package web

import (
	"errors"
	"fmt"
	"testing"

	"github.com/jackc/pgx/v5/pgconn"
)

func TestFieldErrorsFromDB_ConstraintNameHit(t *testing.T) {
	msgs := ConstraintMessages{
		"workspaces_org_id_slug_key": {Field: "slug", Message: "A workspace with this slug already exists in this organization."},
	}
	// Wrapped, as sqlc/database/sql returns it in practice.
	err := fmt.Errorf("exec insert: %w", &pgconn.PgError{
		Code:           "23505",
		ConstraintName: "workspaces_org_id_slug_key",
		Message:        `duplicate key value violates unique constraint "workspaces_org_id_slug_key"`,
	})

	fe, ok := FieldErrorsFromDB(err, msgs)
	if !ok {
		t.Fatalf("FieldErrorsFromDB ok = false, want true")
	}
	if got := fe.Get("slug"); got != "A workspace with this slug already exists in this organization." {
		t.Errorf("fe.Get(slug) = %q, want the mapped message", got)
	}
	if len(fe) != 1 {
		t.Errorf("len(fe) = %d, want exactly one entry", len(fe))
	}
	// The named match must win over the per-class fallback.
	if fe.Has("") {
		t.Errorf("form-level fallback populated alongside a named constraint hit: %q", fe.Get(""))
	}
}

func TestFieldErrorsFromDB_ClassFallback(t *testing.T) {
	cases := []struct {
		code string
		want string
	}{
		{"23505", "A record with these values already exists."},
		{"23503", "A referenced record no longer exists or is still in use."},
		{"23514", "This combination of values is not allowed."},
		{"22001", "One of the values is too long."},
	}
	for _, tc := range cases {
		t.Run(tc.code, func(t *testing.T) {
			err := &pgconn.PgError{Code: tc.code, ConstraintName: "not_in_the_map"}
			fe, ok := FieldErrorsFromDB(err, ConstraintMessages{
				"some_other_constraint": {Field: "name", Message: "unrelated"},
			})
			if !ok {
				t.Fatalf("ok = false, want true for SQLSTATE %s", tc.code)
			}
			if got := fe.Get(""); got != tc.want {
				t.Errorf("fe.Get(\"\") = %q, want %q", got, tc.want)
			}
			if fe.Has("name") {
				t.Errorf("unrelated named mapping leaked into the result")
			}
		})
	}
}

func TestFieldErrorsFromDB_NilMapStillFallsBack(t *testing.T) {
	fe, ok := FieldErrorsFromDB(&pgconn.PgError{Code: "23503"}, nil)
	if !ok {
		t.Fatalf("ok = false, want true — nil ConstraintMessages must still allow class fallback")
	}
	if fe.Get("") == "" {
		t.Errorf("expected a form-level fallback message, got none")
	}
}

func TestFieldErrorsFromDB_NotOK(t *testing.T) {
	cases := []struct {
		name string
		err  error
	}{
		{"non-pg error", errors.New("dial tcp 127.0.0.1:5432: connection refused")},
		{"wrapped non-pg error", fmt.Errorf("query: %w", errors.New("context canceled"))},
		{"pg error with unrecognized class", &pgconn.PgError{Code: "42703", Message: `column "nope" does not exist`}},
		{"nil-ish sql error text mentioning SQLSTATE", errors.New("ERROR: something (SQLSTATE 23505)")},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			fe, ok := FieldErrorsFromDB(tc.err, ConstraintMessages{
				"chk_grants_recipient": {Field: "", Message: "A grant must name exactly one recipient."},
			})
			if ok {
				t.Fatalf("ok = true, want false (fe=%v) — caller must slog + render a generic message", fe)
			}
			if fe != nil {
				t.Errorf("fe = %v, want nil on ok=false", fe)
			}
		})
	}
}

func TestFieldErrorsFromDB_ExclusionConstraintNeedsNamedEntry(t *testing.T) {
	// SQLSTATE 23P01 (exclusion_violation) has no per-class fallback: without
	// a named entry it must return ok=false, and with one the name must win.
	exclErr := &pgconn.PgError{Code: "23P01", ConstraintName: "excl_pool_provision_ladders_active_overlap"}

	if _, ok := FieldErrorsFromDB(exclErr, nil); ok {
		t.Fatalf("ok = true for unmapped 23P01, want false")
	}

	fe, ok := FieldErrorsFromDB(exclErr, ConstraintMessages{
		"excl_pool_provision_ladders_active_overlap": {Field: "product_id", Message: "This pool already has an active plan on that ladder."},
	})
	if !ok {
		t.Fatalf("ok = false for mapped 23P01, want true")
	}
	if got := fe.Get("product_id"); got != "This pool already has an active plan on that ladder." {
		t.Errorf("fe.Get(product_id) = %q, want the mapped message", got)
	}
}