// Command seed-house-depreciation-standards membaca kurva depresiasi per-day
// dari file Excel untuk SATU project flock LAYING, lalu meng-generate file
// migration {up,down}.sql yang menyisipkan baris house_depreciation_standards
// khusus flock tersebut.
//
// Hanya multiplication_percentage yang di-override; house_type & standard_week
// diwarisi dari baris global (project_flock_id IS NULL) untuk hari yang sama,
// dan depreciation_percent diturunkan = (1 - multiplication_percentage) * 100.
//
// Jalankan lokal: dry-run mencetak SQL ke stdout, -apply menulis file migration
// untuk di-review & di-commit. Tidak ada API yang di-hit di production — data
// masuk lewat `make migrate-up` saat deploy.
//
//	go run ./cmd/seed-house-depreciation-standards -project-flock-id=52 -file=curve.xlsx          # dry-run
//	go run ./cmd/seed-house-depreciation-standards -project-flock-id=52 -file=curve.xlsx -apply    # tulis migration
package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"os"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/xuri/excelize/v2"
	"gitlab.com/mbugroup/lti-api.git/internal/config"
	"gitlab.com/mbugroup/lti-api.git/internal/database"
	"gitlab.com/mbugroup/lti-api.git/internal/utils"
	"gorm.io/gorm"
)

const (
	dateLayout       = "2006-01-02"
	timestampLayout  = "20060102150405"
	defaultMigrions  = "internal/database/migrations"
	headerDay        = "day"
	headerMultiplier = "multiplication_percentage"
)

type options struct {
	ProjectFlockID uint
	FilePath       string
	Sheet          string
	EffectiveDate  string
	HouseType      string
	OutDir         string
	Apply          bool
}

type curveRow struct {
	RowNumber int
	Day       int
	Mult      float64
}

type validationIssue struct {
	Row     int
	Field   string
	Message string
}

func (i validationIssue) String() string {
	if i.Row > 0 {
		return fmt.Sprintf("row=%d field=%s message=%s", i.Row, i.Field, i.Message)
	}
	return fmt.Sprintf("field=%s message=%s", i.Field, i.Message)
}

func main() {
	var opts options
	flag.UintVar(&opts.ProjectFlockID, "project-flock-id", 0, "Target LAYING project_flock id (required)")
	flag.StringVar(&opts.FilePath, "file", "", "Path to .xlsx file with columns day, multiplication_percentage (required)")
	flag.StringVar(&opts.Sheet, "sheet", "", "Sheet name (optional, default: first sheet)")
	flag.StringVar(&opts.EffectiveDate, "effective-date", "", "effective_date for the seeded rows (YYYY-MM-DD, default: today)")
	flag.StringVar(&opts.HouseType, "house-type", "", "Override house_type (open_house|close_house). Default: derived from the flock's kandangs")
	flag.StringVar(&opts.OutDir, "out-dir", defaultMigrions, "Directory to write the migration files")
	flag.BoolVar(&opts.Apply, "apply", false, "Write the migration files. If false, print SQL to stdout (dry-run)")
	flag.Parse()

	opts.FilePath = strings.TrimSpace(opts.FilePath)
	opts.Sheet = strings.TrimSpace(opts.Sheet)
	opts.OutDir = strings.TrimSpace(opts.OutDir)

	if opts.ProjectFlockID == 0 {
		log.Fatal("--project-flock-id is required and must be greater than 0")
	}
	if opts.FilePath == "" {
		log.Fatal("--file is required")
	}

	location, err := time.LoadLocation("Asia/Jakarta")
	if err != nil {
		log.Fatalf("failed to load timezone Asia/Jakarta: %v", err)
	}

	effectiveDate, err := resolveEffectiveDate(opts.EffectiveDate, location)
	if err != nil {
		log.Fatalf("invalid --effective-date: %v", err)
	}
	opts.EffectiveDate = effectiveDate.Format(dateLayout)

	sheetName, curve, parseIssues, err := parseCurveFile(opts.FilePath, opts.Sheet)
	if err != nil {
		log.Fatalf("failed reading excel: %v", err)
	}

	ctx := context.Background()
	db := database.Connect(config.DBHost, config.DBName)

