package api

import (
	"strings"
	"testing"
	"time"
)

// The scheduler's clock is the part worth pinning down: it decides on its own,
// with nobody watching, whether to send a car a command. A task that fires in
// the wrong hour is worse than one that does not fire at all, so the zone, the
// weekday and the not-twice-in-one-minute guard are each checked here.

func TestTaskIsDue(t *testing.T) {
	warsaw, err := time.LoadLocation("Europe/Warsaw")
	if err != nil {
		t.Fatalf("Europe/Warsaw: %v", err)
	}
	// A Wednesday, 23:00 in Warsaw — 22:00 UTC.
	at2300 := time.Date(2026, 9, 2, 23, 0, 30, 0, warsaw)

	base := chargingTaskRecord{Time: "23:00", Zone: "Europe/Warsaw", Enabled: true}

	if !taskIsDue(base, at2300) {
		t.Error("a task set for 23:00 is not due at 23:00 in its own zone")
	}
	// The same instant, handed over as UTC. The zone on the task is what the
	// time is read in, so where the server thinks it is must not matter.
	if !taskIsDue(base, at2300.UTC()) {
		t.Error("the task stopped being due when the same instant arrived as UTC")
	}
	if taskIsDue(base, at2300.Add(time.Minute)) {
		t.Error("a task fired a minute after its time")
	}
	if taskIsDue(base, at2300.Add(-time.Minute)) {
		t.Error("a task fired a minute before its time")
	}

	// Weekdays. 2026-09-02 is a Wednesday (3).
	weeknights := base
	weeknights.Days = []int{1, 2, 3, 4, 5}
	if !taskIsDue(weeknights, at2300) {
		t.Error("a weeknight task is not due on a Wednesday")
	}
	weekends := base
	weekends.Days = []int{0, 6}
	if taskIsDue(weekends, at2300) {
		t.Error("a weekend task fired on a Wednesday")
	}

	// Fired already inside this minute: the sweep runs more than once a minute,
	// and the second sweep must not send the command again.
	fired := base
	fired.LastRun = at2300.UTC().Format(time.RFC3339)
	if taskIsDue(fired, at2300.Add(20*time.Second)) {
		t.Error("a task fired twice inside its own minute")
	}
	// Yesterday's firing is not this minute's.
	yesterday := base
	yesterday.LastRun = at2300.Add(-24 * time.Hour).UTC().Format(time.RFC3339)
	if !taskIsDue(yesterday, at2300) {
		t.Error("yesterday's run stopped today's from firing")
	}

	// A time that is not a time of day fires nothing rather than firing at
	// midnight, which is what a zero hour and minute would have meant.
	broken := base
	broken.Time = "later"
	if taskIsDue(broken, at2300) {
		t.Error("a task with an unreadable time fired")
	}
}

// A zone the host has no database for falls back to the server's own clock
// rather than silently shifting the schedule to UTC.
func TestTaskIsDueUnknownZone(t *testing.T) {
	now := time.Now()
	rec := chargingTaskRecord{
		Time: now.Format("15:04"),
		Zone: "Mars/Olympus_Mons",
	}
	if !taskIsDue(rec, now) {
		t.Error("a task in an unknown zone did not fall back to the server's clock")
	}
}

func TestParseHHMM(t *testing.T) {
	for _, tc := range []struct {
		in     string
		h, m   int
		wantOK bool
	}{
		{in: "23:00", h: 23, m: 0, wantOK: true},
		{in: "7:05", h: 7, m: 5, wantOK: true},
		{in: " 00:00 ", h: 0, m: 0, wantOK: true},
		{in: "24:00"},
		{in: "12:60"},
		{in: "12:5"},   // a half-typed minute is not a minute
		{in: "123:00"}, // nor is a three-digit hour
		{in: "12"},
		{in: ""},
		{in: "ab:cd"},
	} {
		h, m, ok := parseHHMM(tc.in)
		if ok != tc.wantOK {
			t.Errorf("parseHHMM(%q) ok = %v, want %v", tc.in, ok, tc.wantOK)
			continue
		}
		if ok && (h != tc.h || m != tc.m) {
			t.Errorf("parseHHMM(%q) = %d:%d, want %d:%d", tc.in, h, m, tc.h, tc.m)
		}
	}
}

func TestNormalizeDays(t *testing.T) {
	got := normalizeDays([]int{5, 1, 5, 9, -1, 0})
	want := []int{0, 1, 5}
	if len(got) != len(want) {
		t.Fatalf("normalizeDays = %v, want %v", got, want)
	}
	for i := range want {
		if got[i] != want[i] {
			t.Fatalf("normalizeDays = %v, want %v", got, want)
		}
	}
	// Empty means every day and stays empty rather than becoming all seven —
	// the two read the same today, but only one keeps meaning "every day".
	if len(normalizeDays(nil)) != 0 {
		t.Error("normalizeDays(nil) invented days")
	}
}

func TestTaskPayloadValidation(t *testing.T) {
	str := func(s string) *string { return &s }
	num := func(f float64) *float64 { return &f }

