package export

import (
	"database/sql"
	"fmt"
	"io"
	"sort"
	"strconv"
	"strings"

	"github.com/xuri/excelize/v2"

	"git.yeij.top/AskaEth/Scoreboard/server/internal/domain"
)

// medalDetailSheet 是「团体奖牌明细」总表的表名。
const medalDetailSheet = "团体奖牌明细"

// 奖牌文案：与名次 1/2/3 一一对应。
const (
	medalGold   = "金牌"
	medalSilver = "银牌"
	medalBronze = "铜牌"
)

// MedalDetailRow 是团体奖牌明细的一行：某单位的一块奖牌来自哪个小项/组别/名次。
type MedalDetailRow struct {
	SportName   string
	EventName   string
	Category    string
	Rank        int
	Medal       string
	Participant string

	// 排序键，只在本包内用，不导出。
	sportSort  int
	eventSort  int
	catSort    int
	eventID    int64
	categoryID int64
	resultID   int64
}

// MedalDetailSheet 是某个有奖牌的单位的一张分表。
type MedalDetailSheet struct {
	Team domain.Team
	Rows []MedalDetailRow
}

// MedalDetailWorkbook 是「团体奖牌明细」的内容：一张总表 + 每个有奖牌的单位一张分表。
type MedalDetailWorkbook struct {
	Meta   Meta
	Sheets []MedalDetailSheet
}

var medalDetailColumns = []column{
	{"单位", 22, kindText},
	{"大项", 14, kindText},
	{"小项", 18, kindText},
	{"组别", 14, kindText},
	{"名次", 8, kindCenter},
	{"奖牌", 8, kindCenter},
	{"运动员/队", 18, kindText},
}

// medalTeamColumns 是单位分表的列：与总表一致，去掉「单位」列。
var medalTeamColumns = medalDetailColumns[1:]

// ExportMedalDetailXLSX 导出团体奖牌明细，落盘到 dst。
func ExportMedalDetailXLSX(db *sql.DB, dst string, opts Options) error {
	wb, err := LoadMedalDetailWorkbook(db, opts)
	if err != nil {
		return err
	}
	f, err := medalDetailFile(wb)
	if err != nil {
		return err
	}
	return saveWorkbook(f, dst)
}

// WriteMedalDetailXLSX 把团体奖牌明细写成 xlsx 流，供 HTTP 直接响应下载。
func WriteMedalDetailXLSX(w io.Writer, wb MedalDetailWorkbook) error {
	f, err := medalDetailFile(wb)
	if err != nil {
		return err
	}
	return f.Write(w)
}

func medalDetailFile(wb MedalDetailWorkbook) (*excelize.File, error) {
	return buildWorkbook(medalDetailSheet, func(f *excelize.File, st *styleSet) error {
		meta := wb.Meta.normalized()
		namer := &sheetNamer{}
		master := namer.add(medalDetailSheet)
		if err := addSheet(f, master); err != nil {
			return err
		}
		if err := writeSheet(f, st, master, meta, sheetTitle(meta, medalDetailSheet),
			medalDetailColumns, medalMasterRows(wb.Sheets)); err != nil {
			return err
		}

		for _, s := range wb.Sheets {
			unit := displayName(s.Team.Name, s.Team.ShortName)
			name := namer.add(unit + "奖牌明细")
			if err := addSheet(f, name); err != nil {
				return err
			}
			if err := writeSheet(f, st, name, meta, sheetTitle(meta, unit+" · 奖牌明细"),
				medalTeamColumns, medalTeamRows(s.Rows)); err != nil {
				return err
			}
		}
		return nil
	})
}

func medalMasterRows(sheets []MedalDetailSheet) [][]any {
	var out [][]any
	for _, s := range sheets {
		unit := displayName(s.Team.Name, s.Team.ShortName)
		for _, r := range s.Rows {
			out = append(out, append([]any{unit}, medalRow(r)...))
		}
	}
	return out
}