	if err := assertActiveLayingFlock(ctx, db, opts.ProjectFlockID); err != nil {
		log.Fatalf("project_flock validation failed: %v", err)
	}

	houseType, err := resolveHouseType(ctx, db, opts.ProjectFlockID, opts.HouseType)
	if err != nil {
		log.Fatalf("house_type resolution failed: %v", err)
	}

	issues := append([]validationIssue{}, parseIssues...)
	if len(curve) > 0 {
		globalDays, err := globalDaysForHouseType(ctx, db, houseType)
		if err != nil {
			log.Fatalf("failed loading global standard days: %v", err)
		}
		issues = append(issues, buildDayCoverageIssues(curve, globalDays, houseType)...)
	}
	sortValidationIssues(issues)

	fmt.Printf("Mode: %s\n", modeLabel(opts.Apply))
	fmt.Printf("File: %s\n", opts.FilePath)
	fmt.Printf("Sheet: %s\n", sheetName)
	fmt.Printf("Project flock id: %d\n", opts.ProjectFlockID)
	fmt.Printf("House type: %s\n", houseType)
	fmt.Printf("Effective date: %s\n", opts.EffectiveDate)
	fmt.Printf("Curve rows parsed: %d\n", len(curve))
	if len(curve) > 0 {
		minDay, maxDay := dayRange(curve)
		fmt.Printf("Day range: %d..%d\n", minDay, maxDay)
	}
	fmt.Printf("Validation errors: %d\n", len(issues))
	fmt.Println()

	if len(issues) > 0 {
		fmt.Println("Validation errors:")
		for _, issue := range issues {
			fmt.Printf("ERROR %s\n", issue.String())
		}
		os.Exit(1)
	}

	upSQL := buildUpSQL(opts, houseType, curve)
	downSQL := buildDownSQL(opts)

	prefix := time.Now().In(location).Format(timestampLayout)
	upName := fmt.Sprintf("%s_seed_house_depreciation_flock_%d.up.sql", prefix, opts.ProjectFlockID)
	downName := fmt.Sprintf("%s_seed_house_depreciation_flock_%d.down.sql", prefix, opts.ProjectFlockID)

	if !opts.Apply {
		fmt.Printf("--- %s ---\n%s\n", upName, upSQL)
		fmt.Printf("--- %s ---\n%s\n", downName, downSQL)
		fmt.Printf("Dry-run: would write 2 files to %s. Re-run with -apply to create them.\n", opts.OutDir)
		return
	}

	upPath := filepath.Join(opts.OutDir, upName)
	downPath := filepath.Join(opts.OutDir, downName)
	if err := os.WriteFile(upPath, []byte(upSQL), 0o644); err != nil {
		log.Fatalf("failed writing %s: %v", upPath, err)
	}
	if err := os.WriteFile(downPath, []byte(downSQL), 0o644); err != nil {
		log.Fatalf("failed writing %s: %v", downPath, err)
	}

	fmt.Printf("WROTE %s\n", upPath)
	fmt.Printf("WROTE %s\n", downPath)
	fmt.Println("Review the SQL, commit it, then deploy runs `make migrate-up`.")
}

func resolveEffectiveDate(raw string, location *time.Location) (time.Time, error) {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		now := time.Now().In(location)
		return time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, location), nil
	}
	parsed, err := time.ParseInLocation(dateLayout, raw, location)
	if err != nil {
		return time.Time{}, fmt.Errorf("must follow format YYYY-MM-DD")
	}
	return parsed, nil
}

func parseCurveFile(filePath, requestedSheet string) (string, []curveRow, []validationIssue, error) {
	workbook, err := excelize.OpenFile(filePath)
	if err != nil {
		return "", nil, nil, err
	}
	defer func() { _ = workbook.Close() }()

	sheetName, err := resolveSheetName(workbook, requestedSheet)
	if err != nil {
		return "", nil, nil, err
	}

	allRows, err := workbook.GetRows(sheetName, excelize.Options{RawCellValue: true})
	if err != nil {
		return "", nil, nil, err
	}
	if len(allRows) == 0 {
		return sheetName, nil, []validationIssue{{Field: "header", Message: "sheet is empty"}}, nil
	}

	dayIdx, multIdx, headerIssues := parseHeaderIndexes(allRows[0])
	if len(headerIssues) > 0 {
		return sheetName, nil, headerIssues, nil
	}

