package cli

import (
	"bytes"
	"context"
	"strings"
	"testing"
	"time"

	"gitea.maximumdirect.net/eric/weatherreporter/internal/app"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
)

func TestRunHelpLongFlag(t *testing.T) {
	var stdout bytes.Buffer
	var stderr bytes.Buffer

	err := Run(context.Background(), []string{"--help"}, &stdout, &stderr)
	if err != nil {
		t.Fatalf("Run() error = %v", err)
	}

	if !strings.Contains(stdout.String(), "generate daily") {
		t.Fatalf("help output missing generate command:\n%s", stdout.String())
	}
}

func TestRunHelpShortFlag(t *testing.T) {
	var stdout bytes.Buffer
	var stderr bytes.Buffer

	err := Run(context.Background(), []string{"-h"}, &stdout, &stderr)
	if err != nil {
		t.Fatalf("Run() error = %v", err)
	}

	if !strings.Contains(stdout.String(), "weatherreporter run evening") {
		t.Fatalf("help output missing run command:\n%s", stdout.String())
	}
}

func TestRunUnknownCommand(t *testing.T) {
	var stdout bytes.Buffer
	var stderr bytes.Buffer

	err := Run(context.Background(), []string{"inspect"}, &stdout, &stderr)
	if err == nil {
		t.Fatal("Run() error = nil, want unknown command error")
	}

	if !strings.Contains(err.Error(), `unknown command "inspect"`) {
		t.Fatalf("Run() error = %q, want unknown command message", err.Error())
	}
}

func TestRunGenerateReturnsNotImplementedAfterResolution(t *testing.T) {
	var stdout bytes.Buffer
	var stderr bytes.Buffer
	runner := Runner{Clock: fixedClock()}

	err := runner.Run(context.Background(), []string{"generate", "tomorrow", "--units", "metric"}, &stdout, &stderr)
	if err == nil {
		t.Fatal("Run() error = nil, want app not implemented error")
	}
	if !strings.Contains(err.Error(), "generate is not implemented") {
		t.Fatalf("Run() error = %q, want app not implemented error", err.Error())
	}
}

func TestResolveGenerateCommands(t *testing.T) {
	runner := Runner{Clock: fixedClock()}
	tests := []struct {
		name string
		args []string
		want app.ReportKind
	}{
		{name: "daily", args: []string{"daily", "--date", "2026-05-29"}, want: app.ReportDaily},
		{name: "tomorrow", args: []string{"tomorrow"}, want: app.ReportTomorrow},
		{name: "three-day", args: []string{"three-day"}, want: app.ReportThreeDay},
		{name: "weekend", args: []string{"weekend"}, want: app.ReportWeekend},
		{name: "storm", args: []string{"storm", "--start", "2026-05-29T18:00", "--end", "2026-05-30T06:00"}, want: app.ReportStorm},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			req, err := runner.resolveGenerate(tt.args)
			if err != nil {
				t.Fatalf("resolveGenerate() error = %v", err)
			}
			if req.Report != tt.want {
				t.Fatalf("Report = %q, want %q", req.Report, tt.want)
			}
		})
	}
}

func TestResolveGenerateDailyDefaultsDateInConfiguredTimezone(t *testing.T) {
	runner := Runner{Clock: fixedClock()}

	req, err := runner.resolveGenerate([]string{"daily"})
	if err != nil {
		t.Fatalf("resolveGenerate() error = %v", err)
	}

	if got := req.Date.Format(timeutil.DateLayout); got != "2026-05-29" {
		t.Fatalf("Date = %s, want 2026-05-29", got)
	}
}

func TestResolveGenerateAppliesSharedFlags(t *testing.T) {
	runner := Runner{Clock: fixedClock()}

	req, err := runner.resolveGenerate([]string{"daily", "--units", "metric", "--tz", "UTC", "--out", "./daily.md"})
	if err != nil {
		t.Fatalf("resolveGenerate() error = %v", err)
	}

	if req.Config.WeatherAPI.Units != "metric" {
		t.Fatalf("Units = %q, want metric", req.Config.WeatherAPI.Units)
	}
	if req.Config.WeatherAPI.Timezone != "UTC" {
		t.Fatalf("Timezone = %q, want UTC", req.Config.WeatherAPI.Timezone)
	}
	if req.OutputPath != "./daily.md" {
		t.Fatalf("OutputPath = %q, want ./daily.md", req.OutputPath)
	}
}

func TestResolveGenerateStormRequiresStartAndEnd(t *testing.T) {
	runner := Runner{Clock: fixedClock()}

	_, err := runner.resolveGenerate([]string{"storm", "--start", "2026-05-29T18:00"})
	if err == nil {
		t.Fatal("resolveGenerate() error = nil, want missing end error")
	}
	if !strings.Contains(err.Error(), "requires --end") {
		t.Fatalf("error = %q, want missing end", err.Error())
	}
}

func TestResolveGenerateStormParsesRFC3339(t *testing.T) {
	runner := Runner{Clock: fixedClock()}

	req, err := runner.resolveGenerate([]string{
		"storm",
		"--start", "2026-05-29T18:00:00-05:00",
		"--end", "2026-05-30T06:00:00-05:00",
	})
	if err != nil {
		t.Fatalf("resolveGenerate() error = %v", err)
	}
	if !req.StormEnd.After(req.StormStart) {
		t.Fatalf("StormEnd = %s, want after %s", req.StormEnd, req.StormStart)
	}
}

func TestResolveRunCommands(t *testing.T) {
	tests := []struct {
		name string
		args []string
		want app.BatchKind
	}{
		{name: "morning", args: []string{"morning"}, want: app.BatchMorning},
		{name: "evening", args: []string{"evening", "--tz", "UTC"}, want: app.BatchEvening},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			req, err := resolveRun(tt.args)
			if err != nil {
				t.Fatalf("resolveRun() error = %v", err)
			}
			if req.Batch != tt.want {
				t.Fatalf("Batch = %q, want %q", req.Batch, tt.want)
			}
		})
	}
}

func TestResolveRunRejectsOutputFlag(t *testing.T) {
	_, err := resolveRun([]string{"morning", "--out", "./report.md"})
	if err == nil {
		t.Fatal("resolveRun() error = nil, want flag error")
	}
	if !strings.Contains(err.Error(), "flag provided but not defined") {
		t.Fatalf("error = %q, want undefined flag error", err.Error())
	}
}

func fixedClock() timeutil.Clock {
	return timeutil.FixedClock{Time: time.Date(2026, 5, 29, 12, 0, 0, 0, time.UTC)}
}