// medalTeamRows 单位分表：逐项奖牌行 + 末尾一行小计（金/银/铜数量）。
func medalTeamRows(rows []MedalDetailRow) [][]any {
	out := make([][]any, 0, len(rows)+1)
	var gold, silver, bronze int
	for _, r := range rows {
		switch r.Medal {
		case medalGold:
			gold++
		case medalSilver:
			silver++
		case medalBronze:
			bronze++
		}
		out = append(out, medalRow(r))
	}
	// 没有奖牌的单位不会进 Sheets，这里的合计行必然跟着数据行；列序 大项/小项/组别/名次/奖牌/运动员-队。
	return append(out, []any{"小计", "", "", "", fmt.Sprintf("金 %d / 银 %d / 铜 %d", gold, silver, bronze), ""})
}

func medalRow(r MedalDetailRow) []any {
	rank := ""
	if r.Rank > 0 {
		rank = strconv.Itoa(r.Rank)
	}
	return []any{r.SportName, r.EventName, r.Category, rank, r.Medal, r.Participant}
}

// LoadMedalDetailWorkbook 读取全部奖牌来源。
// 单位顺序沿用「团体奖牌榜」（与单位总分榜同序），没有奖牌的单位不出分表。
func LoadMedalDetailWorkbook(db *sql.DB, opts Options) (MedalDetailWorkbook, error) {
	if db == nil {
		return MedalDetailWorkbook{}, ErrNoDatabase
	}
	meta, settings, err := resolveMeta(db, opts.Meta)
	if err != nil {
		return MedalDetailWorkbook{}, err
	}
	// 名次输入与榜单同源：loadRanked 只取已发布、有效、计分小项的名次。
	ranked, err := loadRanked(db)
	if err != nil {
		return MedalDetailWorkbook{}, err
	}
	excludeTeam := strings.EqualFold(strings.TrimSpace(settings["standings.medal_counts_team_events"]), "false")
	hits := medalHits(ranked, excludeTeam)
	ctx, err := loadMedalContext(db)
	if err != nil {
		return MedalDetailWorkbook{}, err
	}
	teams, err := loadTeams(db, false)
	if err != nil {
		return MedalDetailWorkbook{}, err
	}
	order, err := teamStandingsOrder(db, opts)
	if err != nil {
		return MedalDetailWorkbook{}, err
	}
	orderTeamsByStandings(teams, order)

	sheets := make([]MedalDetailSheet, 0, len(teams))
	for _, t := range teams {
		rows := medalRowsOfTeam(t.ID, hits, ctx)
		if len(rows) == 0 {
			continue
		}
		sheets = append(sheets, MedalDetailSheet{Team: t, Rows: rows})
	}
	return MedalDetailWorkbook{Meta: meta, Sheets: sheets}, nil
}

// medalHit 是一枚奖牌：来自哪条成绩、什么名次、什么牌。
type medalHit struct {
	resultID int64
	rank     int
	medal    string
}

// medalHits 逐「报名项」判定获奖单位。
//
// 同一报名项在多条计分通道下会展开成多条名次，只能记一枚奖牌——选通道、联队份额展开、
// 名次换牌色这些规则都交给 domain 的团体奖牌榜函数（domain.BuildMedalStandings）判定，
// 导出侧不复制计奖规则。传入的单位/流水/运动员都为空，返回的行只可能来自该报名项的奖牌。
func medalHits(ranked []domain.RankedResult, excludeTeam bool) map[int64][]medalHit {
	out := make(map[int64][]medalHit)
	for _, group := range medalGroups(ranked) {
		if len(group) == 0 {
			continue
		}
		rows := domain.BuildMedalStandings(domain.StandingsInput{
			Ranked:                 group,
			ExcludeTeamEventMedals: excludeTeam,
		})
		rr := group[0]
		for _, row := range rows {
			for i := 0; i < row.Gold; i++ {
				out[row.TeamID] = append(out[row.TeamID], medalHit{rr.ResultID, 1, medalGold})
			}
			for i := 0; i < row.Silver; i++ {
				out[row.TeamID] = append(out[row.TeamID], medalHit{rr.ResultID, 2, medalSilver})
			}
			for i := 0; i < row.Bronze; i++ {
				out[row.TeamID] = append(out[row.TeamID], medalHit{rr.ResultID, 3, medalBronze})
			}
		}
	}
	return out
}