	rows := make([]curveRow, 0, len(allRows)-1)
	issues := make([]validationIssue, 0)
	seenDays := make(map[int]int)

	for idx := 1; idx < len(allRows); idx++ {
		rowNumber := idx + 1
		rawRow := allRows[idx]
		if isRowEmpty(rawRow) {
			continue
		}

		parsed, rowIssues := parseCurveRow(rawRow, rowNumber, dayIdx, multIdx, seenDays)
		if len(rowIssues) > 0 {
			issues = append(issues, rowIssues...)
			continue
		}
		rows = append(rows, *parsed)
	}

	if len(rows) == 0 && len(issues) == 0 {
		issues = append(issues, validationIssue{Field: "rows", Message: "no data rows found"})
	}

	sort.Slice(rows, func(i, j int) bool { return rows[i].Day < rows[j].Day })
	return sheetName, rows, issues, nil
}

func resolveSheetName(workbook *excelize.File, requestedSheet string) (string, error) {
	sheets := workbook.GetSheetList()
	if len(sheets) == 0 {
		return "", fmt.Errorf("workbook has no sheets")
	}
	if strings.TrimSpace(requestedSheet) == "" {
		return sheets[0], nil
	}
	for _, sheet := range sheets {
		if strings.EqualFold(strings.TrimSpace(sheet), strings.TrimSpace(requestedSheet)) {
			return sheet, nil
		}
	}
	return "", fmt.Errorf("sheet %q not found", requestedSheet)
}

func parseHeaderIndexes(headerRow []string) (int, int, []validationIssue) {
	dayIdx, multIdx := -1, -1
	issues := make([]validationIssue, 0)

	for idx, raw := range headerRow {
		switch normalizeHeader(raw) {
		case headerDay:
			if dayIdx >= 0 {
				issues = append(issues, validationIssue{Field: "header", Message: "duplicate header day"})
			}
			dayIdx = idx
		case headerMultiplier:
			if multIdx >= 0 {
				issues = append(issues, validationIssue{Field: "header", Message: "duplicate header multiplication_percentage"})
			}
			multIdx = idx
		}
	}

	if dayIdx < 0 {
		issues = append(issues, validationIssue{Field: headerDay, Message: "required header is missing"})
	}
	if multIdx < 0 {
		issues = append(issues, validationIssue{Field: headerMultiplier, Message: "required header is missing"})
	}
	return dayIdx, multIdx, issues
}

func parseCurveRow(rawRow []string, rowNumber, dayIdx, multIdx int, seenDays map[int]int) (*curveRow, []validationIssue) {
	issues := make([]validationIssue, 0)

	day, err := parsePositiveInt(strings.TrimSpace(cellValue(rawRow, dayIdx)))
	if err != nil {
		issues = append(issues, validationIssue{Row: rowNumber, Field: headerDay, Message: err.Error()})
	}

	mult, err := parseMultiplication(strings.TrimSpace(cellValue(rawRow, multIdx)))
	if err != nil {
		issues = append(issues, validationIssue{Row: rowNumber, Field: headerMultiplier, Message: err.Error()})
	}

	if day > 0 {
		if prev, exists := seenDays[day]; exists {
			issues = append(issues, validationIssue{Row: rowNumber, Field: headerDay, Message: fmt.Sprintf("duplicate day %d (already used in row %d)", day, prev)})
		} else {
			seenDays[day] = rowNumber
		}
	}

	if len(issues) > 0 {
		return nil, issues
	}
	return &curveRow{RowNumber: rowNumber, Day: day, Mult: mult}, nil
}

func parsePositiveInt(raw string) (int, error) {
	if raw == "" {
		return 0, fmt.Errorf("is required")
	}
	value, err := strconv.Atoi(raw)
	if err != nil {
		floatValue, floatErr := strconv.ParseFloat(raw, 64)
		if floatErr != nil || floatValue != float64(int(floatValue)) {
			return 0, fmt.Errorf("must be a positive integer")
		}
		value = int(floatValue)
	}
	if value < 1 {
		return 0, fmt.Errorf("must be greater than or equal to 1")
	}
	return value, nil
}

