package render

import (
	"strings"
	"testing"
	"time"

	"github.com/lukaszkasprzak/prognosis/internal/config"
	"github.com/lukaszkasprzak/prognosis/internal/imgw"
	"github.com/lukaszkasprzak/prognosis/internal/openmeteo"
)

// row builds one hour. mm and pop default to dry.
func row(hour int, temp float64, code int, mm, pop float64) openmeteo.Row {
	return openmeteo.Row{
		When: time.Date(2026, 8, 10, hour, 0, 0, 0, time.UTC),
		Code: code,
		Vals: map[string]float64{
			"temperature_2m":            temp,
			"apparent_temperature":      temp,
			"precipitation":             mm,
			"precipitation_probability": pop,
			"weather_code":              float64(code),
		},
	}
}

func testConfig() config.Config {
	c := config.Default()
	c.Columns = []string{"hour", "temp", "feels", "conditions", "humidity", "mm", "rain"}
	c.Graph = false
	c.Icons = "none"
	c.DisplayLang = "en"
	return c
}

func view(rows ...openmeteo.Row) View {
	return View{Label: "Test, PL", Rows: rows, Sun: map[string][2]string{}}
}

// On a dry day the mm and rain columns are a block of zeroes pushing the real
// content sideways.
func TestDryWindowHidesTheRainColumns(t *testing.T) {
	dry := Render(view(row(12, 25, 3, 0, 0), row(13, 26, 3, 0, 5)), testConfig(), 80, false)
	if strings.Contains(dry, "mm") || strings.Contains(dry, "rain") {
		t.Errorf("dry window still shows rain columns:\n%s", dry)
	}

	wet := Render(view(row(12, 25, 3, 0, 0), row(13, 26, 61, 0.4, 80)), testConfig(), 80, false)
	if !strings.Contains(wet, "mm") || !strings.Contains(wet, "rain") {
		t.Errorf("wet window must show rain columns:\n%s", wet)
	}
}

// Probability alone is enough: rain that has not started yet still matters.
func TestProbabilityAloneBringsBackTheRainColumns(t *testing.T) {
	v := view(row(12, 25, 3, 0, RainInterestPct), row(13, 26, 3, 0, RainInterestPct))
	if out := Render(v, testConfig(), 80, false); !strings.Contains(out, "rain") {
		t.Errorf("%d%% chance must show the columns:\n%s", RainInterestPct, out)
	}
	below := view(row(12, 25, 3, 0, RainInterestPct-1), row(13, 26, 3, 0, 0))
	if out := Render(below, testConfig(), 80, false); strings.Contains(out, "rain") {
		t.Errorf("below the threshold the columns must stay hidden:\n%s", out)
	}
}

// An unbroken column of "overcast" hides the hour it stops being overcast,
// which is the only interesting part.
func TestConditionsPrintOnlyWhenTheyChange(t *testing.T) {
	v := view(
		row(12, 25, 3, 0, 0), // overcast
		row(13, 25, 3, 0, 0), // still overcast: blank
		row(14, 25, 0, 0, 0), // clear: printed
		row(15, 25, 0, 0, 0), // still clear: blank
	)
	out := Render(v, testConfig(), 80, false)
	if n := strings.Count(out, "overcast"); n != 1 {
		t.Errorf("overcast appears %d times, want 1:\n%s", n, out)
	}
	if n := strings.Count(out, "clear"); n != 1 {
		t.Errorf("clear appears %d times, want 1:\n%s", n, out)
	}
}

