/*
Copyright © Brian Buller

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
package models

import (
	"context"
	"encoding/json"
	"fmt"
	"os"
	"slices"
	"time"

	"git.bullercodeworks.com/brian/expds/helpers"
	comatproto "github.com/bluesky-social/indigo/api/atproto"
	"github.com/bluesky-social/indigo/atproto/atdata"
	"github.com/bluesky-social/indigo/atproto/identity"
	"github.com/bluesky-social/indigo/atproto/repo"
	"github.com/bluesky-social/indigo/atproto/syntax"
	"github.com/bluesky-social/indigo/xrpc"
	"github.com/ipfs/go-cid"
	"github.com/spf13/viper"
)

type EntryType int

const (
	TypeNSID = EntryType(iota)
	TypeRecord
)

type Pds struct {
	AtId      syntax.AtIdentifier
	Did       syntax.DID
	localPath string

	Commit          string
	NSIDs           []syntax.NSID
	RecordIds       []string
	nsidToRecordIds map[syntax.NSID][]string
	recordIdsToNSID map[string]syntax.NSID
	Records         map[string]map[string]any

	RefreshTime time.Time
}

func NewPdsFromDid(id string) (*Pds, error) {
	ctx := context.Background()
	atid, err := syntax.ParseAtIdentifier(id)
	if err != nil {
		return nil, err
	}

	// first look up the DID and PDS for this repo
	dir := identity.DefaultDirectory()
	ident, err := dir.Lookup(ctx, atid)
	if err != nil {
		return nil, err
	}

	// create a new API client to connect to the account's PDS
	xrpcc := xrpc.Client{
		Host: ident.PDSEndpoint(),
	}
	if xrpcc.Host == "" {
		return nil, fmt.Errorf("no PDS endpoint for identity")
	}

	carPath := helpers.Path(viper.GetString("data"), ident.DID.String()+".car")
	repoBytes, err := comatproto.SyncGetRepo(ctx, &xrpcc, ident.DID.String(), "")
	if err != nil {
		return nil, err
	}
	if err := os.WriteFile(carPath, repoBytes, 0666); err != nil {
		return nil, err
	}
	ret := &Pds{
		AtId:            atid,
		Did:             ident.DID,
		localPath:       carPath,
		nsidToRecordIds: make(map[syntax.NSID][]string),
		recordIdsToNSID: make(map[string]syntax.NSID),
		Records:         make(map[string]map[string]any),
		RefreshTime:     time.Now(),
	}
	return ret, ret.unpack()
}

func (p *Pds) unpack() error {
	ctx := context.Background()
	fi, err := os.Open(p.localPath)
	if err != nil {
		return fmt.Errorf("error opening local car: %w", err)
	}

	c, r, err := repo.LoadRepoFromCAR(ctx, fi)
	if err != nil {
		return fmt.Errorf("error loading repo from car: %w", err)
	}

	comBytes, err := json.Marshal(c)
	if err != nil {
		return fmt.Errorf("error building commit meta json: %w")
	}
	p.Commit = string(comBytes)

	err = r.MST.Walk(func(k []byte, v cid.Cid) error {
		col, rkey, err := syntax.ParseRepoPath(string(k))
		if err != nil {
			return fmt.Errorf("error parsing repo path (%s): %w", string(k), err)
		}

		sCol, sRKey := string(col), string(rkey)
		recBytes, _, err := r.GetRecordBytes(ctx, col, rkey)
		if err != nil {
			return fmt.Errorf("error getting record bytes (%s/%s): %w", sCol, sRKey, err)
		}

		rec, err := atdata.UnmarshalCBOR(recBytes)
		if err != nil {
			return fmt.Errorf("error unmarshalling cbor (%s/%s): %w", sCol, sRKey, err)
		}
		p.Records[string(k)] = rec

		if !slices.Contains(p.NSIDs, col) {
			p.NSIDs = append(p.NSIDs, col)
		}
		p.nsidToRecordIds[col] = append(p.nsidToRecordIds[col], sRKey)
		p.recordIdsToNSID[sRKey] = col
		return nil
	})
	//slices.Sort(p.NSIDs)
	return err
}

func (p *Pds) NSIDStringList() []string {
	var ret []string
	for _, wrk := range p.NSIDs {
		ret = append(ret, wrk.String())
	}
	return ret
}

func (p *Pds) List() (map[string]string, error) {
	ret := make(map[string]string)
	ctx := context.Background()
	fi, err := os.Open(p.localPath)
	if err != nil {
		return ret, fmt.Errorf("error opening local car: %w", err)
	}
	// read repository tree in to memory
	_, r, err := repo.LoadRepoFromCAR(ctx, fi)
	if err != nil {
		return ret, fmt.Errorf("error loading repo from car: %w", err)
	}

	err = r.MST.Walk(func(k []byte, v cid.Cid) error {
		ret[string(k)] = v.String()
		return nil
	})
	if err != nil {
		return ret, fmt.Errorf("error walking repo: %w", err)
	}
	return ret, nil
}

func (p *Pds) GetRecordIdsFor(n syntax.NSID) []string    { return p.nsidToRecordIds[n] }
func (p *Pds) GetNSIDForRecordId(rId string) syntax.NSID { return p.recordIdsToNSID[rId] }