package export

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

	"github.com/xuri/excelize/v2"

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

// athleteDetailSheet 是「个人积分总明细」总表的表名。
const athleteDetailSheet = "个人积分总明细"

// AthleteDetailRow 是个人得分明细的一行：某运动员一次得分的来源。
// Points 是记到个人的原始分，与个人积分榜同口径，不乘 individual_to_team_weight。
type AthleteDetailRow struct {
	AthleteName string
	SportName   string
	EventName   string
	Category    string
	Rank        int
	ResultText  string
	Points      float64
	Source      string

	// 排序键与所属单位，只在本包内用，不导出。
	teamID     int64
	sportSort  int
	eventSort  int
	catSort    int
	eventID    int64
	categoryID int64
	ledgerID   int64
}

// AthleteDetailSheet 是某个单位的一张分表（按单位分表，不按人分）。
type AthleteDetailSheet struct {
	Team domain.Team
	Rows []AthleteDetailRow
}

// AthleteDetailWorkbook 是「个人积分总明细」的内容：一张总表 + 每个有得分的单位一张分表。
type AthleteDetailWorkbook struct {
	Meta   Meta
	Sheets []AthleteDetailSheet
}

var athleteDetailColumns = []column{
	{"单位", 22, kindText},
	{"运动员", 14, kindText},
	{"大项", 14, kindText},
	{"小项", 18, kindText},
	{"组别", 14, kindText},
	{"名次", 8, kindCenter},
	{"成绩", 12, kindCenter},
	{"得分", 8, kindNumber},
	{"来源", 12, kindCenter},
}

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

// ExportAthleteDetailXLSX 导出个人得分明细，落盘到 dst。
// 仅测试使用（生产走 Load* + Write* 直接写响应体，不落盘）——见 saveWorkbook 的说明。
func ExportAthleteDetailXLSX(db *sql.DB, dst string, opts Options) error {
	wb, err := LoadAthleteDetailWorkbook(db, opts)
	if err != nil {
		return err
	}
	f, err := athleteDetailFile(wb)
	if err != nil {
		return err
	}
	return saveWorkbook(f, dst)
}

// WriteAthleteDetailXLSX 把个人得分明细写成 xlsx 流，供 HTTP 直接响应下载。
func WriteAthleteDetailXLSX(w io.Writer, wb AthleteDetailWorkbook) error {
	f, err := athleteDetailFile(wb)
	if err != nil {
		return err
	}
	return f.Write(w)
}

func athleteDetailFile(wb AthleteDetailWorkbook) (*excelize.File, error) {
	return buildWorkbook(athleteDetailSheet, func(f *excelize.File, st *styleSet) error {
		meta := wb.Meta.normalized()
		namer := &sheetNamer{}
		master := namer.add(athleteDetailSheet)
		if err := addSheet(f, master); err != nil {
			return err
		}
		if err := writeSheet(f, st, master, meta, sheetTitle(meta, athleteDetailSheet),
			athleteDetailColumns, athleteMasterRows(wb.Sheets)); err != nil {
			return err
		}

		for _, s := range wb.Sheets {
			unit := displayName(s.Team.Name, s.Team.ShortName)
			name := namer.add(unit + "个人得分明细")
			if err := addSheet(f, name); err != nil {
				return err
			}
			if err := writeSheet(f, st, name, meta, sheetTitle(meta, unit+" · 个人得分明细"),
				athleteTeamColumns, athleteTeamRows(s.Rows)); err != nil {
				return err
			}
		}
		return nil
	})
}

func athleteMasterRows(sheets []AthleteDetailSheet) [][]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}, athleteRow(r)...))
		}
	}
	return out
}

func athleteTeamRows(rows []AthleteDetailRow) [][]any {
	out := make([][]any, 0, len(rows))
	for _, r := range rows {
		out = append(out, athleteRow(r))
	}
	return out
}

func athleteRow(r AthleteDetailRow) []any {
	rank := ""
	if r.Rank > 0 {
		rank = strconv.Itoa(r.Rank)
	}
	return []any{r.AthleteName, r.SportName, r.EventName, r.Category, rank, r.ResultText, r.Points, r.Source}
}