	// A whole task, as a create sends it.
	full := chargingTaskBody{
		Name:   str("  Night rate  "),
		Action: str("limit"),
		Time:   str("7:05"),
		Amps:   num(10),
	}
	payload, err := taskPayload(full, true)
	if err != nil {
		t.Fatalf("taskPayload: %v", err)
	}
	if payload["name"] != "Night rate" {
		t.Errorf("name = %v, want it trimmed", payload["name"])
	}
	if payload["time"] != "07:05" {
		t.Errorf("time = %v, want the padded 07:05", payload["time"])
	}
	if payload["enabled"] != true {
		t.Error("a new task was written switched off; nobody fills in a schedule to leave it off")
	}

	// The fields a task cannot exist without.
	for _, missing := range []chargingTaskBody{
		{Action: str("start"), Time: str("23:00")},
		{Name: str("x"), Time: str("23:00")},
		{Name: str("x"), Action: str("start")},
		{Name: str("  "), Action: str("start"), Time: str("23:00")},
		{Name: str("x"), Action: str("melt"), Time: str("23:00")},
		{Name: str("x"), Action: str("start"), Time: str("half past")},
	} {
		if _, err := taskPayload(missing, true); err == nil {
			t.Errorf("taskPayload accepted an incomplete task: %+v", missing)
		}
	}

	// The charger's own floor and ceiling.
	for _, amps := range []float64{1, 5, 33} {
		if _, err := taskPayload(chargingTaskBody{Amps: num(amps)}, false); err == nil {
			t.Errorf("taskPayload accepted %g A, outside what the charger will take", amps)
		}
	}

	// A partial write says only what it names, so a task switched off from the
	// list keeps its days and its time.
	on := true
	partial, err := taskPayload(chargingTaskBody{Enabled: &on}, false)
	if err != nil {
		t.Fatalf("taskPayload(partial): %v", err)
	}
	if len(partial) != 1 {
		t.Errorf("a switch-only write touched %v, want only enabled", partial)
	}
}

// A "limit" with no ceiling would fire and ask the charger for 0 A. Both halves
// are read from whatever the write leaves behind, so a PATCH naming one of them
// is checked against the stored other.
func TestCheckLimitAmps(t *testing.T) {
	stored := chargingTaskRecord{Action: "start", Amps: 0}
	if err := checkLimitAmps(map[string]any{"action": "limit"}, stored); err == nil {
		t.Error("a task switched to limit with no amps was accepted")
	}
	if err := checkLimitAmps(map[string]any{"action": "limit", "amps": 16.0}, stored); err != nil {
		t.Errorf("a complete limit task was refused: %v", err)
	}
	// The amps are already on the record; the PATCH only changes the action.
	hasAmps := chargingTaskRecord{Action: "start", Amps: 16}
	if err := checkLimitAmps(map[string]any{"action": "limit"}, hasAmps); err != nil {
		t.Errorf("a limit task with stored amps was refused: %v", err)
	}
	// And the other way round: clearing the amps on a task that limits.
	limits := chargingTaskRecord{Action: "limit", Amps: 16}
	if err := checkLimitAmps(map[string]any{"amps": 0.0}, limits); err == nil {
		t.Error("the amps were cleared off a limit task")
	}
}

func TestSummarizeTaskRun(t *testing.T) {
	all := summarizeTaskRun([]taskRunResult{
		{Name: "Home-DK", Status: "Accepted"},
		{Name: "Home-PL", Status: "Accepted"},
	})
	if all != "2 of 2 sent" {
		t.Errorf("summary = %q, want \"2 of 2 sent\"", all)
	}

	// One charger failing is the case the list has to be able to show: the
	// summary names which, because "1 of 2 sent" alone is not actionable.
	some := summarizeTaskRun([]taskRunResult{
		{Name: "Home-DK", Status: "Accepted"},
		{Name: "Home-PL", Error: "charger is not connected"},
	})
	if !strings.Contains(some, "Home-PL") || !strings.Contains(some, "not connected") {
		t.Errorf("summary = %q, want it to name the charger that failed and why", some)
	}

	// A single failure is its own reason — no count to read past.
	only := summarizeTaskRun([]taskRunResult{{Name: "Home-PL", Error: "control mode is off"}})
	if only != "Home-PL: control mode is off" {
		t.Errorf("summary = %q, want the bare reason", only)
	}
}

// The runner reads a control response the same way whichever transport answered
// it: a status when the charger took the command, the endpoint's own words when
// it did not.
func TestCaptureWriterControlOutcome(t *testing.T) {
	ok := &captureWriter{header: nil}
	ok.WriteHeader(200)
	_, _ = ok.Write([]byte(`{"status":"Accepted"}`))
	if got, err := ok.controlOutcome(); err != nil || got != "Accepted" {
		t.Errorf("controlOutcome = %q, %v; want Accepted", got, err)
	}

	// A 2xx with nothing to read still means the command went.
	bare := &captureWriter{}
	bare.WriteHeader(204)
	if got, err := bare.controlOutcome(); err != nil || got != "sent" {
		t.Errorf("controlOutcome = %q, %v; want sent", got, err)
	}

	bad := &captureWriter{}
	bad.WriteHeader(409)
	_, _ = bad.Write([]byte(`{"error":"charger is not connected to the control backend"}`))
	_, err := bad.controlOutcome()
	if err == nil || !strings.Contains(err.Error(), "not connected") {
		t.Errorf("controlOutcome err = %v, want the endpoint's own reason", err)
	}

	// An error status with no envelope to read still has to say something.
	mute := &captureWriter{}
	mute.WriteHeader(502)
	if _, err := mute.controlOutcome(); err == nil {
		t.Error("a 502 with an empty body was read as a success")
	}
}