package climb_test

import (
	"fmt"
	"testing"

	"github.com/martinlehoux/biking_home/climb"
	"github.com/martinlehoux/biking_home/core"
	"github.com/martinlehoux/biking_home/internal/routetest"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// describe renders a detected climb as the ride-style
// "start-end: length at slope (pts - cat)" string, so positions are asserted.
func describe(route climb.Route, detected climb.DetectedClimb) string {
	seg := detected.Climb
	startKm := route.Distances[detected.Start] / 1000
	endKm := route.Distances[detected.Start+len(seg.Distances)-1] / 1000
	lengthKm := (seg.Distances[len(seg.Distances)-1] - seg.Distances[0]) / 1000
	slopePercent := climb.Slope(seg.Distances, seg.Elevations) * 100
	pts := int(seg.DifficultyScore())
	return fmt.Sprintf("%.1fkm-%.1fkm: %.1fkm at %.1f%% (%d pts - %s)", startKm, endKm, lengthKm, slopePercent, pts, climb.CategoryOf(seg.DifficultyScore()))
}

func TestClimbThenFalseFlat(t *testing.T) {
	route := routetest.MustRoute("2km at 7% | 10km at 1%")
	detected := climb.Detect(route, nil, climb.ClimbSlopeMinimum)

	assert.Len(t, detected, 1)
	assert.Equal(t, "0.0km-2.0km: 2.0km at 7.0% (98 pts - Cat 3)", describe(route, detected[0]))
}

func TestSmallClimbWithDescentInsideFalseFlat(t *testing.T) {
	route := routetest.MustRoute("10km at 1% | 2km at 7% | 1km at -7% | 10km at 1%")
	detected := climb.Detect(route, nil, climb.ClimbSlopeMinimum)

	assert.Len(t, detected, 1)
	assert.Equal(t, "10.0km-12.0km: 2.0km at 7.0% (98 pts - Cat 3)", describe(route, detected[0]))
}

func TestDetectClimbsSkipsMiddleClaim(t *testing.T) {
	// A climb, a false flat giving a saddle, then a climb again. Claiming the
	// saddle's descent base should leave both climbs detected separately.
	route := routetest.MustRoute("2km at 7% | 1km at -7% | 2km at 7%")
	detected := climb.Detect(route, []core.Interval{core.NewInterval(20, 20)}, climb.ClimbSlopeMinimum)

	// No free region falls under the min distance except the two climbs.
	assert.Len(t, detected, 2)
	assert.Equal(t, "0.0km-2.0km: 2.0km at 7.0% (98 pts - Cat 3)", describe(route, detected[0]))
	assert.Equal(t, "3.0km-5.0km: 2.0km at 7.0% (98 pts - Cat 3)", describe(route, detected[1]))
}

func TestDetectClimbsOverlappingClaimDropsClimb(t *testing.T) {
	// Claiming the ascent region entirely swallows the climb.
	route := routetest.MustRoute("2km at 7% | 20km at 0%")
	detected := climb.Detect(route, []core.Interval{core.NewInterval(0, 40)}, climb.ClimbSlopeMinimum)
	assert.Empty(t, detected)
}

func TestDetectClimbsIgnoresOutOfRangeClaim(t *testing.T) {
	route := routetest.MustRoute("2km at 7% | 20km at 0%")
	detected := climb.Detect(route, []core.Interval{core.NewInterval(-5, -1)}, climb.ClimbSlopeMinimum)
	require.Len(t, detected, 1)
	assert.Equal(t, "0.0km-2.0km: 2.0km at 7.0% (98 pts - Cat 3)", describe(route, detected[0]))
}

func TestDetectClimbsWithUnsortedClaimsDropsOverlappingClimb(t *testing.T) {
	// Reproduces ride 6 Chemin des Lauriers bug: Detect must not depend on
	// caller-provided order. Two official claims out of ID order (Bastides
	// 2140-2627 before Lauriers 1215-1588) caused freeRegions to skip the
	// earlier claim and leave the overlapping Cat 4 1352-1601 visible.
	// Minimal reproduction: two climbs 0-2km and 3-5km separated by a descent.
	route := routetest.MustRoute("2km at 7% | 1km at -7% | 2km at 7%")
	// Both climbs claimed, but in reverse order (mimics ORDER BY id returning 30-50 before 0-20).
	// Sorted input correctly yields 0 detected climbs.
	sorted := []core.Interval{core.NewInterval(0, 20), core.NewInterval(30, 50)}
	assert.Empty(t, climb.Detect(route, sorted, climb.ClimbSlopeMinimum))

	unsorted := []core.Interval{core.NewInterval(30, 50), core.NewInterval(0, 20)}
	detected := climb.Detect(route, unsorted, climb.ClimbSlopeMinimum)
	// Before fix this fails: freeRegions skips {0,20} because 20 < 30 and returns 1 climb.
	assert.Empty(t, detected, "unsorted claimed ranges must still suppress overlapping climbs — expected 0, got %v", detected)
}