// LoadAthleteDetailWorkbook 读取记到个人的积分流水，逐条列出来源。
//
// 得分口径 = 个人积分榜：只取未作废且 athlete_id 非空的流水，points 保持原始分，
// 既不乘 standings.individual_to_team_weight，也不按 count_to_team 过滤
// （「个人+团体」项目的个人通道照样算在个人头上）。
// 没有得分流水的运动员不会出现在任何一张表里。
func LoadAthleteDetailWorkbook(db *sql.DB, opts Options) (AthleteDetailWorkbook, error) {
	if db == nil {
		return AthleteDetailWorkbook{}, ErrNoDatabase
	}
	meta, _, err := resolveMeta(db, opts.Meta)
	if err != nil {
		return AthleteDetailWorkbook{}, err
	}
	joints, err := loadJointTeams(db)
	if err != nil {
		return AthleteDetailWorkbook{}, err
	}
	rows, err := loadAthleteDetailRows(db, joints)
	if err != nil {
		return AthleteDetailWorkbook{}, err
	}
	byTeam := make(map[int64][]AthleteDetailRow, len(rows))
	for _, r := range rows {
		byTeam[r.teamID] = append(byTeam[r.teamID], r)
	}

	teams, err := loadTeams(db, false)
	if err != nil {
		return AthleteDetailWorkbook{}, err
	}
	order, err := teamStandingsOrder(db, opts)
	if err != nil {
		return AthleteDetailWorkbook{}, err
	}
	orderTeamsByStandings(teams, order)

	sheets := make([]AthleteDetailSheet, 0, len(teams))
	for _, t := range teams {
		teamRows := byTeam[t.ID]
		if len(teamRows) == 0 {
			continue
		}
		sortAthleteDetailRows(teamRows)
		sheets = append(sheets, AthleteDetailSheet{Team: t, Rows: teamRows})
	}
	return AthleteDetailWorkbook{Meta: meta, Sheets: sheets}, nil
}

// athleteDetailRankExpr 取一条个人流水的名次（devdocs 17 §11.3）：按流水对应的通道与主体关联 channel_ranks。
//
// score_ledger 上没有通道列（域模型 LedgerEntry.ChannelID 没有落库），所以只能按流水自身能确定的主体来找：
//   - 有 entry_id 的流水（成绩流水）：按报名项关联，通道用「主通道」口径（scope=athlete 优先，其次 sort_order）；
//   - entry_id / result_id 都为空的流水（个人聚合名次）：写入侧把 source_id 退化为通道 id，就拿它 + 运动员关联。
//
// 组别用该行能唯一确定的那一个（c = 报名项的组别，ca = 回推出来的组别）；回推不出来时不猜，名次留空。
// channel_ranks 是发布 / 重算才重建的派生数据，没有对应行时回落到 results.rank，不把明细的名次列变成空白。
const athleteDetailRankExpr = `COALESCE((
				SELECT cr.rank
				  FROM channel_ranks cr
				  JOIN event_score_channels ch ON ch.id = cr.channel_id
				 WHERE cr.event_id = l.event_id
				   AND cr.category_id = COALESCE(c.id, ca.id)
				   AND ((l.entry_id IS NOT NULL AND cr.entry_id = l.entry_id)
				     OR (l.entry_id IS NULL AND l.result_id IS NULL AND l.source_type = 'result'
				         AND cr.channel_id = l.source_id
				         AND cr.scope = 'athlete' AND cr.athlete_id = l.athlete_id))
				 ORDER BY CASE WHEN ch.scope = 'athlete' THEN 0 ELSE 1 END, ch.sort_order, ch.id, cr.id
				 LIMIT 1), COALESCE(r.rank, 0))`

