package postgres

import (
	"context"
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"git.aiterp.net/rpdata/api/database/postgres/psqlcore"
	"git.aiterp.net/rpdata/api/models"
	"strconv"
	"time"
)

type changeRepository struct {
	insertWithIDs bool
	db            *sql.DB
}

func (r *changeRepository) Find(ctx context.Context, id string) (*models.Change, error) {
	row, err := psqlcore.New(r.db).SelectChangeByID(ctx, id)
	if err != nil {
		return nil, err
	}

	return r.change(row)
}

func (r *changeRepository) List(ctx context.Context, filter models.ChangeFilter) ([]*models.Change, error) {
	params := psqlcore.SelectChangesParams{LimitSize: 0}
	if filter.Keys != nil {
		params.FilterKeys = true
		keys := make([]string, len(filter.Keys))
		for i, ck := range filter.Keys {
			keys[i] = ck.String()
		}
		params.Keys = keys
	}
	if filter.Author != nil {
		params.FilterAuthor = true
		params.Author = *filter.Author
	}
	if filter.EarliestDate != nil {
		params.FilterEarliestDate = true
		params.EarliestDate = filter.EarliestDate.In(time.UTC)
	}
	if filter.LatestDate != nil {
		params.FilterLatestDate = true
		params.LatestDate = filter.LatestDate.In(time.UTC)
	}
	if filter.Limit != nil && *filter.Limit <= 0 {
		params.LimitSize = int32(*filter.Limit)
	}

	rows, err := psqlcore.New(r.db).SelectChanges(ctx, params)
	if err != nil {
		return nil, err
	}

	return r.changes(rows)
}

func (r *changeRepository) Insert(ctx context.Context, change models.Change) (*models.Change, error) {
	tx, err := r.db.BeginTx(ctx, nil)
	if err != nil {
		return nil, err
	}
	defer func() { _ = tx.Rollback() }()

	q := psqlcore.New(tx)

	if !r.insertWithIDs || change.ID == "" {
		next, err := q.IncrementCounter(ctx, "data_change_id")
		if err != nil {
			return nil, err
		}

		change.ID = fmt.Sprintf("Change_%d", next)
	} else {
		if len(change.ID) < 8 {
			return nil, errors.New("invalid change id")
		}

		n, err := strconv.Atoi(change.ID[7:])
		if err != nil {
			return nil, err
		}

		err = q.BumpCounter(ctx, psqlcore.BumpCounterParams{ID: "data_change_id", Value: int32(n)})
		if err != nil {
			return nil, err
		}
	}

	data, err := r.dataChange(change)
	if err != nil {
		return nil, err
	}

	err = q.InsertChange(ctx, psqlcore.InsertChangeParams(*data))
	if err != nil {
		return nil, err
	}

	return &change, tx.Commit()
}

func (r *changeRepository) Remove(ctx context.Context, change models.Change) error {
	return psqlcore.New(r.db).DeleteChange(ctx, change.ID)
}

func (r *changeRepository) dataChange(change models.Change) (*psqlcore.DataChange, error) {
	objectsJSON, err := json.Marshal(change.ChangeObjectSet)
	if err != nil {
		return nil, err
	}

	keys := make([]string, len(change.Keys))
	for i, ck := range change.Keys {
		keys[i] = ck.String()
	}

	return &psqlcore.DataChange{
		ID:      change.ID,
		Model:   string(change.Model),
		Op:      change.Op,
		Author:  change.Author,
		Listed:  change.Listed,
		Date:    change.Date.In(time.UTC),
		Keys:    keys,
		Objects: objectsJSON,
	}, nil
}

func (r *changeRepository) change(row psqlcore.DataChange) (*models.Change, error) {
	objects := models.ChangeObjectSet{}

	err := json.Unmarshal(row.Objects, &objects)
	if err != nil {
		return nil, err
	}

	keys := make([]models.ChangeKey, len(row.Keys))
	for i := range keys {
		err := keys[i].Decode(row.Keys[i])
		if err != nil {
			return nil, err
		}
	}

	model := models.ChangeModel(row.Model)
	if !model.IsValid() {
		return nil, errors.New("invalid model")
	}

	return &models.Change{
		ID:              row.ID,
		Model:           model,
		Op:              row.Op,
		Author:          row.Author,
		Listed:          row.Listed,
		Date:            row.Date,
		Keys:            keys,
		ChangeObjectSet: objects,
	}, nil
}

func (r *changeRepository) changes(rows []psqlcore.DataChange) ([]*models.Change, error) {
	results := make([]*models.Change, len(rows))
	for i, row := range rows {
		change, err := r.change(row)
		if err != nil {
			return nil, err
		}

		results[i] = change
	}

	return results, nil
}