func parseMultiplication(raw string) (float64, error) {
	if raw == "" {
		return 0, fmt.Errorf("is required")
	}
	value, err := strconv.ParseFloat(raw, 64)
	if err != nil {
		return 0, fmt.Errorf("must be numeric")
	}
	if value <= 0 || value > 1 {
		return 0, fmt.Errorf("must be greater than 0 and at most 1")
	}
	return value, nil
}

func buildDayCoverageIssues(curve []curveRow, globalDays map[int]bool, houseType string) []validationIssue {
	issues := make([]validationIssue, 0)
	for _, row := range curve {
		if !globalDays[row.Day] {
			issues = append(issues, validationIssue{
				Row:     row.RowNumber,
				Field:   headerDay,
				Message: fmt.Sprintf("day %d has no global standard row for house_type=%s (cannot inherit standard_week)", row.Day, houseType),
			})
		}
	}
	return issues
}

func buildUpSQL(opts options, houseType string, curve []curveRow) string {
	var b strings.Builder
	fmt.Fprintf(&b, "-- Kurva depresiasi khusus project_flock_id=%d (house_type=%s, effective_date=%s).\n", opts.ProjectFlockID, houseType, opts.EffectiveDate)
	b.WriteString("-- Override hanya multiplication_percentage; house_type & standard_week diwarisi dari baris global.\n")
	b.WriteString("-- depreciation_percent diturunkan = (1 - multiplication_percentage) * 100.\n")
	b.WriteString("INSERT INTO house_depreciation_standards\n")
	b.WriteString("    (project_flock_id, house_type, day, effective_date,\n")
	b.WriteString("     multiplication_percentage, depreciation_percent, standard_week, name)\n")
	b.WriteString("SELECT\n")
	fmt.Fprintf(&b, "    %d, g.house_type, g.day, DATE '%s',\n", opts.ProjectFlockID, opts.EffectiveDate)
	b.WriteString("    v.mult, (1 - v.mult) * 100, g.standard_week,\n")
	fmt.Fprintf(&b, "    'Custom depreciation flock %d (eff %s)'\n", opts.ProjectFlockID, opts.EffectiveDate)
	b.WriteString("FROM (VALUES\n")
	b.WriteString(formatValuesTuples(curve))
	b.WriteString("\n) AS v(day, mult)\n")
	b.WriteString("JOIN LATERAL (\n")
	b.WriteString("    SELECT DISTINCT ON (day) house_type, day, standard_week\n")
	b.WriteString("    FROM house_depreciation_standards\n")
	b.WriteString("    WHERE project_flock_id IS NULL\n")
	fmt.Fprintf(&b, "      AND house_type = '%s'::house_type_enum\n", houseType)
	b.WriteString("      AND day = v.day\n")
	b.WriteString("    ORDER BY day, effective_date DESC NULLS LAST\n")
	b.WriteString(") g ON TRUE;\n\n")
	b.WriteString("-- Recompute snapshot depresiasi flock ini dengan kurva baru.\n")
	fmt.Fprintf(&b, "DELETE FROM farm_depreciation_snapshots WHERE project_flock_id = %d;\n", opts.ProjectFlockID)
	return b.String()
}

// formatValuesTuples renders the (day, mult) tuples 5 per line. The first tuple's
// multiplier is cast ::numeric so PostgreSQL types the whole VALUES column as
// numeric even if every value happens to render without a decimal point.
func formatValuesTuples(curve []curveRow) string {
	tuples := make([]string, len(curve))
	for i, row := range curve {
		mult := formatFloat(row.Mult)
		if i == 0 {
			mult += "::numeric"
		}
		tuples[i] = fmt.Sprintf("(%d, %s)", row.Day, mult)
	}

	var b strings.Builder
	const perLine = 5
	for i := 0; i < len(tuples); i += perLine {
		end := i + perLine
		if end > len(tuples) {
			end = len(tuples)
		}
		b.WriteString("    ")
		b.WriteString(strings.Join(tuples[i:end], ", "))
		if end < len(tuples) {
			b.WriteString(",")
		}
		if end < len(tuples) {
			b.WriteString("\n")
		}
	}
	return b.String()
}

