package api

import (
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"testing"

	"github.com/thepeterstone/claudomator/internal/budget"
)

type fakeBudget struct {
	hs  []budget.Headroom
	err error
}

func (f fakeBudget) All() ([]budget.Headroom, error) { return f.hs, f.err }

func TestHandleGetBudget_NoBudgetConfigured_ReturnsEmpty(t *testing.T) {
	srv, _ := testServer(t)
	req := httptest.NewRequest("GET", "/api/budget", nil)
	w := httptest.NewRecorder()
	srv.Handler().ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("status: want 200, got %d", w.Code)
	}
	var hs []budget.Headroom
	if err := json.Unmarshal(w.Body.Bytes(), &hs); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if len(hs) != 0 {
		t.Errorf("want empty list, got %+v", hs)
	}
}

func TestHandleGetBudget_ReportsHeadroom(t *testing.T) {
	srv, _ := testServer(t)
	srv.SetBudget(fakeBudget{hs: []budget.Headroom{
		{Provider: "claude", Limited: true, Limit: 10, Spent: 4, Remaining: 6, Fraction: 0.6},
	}})
	req := httptest.NewRequest("GET", "/api/budget", nil)
	w := httptest.NewRecorder()
	srv.Handler().ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("status: want 200, got %d", w.Code)
	}
	var hs []budget.Headroom
	if err := json.Unmarshal(w.Body.Bytes(), &hs); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if len(hs) != 1 || hs[0].Provider != "claude" || hs[0].Remaining != 6 {
		t.Errorf("unexpected headroom: %+v", hs)
	}
}

func TestHandleGetBudget_ErrorReturns500(t *testing.T) {
	srv, _ := testServer(t)
	srv.SetBudget(fakeBudget{err: errors.New("db down")})
	req := httptest.NewRequest("GET", "/api/budget", nil)
	w := httptest.NewRecorder()
	srv.Handler().ServeHTTP(w, req)
	if w.Code != http.StatusInternalServerError {
		t.Errorf("want 500, got %d", w.Code)
	}
}