package synastry

import (
	"fmt"
	"time"

	"github.com/yuxingu/digital-psychology/apps/api/internal/star/ephemeris"
	"github.com/yuxingu/digital-psychology/apps/api/internal/star/natal"
)

// ChartPack holds all synastry chart modes for one pair.
type ChartPack struct {
	Composite           natal.Chart
	Davison             natal.Chart
	MarksMe             natal.Chart
	MarksOther          natal.Chart
	Overlay             OverlayChart
	CompositeProgressed natal.Chart
	DavisonProgressed   natal.Chart
	MarksProgressed     natal.Chart
	AsOf                time.Time
}

// OverlayHouse is B's planet in A's whole-sign house.
type OverlayHouse struct {
	PlanetKey string `json:"planet_key"`
	Planet    string `json:"planet"`
	Sign      string `json:"sign"`
	House     int    `json:"house"`
	HouseTip  string `json:"house_tip"`
}

// OverlayChart is the pairing/overlay table.
type OverlayChart struct {
	HousesA []natal.House   `json:"houses_a"`
	Entries []OverlayHouse  `json:"entries"`
	Tip     string          `json:"tip"`
}

// BuildCharts computes five main charts + three progressed variants.
func BuildCharts(a, b natal.Chart, asOf time.Time) (ChartPack, error) {
	if asOf.IsZero() {
		asOf = time.Now().In(time.FixedZone("CST", 8*3600))
	}
	comp := CompositeChart(a, b)
	dav, err := DavisonChart(a, b)
	if err != nil {
		return ChartPack{}, err
	}
	marksMe := MarksChart(dav, a)
	marksOther := MarksChart(dav, b)
	overlay := Overlay(a, b)

	progA, err := ProgressChart(a, asOf)
	if err != nil {
		return ChartPack{}, err
	}
	progB, err := ProgressChart(b, asOf)
	if err != nil {
		return ChartPack{}, err
	}
	compProg := CompositeChart(progA, progB)
	davProg, err := ProgressChart(dav, asOf)
	if err != nil {
		return ChartPack{}, err
	}
	marksProg := MarksChart(davProg, progA)

	return ChartPack{
		Composite: comp, Davison: dav,
		MarksMe: marksMe, MarksOther: marksOther,
		Overlay: overlay,
		CompositeProgressed: compProg,
		DavisonProgressed:   davProg,
		MarksProgressed:     marksProg,
		AsOf:                asOf,
	}, nil
}

// CompositeChart midpoints each body longitude (shortest arc); ASC mid of rises.
func CompositeChart(a, b natal.Chart) natal.Chart {
	lons := map[string]float64{}
	for _, k := range ephemeris.PlanetOrder {
		lons[k] = natal.MidpointLon(natal.BodyLon(a, k), natal.BodyLon(b, k))
	}
	asc := natal.MidpointLon(a.Rise.Lon, b.Rise.Lon)
	lat := (a.Lat + b.Lat) / 2
	lng := midLng(a.Lng, b.Lng)
	ch := natal.ChartFromLons(lons, asc, lat, lng, "组合盘", a.HasTime && b.HasTime, a.HasPlace || b.HasPlace)
	ch.Instant = midTime(a.Instant, b.Instant)
	ch.Note = "组合盘：双方行星黄经中点，看关系整体气质。"
	return ch
}

// DavisonChart uses midpoint birth time + midpoint coordinates, then recomputes.
func DavisonChart(a, b natal.Chart) (natal.Chart, error) {
	inst := midTime(a.Instant, b.Instant)
	lat := (a.Lat + b.Lat) / 2
	lng := midLng(a.Lng, b.Lng)
	ch, err := natal.ComputeAt(inst, lat, lng, "时空盘", true, true)
	if err != nil {
		return natal.Chart{}, err
	}
	ch.Note = "时空盘：出生时刻与坐标中点再排盘，看长期现实走向。"
	return ch, nil
}

// MarksChart midpoints each Davison body with a natal chart (我/TA 视角).
func MarksChart(davison, natalCh natal.Chart) natal.Chart {
	lons := map[string]float64{}
	for _, k := range ephemeris.PlanetOrder {
		lons[k] = natal.MidpointLon(natal.BodyLon(davison, k), natal.BodyLon(natalCh, k))
	}
	asc := natal.MidpointLon(davison.Rise.Lon, natalCh.Rise.Lon)
	ch := natal.ChartFromLons(lons, asc, natalCh.Lat, natalCh.Lng, "马克斯盘", true, true)
	ch.Instant = midTime(davison.Instant, natalCh.Instant)
	ch.Note = "马克斯盘：时空盘与本命中点，看关系中的内在态度。"
	return ch
}