func buildDownSQL(opts options) string {
	var b strings.Builder
	b.WriteString("DELETE FROM house_depreciation_standards\n")
	fmt.Fprintf(&b, "WHERE project_flock_id = %d AND effective_date = DATE '%s';\n\n", opts.ProjectFlockID, opts.EffectiveDate)
	fmt.Fprintf(&b, "DELETE FROM farm_depreciation_snapshots WHERE project_flock_id = %d;\n", opts.ProjectFlockID)
	return b.String()
}

func formatFloat(value float64) string {
	return strconv.FormatFloat(value, 'g', -1, 64)
}

func assertActiveLayingFlock(ctx context.Context, db *gorm.DB, projectFlockID uint) error {
	var count int64
	err := db.WithContext(ctx).
		Table("project_flocks").
		Where("id = ?", projectFlockID).
		Where("deleted_at IS NULL").
		Where("category = ?", string(utils.ProjectFlockCategoryLaying)).
		Count(&count).Error
	if err != nil {
		return err
	}
	if count == 0 {
		return fmt.Errorf("project_flock_id %d must reference an active LAYING project_flock", projectFlockID)
	}
	return nil
}

func resolveHouseType(ctx context.Context, db *gorm.DB, projectFlockID uint, override string) (string, error) {
	if strings.TrimSpace(override) != "" {
		normalized, err := normalizeHouseType(override)
		if err != nil {
			return "", err
		}
		return normalized, nil
	}

	houseTypes := make([]string, 0)
	err := db.WithContext(ctx).Raw(`
		SELECT DISTINCT k.house_type::text AS house_type
		FROM project_flock_kandangs pfk
		JOIN kandangs k ON k.id = pfk.kandang_id
		WHERE pfk.project_flock_id = ? AND k.house_type IS NOT NULL
		ORDER BY house_type
	`, projectFlockID).Scan(&houseTypes).Error
	if err != nil {
		return "", err
	}

	switch len(houseTypes) {
	case 0:
		return "", fmt.Errorf("flock %d has no kandang house_type set; pass -house-type explicitly", projectFlockID)
	case 1:
		return houseTypes[0], nil
	default:
		return "", fmt.Errorf("flock %d spans multiple house_types %v; pass -house-type explicitly", projectFlockID, houseTypes)
	}
}

func normalizeHouseType(raw string) (string, error) {
	normalized := strings.ToLower(strings.TrimSpace(raw))
	switch normalized {
	case "open_house", "close_house":
		return normalized, nil
	default:
		return "", fmt.Errorf("house_type %q must be open_house or close_house", raw)
	}
}

func globalDaysForHouseType(ctx context.Context, db *gorm.DB, houseType string) (map[int]bool, error) {
	days := make([]int, 0)
	err := db.WithContext(ctx).Raw(`
		SELECT DISTINCT day
		FROM house_depreciation_standards
		WHERE project_flock_id IS NULL AND house_type = ?::house_type_enum
	`, houseType).Scan(&days).Error
	if err != nil {
		return nil, err
	}
	set := make(map[int]bool, len(days))
	for _, day := range days {
		set[day] = true
	}
	return set, nil
}

func dayRange(curve []curveRow) (int, int) {
	minDay, maxDay := curve[0].Day, curve[0].Day
	for _, row := range curve {
		if row.Day < minDay {
			minDay = row.Day
		}
		if row.Day > maxDay {
			maxDay = row.Day
		}
	}
	return minDay, maxDay
}

func sortValidationIssues(issues []validationIssue) {
	sort.Slice(issues, func(i, j int) bool {
		if issues[i].Row == issues[j].Row {
			if issues[i].Field == issues[j].Field {
				return issues[i].Message < issues[j].Message
			}
			return issues[i].Field < issues[j].Field
		}
		return issues[i].Row < issues[j].Row
	})
}

func isRowEmpty(row []string) bool {
	for _, cell := range row {
		if strings.TrimSpace(cell) != "" {
			return false
		}
	}
	return true
}

func normalizeHeader(raw string) string {
	return strings.ToLower(strings.TrimSpace(raw))
}

func cellValue(row []string, index int) string {
	if index < 0 || index >= len(row) {
		return ""
	}
	return row[index]
}

func modeLabel(apply bool) string {
	if apply {
		return "APPLY"
	}
	return "DRY-RUN"
}