// Across a day boundary the conditions are repeated once, so a reader starting
// at the new day is not looking at a blank column.
func TestConditionsRepeatAfterADaySeparator(t *testing.T) {
	next := row(0, 20, 3, 0, 0)
	next.When = time.Date(2026, 8, 11, 0, 0, 0, 0, time.UTC)
	v := view(row(23, 22, 3, 0, 0), next)
	v.Sun["2026-08-11"] = [2]string{"05:16", "19:59"}

	out := Render(v, testConfig(), 80, false)
	if n := strings.Count(out, "overcast"); n != 2 {
		t.Errorf("conditions must repeat once per day, appeared %d times:\n%s", n, out)
	}
	if !strings.Contains(out, "Tue 11 Aug") {
		t.Errorf("missing the day separator:\n%s", out)
	}
}

func TestFeelsLikeOnlyWhenItDiffers(t *testing.T) {
	same := row(12, 25, 3, 0, 0)
	diff := row(13, 25, 3, 0, 0)
	diff.Vals["apparent_temperature"] = 28

	out := Render(view(same, diff), testConfig(), 80, false)
	if strings.Count(out, "(") != 1 {
		t.Errorf("feels-like must appear once, only where it differs:\n%s", out)
	}
	if !strings.Contains(out, "(28)") {
		t.Errorf("expected (28):\n%s", out)
	}
}

// The four warning states must stay distinguishable: silence read as all-clear
// is the failure that matters.
func TestWarningStatesAreDistinct(t *testing.T) {
	cfg := testConfig()
	base := view(row(12, 25, 3, 0, 0))

	inForce := base
	inForce.Warnings = []imgw.Warning{{
		Event: "Upal", Level: "1", Probability: "85",
		From: "2026-08-10 11:00:00", To: "2026-08-10 20:00:00",
		Text: "Prognozuje sie upal.",
	}}
	out := Render(inForce, cfg, 80, false)
	if !strings.Contains(out, "Upal") || !strings.Contains(out, "level 1") {
		t.Errorf("a live warning must be shown:\n%s", out)
	}

	if out := Render(base, cfg, 80, false); strings.Contains(out, "warnings:") {
		t.Errorf("checked-and-none must print nothing about warnings:\n%s", out)
	}

	failed := base
	failed.WarnFailed = true
	if out := Render(failed, cfg, 80, false); !strings.Contains(out, "could not check") {
		t.Errorf("a failed check must say so, not stay silent:\n%s", out)
	}

	abroad := base
	abroad.WarnNote = "IMGW covers Poland only"
	if out := Render(abroad, cfg, 80, false); !strings.Contains(out, "Poland only") {
		t.Errorf("an abroad location must explain itself:\n%s", out)
	}
}

func TestWarningsDisabledSuppressesEvenAFailure(t *testing.T) {
	cfg := testConfig()
	cfg.Warnings = false
	v := view(row(12, 25, 3, 0, 0))
	v.WarnFailed = true
	if out := Render(v, cfg, 80, false); strings.Contains(out, "could not check") {
		t.Errorf("warnings=false must suppress the notice too:\n%s", out)
	}
}

// -weather strips everything that is not the forecast.
func TestMinimalStripsTheExtras(t *testing.T) {
	cfg := testConfig()
	cfg.Minimal = true
	v := view(row(12, 25, 3, 0, 0))
	v.Sun["2026-08-10"] = [2]string{"05:15", "20:01"}
	v.Daily = map[string]float64{"temperature_2m_min": 12, "temperature_2m_max": 30}
	v.Pollen = map[string]float64{"grass": 10}

	out := Render(v, cfg, 80, false)
	for _, unwanted := range []string{"sun", "up", "day", "pollen", "grass"} {
		if strings.Contains(out, unwanted) {
			t.Errorf("minimal output still contains %q:\n%s", unwanted, out)
		}
	}
	if !strings.Contains(out, "Test, PL") || !strings.Contains(out, "25°") {
		t.Errorf("minimal output must still carry place and forecast:\n%s", out)
	}
}

func chartOf(t *testing.T, hours int, width int) []string {
	t.Helper()
	cfg := testConfig()
	cfg.Graph = true
	var rows []openmeteo.Row
	for i := 0; i < hours; i++ {
		when := time.Date(2026, 8, 10, 0, 0, 0, 0, time.UTC).Add(time.Duration(i) * time.Hour)
		r := row(0, 20+float64(i%10), 3, 0, 0)
		r.When = when
		rows = append(rows, r)
	}
	out := Render(view(rows...), cfg, width, false)
	return strings.Split(out, "\n")
}