// Overlay maps B planets into A's whole-sign houses.
func Overlay(a, b natal.Chart) OverlayChart {
	ascIdx := natal.SignIndex(a.Rise.Lon)
	tips := houseTips()
	entries := make([]OverlayHouse, 0, len(b.Planets))
	for _, p := range b.Planets {
		if p.Key == "rise" {
			continue
		}
		h := natal.WholeSignHouse(ascIdx, natal.SignIndex(p.Lon))
		tip := tips[h]
		entries = append(entries, OverlayHouse{
			PlanetKey: p.Key, Planet: p.Title, Sign: p.Sign, House: h, HouseTip: tip,
		})
	}
	return OverlayChart{
		HousesA: a.Houses,
		Entries: entries,
		Tip:     "配对盘：对方行星落入我方整宫制宫位，提示生活领域互动。",
	}
}

// ProgressChart applies secondary progression (1 day ≈ 1 year) from chart.Instant to asOf.
func ProgressChart(ch natal.Chart, asOf time.Time) (natal.Chart, error) {
	if ch.Instant.IsZero() {
		return ch, nil
	}
	years := asOf.UTC().Sub(ch.Instant).Hours() / 24.0 / 365.24219
	if years < 0 {
		years = 0
	}
	// Add whole days to avoid time.Duration overflow/precision issues for large ages.
	days := int(years + 0.5)
	progUTC := ch.Instant.AddDate(0, 0, days)
	out, err := natal.ComputeAt(progUTC, ch.Lat, ch.Lng, ch.PlaceLabel+"·次限", ch.HasTime, ch.HasPlace)
	if err != nil {
		return natal.Chart{}, err
	}
	out.Note = fmt.Sprintf("次限推运至 %s（约 %.1f 年）。", asOf.Format("2006-01-02"), years)
	return out, nil
}

func midTime(a, b time.Time) time.Time {
	if a.IsZero() && b.IsZero() {
		return time.Time{}
	}
	if a.IsZero() {
		return b
	}
	if b.IsZero() {
		return a
	}
	return a.Add(b.Sub(a) / 2)
}

func midLng(a, b float64) float64 {
	// Geographic mean (CN MVP; both births typically East Asia).
	return (a + b) / 2
}

func houseTips() map[int]string {
	return map[int]string{
		1: "自我与第一印象", 2: "资源与安全感", 3: "沟通与日常", 4: "家庭与根基",
		5: "恋爱表达与创造", 6: "协作与健康节奏", 7: "一对一关系", 8: "深度与共享",
		9: "视野与信念", 10: "事业与对外形象", 11: "社群与愿景", 12: "内在与疗愈",
	}
}

func chartSummaryOut(c natal.Chart, tip string) map[string]any {
	asp := natal.Aspects(c)
	aspMaps := natal.AspectsAsMaps(asp)
	previewN := 4
	if len(aspMaps) < previewN {
		previewN = len(aspMaps)
	}
	t := tip
	if t == "" {
		t = c.Note
	}
	return map[string]any{
		"asc_lon":         c.Rise.Lon,
		"planets":         bodiesOut(c),
		"houses":          housesOut(c),
		"note":            c.Note,
		"place":           c.PlaceLabel,
		"tip":             t,
		"aspects_preview": aspMaps[:previewN],
		"sun":             c.Sun.Sign,
		"moon":            c.Moon.Sign,
		"rise":            c.Rise.Sign,
	}
}

func overlayOut(o OverlayChart) map[string]any {
	entries := make([]map[string]any, 0, len(o.Entries))
	for _, e := range o.Entries {
		entries = append(entries, map[string]any{
			"planet_key": e.PlanetKey, "planet": e.Planet, "sign": e.Sign,
			"house": e.House, "house_tip": e.HouseTip,
		})
	}
	return map[string]any{
		"tip": o.Tip, "entries": entries, "houses_a": housesOut(natal.Chart{Houses: o.HousesA}),
	}
}