func loadAthleteDetailRows(db *sql.DB, joints map[int64]jointTeam) ([]AthleteDetailRow, error) {
	// 聚合流水的组别回推与单位明细同一条思路：某个运动员在本小项只参加了一个组别时，那个组别就是答案；
	// 多个组别时回推不出来，宁可留空也不猜（回推只对 entry_id / result_id 都为空的聚合流水生效）。
	rows, err := db.Query(`
		SELECT l.team_id, COALESCE(a.name, ''),
		       COALESCE(s.name, ''), COALESCE(e.name, ''), COALESCE(c.name, ca.name, ''),
		       ` + athleteDetailRankExpr + `, COALESCE(r.result_text, ''), COALESCE(r.unit, ''),
		       l.points, l.source_type,
		       COALESCE(s.sort_order, 0), COALESCE(e.sort_order, 0), COALESCE(c.sort_order, ca.sort_order, 0),
		       COALESCE(l.event_id, 0), COALESCE(c.id, ca.id, 0), l.id, COALESCE(l.entry_id, 0)
		  FROM score_ledger l
		  LEFT JOIN athletes a ON a.id = l.athlete_id
		  LEFT JOIN events e ON e.id = l.event_id
		  LEFT JOIN sports s ON s.id = e.sport_id
		  LEFT JOIN entries en ON en.id = l.entry_id
		  LEFT JOIN event_categories c ON c.id = en.category_id
		  LEFT JOIN (
			SELECT en2.athlete_id, en2.event_id, MIN(en2.category_id) AS category_id
			  FROM entries en2
			 WHERE en2.athlete_id IS NOT NULL
			 GROUP BY en2.athlete_id, en2.event_id
			HAVING COUNT(DISTINCT en2.category_id) = 1
		  ) aac ON aac.event_id = l.event_id AND aac.athlete_id = l.athlete_id
		      AND l.entry_id IS NULL AND l.result_id IS NULL AND l.source_type = 'result'
		  LEFT JOIN event_categories ca ON ca.id = aac.category_id
		  LEFT JOIN results r ON r.id = l.result_id
		 WHERE l.athlete_id IS NOT NULL AND l.athlete_id <> 0 AND l.voided = 0`)
	if err != nil {
		return nil, fmt.Errorf("export: 读取个人得分明细: %w", err)
	}
	defer func() { _ = rows.Close() }()

	var out []AthleteDetailRow
	for rows.Next() {
		var (
			row        AthleteDetailRow
			source     string
			resultText string
			unit       string
			entryID    int64
		)
		if err := rows.Scan(&row.teamID, &row.AthleteName,
			&row.SportName, &row.EventName, &row.Category,
			&row.Rank, &resultText, &unit, &row.Points, &source,
			&row.sportSort, &row.eventSort, &row.catSort,
			&row.eventID, &row.categoryID, &row.ledgerID, &entryID); err != nil {
			return nil, fmt.Errorf("export: 扫描个人得分明细: %w", err)
		}
		row.ResultText = displayResult(resultText, unit)
		row.Source = sourceLabel(source)
		// 联队说明挂在「来源」列：这张表没有备注列，而「来源」写的正是这一分是从哪来的
		//（成绩 / 破纪录加分 / 人工调整）。联队的一条成绩会给每个成员单位各留一行流水，
		// 不写这一句，读表的人只会看到同一个人在同一小项出现了两次、每次半份分。
		if joint, ok := joints[entryID]; ok {
			row.Source += "（" + joint.shareNote() + "）"
		}
		out = append(out, row)
	}
	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("export: 遍历个人得分明细: %w", err)
	}
	return out, nil
}

// sortAthleteDetailRows 按运动员分组、组内按项目既有顺序排列，读起来像「某人的得分清单」。
func sortAthleteDetailRows(rows []AthleteDetailRow) {
	sort.SliceStable(rows, func(i, j int) bool {
		a, b := rows[i], rows[j]
		switch {
		case a.AthleteName != b.AthleteName:
			return a.AthleteName < b.AthleteName
		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
		default:
			return a.ledgerID < b.ledgerID
		}
	})
}