// A 12-hour chart drawn one column per hour would occupy 12 of 80 columns.
func TestChartWidensShortSpansToFillTheTerminal(t *testing.T) {
	lines := chartOf(t, 12, 80)
	var widest int
	for _, l := range lines {
		if strings.Contains(l, "│") {
			if w := DisplayWidth(l); w > widest {
				widest = w
			}
		}
	}
	if widest < 40 {
		t.Fatalf("chart is only %d columns wide for a 12-hour span; it should widen", widest)
	}
}

// A week is 168 points and would wrap into mush; columns must cover several
// hours and the label must say so.
func TestChartDownsamplesLongSpansAndSaysSo(t *testing.T) {
	out := strings.Join(chartOf(t, 168, 80), "\n")
	if !strings.Contains(out, "h/col") {
		t.Fatalf("a downsampled chart must disclose the ratio:\n%s", out)
	}
	for _, l := range strings.Split(out, "\n") {
		if w := DisplayWidth(l); w > 80 {
			t.Fatalf("chart line is %d columns wide, wider than the terminal:\n%s", w, l)
		}
	}
}

func TestChartNeverExceedsTheTerminalWidth(t *testing.T) {
	for _, width := range []int{32, 53, 80, 96} {
		for _, hours := range []int{1, 6, 24, 72} {
			lines := chartOf(t, hours, width)
			// Only the chart: the table has fixed column widths and is measured
			// separately, below.
			for i, l := range lines {
				isChart := strings.Contains(l, "│") ||
					(i >= len(lines)-2 && strings.TrimSpace(l) != "")
				if !isChart {
					continue
				}
				if w := DisplayWidth(l); w > width {
					t.Errorf("width=%d hours=%d: chart line is %d columns:\n%s", width, hours, w, l)
				}
			}
		}
	}
}

// The table has fixed column widths, so unlike the chart it does not shrink to
// fit. This pins the width the default column set needs: the phone is 53
// columns, so there is headroom, but a narrower terminal will wrap and there is
// no code preventing it. Narrow the columns instead -- see -columns.
func TestTableMinimumWidthIsKnown(t *testing.T) {
	cfg := testConfig()
	out := Render(view(row(12, 25, 3, 0, 0)), cfg, 80, false)
	widest := 0
	for _, l := range strings.Split(out, "\n") {
		if w := DisplayWidth(l); w > widest {
			widest = w
		}
	}
	const documented = 40
	if widest != documented {
		t.Fatalf("the default table now needs %d columns, not the documented %d; "+
			"update the README if this is intended", widest, documented)
	}
	// A narrower column set must actually be narrower, or -columns is no remedy.
	cfg.Columns = []string{"hour", "temp", "conditions"}
	narrow := 0
	for _, l := range strings.Split(Render(view(row(12, 25, 3, 0, 0)), cfg, 80, false), "\n") {
		if w := DisplayWidth(l); w > narrow {
			narrow = w
		}
	}
	if narrow >= documented {
		t.Errorf("narrow column set is %d columns, no better than %d", narrow, documented)
	}
}

// A label that would run off the end is skipped, never printed as half a label.
func TestChartAxisLabelsAreWholeOrAbsent(t *testing.T) {
	for _, hours := range []int{1, 2, 3, 5, 12, 24} {
		lines := chartOf(t, hours, 40)
		axis := lines[len(lines)-2] // axis sits above the range note
		for _, field := range strings.Fields(axis) {
			if len(field) != 2 {
				t.Errorf("hours=%d: axis has a partial label %q in %q", hours, field, axis)
			}
		}
	}
}

func customCfg() config.Config {
	c := testConfig()
	c.Columns = []string{"hour", "temp", "birch", "soil"}
	c.Custom = map[string]config.CustomColumn{
		"birch": {Source: "air", Field: "birch_pollen", Label: "brzoza", Decimals: 1},
		"soil":  {Source: "forecast", Field: "soil_temperature_0cm", Suffix: "°", Decimals: 0},
	}
	return c
}

