package callwindow

import (
	"encoding/json"
	"os"
	"strings"
	"testing"
	"time"
)

func week(windows ...Window) map[string][]Window {
	return map[string][]Window{
		"monday": windows, "tuesday": windows, "wednesday": windows,
		"thursday": windows, "friday": windows, "saturday": windows, "sunday": windows,
	}
}

func atShanghai(t *testing.T, dateTime string) time.Time {
	t.Helper()
	at, err := time.Parse(time.RFC3339, dateTime)
	if err != nil {
		t.Fatal(err)
	}
	return at
}

func TestEvaluateTaskAndLineIntersectionAtBoundaries(t *testing.T) {
	task := TaskSchedule{WeeklySchedule: WeeklySchedule{TimeZone: "Asia/Shanghai", WeeklyWindows: week(Window{"09:00", "20:00"})}}
	line := WeeklySchedule{TimeZone: "Asia/Shanghai", WeeklyWindows: week(Window{"10:00", "18:00"})}
	for _, tc := range []struct {
		when, end string
		allow     bool
	}{
		{"2026-09-21T09:59:59+08:00", "", false},
		{"2026-09-21T10:00:00+08:00", "2026-09-21T18:00:00+08:00", true},
		{"2026-09-21T17:59:59+08:00", "2026-09-21T18:00:00+08:00", true},
		{"2026-09-21T18:00:00+08:00", "", false},
	} {
		end, err := Evaluate(task, line, atShanghai(t, tc.when))
		if (err == nil) != tc.allow {
			t.Errorf("at %s: end=%v err=%v allow=%v", tc.when, end, err, tc.allow)
		} else if tc.allow && !end.Equal(atShanghai(t, tc.end)) {
			t.Errorf("at %s: end=%v, want %s", tc.when, end, tc.end)
		}
	}
}

func TestEvaluateActualTaskAndLineConfigShape(t *testing.T) {
	readSchedule := func(path string, dest any) {
		t.Helper()
		body, err := os.ReadFile(path)
		if err != nil {
			t.Fatal(err)
		}
		if err := json.Unmarshal(body, dest); err != nil {
			t.Fatal(err)
		}
	}
	var task struct {
		Schedule TaskSchedule `json:"schedule"`
	}
	readSchedule("../../docs/contracts/examples/config-read-task-v0.1.json", &task)
	var sip struct {
		TrunkDetails []struct {
			Schedule WeeklySchedule `json:"schedule"`
		} `json:"trunk_details"`
	}
	readSchedule("../../docs/contracts/examples/config-read-sip-v0.1.json", &sip)
	if len(sip.TrunkDetails) != 1 {
		t.Fatalf("line sample count=%d", len(sip.TrunkDetails))
	}
	end, err := Evaluate(task.Schedule, sip.TrunkDetails[0].Schedule, atShanghai(t, "2026-09-21T09:30:00+08:00"))
	if err != nil || !end.Equal(atShanghai(t, "2026-09-21T11:00:00+08:00")) {
		t.Fatalf("actual task and line schedules: end=%v err=%v", end, err)
	}
}

func TestEvaluateCrossMidnightSplitAndExcludedDate(t *testing.T) {
	weekly := week()
	weekly["monday"] = []Window{{"23:00", "24:00"}}
	weekly["tuesday"] = []Window{{"00:00", "01:00"}}
	task := TaskSchedule{WeeklySchedule: WeeklySchedule{TimeZone: "Asia/Shanghai", WeeklyWindows: weekly}}
	line := WeeklySchedule{TimeZone: "Asia/Shanghai", WeeklyWindows: weekly}
	for _, tc := range []struct{ when, end string }{
		{"2026-09-21T23:59:59+08:00", "2026-09-22T00:00:00+08:00"},
		{"2026-09-22T00:00:00+08:00", "2026-09-22T01:00:00+08:00"},
	} {
		end, err := Evaluate(task, line, atShanghai(t, tc.when))
		if err != nil || !end.Equal(atShanghai(t, tc.end)) {
			t.Fatalf("cross-midnight at %s: end=%v err=%v", tc.when, end, err)
		}
	}
	task.ExcludedDates = []string{"2026-09-22"}
	if _, err := Evaluate(task, line, atShanghai(t, "2026-09-22T00:00:00+08:00")); err == nil {
		t.Fatal("excluded Shanghai calendar date allowed")
	}
}

func TestEvaluateTaskValidityAndAuthorizationBounds(t *testing.T) {
	task := TaskSchedule{WeeklySchedule: WeeklySchedule{TimeZone: "Asia/Shanghai", WeeklyWindows: week(Window{"09:00", "20:00"})},
		StartsAt: "2026-09-21T10:00:00+08:00", EndsAt: "2026-09-21T11:00:00+08:00"}
	line := WeeklySchedule{TimeZone: "Asia/Shanghai", WeeklyWindows: week(Window{"09:00", "20:00"})}
	if _, err := Evaluate(task, line, atShanghai(t, "2026-09-21T09:59:59+08:00")); err == nil {
		t.Fatal("before task validity allowed")
	}
	end, err := Evaluate(task, line, atShanghai(t, "2026-09-21T10:00:00+08:00"))
	if err != nil || !end.Equal(atShanghai(t, "2026-09-21T11:00:00+08:00")) {
		t.Fatalf("task start/end: %v %v", end, err)
	}
	if _, err := Evaluate(task, line, atShanghai(t, "2026-09-21T11:00:00+08:00")); err == nil {
		t.Fatal("at task validity end allowed")
	}
}

func TestEvaluateRejectsInvalidOrAmbiguousSchedules(t *testing.T) {
	for _, tc := range []struct {
		name    string
		windows []Window
	}{
		{"cross-day unsplit", []Window{{"23:00", "01:00"}}},
		{"overlap", []Window{{"09:00", "11:00"}, {"10:00", "12:00"}}},
		{"24:00 start", []Window{{"24:00", "24:00"}}},
		{"non-time", []Window{{"9:00", "20:00"}}},
	} {
		t.Run(tc.name, func(t *testing.T) {
			bad := TaskSchedule{WeeklySchedule: WeeklySchedule{TimeZone: "Asia/Shanghai", WeeklyWindows: week(tc.windows...)}}
			line := WeeklySchedule{TimeZone: "Asia/Shanghai", WeeklyWindows: week(Window{"09:00", "20:00"})}
			if _, err := Evaluate(bad, line, atShanghai(t, "2026-09-21T10:00:00+08:00")); err == nil {
				t.Fatal("invalid schedule allowed")
			}
		})
	}
	badDate := TaskSchedule{WeeklySchedule: WeeklySchedule{TimeZone: "Asia/Shanghai", WeeklyWindows: week(Window{"09:00", "20:00"})}, ExcludedDates: []string{"2026-02-30"}}
	if _, err := Evaluate(badDate, badDate.WeeklySchedule, atShanghai(t, "2026-09-21T10:00:00+08:00")); err == nil || !strings.Contains(err.Error(), "date") {
		t.Fatalf("invalid excluded date: %v", err)
	}
	badZone := badDate
	badZone.ExcludedDates = nil
	badZone.TimeZone = "UTC"
	if _, err := Evaluate(badZone, badDate.WeeklySchedule, atShanghai(t, "2026-09-21T10:00:00+08:00")); err == nil {
		t.Fatal("wrong timezone allowed")
	}
}