package store

import (
	"context"
	"fmt"
	"strings"
	"time"

	ext "git.warky.dev/wdevs/amcs/internal/types"
)

func (db *DB) AddMaintenanceTask(ctx context.Context, t ext.MaintenanceTask) (ext.MaintenanceTask, error) {
	row := db.pool.QueryRow(ctx, `
		insert into maintenance_tasks (name, category, frequency_days, next_due, priority, notes)
		values ($1, $2, $3, $4, $5, $6)
		returning id, created_at, updated_at
	`, t.Name, nullStr(t.Category), t.FrequencyDays, t.NextDue, t.Priority, nullStr(t.Notes))

	created := t
	if err := row.Scan(&created.ID, &created.CreatedAt, &created.UpdatedAt); err != nil {
		return ext.MaintenanceTask{}, fmt.Errorf("insert maintenance task: %w", err)
	}
	return created, nil
}

func (db *DB) LogMaintenance(ctx context.Context, log ext.MaintenanceLog) (ext.MaintenanceLog, error) {
	completedAt := log.CompletedAt
	if completedAt.IsZero() {
		completedAt = time.Now()
	}

	row := db.pool.QueryRow(ctx, `
		insert into maintenance_logs (task_id, completed_at, performed_by, cost, notes, next_action)
		values ($1, $2, $3, $4, $5, $6)
		returning id
	`, log.TaskID, completedAt, nullStr(log.PerformedBy), log.Cost, nullStr(log.Notes), nullStr(log.NextAction))

	created := log
	created.CompletedAt = completedAt
	if err := row.Scan(&created.ID); err != nil {
		return ext.MaintenanceLog{}, fmt.Errorf("insert maintenance log: %w", err)
	}
	return created, nil
}

func (db *DB) GetUpcomingMaintenance(ctx context.Context, daysAhead int) ([]ext.MaintenanceTask, error) {
	if daysAhead <= 0 {
		daysAhead = 30
	}
	cutoff := time.Now().Add(time.Duration(daysAhead) * 24 * time.Hour)

	rows, err := db.pool.Query(ctx, `
		select id, name, category, frequency_days, last_completed, next_due, priority, notes, created_at, updated_at
		from maintenance_tasks
		where next_due <= $1 or next_due is null
		order by next_due asc nulls last, priority desc
	`, cutoff)
	if err != nil {
		return nil, fmt.Errorf("get upcoming maintenance: %w", err)
	}
	defer rows.Close()

	return scanMaintenanceTasks(rows)
}

func (db *DB) SearchMaintenanceHistory(ctx context.Context, query, category string, start, end *time.Time) ([]ext.MaintenanceLogWithTask, error) {
	args := []any{}
	conditions := []string{}

	if q := strings.TrimSpace(query); q != "" {
		args = append(args, "%"+q+"%")
		conditions = append(conditions, fmt.Sprintf("(mt.name ILIKE $%d OR ml.notes ILIKE $%d)", len(args), len(args)))
	}
	if c := strings.TrimSpace(category); c != "" {
		args = append(args, c)
		conditions = append(conditions, fmt.Sprintf("mt.category = $%d", len(args)))
	}
	if start != nil {
		args = append(args, *start)
		conditions = append(conditions, fmt.Sprintf("ml.completed_at >= $%d", len(args)))
	}
	if end != nil {
		args = append(args, *end)
		conditions = append(conditions, fmt.Sprintf("ml.completed_at <= $%d", len(args)))
	}

	q := `
		select ml.id, ml.task_id, ml.completed_at, ml.performed_by, ml.cost, ml.notes, ml.next_action,
		       mt.name, mt.category
		from maintenance_logs ml
		join maintenance_tasks mt on mt.id = ml.task_id
	`
	if len(conditions) > 0 {
		q += " where " + strings.Join(conditions, " and ")
	}
	q += " order by ml.completed_at desc"

	rows, err := db.pool.Query(ctx, q, args...)
	if err != nil {
		return nil, fmt.Errorf("search maintenance history: %w", err)
	}
	defer rows.Close()

	var logs []ext.MaintenanceLogWithTask
	for rows.Next() {
		var l ext.MaintenanceLogWithTask
		var performedBy, notes, nextAction, taskCategory *string
		if err := rows.Scan(
			&l.ID, &l.TaskID, &l.CompletedAt, &performedBy, &l.Cost, &notes, &nextAction,
			&l.TaskName, &taskCategory,
		); err != nil {
			return nil, fmt.Errorf("scan maintenance log: %w", err)
		}
		l.PerformedBy = strVal(performedBy)
		l.Notes = strVal(notes)
		l.NextAction = strVal(nextAction)
		l.TaskCategory = strVal(taskCategory)
		logs = append(logs, l)
	}
	return logs, rows.Err()
}

func scanMaintenanceTasks(rows interface {
	Next() bool
	Scan(...any) error
	Err() error
	Close()
}) ([]ext.MaintenanceTask, error) {
	defer rows.Close()
	var tasks []ext.MaintenanceTask
	for rows.Next() {
		var t ext.MaintenanceTask
		var category, notes *string
		if err := rows.Scan(&t.ID, &t.Name, &category, &t.FrequencyDays, &t.LastCompleted, &t.NextDue, &t.Priority, &notes, &t.CreatedAt, &t.UpdatedAt); err != nil {
			return nil, fmt.Errorf("scan maintenance task: %w", err)
		}
		t.Category = strVal(category)
		t.Notes = strVal(notes)
		tasks = append(tasks, t)
	}
	return tasks, rows.Err()
}