func TestCustomColumnsRender(t *testing.T) {
	r := row(12, 25, 3, 0, 0)
	r.Vals[CustomKey("birch")] = 12.34
	r.Vals["soil_temperature_0cm"] = 21.6

	out := Render(view(r), customCfg(), 80, false)
	if !strings.Contains(out, "brzoza") {
		t.Errorf("the declared label must be the header:\n%s", out)
	}
	if !strings.Contains(out, "12.3") {
		t.Errorf("decimals=1 should give 12.3:\n%s", out)
	}
	if !strings.Contains(out, "22°") {
		t.Errorf("decimals=0 with a suffix should give 22°:\n%s", out)
	}
}

// "No data" and "zero" are different claims, and for an allergen the difference
// matters.
func TestCustomColumnBlankWhenTheApiGaveNothing(t *testing.T) {
	r := row(12, 25, 3, 0, 0) // no custom values set at all
	out := Render(view(r), customCfg(), 80, false)
	if strings.Contains(out, "0.0") {
		t.Errorf("a missing value must render blank, not as zero:\n%s", out)
	}
	if !strings.Contains(out, "brzoza") {
		t.Errorf("the column should still be present:\n%s", out)
	}
}

// A custom column named after a built-in API field must not read that field's
// value; the prefix is what keeps them apart.
func TestCustomKeyDoesNotCollideWithApiFields(t *testing.T) {
	if CustomKey("temperature_2m") == "temperature_2m" {
		t.Fatal("custom values must be stored under a distinct key")
	}
	r := row(12, 25, 3, 0, 0) // temperature_2m = 25
	cfg := testConfig()
	cfg.Columns = []string{"hour", "mine"}
	cfg.Custom = map[string]config.CustomColumn{
		"mine": {Source: "air", Field: "temperature_2m", Decimals: 0},
	}
	if out := Render(view(r), cfg, 80, false); strings.Contains(out, "25") {
		t.Errorf("the custom column picked up the built-in field's value:\n%s", out)
	}
}

func TestCustomColumnWidthFromLabelWhenUnset(t *testing.T) {
	cfg := testConfig()
	cfg.Columns = []string{"hour", "verylongname"}
	cfg.Custom = map[string]config.CustomColumn{
		"verylongname": {Source: "air", Field: "f", Label: "verylongname"},
	}
	r := row(12, 25, 3, 0, 0)
	r.Vals[CustomKey("verylongname")] = 1
	out := Render(view(r), cfg, 80, false)
	for _, l := range strings.Split(out, "\n") {
		if strings.Contains(l, "verylongname") && DisplayWidth(l) < 12 {
			t.Errorf("header was truncated: %q", l)
		}
	}
}

// A species the user named is shown even at zero: they named it because they
// react to it, and "none today" is the answer they wanted.
func TestNamedPollenSpeciesShownEvenAtZero(t *testing.T) {
	cfg := testConfig()
	cfg.Pollen = []string{"birch"}
	cfg.PollenExplicit = true
	v := view(row(12, 25, 3, 0, 0))
	v.Pollen = map[string]float64{"birch": 0}

	out := Render(v, cfg, 80, false)
	if !strings.Contains(out, "birch") {
		t.Errorf("a named species must appear even at zero:\n%s", out)
	}
}

// With pollen=all nobody chose, so a line of six zeroes is noise.
func TestPollenAllHidesAbsentSpecies(t *testing.T) {
	cfg := testConfig()
	cfg.Pollen = []string{"grass", "birch"}
	cfg.PollenExplicit = false
	v := view(row(12, 25, 3, 0, 0))
	v.Pollen = map[string]float64{"grass": 12, "birch": 0}

	out := Render(v, cfg, 80, false)
	if !strings.Contains(out, "grass") {
		t.Errorf("a present species must be shown:\n%s", out)
	}
	if strings.Contains(out, "birch") {
		t.Errorf("an absent species must be dropped when nobody named it:\n%s", out)
	}
}

