	body.Gender = clip(trim(body.Gender), 32)
	body.Notes = clip(trim(body.Notes), 2000)
	if body.DateOfBirth != "" {
		if _, err := time.Parse("2006-01-02", body.DateOfBirth); err != nil {
			badRequest(w, "date of birth must look like 2001-04-23")
			return
		}
	}
	if body.FullName == "" && body.Phone == "" && body.Email == "" {
		badRequest(w, "give at least a name, a phone number or an email")
		return
	}

	if err := s.Store.SaveProfile(r.Context(), p.ClientID, body, p.UserID); err != nil {
		if strings.Contains(err.Error(), "no such visitor") {
			// 404, not 403: within one client this is a typo, and the tenant
			// scoping in the query already made a cross-tenant id unfindable.
			writeErr(w, http.StatusNotFound, "not_found",
				"That customer no longer exists.")
			return
		}
		s.serverError(w, "save profile", err)
		return
	}
	// Audited because it links a real name to a biometric template. If a client
	// ever asks who put a name to a face, a guess is not an answer.
	s.Store.Audit(r.Context(), AuditEntry{
		ClientID: p.ClientID, ActorID: p.UserID, ActorKind: "user",
		Action: "profile.save", Entity: "visitor", EntityID: body.VisitorID,
		Detail: map[string]any{"consent": body.Consent},
	})
	w.WriteHeader(http.StatusNoContent)
}

func (s *Server) handlePurchase(w http.ResponseWriter, r *http.Request) {
	p := PrincipalFrom(r.Context())
	if !p.CanWriteProfiles() {
		writeErr(w, http.StatusForbidden, "forbidden",
			"Your account cannot record purchases.")
		return
	}
	var body PurchaseInput
	if err := decode(w, r, &body); err != nil {
		badRequest(w, err.Error())
		return
	}
	body.VisitorID = trim(body.VisitorID)
	if body.VisitorID == "" {
		badRequest(w, "visitor_id is required")
		return
	}
	visitorID, ok := s.resolveVisitor(w, r, body.VisitorID)
	if !ok {
		return
	}
	body.VisitorID = visitorID
	if body.Amount < 0 {
		// A refund is a different record with a different meaning, not a
		// negative sale. Allowing it here would quietly deflate the revenue
		// figure the conversion report is judged by.
		badRequest(w, "amount cannot be negative")
		return
	}
	if body.Currency == "" {
		body.Currency = "INR"
	}
	if len(body.Currency) != 3 {
		badRequest(w, "currency must be a 3-letter code")
		return
	}
	body.Currency = strings.ToUpper(body.Currency)
	if body.Source == "" {
		body.Source = "manual"
	}
	body.Notes = clip(trim(body.Notes), 2000)

	if err := s.Store.RecordPurchase(r.Context(), p.ClientID, body, p.UserID); err != nil {
		switch {
		case strings.Contains(err.Error(), "no such visitor"):
			writeErr(w, http.StatusNotFound, "not_found",
				"That customer no longer exists.")
		case strings.Contains(err.Error(), "no site"):
			// This is actionable, so it says what to do rather than failing
			// with a foreign key error nobody can read.
			badRequest(w, "this customer has never been seen at a store, "+
				"so there is no site to book the sale against - pass site_id")
		default:
			s.serverError(w, "record purchase", err)
		}
		return
	}
	s.Store.Audit(r.Context(), AuditEntry{
		ClientID: p.ClientID, ActorID: p.UserID, ActorKind: "user",
		Action: "purchase.record", Entity: "visitor", EntityID: body.VisitorID,
		Detail: map[string]any{"amount": body.Amount, "currency": body.Currency},
	})
	w.WriteHeader(http.StatusNoContent)
}