// medalGroupKey 与 domain 的奖牌去重键同构：同一小项、同一组别的同一报名项只记一枚奖牌。
// 聚合通道不对应单条报名项（entryID = 0）时退回「名次主体」，仍无法识别主体时每条自成一枚。
type medalGroupKey struct {
	eventID    int64
	categoryID int64
	entryID    int64
	scope      domain.Scope
	subject    int64
	unique     int
}

func medalGroups(ranked []domain.RankedResult) [][]domain.RankedResult {
	index := make(map[medalGroupKey]int, len(ranked))
	var groups [][]domain.RankedResult
	degenerate := 0
	for _, rr := range ranked {
		k := medalGroupKey{eventID: rr.EventID, categoryID: rr.CategoryID, entryID: rr.EntryID}
		if k.entryID == 0 {
			k.scope = rr.Scope
			if rr.Scope == domain.ScopeAthlete {
				k.subject = rr.AthleteID
			} else {
				k.subject = rr.TeamID
			}
			if k.subject == 0 {
				degenerate++
				k.unique = degenerate
			}
		}
		i, ok := index[k]
		if !ok {
			i = len(groups)
			index[k] = i
			groups = append(groups, nil)
		}
		groups[i] = append(groups[i], rr)
	}
	return groups
}

// medalContext 是一条成绩的展示字段与排序键。
type medalContext struct {
	sportName   string
	eventName   string
	category    string
	participant string
	sportSort   int
	eventSort   int
	catSort     int
	eventID     int64
	categoryID  int64
}

func loadMedalContext(db *sql.DB) (map[int64]medalContext, error) {
	rows, err := db.Query(`
		SELECT r.id, COALESCE(s.name, ''), e.name, COALESCE(c.name, ''),
		       COALESCE(a.name, ''), COALESCE(en.member_names, ''),
		       COALESCE(s.sort_order, 0), e.sort_order, COALESCE(c.sort_order, 0),
		       e.id, COALESCE(c.id, 0)
		  FROM results r
		  JOIN entries en ON en.id = r.entry_id
		  JOIN events e ON e.id = r.event_id
		  LEFT JOIN sports s ON s.id = e.sport_id
		  LEFT JOIN event_categories c ON c.id = en.category_id
		  LEFT JOIN athletes a ON a.id = en.athlete_id`)
	if err != nil {
		return nil, fmt.Errorf("export: 读取奖牌来源: %w", err)
	}
	defer func() { _ = rows.Close() }()

	out := make(map[int64]medalContext)
	for rows.Next() {
		var (
			resultID    int64
			athleteName string
			memberJSON  string
			c           medalContext
		)
		if err := rows.Scan(&resultID, &c.sportName, &c.eventName, &c.category,
			&athleteName, &memberJSON, &c.sportSort, &c.eventSort, &c.catSort,
			&c.eventID, &c.categoryID); err != nil {
			return nil, fmt.Errorf("export: 扫描奖牌来源: %w", err)
		}
		c.participant = participantName(athleteName, memberJSON)
		out[resultID] = c
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("export: 遍历奖牌来源: %w", err)
	}
	return out, nil
}

// medalRowsOfTeam 把某单位的奖牌拼成展示行，按大项/小项/组别/名次的既有顺序排列。
func medalRowsOfTeam(teamID int64, hits map[int64][]medalHit, ctx map[int64]medalContext) []MedalDetailRow {
	list := hits[teamID]
	rows := make([]MedalDetailRow, 0, len(list))
	for _, h := range list {
		c := ctx[h.resultID]
		rows = append(rows, MedalDetailRow{
			SportName:   c.sportName,
			EventName:   c.eventName,
			Category:    c.category,
			Rank:        h.rank,
			Medal:       h.medal,
			Participant: c.participant,
			sportSort:   c.sportSort,
			eventSort:   c.eventSort,
			catSort:     c.catSort,
			eventID:     c.eventID,
			categoryID:  c.categoryID,
			resultID:    h.resultID,
		})
	}
	sort.SliceStable(rows, func(i, j int) bool {
		a, b := rows[i], rows[j]
		switch {
		case a.sportSort != b.sportSort:
			return a.sportSort < b.sportSort
		case a.eventSort != b.eventSort:
			return a.eventSort < b.eventSort
		case a.eventID != b.eventID:
			return a.eventID < b.eventID
		case a.catSort != b.catSort:
			return a.catSort < b.catSort
		case a.categoryID != b.categoryID:
			return a.categoryID < b.categoryID
		case a.Rank != b.Rank:
			return a.Rank < b.Rank
		default:
			return a.resultID < b.resultID
		}
	})
	return rows
}