// No species is privileged. Grass used to be special-cased, which forced it on
// someone allergic to birch while hiding theirs.
func TestNoSpeciesIsPrivileged(t *testing.T) {
	cfg := testConfig()
	cfg.PollenExplicit = false
	v := view(row(12, 25, 3, 0, 0))
	v.Pollen = map[string]float64{"grass": 0, "birch": 0}

	if out := Render(v, cfg, 80, false); strings.Contains(out, "grass") {
		t.Errorf("grass at zero must be dropped like any other species:\n%s", out)
	}
}

// A narrow range cannot be labelled in whole degrees: rounding makes adjacent
// rows read the same, so the axis claims two different temperatures are equal.
func TestNarrowRangeGetsDecimalAxisLabels(t *testing.T) {
	cfg := testConfig()
	cfg.Graph = true
	var rows []openmeteo.Row
	for i, temp := range []float64{15.7, 16.0, 16.0, 15.2, 14.8, 15.1, 15.2, 15.2} {
		r := row(0, temp, 3, 0, 0)
		r.When = time.Date(2026, 8, 25, 15+i, 0, 0, 0, time.UTC)
		rows = append(rows, r)
	}
	out := Render(view(rows...), cfg, 80, false)

	var labels []string
	for _, l := range strings.Split(out, "\n") {
		if i := strings.Index(l, "│"); i > 0 {
			if lbl := strings.TrimSpace(l[:i]); lbl != "" && lbl != "rain" {
				labels = append(labels, lbl)
			}
		}
	}
	if len(labels) < 3 {
		t.Fatalf("expected three axis labels, got %v\n%s", labels, out)
	}
	seen := map[string]bool{}
	for _, l := range labels {
		if seen[l] {
			t.Errorf("axis label %q repeats; a 1.2 degree span needs decimals:\n%s", l, out)
		}
		seen[l] = true
		if !strings.Contains(l, ".") {
			t.Errorf("label %q should carry a decimal for a narrow range", l)
		}
	}
}

// A wide range stays in whole degrees: decimals there are noise.
func TestWideRangeKeepsWholeDegreeLabels(t *testing.T) {
	cfg := testConfig()
	cfg.Graph = true
	var rows []openmeteo.Row
	for i, temp := range []float64{5, 12, 18, 24, 28, 22, 14, 7} {
		r := row(0, temp, 3, 0, 0)
		r.When = time.Date(2026, 8, 25, 15+i, 0, 0, 0, time.UTC)
		rows = append(rows, r)
	}
	out := Render(view(rows...), cfg, 80, false)
	for _, l := range strings.Split(out, "\n") {
		if i := strings.Index(l, "│"); i > 0 {
			lbl := strings.TrimSpace(l[:i])
			if strings.Contains(lbl, ".") {
				t.Errorf("wide range should use whole degrees, got %q", lbl)
			}
		}
	}
}

func TestAxisLabelPrecisionAndWidth(t *testing.T) {
	cases := []struct {
		lo, hi   float64
		maxWidth int
		wantDot  bool
		why      string
	}{
		{14.8, 16.0, 5, true, "1.2 degrees needs decimals"},
		{12, 28, 5, false, "16 degrees does not"},
		{15, 17, 5, false, "exactly the threshold stays whole"},
		{-20.4, -19.6, 5, false, "decimals would not fit, so fall back"},
	}
	for _, c := range cases {
		f := tempLabeller(c.lo, c.hi, c.maxWidth)
		got := f(c.lo)
		if strings.Contains(got, ".") != c.wantDot {
			t.Errorf("lo=%v hi=%v gave %q; %s", c.lo, c.hi, got, c.why)
		}
		for _, v := range []float64{c.lo, c.hi} {
			if w := DisplayWidth(f(v)); w > c.maxWidth {
				t.Errorf("label %q is %d cells, over the %d-cell gutter", f(v), w, c.maxWidth)
			}
		}
	}
}